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MGR University - BSc Cardiac Technology

3rd Year | Paper I: Cardiac Catheterization Laboratory - Basics

Exam Pattern: Theory 100 marks (pass: 50) | Practical 50 marks (pass: 25) | Internal Assessment 50 marks (pass: 25) Total Hours: 120 hours (Theory + Clinical)

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CHAPTER 1 - Types of Catheters & Laboratory Equipment

• Types of Catheters used in the Cath Lab:
  • Diagnostic catheters (Judkins Left/Right, Amplatz, Pigtail, Multi-purpose)
  • Guiding catheters for interventions
  • Electrophysiology (EP) catheters
  • Balloon catheters
• Catheter Cleaning and Packing:
  • Pre-cleaning to remove blood/contrast residue
  • Packing in sterile pouches before sterilization
• Techniques of Sterilization - Advantages & Disadvantages:

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CHAPTER 2 - Cath Lab Setup & Equipment Operation

• Preparing the Cath Lab for a Diagnostic Study:
  • Checking fluoroscopy equipment, contrast injector, hemodynamic monitoring
  • Preparing sterile field, catheter tray, emergency drugs
• Table Movement: C-arm or flat-panel detector table - can rotate, tilt (cranial/caudal), and move laterally for optimal views
• Image Intensifier Movement:
  • RAO (Right Anterior Oblique) and LAO (Left Anterior Oblique) projections
  • Cranial and Caudal angulations for coronary views
• Image Playback:
  • Cine loop replay, digital subtraction angiography (DSA)

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CHAPTER 3 - Intracardiac Pressures & Pressure Recording Systems

• Normal Intracardiac Pressures:

• Fluid-filled Catheters vs Catheter-tipped Manometers:
  • Fluid-filled: Simple, cheaper, prone to artifacts (air bubbles, clots)
  • Catheter-tipped manometer (Millar): More accurate, high-fidelity, expensive
• Artifacts in Pressure Recording:
  • Damping (due to air bubbles, clots, catheter kinking) - causes falsely low peak/broad waveform
  • Overshoot/ringing - due to underdamped system
  • Ventriculization - when catheter slips into ventricle during pullback
• Pressure Gradient Recording:
  • Pullback gradient - measured as catheter pulled from distal to proximal chamber
  • Peak-to-peak gradient - non-simultaneous measurement of systolic peaks
  • Used to assess valve stenosis severity

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CHAPTER 4 - Cardiac Output Determination

• Thermodilution Method (Fick Principle):
  • Cold saline injected into right atrium
  • Temperature change detected by thermistor in pulmonary artery
  • CO = (V × ΔT) / (area under curve) using Stewart-Hamilton equation
  • Normal Cardiac Output: 4-8 L/min; Cardiac Index: 2.5-4 L/min/m²
• Oxygen Dilution (Fick) Method:
  • CO = O₂ consumption / (Arterial O₂ content - Venous O₂ content)
  • Gold standard but requires measurement of oxygen consumption
• Principles of Oximetry:
  • Based on differential light absorption by oxyhemoglobin vs deoxyhemoglobin
  • Normal SaO2 >95%, Mixed venous SvO2 ~65-75%

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CHAPTER 5 - Shunt Detection and Calculations

• Left-to-Right Shunt (ASD, VSD, PDA):
  • Step-up in oxygen saturation as catheter moves from right atrium to right ventricle to pulmonary artery
  • Qp:Qs ratio (Pulmonary:Systemic flow) - if >1.5:1, shunt is significant
• Right-to-Left Shunt:
  • Systemic arterial desaturation
  • Qp:Qs <1
• Shunt Calculation Formula:
  • Qp/Qs = (SAT aorta - SAT MV) / (SAT PV - SAT PA)
  • Where MV = mixed venous, PV = pulmonary vein, PA = pulmonary artery

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CHAPTER 6 - Coronary Angiography

• Coronary Angiographic Catheters:
  • Judkins Left (JL) 3.5, 4, 5 - for left coronary artery
  • Judkins Right (JR) 4 - for right coronary artery
  • Amplatz Left/Right - alternative shapes
  • Sones catheter (brachial approach)
• Use of the Manifold:
  • 4-way stopcock system to connect contrast, pressure transducer, flush line, and catheter
  • Prevents air embolism during injections
• Angiographic Views (Projections) for Coronary Angiography:
  • LCA views: LAO Cranial, LAO Caudal (spider view), RAO Caudal, RAO Cranial, AP Cranial, AP Caudal
  • RCA views: LAO, RAO, Left lateral
• Laboratory Preparation for Coronary Angiography:
  • Sterile preparation, groin/radial site preparation
  • Heparin anticoagulation
  • Checking hemodynamic equipment and defibrillator

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CHAPTER 7 - Left Ventriculography

• Catheters used: Pigtail catheter (most common) - multiple side holes reduce jet effect
• Standard Views:
  • RAO 30° - best for wall motion, mitral regurgitation
  • LAO 60° - for septal wall motion
• Use of Power Injector:
  • 30-45 mL contrast at 12-14 mL/second
  • Assesses LV wall motion, ejection fraction, MR grade
• Ejection Fraction (EF):
  • Normal EF >55%
  • EF = (EDV - ESV) / EDV × 100

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CHAPTER 8 - Right Heart Catheterization & Angiography

• Procedure: Via femoral vein or internal jugular/subclavian vein; catheter advanced through RA → RV → PA → PCWP position
• Swan-Ganz Catheter: Balloon-tipped, flow-directed catheter used to measure:
  • RA pressure, RV pressure, PA pressure
  • PCWP (Pulmonary Capillary Wedge Pressure) - reflects left heart filling pressure
  • Normal PCWP: 6-12 mmHg (elevated in LV failure)
• Right Heart Angiography: Pulmonary artery injection to visualize pulmonary circulation

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CHAPTER 9 - Radiation Protection

• Sources of Radiation in Cath Lab: Fluoroscopy, cine angiography
• Principles of Radiation Protection (3 principles):
  1. Time - minimize exposure time
  2. Distance - increase distance from source (inverse square law)
  3. Shielding - lead apron (0.5 mm Pb equivalent), thyroid collar, lead glasses, lead curtain
• Radiation Units:
  • Roentgen (R) - air exposure
  • Rad/Gray (Gy) - absorbed dose
  • Rem/Sievert (Sv) - effective dose
  • Maximum permissible dose: 20 mSv/year for occupational exposure

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CHAPTER 10 - Electrophysiology (EP) Study Basics

• Catheters used in EP Studies:
  • Quadripolar catheters (HRA, HBE, RVA positions)
  • Decapolar or multipolar catheters for coronary sinus recording
• Connection of Catheters during EP Study:
  • High Right Atrium (HRA), His Bundle Electrogram (HBE), Coronary Sinus (CS), Right Ventricular Apex (RVA)
• Equipment for Arrhythmia Induction & Mapping:
  • Programmed electrical stimulator (PES)
  • EP recording system with multiple channels
• Radiofrequency Ablation (RFA):
  • Delivery of RF energy (300-750 kHz) at tip of ablation catheter
  • Creates localized thermal injury (50-60°C) to ablate arrhythmia focus
  • Used for SVT, WPW, atrial flutter, VT

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CHAPTER 11 - Pacemaker Fundamentals

• Basic Pacemaker Components:
  • Pulse generator (battery + electronic circuit)
  • Leads (endocardial or epicardial)
• Pacing Modes (NBG Code):
  • VVI - ventricular paced, sensed, inhibited (most common temporary pacing)
  • DDD - dual chamber, fully automatic
  • VOO - asynchronous
• Temporary vs Permanent Pacing:
  • Temporary - transvenous lead, external generator; used in complete heart block, post-MI
  • Permanent - implanted generator, subcutaneous

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CHAPTER 12 - Ventricular Assist Device (VAD) - Basics

• Purpose: Mechanical circulatory support for severe LV failure
• Types:
  • IABP (Intra-Aortic Balloon Pump) - most commonly used in Cath Lab; diastolic augmentation and systolic unloading
  • LVAD (Left Ventricular Assist Device) - for bridge to transplant or destination therapy
  • Impella - microaxial pump across aortic valve
• Intra-Aortic Balloon Pump (IABP):
  • Balloon inflates in diastole (increases coronary perfusion)
  • Deflates in systole (reduces afterload)
  • Trigger: ECG (R-wave) or arterial pressure waveform
  • Contraindicated in: AR (aortic regurgitation), aortic dissection

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Exam Tips - Important High-Yield Topics

1. Shunt calculation formula - frequently asked
2. Coronary catheter names and which artery they access
3. Manifold use and importance
4. Thermodilution vs Fick method differences
5. Radiation protection principles (Time, Distance, Shielding)
6. IABP - inflation/deflation timing
7. Normal intracardiac pressure values
8. Ventriculography - pigtail catheter, RAO view, EF calculation
9. RF ablation mechanism
10. Pacemaker NBG code (VVI, DDD)

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📚 BSc Cardiac Technology - 3rd Year

Paper I: Cardiac Catheterization Laboratory - Basics

Complete Study Guide | Target: 90%+ Marks

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CHAPTER 1 - TYPES OF CATHETERS & STERILIZATION

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🔑 Definition

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1.1 Types of Catheters

A) Diagnostic Catheters (for recording pressures and angiography)

B) Interventional Catheters (for procedures)

• Guiding catheters - larger lumen to pass wires and balloons during PTCA
• Balloon catheters - used in PTCA (angioplasty)
• Ablation catheters - used in EP study for radiofrequency ablation

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📊 DIAGRAM 1 - Catheter Shapes

JUDKINS LEFT         JUDKINS RIGHT         PIGTAIL
     ___                  __               ___
    /   \                /  |             /   o  <-- curled tip
   |     |              |   |            |
   |     |              |   |            |
   |     |               \__|            |
   |                                     |
 (Double curve)      (Single curve)   (Multiple holes)

SWAN-GANZ CATHETER
  ===========================O  <-- Balloon at tip
  Port 1 (Proximal - RA)
  Port 2 (Distal - PA)
  Thermistor port
  Balloon inflation port

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1.2 Catheter Sizes

• Measured in French (Fr) size
• 1 Fr = 0.33 mm diameter
• Common sizes: 5Fr, 6Fr, 7Fr, 8Fr

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1.3 Catheter Cleaning and Packing

Steps:

1. Rinse immediately after use with sterile water
2. Flush lumen to remove blood/contrast
3. Check for cracks, kinks, or damage
4. Dry completely
5. Coil loosely and pack in sterilization pouch
6. Label with date and catheter type
7. Sterilize and store

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1.4 Sterilization Techniques

📊 DIAGRAM 2 - Sterilization Methods

STERILIZATION METHODS FOR CATHLAB
         |
    _____|_____
   |     |     |
HEAT  CHEMICAL RADIATION
  |       |        |
Steam  Glutaraldehyde  Gamma rays
(Autoclave) / ETO gas

Detailed Table:

✏️ Model Exam Answer (5 marks):

1. Ethylene Oxide (ETO) Gas - Most preferred for heat-sensitive catheters and electronic equipment. The gas acts by alkylation of DNA of microorganisms. Advantage: effective on all materials. Disadvantage: toxic, requires 24-48 hours aeration before use.
2. Glutaraldehyde (2% solution) - Used for cold sterilization. Items are soaked for 10 hours for complete sterilization. Used for endoscopes and catheters that cannot withstand heat. Disadvantage: toxic fumes.
3. Autoclave (Steam under pressure) - 121°C at 15 psi for 15 minutes. Most reliable and fastest. Used for metal instruments, linen, glassware. Not suitable for catheters.
4. Gamma Radiation - Used industrially for pre-packaged disposable items like catheters and syringes.

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═══════════════════════════════════

CHAPTER 2 - CATH LAB SETUP & IMAGING EQUIPMENT

═══════════════════════════════════

2.1 Preparing the Cath Lab for a Diagnostic Study

Steps of Preparation:

1. Clean and disinfect the table and lab
2. Switch on and test fluoroscopy / X-ray equipment
3. Test pressure monitoring system - zero and calibrate transducers
4. Load contrast media in power injector
5. Test defibrillator and emergency resuscitation cart
6. Prepare sterile trolley with catheters, wires, manifold, syringes
7. Check oxygen supply, suction machine
8. Enter patient data in computer/cine system

1. Confirm patient identity, allergy history
2. Check informed consent
3. Connect ECG leads and pulse oximeter
4. Set up IV line
5. Prepare access site (groin/wrist)

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📊 DIAGRAM 3 - Cath Lab Layout

╔══════════════════════════════════════════╗
║           CARDIAC CATH LAB               ║
║                                          ║
║   [Control Room]   [Monitor Bank]        ║
║   ┌──────────┐    ┌───────────────┐      ║
║   │ Computer │    │ BP | ECG | O2 │      ║
║   │ Recorder │    │ Monitors      │      ║
║   └──────────┘    └───────────────┘      ║
║                                          ║
║   ┌──────────────────────────────┐       ║
║   │    C-ARM FLUOROSCOPY UNIT    │       ║
║   │                              │       ║
║   │  [X-ray tube] ─── [Patient] ─│─ [Image Intensifier/FPD]
║   │                              │       ║
║   └──────────────────────────────┘       ║
║                                          ║
║   [Power Injector]  [Emergency Cart]     ║
║   [Defibrillator]   [Sterile Trolley]    ║
╚══════════════════════════════════════════╝

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2.2 Table Movement

• Longitudinal (head-to-foot) movement
• Lateral (side-to-side) movement
• Isocentric rotation - table and C-arm rotate together, keeping the heart in center

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2.3 Image Intensifier Movement (C-Arm Angulations)

📊 DIAGRAM 4 - C-Arm Projections

              CRANIAL (+)
                  ↑
                  |
    LAO (Left) ←──┼──→ RAO (Right)
                  |
                  ↓
              CAUDAL (-)

LAO = Left Anterior Oblique (X-ray tube to RIGHT of patient)
RAO = Right Anterior Oblique (X-ray tube to LEFT of patient)

Standard Coronary Views:

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2.4 Image Playback and Recording

• Cine recording - 15-30 frames per second digital recording
• Fluoroscopy - real-time low-dose X-ray
• Digital Subtraction Angiography (DSA) - background bone/tissue subtracted, only vessels visible
• Road mapping - saved image used as reference while navigating catheter/wire

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═══════════════════════════════════

CHAPTER 3 - INTRACARDIAC PRESSURES & PRESSURE RECORDING

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3.1 Normal Intracardiac Pressures

📊 DIAGRAM 5 - Heart with Normal Pressures

                    PULMONARY CIRCULATION
                    PA: 25/10 mmHg (mean 15)
                    PV: ~8 mmHg
         _______________↑_______________
        |                               |
   RA: 2-8 mmHg     HEART          LA: 6-12 mmHg
        |                               |
   RV: 25/4 mmHg               LV: 120/8 mmHg
        |_____________↓_________________|
                    AORTA: 120/80 mmHg
                    (Systemic Circulation)

Complete Normal Pressure Table:

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3.2 Pressure Recording Systems

Components:

1. Catheter (intravascular)
2. Connecting tubing (stiff, non-compliant)
3. Transducer (converts pressure to electrical signal)
4. Amplifier
5. Display monitor/recorder

📊 DIAGRAM 6 - Pressure Transducer Setup

PATIENT'S BLOOD VESSEL
        |
   [Catheter]
        |
   [Connecting Tubing] ←── Flush system (heparinized saline)
        |
   [Transducer] ← converts mechanical pressure → electrical signal
        |
   [Amplifier]
        |
   [Monitor/Recorder] → Displays waveform

Zeroing the Transducer:

• Place transducer at level of mid-axillary line (phlebostatic axis)
• Open to atmosphere and zero
• This corrects for hydrostatic pressure

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3.3 Fluid-filled Catheters vs Catheter-tipped Manometers

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3.4 Artifacts in Pressure Recording

📊 DIAGRAM 7 - Types of Damping

NORMAL WAVEFORM:
    /\      /\      /\
   /  \    /  \    /  \
  /    \  /    \  /    \
 /      \/      \/      \

OVERDAMPED (Air bubble/clot):
    __        __
   /  \      /  \      ← Peak is blunted/rounded
  /    \____/    \     ← Diastolic not accurate

UNDERDAMPED (Ringing/Overshoot):
   /\/\    /\/\        ← Spiky, exaggerated peaks
  /    \  /    \       ← False high systolic

Causes of Damping:

1. Air bubbles in tubing
2. Blood clot in catheter
3. Catheter kinking
4. Loose connections
5. Catheter against vessel wall

How to Fix Damping:

• Flush catheter firmly
• Aspirate and re-flush
• Rotate/reposition catheter

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3.5 Ventriculization

NORMAL PA WAVEFORM:        VENTRICULIZED PA:
    __                          __
   /  \                        /  \
  /    \_____                 /    \
              (diastolic      /      \___  ← no dicrotic
               notch present)              notch, diastolic
                                           falls to near zero

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3.6 Pressure Gradient Recording

Peak-to-Peak Gradient:

• Measured when catheter is pulled from LV to Aorta
• Difference between LV systolic peak and Aortic systolic peak
• Non-simultaneous measurement

Pull-back Gradient:

• Catheter pulled back slowly from distal to proximal chamber
• Records continuous pressure change
• Used to locate exact site of obstruction in valvular/subvalvular stenosis

📊 DIAGRAM 8 - Aortic Stenosis Gradient

LV PRESSURE:                AORTIC PRESSURE:
    ___                           __
   /   \                         /  \
  /     \                       /    \
 /       \                     /      \
          \___                          \___

      |←── GRADIENT ──→|
   (LV systolic peak)  (Aortic systolic peak)
   e.g., 200 mmHg      e.g., 120 mmHg
   Gradient = 80 mmHg (significant AS)

• Mild: <25 mmHg
• Moderate: 25-50 mmHg
• Severe: >50 mmHg

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═══════════════════════════════════

CHAPTER 4 - CARDIAC OUTPUT DETERMINATION

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4.1 Definition

• Normal: 4-8 L/min
• Formula: CO = Heart Rate × Stroke Volume

• Normal: 2.5-4.0 L/min/m²

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4.2 Thermodilution Method

Principle:

📊 DIAGRAM 9 - Thermodilution Method

SWAN-GANZ CATHETER POSITIONED IN PA:

  [RA Port] ──→ Inject 10 mL cold saline (0-4°C)
      |
   Right Atrium
      ↓
   Right Ventricle
      ↓
  Pulmonary Artery ──→ [Thermistor detects temperature change]
                              ↓
                    [CO Computer calculates]
                              ↓
                    [Cardiac Output displayed]

THERMODILUTION CURVE:
Temperature
change   |\ 
         | \
         |  \
         |   \___________  ← Area under curve is inversely
         └──────────────     proportional to cardiac output
              Time
(Large area = low CO; Small area = high CO)

Stewart-Hamilton Equation:

CO = V × (TB - TI) × K
    ─────────────────────
       ∫ ΔTB(t) dt

Where:
V = Volume of injectate
TB = Blood temperature
TI = Injectate temperature
K = Correction factor
∫ ΔTB(t) dt = Area under temperature-time curve

Steps:

1. Patient at rest
2. Inject 10 mL cold (0-4°C) saline quickly (<4 seconds) into proximal port (RA)
3. Computer calculates from temperature curve
4. Take 3 readings and average them
5. Values should be within 10% of each other

Causes of Error:

• Slow injection
• Wrong injectate temperature
• Tricuspid regurgitation (TR) - gives falsely high CO
• Intracardiac shunts

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4.3 Fick Method (Oxygen Dilution)

Principle:

Formula:

         VO2 (Oxygen Consumption in mL/min)
CO = ─────────────────────────────────────────────────────
     (Arterial O2 Content - Venous O2 Content) × 10

Where:
VO2 = O2 consumption (measured or assumed ~125 mL/min/m²)
Arterial O2 content = Hb × 1.36 × SaO2 × 10
Venous O2 content = Hb × 1.36 × SvO2 × 10

📊 DIAGRAM 10 - Fick Principle

LUNGS
  ↑ O2 added (VO2 = 250 mL/min)
  |
Pulmonary Vein (SaO2 = 98%)
  ↓
HEART → Body
  ↑
Superior Vena Cava (SvO2 = 70%)

CO = VO2 / (CaO2 - CvO2)
   = 250 / (200 - 150) mL/L
   = 250 / 50
   = 5 L/min

Fick vs Thermodilution Comparison:

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4.4 Principles of Oximetry

How Pulse Oximetry Works:

• Uses Beer-Lambert Law
• Oxyhemoglobin (HbO2) absorbs more infrared light (940 nm)
• Deoxyhemoglobin (Hb) absorbs more red light (660 nm)
• Ratio of absorption at two wavelengths = oxygen saturation

📊 DIAGRAM 11 - Oximetry Principle

RED LIGHT (660 nm)          INFRARED (940 nm)
     →→→→→→→→→→→                →→→→→→→→→→→
[LED] → Finger → [Detector]   [LED] → Finger → [Detector]

Deoxyhemoglobin absorbs       Oxyhemoglobin absorbs
more RED                      more INFRARED

Ratio = R = (AC660/DC660) / (AC940/DC940)
SpO2 calculated from empirical calibration curve

Normal SpO2: 95-100%

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═══════════════════════════════════

CHAPTER 5 - SHUNT DETECTION AND CALCULATIONS

═══════════════════════════════════

5.1 Definition

5.2 Types of Shunts

📊 DIAGRAM 12 - Shunt Types

LEFT-TO-RIGHT SHUNT:                RIGHT-TO-LEFT SHUNT:
(Acyanotic defects)                 (Cyanotic defects)

  LA ──→ RA  (ASD)                    RA ──→ LA  (Severe ASD with PHT)
  LV ──→ RV  (VSD)                    RV ──→ LV  (Severe VSD with PHT)
  Aorta→PA   (PDA)                    Aorta←PA   (Eisenmenger)

Oxygenated blood flows RIGHT       Deoxygenated blood flows LEFT
Causes: volume overload RV,        Causes: CYANOSIS, low O2 sat
pulmonary hypertension             (Eisenmenger syndrome)

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5.3 Shunt Detection - Step-up Method

Oxygen Saturation Sampling:

Significant Step-up (indicating L-R shunt):

• RA step-up >7% → ASD (L→R shunt at atrial level)
• RV step-up >5% → VSD (L→R shunt at ventricular level)
• PA step-up >5% → PDA (L→R shunt at great vessel level)

📊 DIAGRAM 13 - Oxygen Saturation in ASD

            NORMAL             ASD (L→R Shunt)
SVC: 70%   →  RA: 72%    SVC: 70% → RA: 85% ← (STEP UP!)
                ↓                       ↓
            RV: 74%                 RV: 85%
                ↓                       ↓
            PA: 74%                 PA: 85%
                                        ↑
                                   (LA blood mixing
                                    via ASD)

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5.4 Shunt Calculation (Qp:Qs Ratio)

Formula:

Qp     SaO2 - MVO2
── = ──────────────────
Qs     PVO2 - PAO2

Where:
Qp = Pulmonary blood flow
Qs = Systemic blood flow
SaO2 = Systemic arterial O2 saturation (Aorta)
MVO2 = Mixed venous O2 saturation
PVO2 = Pulmonary vein O2 saturation (or assumed 98%)
PAO2 = Pulmonary artery O2 saturation

MVO2 = (3 × SVC sat + 1 × IVC sat) / 4

Interpretation:

✏️ Model Answer (10 marks):

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CHAPTER 6 - CORONARY ANGIOGRAPHY

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6.1 Definition

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6.2 Coronary Anatomy

📊 DIAGRAM 14 - Coronary Arteries

                    AORTA
                      |
              Left Main (LM) ──────── RCA (Right Coronary Artery)
                 /      \                          |
               LAD       LCx                   Conus Br.
(Left Anterior  (Left    (Left                  |
Descending)  Circumflex) Circumflex)         SA Node Artery
    |              |                             |
  Diagonal       Obtuse                    Right marginal
  branches      Marginal                        |
    |            branches                    PDA (Post Descending)
  Septal                                        |
  perforators                               AV Node Artery

LAD supplies: Anterior wall LV, anterior 2/3 septum
LCx supplies: Lateral wall LV, posterior wall (if dominant)
RCA supplies: Right ventricle, inferior wall LV (if dominant)

DOMINANCE:
- Right dominant (85%): RCA gives PDA
- Left dominant (10%): LCx gives PDA
- Codominant (5%): Both give PDA

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6.3 Coronary Angiographic Catheters

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6.4 Use of the Manifold

📊 DIAGRAM 15 - Manifold Setup

MANIFOLD = 4-WAY STOPCOCK SYSTEM

         [Pressure Transducer]
                  |
[Contrast Syringe] ── MANIFOLD ── [Catheter to Patient]
                  |
            [Flush Line]
          (Heparinized saline)
                  |
          [Waste/Discard]

FUNCTION: Allows operator to:
1. Flush catheter with saline
2. Aspirate blood (to check catheter position)
3. Inject contrast
4. Monitor pressure
5. Prevent air entry (CRITICAL - air embolism is deadly!)

Steps for Manifold Use:

1. Connect all lines and remove all air bubbles
2. Flush catheter with saline before entering patient
3. Check pressure waveform after catheter enters coronary
4. If pressure dampens - DO NOT inject; reposition catheter
5. Aspirate blood before injection to confirm no air
6. Inject contrast

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6.5 Coronary Angiography Views

📊 DIAGRAM 16 - Views for LCA

LCA VIEWS:

    RAO Cranial          LAO Cranial           AP Cranial
    (30°/20°)            (45°/25°)             (0°/25°)
    ↗ LAD proximal       ↗ LAD mid/distal      ↗ LAD proximal/mid
    ↗ Diagonals          ↗ Diagonals           ↗ Diagonals

    RAO Caudal           LAO Caudal (Spider)   AP Caudal
    (30°/25°)            (40°/30°)             (0°/30°)
    ↗ LCx, OM branches   ↗ LM, LAD/LCx fork    ↗ LM, LCx

Views for RCA:

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6.6 Degrees of Coronary Stenosis

NORMAL:     |████████████████|   100% lumen
50% STENOSIS:|████████|         50% lumen (not significant*)
70% STENOSIS:|█████|            30% lumen (significant!)
90% STENOSIS:|██|               10% lumen (critical!)
100%/TOTAL  :|                  OCCLUSION
OCCLUSION

*Flow-limiting stenosis: >70% (or >50% in LM)

Reporting Stenosis (TIMI Flow):

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6.7 Lab Preparation for Coronary Angiography

1. Patient prep: NPO 4-6 hours, consent, IV access, pre-medication (antiplatelet, anticoagulant)
2. Access site: Radial (preferred) or femoral; local anesthesia
3. Arterial sheath inserted (5Fr or 6Fr)
4. IV Heparin 5000 units to prevent clotting
5. Catheter advanced to coronary ostium under fluoroscopy
6. Contrast injected (5-10 mL per injection, hand injection)
7. Multiple views recorded
8. Sheath removed, hemostasis achieved

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═══════════════════════════════════

CHAPTER 7 - LEFT VENTRICULOGRAPHY

═══════════════════════════════════

7.1 Definition

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7.2 Catheter Used

• Multiple side holes (12-14 holes)
• Reduces jet effect against LV wall
• Prevents arrhythmia and perforation
• Curled tip prevents direct wall injury

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7.3 Standard Views for LV Angiography

📊 DIAGRAM 17 - LV Wall Segments in RAO View

LV IN RAO 30° VIEW:

         ANTERIOR WALL
              |
   ___________↓___________
  /  Antero-  | Antero-   \
 /    basal   | apical     \
|     _______→ APEX        |
|    |                     |
 \  Infero-  Infero-       /
  \  basal   apical       /
   \_________↑____________/
         INFERIOR WALL

Wall segments:
1. Anterolateral
2. Anterior
3. Apical
4. Inferior
5. Inferoposterior/Posterior

Normal: ALL segments contract inward (uniform)

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7.4 Wall Motion Abnormalities

📊 DIAGRAM 18 - Wall Motion

NORMAL:        HYPOKINESIS:    AKINESIS:       DYSKINESIS:
Systole  ↗↖    Systole  ↗↖     Systole  ─ ─    Systole  ↙↘
         │                                              │
Diastole  ─            ─               ─               ─

(Arrow = direction of wall motion during systole)

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7.5 Ejection Fraction (EF) Calculation

Formula:

EF = (EDV - ESV) / EDV × 100

Where:
EDV = End Diastolic Volume (LV at its largest)
ESV = End Systolic Volume (LV at its smallest)
Stroke Volume = EDV - ESV

Normal EF: ≥55%
Mild dysfunction: 45-54%
Moderate: 35-44%
Severe: <35%

How EDV and ESV are Measured:

• Area-Length method (most common in cath lab)
• Measure LV area in RAO view at end-diastole and end-systole
• Use formula: V = 8A²/3πL

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7.6 Power Injector Settings for LV Angiography

Complications of LV Angiography:

• Ventricular arrhythmias (PVCs, VT)
• Contrast injection causing staining (subendocardial)
• Perforation (rare, pigtail catheter reduces this risk)

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7.7 Mitral Regurgitation Assessment

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═══════════════════════════════════

CHAPTER 8 - RIGHT HEART CATHETERIZATION

═══════════════════════════════════

8.1 Definition

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8.2 Swan-Ganz (Pulmonary Artery) Catheter

📊 DIAGRAM 19 - Swan-Ganz Catheter

SWAN-GANZ CATHETER (4 lumens):

  |──── 30 cm ────|──────── 70 cm ───────────|
  |               |         |                 |
[Proximal port   [Distal   [Thermistor      [Balloon]
 (RA position)]   port      port]            O ← inflate 1.5 mL air
                 (PA pos.)]
                 
PORTS:
1. Proximal (RA): inject cold saline for thermodilution, CVP monitoring
2. Distal (PA): measure PA pressure and PCWP
3. Thermistor: temperature sensing for CO measurement
4. Balloon: floats catheter forward, wedges in PA branch

POSITION SEQUENCE:
Vein → RA → RV → PA → Wedge (PCWP)

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8.3 PCWP (Pulmonary Capillary Wedge Pressure)

Normal PCWP: 6-12 mmHg

Clinical Significance:

📊 DIAGRAM 20 - PCWP Waveform

PA PRESSURE:          PA WEDGE (PCWP):
   __                      a    v
  /  \  __                /\  /\
 /    \/  \              /  \/  \
/          \____________/        \_____

(Pulsatile PA waveform)     (Low phasic PCWP waveform)
Systolic/diastolic          a wave = atrial contraction
                            v wave = ventricular filling

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8.4 Procedure - Right Heart Catheterization

1. Insert sheath into vein under sterile conditions
2. Connect Swan-Ganz catheter to pressure monitor
3. Inflate balloon with 1.0-1.5 mL air
4. Advance catheter - it floats with blood flow:
   • RA position → record RA pressure
   • RV position → record RV pressure (deflate balloon briefly)
   • PA position → record PA pressure
   • Wedge position → inflate balloon, record PCWP
5. Deflate balloon when in wedge position (to avoid PA infarction!)
6. Measure cardiac output by thermodilution

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═══════════════════════════════════

CHAPTER 9 - RADIATION PROTECTION

═══════════════════════════════════

9.1 Why Radiation Safety Matters

• Skin erythema and burns (acute)
• Cataracts (lens of eye)
• Cancer (malignancy - long term)
• Genetic damage

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9.2 Three Cardinal Principles of Radiation Protection

📊 DIAGRAM 21 - Radiation Protection

╔═══════════════════════════════════════════╗
║        3 CARDINAL PRINCIPLES              ║
║                                           ║
║  1. TIME          2. DISTANCE   3. SHIELDING
║  ↓                ↓              ↓        ║
║  Minimize         Maximize       Use lead  ║
║  exposure         distance       protection║
║  time             from source             ║
║                                           ║
║  Dose ∝ Time    Dose ∝ 1/D²    Lead apron ║
║                 (Inverse square            ║
║                  law)                     ║
╚═══════════════════════════════════════════╝

1. TIME:

• Radiation dose is directly proportional to time
• Use fluoroscopy only when necessary
• Use last image hold feature (not continuous fluoro)
• Collimate X-ray beam to smallest needed area

2. DISTANCE (Inverse Square Law):

If distance doubles → dose reduces to 1/4
If distance triples → dose reduces to 1/9

Example:
At 1 meter: dose = 100 mR/hr
At 2 meters: dose = 25 mR/hr
At 3 meters: dose = 11 mR/hr

STAND AS FAR FROM X-RAY TUBE AS POSSIBLE

3. SHIELDING:

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9.3 Radiation Units

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9.4 Dose Limits (ICRP Recommendations)

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9.5 ALARA Principle

• Minimize dose while achieving diagnostic quality
• Use lowest possible fluoroscopy frame rate (7.5 fps instead of 15 fps)
• Collimate (narrow the X-ray beam)
• Use copper filters to reduce low-energy radiation

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9.6 Additional Radiation Safety Measures in Cath Lab

X-RAY TUBE (below table)
        ↓ Primary beam
    [PATIENT]
        ↑ Scatter radiation (most dangerous to staff)
        
Tips to reduce scatter:
- Keep X-ray tube BELOW table (not above)
- Stand on IMAGE INTENSIFIER side (not tube side)
- Use steep angulations less - more scatter at extreme angles
- Keep II close to patient (reduces scatter and improves image)

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═══════════════════════════════════

CHAPTER 10 - ELECTROPHYSIOLOGY (EP) STUDY BASICS

═══════════════════════════════════

10.1 Definition

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10.2 Catheters Used in EP Study

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10.3 Connection of Catheters in EP Study

📊 DIAGRAM 22 - EP Catheter Positions

HEART (posterior view):
                    ┌──────────────────┐
HRA catheter ──────→│   Right Atrium   │←── Coronary Sinus (CS)
                    │                  │    catheter (in LA vicinity)
His catheter ──────→│ Tricuspid Valve  │
                    │   area (HBE)     │
                    │   Right          │
RVA catheter ──────→│   Ventricle      │
                    └──────────────────┘

EP RECORDING DISPLAY (simultaneous channels):
Ch1: HRA (High Right Atrium)
Ch2: HBE (His Bundle Electrogram) - shows A, H, V deflections
Ch3: CS 1-2 (proximal)
Ch4: CS 9-10 (distal)
Ch5: RVA
Ch6: Surface ECG (I, II, V1)

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10.4 His Bundle Electrogram (HBE)

📊 DIAGRAM 23 - HBE Components

HBE SIGNAL:
    A          H          V
   ___        _          ___
  /   \      / \        /   \
 /     \    /   \      /     \
/       \__/     \____/       \___

A = Atrial signal (depolarization of atrium near His)
H = His bundle potential (small, sharp spike)
V = Ventricular signal

INTERVALS:
PA interval: P wave to A → intra-atrial conduction (normal: 20-40 ms)
AH interval: A to H → AV nodal conduction (normal: 60-125 ms)
HV interval: H to V → His-Purkinje conduction (normal: 35-55 ms)

HV >100ms = risk of complete heart block

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10.5 Arrhythmia Induction - Programmed Electrical Stimulation (PES)

Purpose:

• Induce tachyarrhythmias to diagnose mechanism (SVT, VT, WPW)
• Test effectiveness of medications or ablation

Types:

1. Burst pacing - rapid pacing to induce atrial flutter, VT
2. Programmed stimulation - basic drive train with 1-3 extra stimuli (S1-S2-S3)

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10.6 Radiofrequency Ablation (RFA)

📊 DIAGRAM 24 - RF Ablation Mechanism

ABLATION CATHETER TIP:
     ___
    /   \ ← 4-8 mm tip electrode (active)
   │ ● ● │ ← Temperature sensor (37-60°C target)
    \___/
      |
  RF Generator
  300-750 kHz
  25-50 Watts

MECHANISM:
RF current → resistive heating → tip heats tissue
Temperature 50-60°C → irreversible cell death (necrosis)
Lesion size: 5-7 mm diameter, 3-5 mm depth

Conditions Treated by RFA:

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═══════════════════════════════════

CHAPTER 11 - PACEMAKER FUNDAMENTALS

═══════════════════════════════════

11.1 Definition

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11.2 Indications for Pacing

1. Complete (3rd degree) AV Block - No conduction from atria to ventricles
2. Sick Sinus Syndrome (SSS) - Sinus node dysfunction
3. Symptomatic Bradycardia - HR <40 bpm with symptoms
4. Bifascicular/Trifascicular block with symptoms
5. Post-MI with persistent heart block
6. After cardiac surgery

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11.3 Components of a Pacemaker

📊 DIAGRAM 25 - Pacemaker System

PACEMAKER SYSTEM:

[Pulse Generator]
 ┌─────────────┐
 │  Battery    │ ← Lithium iodide, lasts 7-10 years
 │  Electronic │
 │  circuit    │
 └──────┬──────┘
        │ (connector block)
    ════╪════ Lead wire
        │
   [Electrode tip]
   (in contact with heart muscle)

Types of Leads:
- Unipolar: 1 electrode (tip only)
- Bipolar: 2 electrodes (tip + ring, 1 cm apart)
  Bipolar preferred (less noise, less myopotential sensing)

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11.4 NBG Pacemaker Code (5 letter code)

📊 DIAGRAM 26 - NBG Code

POSITION:    I        II       III      IV        V
MEANING:  Chamber  Chamber  Response  Rate     Multisite
          Paced    Sensed   to Sensing Modulation Pacing
          
OPTIONS:     O        O        O         O         O
(O=None)     A        A        T(trigger) R         A
             V        V        I(inhibit)           V
             D(both)  D(both)  D(T+I)               D
             
COMMON MODES:
VVI = Ventricle Paced, Ventricle Sensed, Inhibited
      (paces ventricle; inhibited if native beat sensed)
      
DDD = Dual chamber paced, Dual sensed, Dual response
      (most physiological mode)
      
VOO = Asynchronous ventricular pacing
      (fixed rate, ignores native beats - used in interference)
      
AAI = Atrium paced, Atrium sensed, Inhibited
      (for sick sinus syndrome with intact AV node)

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11.5 Temporary vs Permanent Pacing

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11.6 Pacemaker Malfunction

📊 DIAGRAM 27 - Pacemaker ECG

NORMAL PACED RHYTHM:
Spike → wide QRS
  |      _______
  |     /       \
  ↓    /         \
─ ↑ ─/─────────────\──────── ↑ ──/───
  (pacing spike)   (paced     (next spike + QRS)
                   QRS - wide,
                   LBBB pattern)

FAILURE TO PACE:
─ ─ ─ ─ ─ ─ ─ ─   ← No spikes seen despite bradycardia
(Check battery, connections, lead)

FAILURE TO CAPTURE:
─ ↑ ─ ─ ─ ─ ↑ ─   ← Spikes present but no QRS follows
(Check threshold, lead displacement)

FAILURE TO SENSE (Undersensing):
─ ↑ ↑  ↑  ↑       ← Paces even when native beats present
(Pacemaker does not see native R-wave)

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═══════════════════════════════════

CHAPTER 12 - VENTRICULAR ASSIST DEVICES (VAD) - BASICS

═══════════════════════════════════

12.1 Definition

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12.2 Intra-Aortic Balloon Pump (IABP)

Mechanism:

• Balloon is positioned in the descending thoracic aorta just distal to left subclavian artery
• Inflates with helium gas during diastole
• Deflates rapidly before systole

📊 DIAGRAM 28 - IABP Working

DIASTOLE (balloon INFLATES):        SYSTOLE (balloon DEFLATES):
                                    
   Aortic arch                        Aortic arch
        │                                  │
        │    BALLOON                       │    (empty)
        │    ╔═════╗ ←INFLATED            │    ╔     ╗ ←DEFLATED
        │    ║▓▓▓▓▓║ (helium)             │    ║     ║
        │    ╚═════╝                       │    ╚     ╝
        │                                  │
        
EFFECT OF INFLATION:              EFFECT OF DEFLATION:
↑ Diastolic pressure              ↓ Systolic aortic pressure
↑ Coronary perfusion              ↓ LV afterload (LV works less)
↑ O2 delivery to heart            ↓ LV oxygen demand

Benefits of IABP:

1. Increases coronary blood flow (diastolic augmentation)
2. Reduces cardiac workload (afterload reduction)
3. Improves cardiac output by 0.5-1 L/min

Triggering Modes:

Timing:

📊 DIAGRAM 29 - IABP Timing on Aortic Waveform

AORTIC PRESSURE WITH IABP:

              ___
             /   \  Augmented
    ___      /     \  diastolic
   /   \    / ↑↑   \ pressure
  /     \  /  IABP  \___
 /       \/  inflate   \  Assisted
/          DICROTIC     \ systole
           NOTCH         \___
                              
Inflate at: Dicrotic notch (beginning of diastole)
Deflate at: Just before next systole (before next upstroke)

Contraindications to IABP:

1. Aortic regurgitation (AR) - IABP worsens regurgitation
2. Aortic dissection - risk of extending dissection
3. Severe aorto-iliac disease - cannot insert balloon
4. Abdominal aortic aneurysm

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12.3 Impella Device

• Microaxial flow pump placed across aortic valve
• Draws blood from LV and ejects into aorta
• Provides 2.5 - 5.0 L/min support
• Positioned: LV inlet → Aortic outlet

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12.4 Extracorporeal Membrane Oxygenation (ECMO)

• Most powerful support device
• Drains blood from RA, oxygenates externally, returns to aorta
• VA-ECMO (veno-arterial) for cardiac support
• Used in cardiogenic shock, cardiac arrest

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═══════════════════════════════════════

🎯 EXAM STRATEGY & HIGH-YIELD SUMMARY

═══════════════════════════════════════

✅ Must-Know for 90%+ Marks

Long Answer Questions (10 marks) - Likely Topics:

1. Coronary angiography - procedure, catheters, views, complications
2. Cardiac output measurement - Thermodilution and Fick method
3. Shunt detection and calculation with Qp:Qs formula
4. Intra-aortic balloon pump - mechanism, timing, indications, contraindications
5. Sterilization methods in cath lab
6. Radiation protection in cath lab

Short Answer Questions (5 marks) - Likely Topics:

1. Types of catheters and their uses
2. Normal intracardiac pressures
3. Pressure damping - causes and correction
4. Ejection fraction - definition and calculation
5. Manifold - use and importance
6. Swan-Ganz catheter - ports and positions
7. PCWP - definition and significance
8. NBG pacemaker code
9. RF ablation - mechanism
10. TIMI flow grades

Very Short Answers (2 marks) - Likely Topics:

1. Definition of cardiac output (Normal = 4-8 L/min)
2. ALARA principle
3. Thermodilution injectate temperature (0-4°C)
4. Balloon gas in IABP (Helium)
5. Normal EF (≥55%)
6. Qp:Qs ratio significance (>1.5:1 = significant shunt)
7. PCWP normal value (6-12 mmHg)
8. Fr size formula (1 Fr = 0.33 mm)
9. TIMI 3 flow (normal flow)
10. Catheter for LV angiography (Pigtail)

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📝 Model Exam Answer Template

1. Definition (1 mark)
2. Principle/Mechanism (2 marks)
3. Steps/Procedure/Types (4 marks) + Diagram (1 mark)
4. Clinical significance/Complications (1 mark)
5. Conclusion (1 mark)

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🗓️ Study Plan (7 Days to Exam)

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📊 Realistic Mark Prediction - If You Study ONLY This Material

Your Exam Pattern (MGR University)

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✅ What This Study Material Covers

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🎯 Expected Marks - Honest Assessment

If you READ and memorize this material (without writing practice):

Estimated score: 55-65 / 75 = 73-87%

If you read + write practice (practice each answer once):

Estimated score: 62-68 / 75 = 83-91%

If you read + write + revise 3 times (full preparation):

Estimated score: 68-72 / 75 = 90-96%

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⚠️ Where Marks May Be Lost

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🔑 The Honest Truth

• Very specific numerical values your college teachers may emphasize
• Practical-based questions from your clinical postings
• Any institution-specific topics your professor added to class

What this means:

• If you only read without writing → 70-80%
• If you write answers in your own words at least once → 85-90%
• If you also revise your class notes + practical records alongside this → 90%+ is very achievable

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💡 3 Things to Do RIGHT NOW for 90%+

1. Write the 6 likely long-answer topics once each in your notebook (don't just read)
2. Memorize all formulas - EF, Qp:Qs, Fick, CO = HR × SV, PCWP values, normal pressures
3. Review your practical record book - examiners often pick 2-3 questions from clinical procedures you have actually done

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🏥 TAMIL NADU DR. M.G.R. MEDICAL UNIVERSITY

MOCK QUESTION PAPER

B.Sc. CARDIAC TECHNOLOGY - THIRD YEAR

PAPER I - CARDIAC CATHETERIZATION LABORATORY BASICS

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Instructions:

• Answer ALL questions in Part C
• Answer ANY FIVE from Part B
• Answer ANY TWO from Part A
• Draw diagrams wherever necessary
• Figures in brackets indicate marks

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═══════════════════════════

PART - A (Long Essay) 2 × 10 = 20 Marks

═══════════════════════════

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═══════════════════════════

PART - B (Short Essay) 5 × 5 = 25 Marks

═══════════════════════════

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═══════════════════════════

PART - C (Short Answers) 10 × 2 = 20 Marks

═══════════════════════════

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🔑 MODEL ANSWERS

(Read ONLY after you have attempted the paper)

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═══════════════════════════

PART A - MODEL ANSWERS

═══════════════════════════

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ANSWER 1 - Coronary Angiography (10 Marks)

Definition: (1 mark)

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Types of Catheters Used: (2 marks)

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Laboratory Preparation: (1 mark)

• Check and calibrate fluoroscopy, hemodynamic monitoring equipment
• Prepare sterile trolley with catheters, manifold, guidewires, contrast
• Charge and test defibrillator
• Load contrast in power injector
• IV access, ECG monitoring, pulse oximetry connected to patient
• Obtain informed consent; pre-medicate (antiplatelet, anticoagulant)
• Administer IV heparin 5000 units after arterial access

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Use of the Manifold: (1 mark)

[Contrast Syringe] ─┐
[Pressure Transducer]├── MANIFOLD ──── Catheter → Patient
[Saline Flush Line]─┘
[Waste port]

1. Flush catheter with heparinized saline (prevents clot)
2. Aspirate blood (to confirm position, clear air)
3. Inject contrast dye
4. Monitor coronary pressure simultaneously
5. Prevent air entry into the system (fatal air embolism prevention)

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Standard Angiographic Views: (2 marks)

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Grading of Coronary Stenosis (TIMI Flow): (1 mark)

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Complications of Coronary Angiography: (1 mark)

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Diagram: (1 mark)

CORONARY ARTERY CATHETER POSITIONS:

        AORTA
          |
     LEFT MAIN ──────────── RCA
       /    \                 |
     LAD     LCx           JR4 catheter
      |       |             seats here
   JL4 catheter           (from below)
  seats at LM ostium

C-ARM VIEWS (patient supine):
              CRANIAL
                ↑
    LAO ←───────┼───────→ RAO
                ↓
              CAUDAL

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ANSWER 2 - Cardiac Output Determination (10 Marks)

Definition: (1 mark)

• Normal CO: 4-8 L/min
• Formula: CO = Heart Rate × Stroke Volume
• Cardiac Index (CI): CO / BSA = 2.5-4.0 L/min/m²

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METHOD 1 - Thermodilution Method: (4 marks)

• Swan-Ganz (pulmonary artery) catheter
• CO computer
• 10 mL cold saline (0-4°C) in iced syringe

1. Position Swan-Ganz catheter tip in pulmonary artery (confirmed by PA waveform)
2. Patient at rest; no fluid boluses running
3. Draw 10 mL ice-cold saline (0-4°C) into syringe
4. Inject rapidly and smoothly into proximal port (RA) within 4 seconds
5. CO computer records temperature change at distal thermistor
6. Repeat 3 times; average values within 10% of each other

         V × (TB - TI) × K
CO = ────────────────────────
          ∫ ΔTB(t) dt

V = volume (10 mL)
TB = Blood temperature
TI = Injectate temperature
K = Correction constant
Denominator = area under temperature-time curve

Temperature  |↑
change       | \
             |  \
             |   \──────────────  ← baseline
             └─────────────────
                  Time
Large curve area = LOW cardiac output
Small curve area = HIGH cardiac output

• Slow injection (>4 sec) → falsely high CO
• Wrong temperature of injectate
• Tricuspid regurgitation (TR) → falsely elevated CO
• Intracardiac shunts
• Respiratory variation (breathe regularly during injection)

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METHOD 2 - Fick Method (Oxygen Dilution): (4 marks)

             O2 Consumption (VO2) in mL/min
CO = ─────────────────────────────────────────────────────
     (Arterial O2 Content - Mixed Venous O2 Content) × 10

O2 Content = Hemoglobin (g/dL) × 1.36 × O2 Saturation × 10

Arterial (CaO2): Hb × 1.36 × SaO2 × 10  (from aorta/femoral artery)
Venous (CvO2):   Hb × 1.36 × SvO2 × 10  (from pulmonary artery = mixed venous)

VO2 = 250 mL/min (measured by metabolic cart)
Hb = 14 g/dL
SaO2 = 98% = 0.98
SvO2 = 70% = 0.70

CaO2 = 14 × 1.36 × 0.98 × 10 = 186.6 mL/L
CvO2 = 14 × 1.36 × 0.70 × 10 = 133.3 mL/L

CO = 250 / (186.6 - 133.3) = 250 / 53.3 = 4.7 L/min ✓ (Normal)

            LUNGS
              ↑
    O2 added = VO2 (250 mL/min)
              ↑
    Pulmonary vein SaO2 = 98%
              ↓
           HEART
              ↓
          Body tissues
              ↑
    SVC/IVC → Mixed venous SvO2 = 70%

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Conclusion: (1 mark)

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ANSWER 3 - Intra-Aortic Balloon Pump (IABP) (10 Marks)

Definition: (1 mark)

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Components: (1 mark)

• Balloon catheter: 25-50 mL polyurethane balloon, 7-8 Fr
• Console: Electronic control unit with trigger selector and timing controls
• Gas supply: Helium (shuttled in and out of balloon)
• Drive line: Connects balloon catheter to console

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Mechanism of Action: (3 marks)

Balloon INFLATES during DIASTOLE:

AORTA                          CORONARIES
  │    ╔═══════╗                    ↑
  │    ║ BALLOON║  →  ↑ Diastolic   │ ↑ Coronary
  │    ║ INFLATED║     pressure in   │   blood flow
  │    ╚═══════╝     aortic root   (angina improved)
  │
Effect: Increases perfusion pressure → more blood into coronary arteries

Balloon DEFLATES just BEFORE SYSTOLE:

AORTA                          LV
  │    ╔       ╗                 │ LV ejects against
  │    ║(EMPTY)║  →  ↓ Aortic   │ LOWER pressure
  │    ╚       ╝     pressure    │ (afterload ↓)
  │
Effect: LV works against less resistance → reduced O2 demand
        → increased stroke volume and cardiac output

1. Diastolic augmentation → ↑ Coronary perfusion → ↑ O2 supply
2. Systolic unloading → ↓ Afterload → ↓ O2 demand
3. Net improvement in cardiac output by 0.5-1.0 L/min

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Timing of IABP: (2 marks)

CORRECT TIMING ON AORTIC WAVEFORM:

          ___                ___
         /   \              /   \  Augmented
        /     \            /     \  diastolic
       /       \          / ↑    \  peak
      /         \        / IABP   \
─────/           \──────/  inflate  \───
                  ↑                  ↑
           Dicrotic notch        Assisted
           = Inflation point      systolic
                                  upstroke

INFLATE at: Dicrotic notch (T-wave on ECG)
DEFLATE at: Just before next R-wave (systole)

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Indications: (1 mark)

1. Cardiogenic shock (post-MI or acute heart failure)
2. Unstable angina refractory to medical therapy
3. High-risk PTCA / coronary angioplasty support
4. Mechanical complications of MI (acute MR, VSD)
5. Bridge to cardiac surgery (CABG, valve replacement)
6. Weaning from cardiopulmonary bypass (post-surgery)

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Contraindications: (1 mark)

1. Aortic regurgitation (AR) - balloon inflation worsens regurgitation back into LV
2. Aortic dissection - balloon can extend the dissection
3. Severe peripheral vascular disease / aorto-iliac occlusion - cannot pass balloon
4. Abdominal aortic aneurysm (AAA) - risk of rupture
5. Severe coagulopathy (relative)

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Complications: (1 mark)

1. Limb ischemia (most common - from femoral artery occlusion)
2. Balloon rupture (helium embolism)
3. Aortic perforation
4. Thrombocytopenia (platelet destruction)
5. Infection at insertion site
6. Balloon malposition (too high → blocks renal/subclavian arteries)

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═══════════════════════════

PART B - MODEL ANSWERS

═══════════════════════════

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ANSWER 4 - Sterilization Methods (5 Marks)

• Most widely used for heat-sensitive cath lab equipment
• Temperature: 55°C; Time: 4-8 hours
• Mechanism: Alkylation of DNA and proteins of microorganisms
• Advantage: Effective for all materials including plastic, rubber, electronic items
• Disadvantage: Toxic gas; requires 24-48 hour aeration; carcinogenic
• Used for: Catheters, endoscopes, electronic equipment

• Immersion in 2% activated glutaraldehyde solution
• Disinfection: 20-30 minutes; Sterilization: 10 hours
• Mechanism: Alkylates proteins and nucleic acids
• Advantage: Effective at room temperature; cheap
• Disadvantage: Toxic fumes; irritant to eyes and skin; not a true sterilant with short soak

• 121°C at 15 psi for 15-20 minutes, OR 134°C for 3 minutes
• Mechanism: Protein denaturation by moist heat
• Advantage: Fastest, most reliable, non-toxic
• Disadvantage: Damages heat-sensitive items (catheters, plastics)
• Used for: Metal instruments, linen, glassware, surgical drapes

• Electromagnetic radiation (cobalt-60 source)
• Used for pre-packaged disposable items (syringes, catheters)
• Advantage: No heat or moisture; long shelf life; penetrates packaging
• Disadvantage: Industrial use only; cannot be used in clinical setting

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ANSWER 5 - Normal Intracardiac Pressures & PCWP (5 Marks)

DIAGRAM - Heart Pressures:
                    Pulmonary Artery
                    Systolic: 15-30 mmHg
                    Diastolic: 4-12 mmHg
                    Mean: 9-16 mmHg
          ___________________↑__________________
         |                                       |
   Right Atrium                           Left Atrium
   Mean: 2-8 mmHg                         Mean: 6-12 mmHg
         |                                       |
   Right Ventricle                         Left Ventricle
   Systolic: 15-30                          Systolic: 100-140
   Diastolic: 0-8 mmHg                     Diastolic: 4-12 mmHg
         |_____________________↓_________________|
                          Aorta
                    Systolic: 100-140 mmHg
                    Diastolic: 60-90 mmHg

a wave = atrial contraction (LA contracts)
x descent = atrial relaxation
v wave = ventricular systole (mitral valve closed, LA fills)
y descent = mitral valve opens, blood flows into LV

• Diagnosing LV failure vs RV failure
• Monitoring fluid therapy in ICU
• Differentiating cardiac pulmonary edema from non-cardiac
• Guiding treatment in cardiogenic shock
• Elevated PCWP in: LV failure, mitral stenosis, mitral regurgitation
• Low PCWP in: Hypovolemia, right heart failure only

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ANSWER 6 - Shunt Detection and Qp:Qs Calculation (5 Marks)

• Left-to-right shunt: Oxygenated blood flows right (ASD, VSD, PDA) - Acyanotic
• Right-to-left shunt: Deoxygenated blood flows left - Cyanotic (Eisenmenger)

Step-up at RA (>7%): ASD (L→R at atrial level)
Step-up at RV (>5%): VSD (L→R at ventricular level)
Step-up at PA (>5%): PDA (L→R at great vessel level)

EXAMPLE - ASD:
Normal:  SVC=70% → RA=72% → RV=74% → PA=74%
With ASD: SVC=70% → RA=85% ← STEP UP! (LA blood mixing via ASD)
                   → RV=85% → PA=85%

     Qp      SaO2 - MVO2
    ──── = ─────────────────
     Qs      PVO2 - PAO2

Where:
Qp = Pulmonary blood flow
Qs = Systemic blood flow
SaO2 = Systemic arterial O2 saturation (Aorta)
MVO2 = Mixed venous O2 saturation = (3×SVC + 1×IVC) / 4
PVO2 = Pulmonary vein saturation (assumed 98% if not measured)
PAO2 = Pulmonary artery saturation

SaO2 = 98%, MVO2 = 72%, PVO2 = 98%, PAO2 = 85%

Qp/Qs = (98 - 72) / (98 - 85) = 26/13 = 2:1

This means pulmonary flow is twice systemic flow → Large L-R shunt
→ CLOSURE INDICATED

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ANSWER 7 - Radiofrequency Ablation (5 Marks)

RF ABLATION MECHANISM:

RF Generator (300-750 kHz)
         ↓ electrical current
  [Ablation Catheter Tip]
       4-8 mm electrode
         ↓ resistive heating
  Tissue temperature → 50-60°C
         ↓
  Irreversible cell death (coagulation necrosis)
         ↓
  Lesion: 5-7 mm diameter, 3-5 mm depth
  (Arrhythmia focus permanently destroyed)

Temperature monitoring:
- Target: 50-60°C
- >60°C: Char formation, steam pops → catheter damage
- <50°C: Inadequate lesion (reversible, not permanent)

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ANSWER 8 - Pacemaker NBG Code (5 Marks)

POSITION:     I          II        III        IV         V
DESCRIBES: Chamber    Chamber   Response   Rate      Multisite
           Paced      Sensed    to Sensing Modulation Pacing

OPTIONS:
O = None      O = None   O = None   O = None   O = None
A = Atrium    A = Atrium T = Trigger R = Rate   A = Atrium
V = Ventricle V = Ventricle I = Inhibit  responsive V = Ventricle
D = Dual(A+V) D = Dual    D = Dual              D = Dual
              (A+V)      (T+I)

V = Ventricle paced
V = Ventricle sensed
I = Inhibited (if native beat sensed, pacing stopped)

Use: Complete AV block, atrial fibrillation with slow ventricular rate
Limitation: No AV synchrony (no physiological timing of atrial kick)
ECG: Pacing spike → wide QRS (LBBB pattern)

D = Both atrium and ventricle paced
D = Both atrium and ventricle sensed
D = Both triggered and inhibited

Use: Complete AV block WITH intact sinus node function
Advantage: Maintains AV synchrony; most physiological
ECG: Atrial spike → P wave → AV delay → Ventricular spike → QRS

A = Atrium paced
A = Atrium sensed
I = Inhibited

Use: Sick Sinus Syndrome with intact AV conduction

V = Ventricle paced
O = Nothing sensed
O = No response

Use: When electromagnetic interference is suspected
Risk: Can pace during T-wave → VF (R-on-T phenomenon)

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ANSWER 9 - Pressure Damping (5 Marks)

NORMAL WAVEFORM:         OVERDAMPED:           UNDERDAMPED (Ringing):
     /\    /\                __    __               /\/\  /\/\
    /  \  /  \              /  \  /  \             /    \/    \
───/    \/    \───       ───/    \/    \───     ───/            \───

Sharp systolic peak       Blunted/rounded peak    Exaggerated/spiky peaks
Accurate diastolic        False LOW systolic       False HIGH systolic
                          False HIGH diastolic     False LOW diastolic

1. Air bubbles in the catheter or tubing
2. Blood clot inside catheter lumen
3. Catheter kinking or bending
4. Loose connection at any port
5. Catheter tip against vessel wall
6. Soft, compliant tubing (absorbs pressure wave)

1. Stiff tubing (high frequency response)
2. Long tubing (resonance)
3. Patient with hyperdynamic circulation (high CO, fever, anemia)

• Overdamped: Falsely low systolic, falsely high diastolic → mean pressure relatively accurate
• Underdamped: Falsely high systolic, falsely low diastolic → mean pressure relatively accurate

• Rapidly flush catheter then suddenly stop
• Normal: 1-2 oscillations before returning to baseline
• Overdamped: Slow return, no oscillations
• Underdamped: >2 oscillations (ringing)

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ANSWER 10 - Radiation Protection (5 Marks)

• Radiation dose is directly proportional to exposure time
• Dose = Dose Rate × Time
• Strategies:
  • Use fluoroscopy only when necessary (last image hold)
  • Minimize cine run duration
  • Pre-plan procedure to reduce fluoroscopy time
  • Use roadmapping to reduce repeat screening

Dose ∝ 1 / Distance²

At 1 m: 100 mR/hr
At 2 m: 25 mR/hr  (1/4 of original)
At 3 m: 11 mR/hr  (1/9 of original)

RULE: Every time you double the distance, dose reduces by 75%
ALWAYS: Stand on Image Intensifier side (NOT X-ray tube side)
         X-ray tube below table generates upward scatter

• Collimate X-ray beam to smallest required area
• Use lowest fluoroscopy frame rate (7.5 fps vs 15 fps)
• Keep image intensifier close to patient (less magnification scatter)
• Use copper spectral filters
• Regular dosimeter (TLD badge) monitoring for all staff

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PART C - MODEL ANSWERS

═══════════════════════════

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• Formula: CO = Heart Rate × Stroke Volume
• Normal value: 4-8 L/min (average ~5 L/min at rest)
• Cardiac Index (CI): CO/BSA = 2.5-4.0 L/min/m²

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1. Multiple side holes allow rapid contrast injection without a high-velocity jet from a single end-hole, preventing LV wall injury
2. The curled pigtail tip prevents perforation of the LV wall
3. It minimizes ventricular ectopy during injection
4. Allows injection of large volumes (30-45 mL) needed to opacify the LV

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EF = (EDV - ESV) / EDV × 100
   = Stroke Volume / End-Diastolic Volume × 100

• Normal EF: ≥55%
• Mild LV dysfunction: 45-54%
• Moderate dysfunction: 35-44%
• Severe dysfunction: <35%

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• The catheter tip is positioned in the PA but falls back slightly toward the right ventricle
• The PA waveform loses its dicrotic notch
• Diastolic pressure falls to near zero (like RV diastole) instead of remaining at PA diastolic level (4-12 mmHg)

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• Qp:Qs of 1.5:1 to 1.9:1 = borderline; decision depends on symptoms and other factors
• Qp:Qs ≥ 2:1 = closure indicated in ASD, VSD, PDA
• Qp:Qs < 1:1 = right-to-left shunt (Eisenmenger) = closure contraindicated

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1. Low molecular weight and density - moves very rapidly in and out of the balloon, allowing fast inflation and deflation (especially important at high heart rates)
2. Low solubility in blood - in case of balloon rupture, helium is rapidly absorbed from the bloodstream, minimizing the risk of gas embolism
3. Inert and non-toxic - safe if small amounts enter the bloodstream

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• Complete and rapid filling of the coronary artery distal to the stenosis or occlusion
• Contrast clears the vessel as quickly as it fills
• Considered the target of successful coronary intervention (PTCA/thrombolysis)

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1. His Bundle Catheter (HBE catheter) - Quadripolar catheter positioned across the tricuspid valve at the bundle of His. Records the His bundle electrogram (A wave, H spike, V wave) and measures AH and HV intervals.
2. Coronary Sinus (CS) catheter - Decapolar (10-pole) catheter positioned inside the coronary sinus vein (which runs in the AV groove). Records electrical activity from the left atrium and left ventricle. Essential for mapping accessory pathways in WPW and for AF ablation.

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