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B.Sc. Cardiac Technology - 3rd Year Paper I

Cardiac Catheterization Laboratory Basics

Complete Exam Preparation Guide

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SECTION A: ESSAY QUESTIONS (10 Marks Each)

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ESSAY 1: Coronary Angiography - Technique, Views, Catheters and Complications

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1. Indications

• Stable angina not responding to medical therapy
• Unstable angina / Non-ST elevation MI (NSTEMI)
• ST elevation MI (STEMI) for primary PCI
• Pre-operative assessment before cardiac surgery
• Evaluation of valvular heart disease
• Assessment of coronary anomalies
• Positive stress test or stress echo

2. Catheters Used

• Catheters are 5F, 6F, or 7F in diameter
• Made of polyurethane or nylon
• Introduced via femoral artery (Judkins technique) or radial artery (Sones/transradial approach)

3. Vascular Access

• Femoral approach (Judkins): Seldinger technique through femoral artery; 6F sheath used commonly; arterial entry at femoral head level
• Radial approach (transradial): Preferred today; less bleeding, early ambulation; Allen's test done beforehand to check dual circulation

4. Manifold System

• Contrast syringe
• Pressure line (for pressure monitoring)
• Flush/saline line
• Waste/aspiration line

5. Angiographic Views - Left Coronary Artery

6. Angiographic Views - Right Coronary Artery

7. Contrast Agents

• Non-ionic agents preferred: Iohexol (Omnipaque), Iopamidol, Iodixanol (iso-osmolar)
• Usual volume: 5-8 mL per coronary injection; 30-40 mL for ventriculography
• Side effects: Contrast nephropathy, allergic reaction, osmotic effects

8. Assessment of Stenosis

• Severity graded as % diameter stenosis (visual estimate or QCA)
• Significant stenosis: ≥70% in major epicardial vessel; ≥50% in LM
• TIMI flow grade (0 to 3) used to describe flow

9. Complications

10. Radiation Protection

• Lead apron, thyroid shield, leaded glasses
• Keep distance from X-ray source (inverse square law)
• Minimize fluoroscopy time and cine runs
• Use pulsed fluoroscopy

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ESSAY 2: Pressure Recording in Cardiac Catheterization - Systems, Waveforms, Gradients and Artifacts

Introduction

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1. Pressure Recording Systems

• Catheter filled with saline connected via tubing to an external pressure transducer
• Transducer converts mechanical pressure to electrical signal
• Must be zeroed at mid-chest (phlebostatic axis)
• Advantages: Simple, cheap
• Disadvantages: Signal distortion due to resonance, damping; artifacts with air bubbles or clots

• Miniature transducer mounted at catheter tip
• Records pressure at actual site without tubing artefact
• Very accurate - used for research
• Disadvantages: Expensive, fragile

2. Normal Pressure Values

3. Pressure Waveforms

• a wave: Atrial contraction (absent in AF)
• c wave: Tricuspid/mitral valve closure (small, often merged with 'a')
• v wave: Ventricular systole with atria filling passively; giant v wave in MR/TR
• x descent: Atrial relaxation
• y descent: AV valve opening and ventricular filling

• Rapid rise during systole, fall during diastole
• LV end-diastolic pressure (LVEDP): Marker of LV function; elevated in heart failure

• Reflects left atrial pressure when balloon-tipped catheter is wedged in pulmonary capillary
• Used to assess LV filling pressure and diagnose pulmonary venous hypertension

4. Damping and Artifacts

• Causes: Air bubble, clot, kinked tubing, soft catheter
• Effect: Falsely low systolic, falsely high diastolic; blunted waveform

• Causes: Stiff catheter, long tubing, high natural frequency
• Effect: Falsely high systolic, falsely low diastolic; overshoot artifact

• In high-flow areas (PA, aorta); catheter tip movement generates spurious pressure changes
• Solution: Use catheter-tipped transducer or average multiple cycles

• Catheter slips out of wedge position, records RV pressure instead of PCWP
• Recognized by increased pulse pressure; correct by re-inflating balloon

5. Pressure Gradient Recording

• Two transducers used simultaneously (one each side of valve)
• Most accurate; used for aortic stenosis (LV vs. Ao) and mitral stenosis (LA vs. LV via transseptal)

• Non-simultaneous; peak LV pressure vs. peak Ao pressure recorded at different time points
• Convenient but overestimates physiological gradient because peaks don't occur simultaneously

• Single catheter slowly withdrawn across valve
• Used for aortic stenosis (LV to Ao pullback) and pulmonic stenosis (RV to PA pullback)
• Identifies level of obstruction (valvular vs. subvalvular vs. supravalvular)

6. Clinical Applications of Pressure Data

• Mitral stenosis: Mean transmitral gradient >5 mmHg; PCWP elevated; LA-LV diastolic gradient
• Aortic stenosis: Peak-to-peak LV-Ao gradient; severe if mean gradient >40 mmHg or valve area <1.0 cm²
• Pulmonary hypertension: mPAP ≥25 mmHg; Eisenmenger when pulmonary > systemic resistance
• Constrictive pericarditis: Equalization of diastolic pressures in all four chambers
• Cardiac tamponade: Equalization of RA, RV diastolic, and PCWP; "pulsus paradoxus"

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ESSAY 3: Cardiac Output Determination - Methods, Principles and Clinical Significance

Introduction

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1. Thermodilution Method (Most Common)

• Has proximal port (RA), distal port (PA), balloon port, thermistor (near tip)

1. 10 mL of cold (iced) or room-temperature saline injected rapidly into proximal (RA) port
2. Thermistor near tip measures temperature change over time in PA
3. Modified Stewart-Hamilton equation calculates CO:

CO = [V × (Tb - Ti) × K] / ∫ΔTb(t)dt

• V = injectate volume
• Tb = blood temperature
• Ti = injectate temperature
• K = computation constant
• ∫ΔTb = area under thermodilution curve

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2. Fick Principle (Oxygen Consumption Method)

CO = O₂ consumption (mL/min) / [Arteriovenous O₂ difference (mL/L)]

• O₂ consumption measured by spirometry (or assumed as 125 mL/min/m²)
• AV O₂ difference = (Aortic O₂ content) - (Pulmonary artery O₂ content)
• O₂ content = Hb × 1.34 × O₂ saturation

• O₂ consumption = 250 mL/min
• Aortic sat = 98%, PA sat = 75%, Hb = 15 g/dL
• O₂ content difference = 15 × 1.34 × (0.98 - 0.75) = 4.63 mL/dL = 46.3 mL/L
• CO = 250 / 46.3 = 5.4 L/min

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3. Indicator Dilution Method (Dye Dilution)

• Dye injected into RA or pulmonary artery
• Arterial blood sampled continuously from aorta
• Concentration-time curve plotted; area under curve used to calculate CO

CO = Dose of indicator (mg) / [Mean concentration × Duration of curve]

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4. Shunt Detection and Calculation

Qp/Qs = (Aortic sat - Mixed venous sat) / (Pulmonary vein sat - PA sat)

• Normal = 1:1
• Qp/Qs >1.5: Significant left-to-right shunt; consider closure
• Qp/Qs >2.0: Large shunt; surgery/device closure indicated

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5. Clinical Significance

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SECTION B: SHORT NOTES (5 Marks Each)

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1. Types of Catheters and Their Uses

• Diagnostic catheters: Judkins Left/Right, Amplatz, Multipurpose, Pigtail
• Guiding catheters: For PCI; provide back-up support (EBU, XB, JL, JR)
• Special purpose: Balloon-tipped (Swan-Ganz), EP catheters (ablation, mapping), IABP catheters, intravascular ultrasound (IVUS) catheters

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2. Sterilization Methods in Cath Lab

• Single-use (disposable) catheters should never be resterilized
• High-level disinfection vs. sterilization: sterilization kills ALL organisms including spores
• Prion safety requires special protocols

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3. Left Ventriculography - Technique, Catheters and Views

• LV systolic function (EF calculation)
• Wall motion abnormalities (regional in IHD)
• Mitral regurgitation (severity grading)
• LV thrombus, VSD

• Pigtail catheter (most common): Multiple side holes prevent high jet injury
• Alternatively: NIH catheter, Berman catheter

• Catheter advanced retrogradely across aortic valve into LV
• Contrast (30-40 mL) injected at 10-15 mL/sec using power injector
• Injector pressure: 600-900 psi

• RAO 30°: Best for anterior and inferior wall; MR jet visible to LA; standard view
• LAO 60° (cranial): Interventricular septum viewed en face; septal motion; lateral wall

• EF = (EDV - ESV) / EDV × 100
• Normal EF >55%
• Regional wall motion: Normal, hypokinesis, akinesis, dyskinesis

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4. Intra-cardiac Pressures and Normal Values

• RA: Mean 0-8 mmHg; a wave 2-10, v wave 2-10
• RV: Systolic 15-30 / Diastolic 0-8 mmHg
• PA: Systolic 15-30 / Diastolic 8-15 / Mean 10-20 mmHg
• PCWP: Mean 6-12 mmHg

• LV: Systolic 100-140 / LVEDP 5-12 mmHg
• Aorta: Systolic 100-140 / Diastolic 60-90 / Mean 70-105 mmHg

• Elevated LVEDP (>18 mmHg): LV failure
• Elevated PCWP (>18 mmHg): Pulmonary venous hypertension; risk of pulmonary edema
• Mean PA >25 mmHg: Pulmonary arterial hypertension
• Equalization of diastolic pressures: Constrictive pericarditis or tamponade

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5. Radiation Protection in Cath Lab

• Lead apron: 0.35-0.5 mm lead equivalent; protects trunk
• Thyroid collar: Protects thyroid
• Lead glasses: Protects lens (prevents radiation cataract)
• Lead acrylic screen (ceiling-mounted or table-mounted): Scatter protection

• Increase source-to-image distance
• Decrease image intensifier-to-patient distance
• Collimate beam to area of interest
• Use pulsed fluoroscopy (7.5 or 15 frames/sec instead of 30)

• Occupational: 20 mSv/year (averaged over 5 years)
• Pregnant worker: 1 mSv to fetus during pregnancy

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6. Oxygen Dilution Method (Fick Principle) - Shunts and CO

• Fick principle: CO = O₂ consumption / AV O₂ difference
• Most accurate method; gold standard
• Used for shunt calculations in congenital heart disease
• Requires blood samples from PA, Ao, and O₂ consumption measurement
• Shunt detected by saturation step-up at level of defect
• Qp:Qs ratio quantifies magnitude of shunt

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7. Image Intensifier and Table Movement

• Converts X-ray to visible light image
• Components: Input phosphor (CsI) → photocathode → electronic focusing → output phosphor → TV camera
• Modern systems use flat panel detectors (FPD) instead of II; better image quality, less distortion

• Cranial/Caudal: Tilts toward patient's head or feet; changes the angle of view along the long axis of body
• LAO/RAO: Rotates left or right around patient; changes lateral viewing angle
• Panning: Moves II over the patient to center over region of interest

• Longitudinal: Head-to-foot movement (to follow catheter from groin to heart)
• Lateral: Left-right movement
• Height adjustment: Raises/lowers patient to optimize geometry
• Tilt (Trendelenburg/Reverse): Head-down or head-up

• Cine images stored on digital archive (DICOM format)
• Can be replayed frame-by-frame or in real-time
• Used for review, reporting, and comparison with previous studies

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8. Electrophysiology Study (EP Study) - Basics

• High right atrium (HRA) catheter
• His bundle catheter
• Coronary sinus (CS) catheter
• Right ventricular apex (RVA) catheter

• PA interval: 25-55 ms (intra-atrial conduction)
• AH interval: 55-130 ms (AV nodal conduction)
• HV interval: 35-55 ms (His-Purkinje conduction)

• Programmed electrical stimulation (PES) using extra stimuli (S1, S2, S3)
• Burst pacing to induce tachycardia

• Thermal energy (RF current) delivered via ablation catheter tip
• Tip heats to 50-60°C; creates controlled necrotic lesion destroying arrhythmia circuit
• Used for: SVT, WPW, atrial flutter, atrial fibrillation, VT

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SECTION C: SHORT ANSWERS (3 Marks Each)

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• TIMI 0: No flow (complete occlusion)
• TIMI 1: Minimal flow; contrast enters but doesn't fill distal vessel
• TIMI 2: Partial flow; slow filling of entire vessel
• TIMI 3: Normal flow; brisk filling and washout of entire vessel

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• Ionic: High-osmolality; cheaper; more side effects (pain, arrhythmias); e.g., diatrizoate (Hypaque)
• Non-ionic (low-osmolality): Safer; less pain; preferred today; e.g., Iohexol (Omnipaque), Iopamidol, Iodixanol (iso-osmolar, best for renal impairment)

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QUICK REFERENCE: High-Probability Exam Topics Summary

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Exam pattern reminder: 3 Essays × 10 = 30 marks | 8 Short Notes × 5 = 40 marks | 10 Short Answers × 3 = 30 marks | Total = 100 marks

• 10 mark = 2-3 pages எழுதணும், maximum marks வாங்கணும்
• 5 mark = 1 page போதும்
• 3 mark = half page போதும்

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✅ Exam Writing Strategy - எவ்வளவு எழுதணும்?

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📝 10 Mark Question (Essay)

• 4-5 points with explanation = Full marks
• 2-3 pages (handwriting normal size)
• Time: ~15-18 minutes

1. Definition / Introduction  (2-3 lines)
2. Point 1 with explanation   (3-4 lines)
3. Point 2 with explanation   (3-4 lines)
4. Point 3 with explanation   (3-4 lines)
5. Point 4 with explanation   (3-4 lines)
6. Diagram (if possible)      (+bonus marks)
7. Conclusion                 (1-2 lines)

Definition: Coronary angiography is the gold standard invasive test to visualize coronary arteries using contrast dye under X-ray guidance.

Indications:

• Chest pain not responding to medicines
• Before heart surgery
• Positive stress test

Catheters Used:

• Judkins Left (JL 4.0) - for Left coronary
• Judkins Right (JR 4.0) - for Right coronary

Views:

• RAO Caudal - LM, LCx seen
• LAO Cranial - LAD seen
• RAO 30° - RCA distal seen

Complications:

• Contrast allergy
• Arterial hematoma
• Coronary dissection

Conclusion: Coronary angiography helps plan further treatment like PTCA or CABG.

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📝 5 Mark Question (Short Note)

• 3-4 points = Full marks
• 1 page (or 15-20 lines)
• Time: ~8-10 minutes

1. One-line definition
2. Point 1 (2-3 lines)
3. Point 2 (2-3 lines)
4. Point 3 (2-3 lines)
5. One diagram or table (optional but good)

Definition: Measures taken to minimize X-ray exposure in cath lab (ALARA principle).

Methods:

1. Distance - Stand far from X-ray source
2. Shielding - Lead apron, thyroid collar, lead glasses
3. Time - Minimize fluoroscopy time
4. Dosimeter - Wear TLD badge to monitor dose

Safe dose limit: 20 mSv/year for cath lab staff.

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📝 3 Mark Question (Short Answer)

• 3 points (one line each) = Full marks
• Half page (6-8 lines)
• Time: ~4-5 minutes

1. Definition (1 line)
2. Point 1
3. Point 2
4. Point 3

Allen Test is done before radial artery access.

1. Compress both radial and ulnar arteries → hand blanches
2. Release radial artery pressure
3. If hand turns pink within 10 seconds → safe to use radial artery

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🎯 Key Rule - எல்லா question-க்கும்:

• ✅ Headings போடுங்க (examiner-க்கு easy to read)
• ✅ Numbered points use பண்ணுங்க
• ✅ One simple diagram போட்டா bonus marks
• ✅ Definition + Points + Conclusion = guaranteed marks
• ❌ Long paragraphs வேண்டாம் - points போதும்

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3rd Year Paper I - Cardiac Catheterization Laboratory Basics

Exam-Ready Answers (Exact Length Format)

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10 MARK ANSWERS (3-4 Pages Length)

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Q1. Coronary Angiography - Technique, Catheters, Views and Complications

Introduction

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Indications

1. Stable angina not adequately controlled with medical therapy
2. Unstable angina / NSTEMI (Non-ST Elevation Myocardial Infarction)
3. STEMI (ST Elevation Myocardial Infarction) - for primary PCI
4. Positive treadmill test or stress echocardiography
5. Pre-operative evaluation before valve surgery or CABG
6. Assessment of coronary anomalies
7. Suspected Prinzmetal (variant) angina
8. Follow-up after previous PTCA or CABG

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Contraindications

1. Severe contrast allergy (relative - can pre-medicate)
2. Severe renal failure (relative - use iso-osmolar contrast + hydration)
3. Uncontrolled hypertension or heart failure
4. Active bleeding or coagulopathy
5. Patient refusal or non-cooperation

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Pre-procedure Preparation

1. Written informed consent
2. NPO (nil by mouth) for 4-6 hours
3. Blood investigations: CBC, RFT, coagulation profile, serum creatinine
4. ECG and echocardiography review
5. IV access secured (18G cannula)
6. Pre-medication: Antihistamines if contrast allergy history
7. Heparin 3000-5000 units IV after sheath insertion
8. Patient positioned on cath table; groin/wrist shaved and cleaned

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Vascular Access

• Right femoral artery punctured using Seldinger technique at the level of femoral head
• 6F arterial sheath inserted
• Catheter advanced through aorta to coronary ostia under fluoroscopy
• Advantage: Larger vessel, easy access, good for complex procedures
• Disadvantage: Patient must lie flat for 4-6 hours post-procedure; bleeding risk

• Allen test done first to confirm dual (ulnar) circulation
• Right radial artery punctured at wrist
• 5F or 6F sheath inserted
• Advantage: Less bleeding, early ambulation, patient comfort, less vascular complications
• Disadvantage: Learning curve; vessel spasm possible

1. Artery punctured with needle
2. Guidewire passed through needle
3. Needle removed
4. Dilator + sheath passed over wire
5. Wire and dilator removed; sheath stays in vessel

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Catheters Used

• Catheters made of polyurethane or braided nylon
• Size in French: 1 French = 0.33 mm diameter
• Pre-shaped curves allow selective engagement of ostia

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The Manifold System

1. Contrast syringe
2. Pressure transducer line (for pressure monitoring)
3. Saline flush line
4. Waste/aspiration line

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Angiographic Views - Left Coronary System

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Angiographic Views - Right Coronary Artery

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Contrast Agents

1. Ionic (High-osmolality): Older agents; painful; more side effects; e.g., Diatrizoate (Hypaque)
2. Non-ionic (Low-osmolality): Safe, painless, preferred; e.g., Iohexol (Omnipaque), Iopamidol
3. Iso-osmolar: Safest for kidney patients; e.g., Iodixanol (Visipaque)

• Usual volume: 5-8 mL per coronary injection; 30-40 mL for LV gram
• Risk: Contrast nephropathy, allergy, osmotic effects

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Stenosis Assessment

• Graded as percentage diameter stenosis by visual estimation or Quantitative Coronary Analysis (QCA)
• Significant stenosis: ≥70% in major vessel; ≥50% in Left Main
• TIMI flow grades:
  • TIMI 0: No flow
  • TIMI 1: Minimal flow only
  • TIMI 2: Partial/slow flow
  • TIMI 3: Normal flow

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Complications

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Radiation Protection in Cath Lab

• Lead apron (0.5 mm Pb equivalent) - mandatory
• Thyroid collar
• Lead glasses (prevent radiation cataract)
• Ceiling-mounted lead acrylic shield
• Keep maximum distance from X-ray tube
• Minimize fluoroscopy time (use pulsed fluoroscopy 7.5 fps)
• Use last-image hold instead of cine when possible
• Wear TLD dosimeter badge - dose limit 20 mSv/year

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Conclusion

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Q2. Cardiac Output Determination - Thermodilution and Fick Principle

Introduction

• Cardiac Output (CO): 4-8 litres per minute
• Cardiac Index (CI) = CO / Body Surface Area = 2.4-4.0 L/min/m²
• Stroke Volume (SV) = CO / Heart Rate = 60-100 mL/beat

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Methods of Cardiac Output Measurement

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Method 1: Thermodilution Method (Most Commonly Used)

• 4-lumen catheter, 7F size
• Proximal port (RA) - for cold saline injection and CVP monitoring
• Distal port (PA) - for PA pressure and PCWP measurement
• Balloon port - for balloon inflation to float catheter and wedge
• Thermistor - located 4 cm from tip; measures temperature changes in PA

1. Swan-Ganz catheter inserted via internal jugular or subclavian vein
2. Balloon inflated with 1.5 mL air; catheter "floats" with blood flow through RA → RV → PA
3. Position confirmed by pressure waveform changes (RA → RV → PA → PCWP)
4. Exactly 10 mL of cold (iced 0-4°C) or room temperature saline drawn in syringe
5. Saline injected rapidly (within 4 seconds) through proximal (RA) port
6. Thermistor at distal end records temperature change over time
7. CO computer integrates the area under temperature-time curve
8. Minimum 3 measurements taken; values within 10% of each other are averaged

CO = [V × (Tb - Ti) × K] / Area under thermodilution curve

• V = volume of injectate (10 mL)
• Tb = blood temperature (°C)
• Ti = temperature of injectate (°C)
• K = computation constant (accounts for catheter dead space, specific heat)
• Area = integral of temperature change over time

• Normal CO: Smooth curve, rapid upstroke, gradual return to baseline
• Low CO: Slow upstroke, prolonged curve, large area under curve
• High CO: Rapid upstroke and downstroke, small area under curve
• Tricuspid regurgitation: Irregular, prolonged curve (injectate recirculates) → falsely HIGH CO reading
• Intracardiac shunt (L→R): Falsely high CO reading

1. Bedside use - no arterial sampling needed
2. Can be repeated multiple times
3. Quick results (within minutes)
4. Widely available in most ICUs and cath labs

1. Inaccurate in tricuspid regurgitation
2. Inaccurate in intracardiac shunts
3. Error with improper injection technique (slow injection)
4. Requires PA catheter insertion (invasive; risk of pneumothorax, arrhythmia)
5. Inaccurate in very low cardiac output states

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Method 2: Fick Principle (Gold Standard)

CO = Oxygen Consumption (VO₂) / Arteriovenous Oxygen Content Difference (C(a-v)O₂)

CO = VO₂ (mL/min) / [CaO₂ - CvO₂] (mL/L)

• VO₂ = oxygen consumption measured by spirometry or assumed (125 mL/min/m²)
• CaO₂ = arterial O₂ content = Hb × 1.34 × SaO₂ × 10
• CvO₂ = mixed venous O₂ content = Hb × 1.34 × SvO₂ × 10
• SaO₂ from aorta; SvO₂ from pulmonary artery (mixed venous)

• O₂ consumption = 250 mL/min
• Hemoglobin = 15 g/dL
• Aortic saturation = 98%
• PA (mixed venous) saturation = 75%
• CaO₂ = 15 × 1.34 × 0.98 × 10 = 196.8 mL/L
• CvO₂ = 15 × 1.34 × 0.75 × 10 = 150.8 mL/L
• AV difference = 196.8 - 150.8 = 46 mL/L
• CO = 250 / 46 = 5.4 L/min (Normal)

• Arterial sample: Aorta or femoral artery
• Venous sample: Pulmonary artery (true mixed venous blood)
• Not from RA or RV - these are not properly mixed

1. Most accurate - true gold standard
2. Valid in presence of intracardiac shunts
3. Valid in arrhythmias and tricuspid regurgitation
4. Can simultaneously calculate shunt ratio (Qp:Qs)

1. Requires measurement of O₂ consumption (spirometry in steady state)
2. Assumed VO₂ introduces error
3. Multiple blood samples required
4. Requires patient in stable, steady state (not valid in acute hemodynamic changes)
5. Time-consuming

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Method 3: Indicator Dye Dilution Method

CO = Amount of dye injected / (Mean concentration × Duration of curve)

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Method 4: Pulse Doppler Method

• Doppler echocardiography used to measure velocity of blood flow across aortic valve
• CO = Stroke Volume × Heart Rate
• Stroke Volume = Cross-sectional area of LVOT × Velocity Time Integral (VTI)
• Non-invasive; can be repeated bedside
• Less accurate than Fick but useful for monitoring trends

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Shunt Detection and Calculation

Qp/Qs = (SaO₂ - SvO₂) / (SpvO₂ - SpaO₂)

• Normal = 1:1

• 1.5:1 = Significant shunt; consider closure

• 2.0:1 = Large shunt; intervention indicated

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Clinical Significance of Cardiac Output

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Conclusion

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Q3. Pressure Recording in Cardiac Catheterization - Systems, Waveforms, Gradients, Normal Values and Artifacts

Introduction

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Pressure Recording Systems

1. Intravascular catheter
2. Saline-filled pressure tubing (non-compliant, rigid)
3. Stopcock/manifold
4. External strain-gauge pressure transducer
5. Amplifier and display monitor

• Pressure wave travels from catheter tip through saline-filled column to transducer
• Transducer diaphragm deflects proportional to pressure
• Strain gauge converts mechanical deflection to electrical signal
• Signal amplified and displayed as pressure waveform

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• Miniature piezoelectric or strain-gauge transducer mounted directly at the catheter tip
• Eliminates all errors caused by fluid-filled tubing
• Records pressure at the exact site of measurement
• Gold standard for research and dP/dt (rate of pressure rise) measurement
• Disadvantage: Expensive, fragile, not used routinely

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Normal Intracardiac Pressure Values

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Pressure Waveforms

• a wave: Due to atrial contraction (end of diastole)
  • Absent in atrial fibrillation (no organized atrial contraction)
  • Cannon a wave: When atrium contracts against closed AV valve (complete heart block, junctional rhythm)
• c wave: Small deflection due to AV valve closure (mitral/tricuspid closure); often not visible
• v wave: Passive atrial filling during ventricular systole (when AV valves are closed)
  • Giant v wave in mitral regurgitation (large blood volume regurgitating into LA during systole)
  • Giant v wave in tricuspid regurgitation (RA)
• x descent: Atrial relaxation + downward displacement of AV valve during ventricular systole
  • Absent or reversed (x' rise) in cardiac tamponade
• y descent: AV valve opens; blood flows from atrium to ventricle in early diastole
  • Steep y descent: Constrictive pericarditis (rapid early filling)
  • Blunted y descent: Cardiac tamponade (restricted filling)

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• Rapid pressure rise during isovolumetric contraction
• Peak during ventricular systole
• Rapid fall during isovolumetric relaxation
• Low, flat baseline during diastole

• Measured at end of diastole just before QRS complex
• Normal: 5-12 mmHg
• Elevated LVEDP (>18 mmHg): Indicates LV failure, reduced compliance, fluid overload

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• Rapid rise during ventricular ejection
• Peak = Systolic pressure
• Dicrotic notch = Aortic/pulmonic valve closure (end of systole)
• Gradual fall during diastole
• Nadir = Diastolic pressure

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• Obtained when balloon-tipped catheter is inflated and advanced until it "wedges" in a small pulmonary artery
• Reflects left atrial pressure (with slight time delay)
• Normal: 6-12 mmHg
• PCWP >18 mmHg: Pulmonary venous hypertension; risk of pulmonary edema
• PCWP >25 mmHg: Pulmonary edema
• Used to differentiate cardiac vs. non-cardiac pulmonary edema (ARDS: PCWP normal or low)

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Artifacts in Pressure Recording

• Causes: Air bubble in tubing, blood clot at catheter tip, kinked tubing, soft/compliant tubing, loose connections
• Effect: Blunted, sluggish waveform; systolic pressure falsely LOW; diastolic pressure falsely HIGH; narrow pulse pressure
• Solution: Flush catheter briskly; check for air bubbles; check connections

• Causes: Stiff catheter, short rigid tubing, high natural frequency of system
• Effect: Overshoot artifact; systolic pressure falsely HIGH; diastolic pressure falsely LOW; wide pulse pressure
• Solution: Add in-line damping device; use appropriate length tubing

• Caused by physical movement of catheter tip in high-flow vessels (PA, aorta)
• Catheter tip moves during cardiac contraction, producing spurious pressure changes
• Solution: Use catheter-tipped transducer; average over multiple cycles

• PCWP catheter slips back from wedge position into main PA; records RV-like pattern
• Recognized by sudden increase in pulse pressure and loss of typical PCWP morphology
• Solution: Re-inflate balloon; advance catheter to re-wedge

• Electrical hum from equipment
• Solution: Proper grounding of equipment; electrical isolation

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Pressure Gradient Recording

• Two transducers used simultaneously, one on each side of valve
• Most accurate method
• Used for: Aortic stenosis (LV + Aorta), Mitral stenosis (LA via transseptal + LV)

• Non-simultaneous method using single catheter
• Peak LV pressure minus peak Aortic pressure recorded at different time points
• Convenient but overestimates gradient (peaks don't occur at the same time physiologically)

• Catheter slowly withdrawn across valve while continuously recording pressure
• Shows pressure drop as catheter crosses the valve
• Used for: Aortic stenosis (LV → Ao), Pulmonic stenosis (RV → PA), Coarctation (distal → proximal Ao)

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Clinical Applications

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Conclusion

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5 MARK ANSWERS (2-3 Pages Length)

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1. Radiation Protection in Cardiac Catheterization Laboratory

Introduction

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Sources of Radiation in Cath Lab

1. Primary X-ray beam (direct beam from X-ray tube)
2. Scattered radiation from patient's body (main source for staff)
3. Leakage radiation from X-ray tube housing

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Protective Measures

• Radiation intensity decreases with the square of distance from source
• Doubling distance reduces dose to one-fourth (inverse square law)
• Staff should stand as far as possible from X-ray tube during cine runs
• Control room with lead-glass window provides maximum protection

• Lead apron: 0.35-0.5 mm lead equivalent; must cover front and sides of torso; protects liver, gonads, bone marrow
• Thyroid collar: Protects thyroid gland (highly radiation-sensitive)
• Lead glasses: Protects eye lens; prevents radiation-induced cataract (dose limit to lens: 20 mSv/year)
• Lead gloves: For staff whose hands are near beam (rarely needed)
• Ceiling-mounted lead acrylic shield: Large transparent shield between patient and staff; reduces scatter by 90%
• Table-mounted side shields: Additional scatter protection at table level

• Reduce fluoroscopy "on" time as much as possible
• Use "last image hold" feature - freezes last fluoroscopy image on screen without live radiation
• Use cine imaging only when essential (much higher dose than fluoroscopy)
• Plan procedure before starting; avoid unnecessary runs

• Pulsed fluoroscopy: Use 7.5 or 15 frames/sec instead of continuous 30 fps - reduces dose by 50-75%
• Collimate beam: Use lead collimators/shutters to restrict beam to area of interest
• Decrease magnification: Higher magnification = higher dose; use only when necessary
• Increase Source-to-Image Distance (SID): Increases distance from tube to patient; reduces skin dose
• Decrease Image Intensifier-to-Patient Distance: Move II as close to patient as possible; reduces dose
• Remove grid when not needed: In paediatric patients; reduces dose by 50%

• All cath lab staff must wear TLD (Thermoluminescent Dosimeter) badge
• Badge worn at collar level outside lead apron (or waist level under apron)
• Dose reports reviewed monthly
• Pregnant staff: Additional fetal dosimeter; dose limit 1 mSv to fetus throughout pregnancy

• Whole body: 20 mSv/year (averaged over 5 years)
• No single year should exceed 30 mSv
• Lens of eye: 20 mSv/year
• Extremities and skin: 500 mSv/year
• Pregnant worker: 1 mSv to fetus during pregnancy

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Special Situations

• Complex PCI / structural interventions: Higher radiation dose - increased attention to protection
• Obese patients: Higher scatter; worse image quality tempts operator to increase dose
• Paediatric patients: Extra protection; gonads shielded

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Conclusion

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2. Sterilization Methods in Cardiac Catheterization Laboratory

Introduction

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Methods of Sterilization

• Temperature: 121°C at 15 psi for 15-20 minutes; or 134°C at 30 psi for 3 minutes
• Mechanism: Moist heat coagulates and denatures microbial proteins
• Used for: Metal instruments, surgical drapes, gowns, gloves, some plastics
• Advantages: Reliable, fast, inexpensive, no toxic residue, kills all organisms including spores
• Disadvantages: Cannot use for heat-sensitive or moisture-sensitive materials; damages some plastics and rubber

• Temperature: 37-60°C; exposure time 2-6 hours; then aeration for 24-48 hours to remove toxic residue
• Mechanism: Alkylation of microbial DNA and proteins
• Used for: Catheters, guidewires, plastic tubing, electronic devices, pacemakers - all heat-labile items
• Advantages: Penetrates packaging; effective at low temperature; sterilizes all heat-sensitive items
• Disadvantages: Ethylene oxide is toxic, carcinogenic; requires long aeration period; special chamber needed; expensive

• Exposure time: 20 minutes for high-level disinfection; 10 hours for sterilization
• Mechanism: Cross-links proteins in microorganisms
• Used for: Endoscopes, reusable equipment that cannot be autoclaved
• Advantages: Effective against bacteria, fungi, viruses, mycobacteria
• Disadvantages: Irritating to skin, eyes, respiratory tract; not a true sterilant at routine immersion times; must be rinsed thoroughly before use

• Temperature: 160°C for 2 hours; or 180°C for 30 minutes
• Mechanism: Oxidation and protein denaturation
• Used for: Metal instruments, glassware, oils, powders
• Advantages: Simple; no moisture damage; good penetration
• Disadvantages: Slow process; cannot use for plastics, rubber, or heat-sensitive items

• Ionizing radiation used in industrial/factory setting
• Used for: Single-use disposable catheters, guidewires, stents - sterilized at manufacturer
• Advantages: Cold process; penetrates packaging; no residue
• Disadvantages: Not available in hospital setting; may degrade some plastics; expensive equipment

• Low temperature (45-50°C); 45-75 minute cycle
• Mechanism: Free radicals destroy microorganisms
• Used for: Delicate instruments, flexible endoscopes, catheters that cannot withstand ETO
• Advantages: Fast; no toxic residue; safe for staff
• Disadvantages: Cannot use with liquids or cellulose-based materials; expensive

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Catheter Cleaning Protocol

1. Flush catheter immediately after use with water
2. Wipe external surface with enzymatic cleaner
3. Inspect for damage (cracks, kinks) - discard if damaged
4. Single-use catheters must NEVER be resterilized - this is illegal and dangerous (protein contamination, structural weakness, prion risk)
5. Reusable catheters sent for sterilization as per protocol

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Hospital Infection Control Measures in Cath Lab

• Strict aseptic technique: Sterile gowns, gloves, drapes
• Skin preparation with chlorhexidine at access site
• Antibiotic prophylaxis for implantable devices (pacemakers, device closures)
• Hand hygiene before and after every patient
• Daily cleaning of cath table and equipment with disinfectant

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Conclusion

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3. Left Ventriculography - Technique, Catheters, Views and Measurements

Introduction

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Indications

1. Assessment of LV ejection fraction (EF)
2. Detection of regional wall motion abnormalities (RWMA) in IHD
3. Grading severity of mitral regurgitation
4. Detection of ventricular septal defect (VSD)
5. Diagnosis of hypertrophic obstructive cardiomyopathy (HOCM) - dynamic obstruction
6. Assessment of LV aneurysm or pseudo-aneurysm
7. Detection of LV thrombus

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Contraindications

1. Severe aortic stenosis (difficulty crossing valve; risk of acute decompensation)
2. Recent myocardial infarction with hemodynamic instability
3. Elevated LVEDP >25 mmHg (adding contrast volume worsens pulmonary edema)
4. Severe LV dysfunction with very low EF
5. Contrast allergy

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Catheters Used

• Has a curl at the end (pigtail shape) to prevent jet injury to endocardium
• Multiple side holes (8-12) for rapid, uniform contrast distribution
• Prevents contact of high-pressure jet with myocardium
• Size: 5F or 6F; inserted retrogradely across aortic valve

• End-hole closed; multiple side holes
• Used when pigtail cannot be advanced across aortic valve

• Balloon-tipped; inflated in LV to prevent jet injury
• Used in children

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Technique

1. Pigtail catheter advanced retrogradely through aortic valve into LV using J-tip guidewire
2. Position confirmed: LV pressure waveform displayed; systolic >100 mmHg, LVEDP recorded
3. Catheter positioned in mid-cavity of LV (not in outflow tract or near mitral valve)
4. Power injector set: Volume 30-40 mL, flow rate 10-15 mL/sec, max pressure 600-900 psi
5. Contrast injected; simultaneous cine recording at 30 frames/sec
6. Patient may feel warm sensation during injection
7. After LVG, pullback from LV to Ao to record aortic valve gradient (if needed)

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Angiographic Views

• Best view for LV function
• Shows: Anterior wall, inferior wall, apex, mitral valve
• Mitral regurgitation: Contrast seen entering left atrium (behind and above LV)
• Wall motion: Anterior (upper border) and inferior (lower border) assessed
• Most commonly used; recorded routinely

• Shows interventricular septum en face
• Septal wall motion and lateral wall motion assessed
• VSD: Contrast seen shunting across to right ventricle
• Used when anterior/inferior RWMA analysis is not sufficient from RAO alone

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LV Function Assessment

• EF = (EDV - ESV) / EDV × 100%
• EDV = End-diastolic volume (largest frame - at QRS)
• ESV = End-systolic volume (smallest frame - at end of T wave)
• Area-length method used on RAO view to calculate volumes
• Normal EF: ≥55%
• Mild dysfunction: 45-54%
• Moderate dysfunction: 30-44%
• Severe dysfunction: <30%

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Mitral Regurgitation Grading (Sellers Classification):

• Grade 1+: Faint contrast entering LA; clears with each beat
• Grade 2+: Mild opacification of LA; clears
• Grade 3+: Dense LA opacification = LV density; does not clear
• Grade 4+: Very dense LA opacification; contrast enters pulmonary veins

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Complications of LVG

1. Ventricular ectopics / VT from catheter stimulation
2. Staining of myocardium if contrast injected in myocardium by mistake
3. Hypotension from contrast volume or LV decompensation
4. Embolism from air or clot
5. Mitral regurgitation worsening from catheter entrapment in chordae

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Conclusion

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3 MARK ANSWERS (Half Page Each)

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1. Artery punctured with hollow needle at 45°
2. Soft-tipped guidewire threaded through needle into vessel
3. Needle removed over wire; wire stays in vessel
4. Dilator followed by sheath passed over wire using rotational movement
5. Wire and dilator removed; sheath remains; catheter introduced through sheath Eliminates surgical cutdown; allows repeated catheter exchanges safely.

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1. Both radial and ulnar arteries at wrist compressed with thumbs
2. Patient makes tight fist until hand blanches (white)
3. Fist opened; radial artery pressure released while ulnar still compressed
4. If hand flushes pink within 5-10 seconds = Positive Allen test = Safe to use radial artery
5. If hand remains pale >10 sec = Negative = Radial artery access contraindicated

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• TIMI 0: No flow; complete occlusion; no contrast beyond obstruction
• TIMI 1: Minimal flow; contrast enters but fails to opacify distal vessel
• TIMI 2: Partial flow; contrast fills entire vessel but more slowly than normal
• TIMI 3: Normal flow; brisk filling and washout of entire coronary artery

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• Risk factors: Pre-existing renal disease, diabetes, dehydration, large contrast volume
• Prevention: IV hydration with normal saline 0.9% before and 6 hours after; use iso-osmolar contrast (Iodixanol); minimize contrast volume; avoid NSAIDs

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1. Contrast syringe
2. Pressure transducer (for waveform monitoring)
3. Saline flush line
4. Waste/aspiration port The operator rotates stopcocks to switch between functions without disconnecting the catheter, preventing air entry and clot formation.

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• Normal: 6-12 mmHg

• 18 mmHg: LV failure; pulmonary venous hypertension; risk of pulmonary edema

• Used to guide fluid therapy in ICU and distinguish cardiac from non-cardiac (ARDS) pulmonary edema

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1. Ablation catheter placed at site of arrhythmia (mapped by EP study)
2. Radiofrequency current (300-500 kHz) delivered through catheter tip
3. Resistive heating raises tissue temperature to 50-60°C
4. Controlled coagulation necrosis destroys the arrhythmia pathway
5. Used for: SVT, WPW syndrome, atrial flutter, atrial fibrillation, ventricular tachycardia

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1. Acts as a port through which multiple catheters can be exchanged without repeated arterial puncture
2. Hemostatic valve prevents blood backflow
3. Side port for flushing and drug/heparin administration
4. Sizes: 4F to 8F (French); length 10-25 cm
5. Removed at end of procedure; hemostasis achieved by manual compression or closure device

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• Normal CO: Smooth curve; rapid temperature fall; gradual return to baseline
• Low CO: Slow fall in temperature; prolonged, large area under curve
• High CO: Rapid fall and rapid return; small area under curve
• Cardiac output is inversely proportional to area under the thermodilution curve

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• Normal: 2.4-4.0 L/min/m²
• CI < 2.2: Heart failure
• CI < 1.8: Cardiogenic shock (Forrester class IV - requires inotropes or IABP)
• Calculated using BSA from DuBois formula: BSA = 0.007184 × Height^0.725 × Weight^0.425

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• 10 mark → 9-10 marks வரும்
• 5 mark → 4-5 marks வரும்
• 3 mark → 3/3 marks வரும்

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உண்மையான நிலைமை இது:

✅ ஒரே topic - மூணு section-லயும் வரலாம்!

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📌 Exam-ல் எப்படி கேட்பாங்க என்று புரிஞ்சுக்கோ:

"Describe Coronary Angiography in detail"

"Write short note on Angiographic views in Coronary Angiography" "Write short note on Complications of Coronary Angiography"

"What is TIMI flow grade?" "Name the catheters used in Coronary Angiography" "What is Allen test?"

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🎯 So நீங்க என்ன பண்ணணும்?

TOPIC: Cardiac Output

3 mark level  → Definition + Formula + Normal value மட்டும் தெரிஞ்சா போதும்
5 mark level  → Thermodilution method OR Fick principle - ஒண்ணு விவரமா
10 mark level → எல்லா methods + Shunt calculation + Clinical significance

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📋 Most Important Topics - எல்லா level-லயும் வரக்கூடியவை:

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💡 Simple Rule:

Top 3 topics (Coronary Angio, Cardiac Output, Pressure Recording) - இதை FULL-ஆ படி → எல்லா section-லயும் வரும்

Baaki topics (Radiation, Sterilization, LVG) - 5 mark + 3 mark level மட்டும் படி

Seldinger, Allen test, TIMI, Manifold - இதை 3 mark level மட்டும் படி

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• 10 mark = 500 words के आसपास
• 5 mark = 300 words के आसपास
• 3 mark = 100 words के आसपास

"The topics you gave for 5 mark and 3 mark answers - are those topics ONLY asked for 5 mark and 3 mark in the actual exam? They won't come as 10 mark questions?"

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Yes! That's correct!

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So your exam preparation is simple:

1. Coronary Angiography
2. Cardiac Output determination
3. Pressure recording in cath lab

1. Radiation Protection
2. Sterilization Methods
3. Left Ventriculography
4. EP Study / RFA
5. PCWP
6. Swan-Ganz catheter
7. Catheters in cath lab
8. Shunt detection

1. Seldinger technique
2. Allen test
3. TIMI grades
4. Manifold
5. Contrast nephropathy
6. Cardiac Index
7. Thermodilution curve
8. Sheath
9. Pullback gradient
10. Fick formula

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3rd Year Paper I Syllabus vs What We Covered

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✅ COVERED Topics:

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❌ MISSING Topics - Need to cover these:

5 Mark level:

1. Preparing cath lab for diagnostic study (lab setup checklist)
2. Lab preparation for coronary angiography
3. Right heart catheterization
4. Equipment used in arrhythmia induction and mapping
5. Ventricular assist device (VAD)
6. Fundamentals of pacemaker

3 Mark level:

1. Principles of oximetry
2. ECM (External Cardiac Massage / CPR basics)
3. Table and image intensifier movements (detailed)

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Shall I write answers for these missing topics now?

Missing Topics - Complete Answers

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5 MARK ANSWERS (2-3 Pages)

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1. Right Heart Catheterization - Technique, Pressures and Indications

Introduction

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Indications

1. Diagnosis and severity assessment of pulmonary arterial hypertension
2. Assessment of heart failure - differentiate cardiac vs. non-cardiac cause
3. Evaluation of valvular heart disease (mitral stenosis, tricuspid disease)
4. Diagnosis of constrictive pericarditis vs. restrictive cardiomyopathy
5. Measurement of cardiac output (thermodilution)
6. Assessment of intracardiac shunts (ASD, VSD, PDA) - oxygen saturation run
7. Guiding therapy in cardiogenic shock and post-cardiac surgery ICU

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Catheter Used - Swan-Ganz Catheter (Balloon-tipped Pulmonary Artery Catheter)

• 7F, 110 cm long; 4 lumens
• Proximal lumen (RA port): At 30 cm from tip; CVP monitoring; thermodilution injectate
• Distal lumen (PA port): At tip; PA pressure + PCWP
• Balloon port: Inflates 1.5 mL air balloon at tip
• Thermistor: 4 cm from tip; measures temperature for thermodilution CO

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Venous Access

• Right internal jugular vein (most common - straight path to RA)
• Subclavian vein
• Femoral vein
• Antecubital vein (less common)

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Technique - Step by Step

1. Venous access obtained using Seldinger technique; 7F sheath inserted
2. Swan-Ganz catheter introduced through sheath
3. Balloon inflated with 1.5 mL air when catheter enters the vein
4. Catheter "floats" with blood flow; position confirmed by pressure waveforms:
   • RA: Low, flat waveform (mean 0-8 mmHg)
   • RV: High systolic, low diastolic (15-30/0-8 mmHg) - "square root sign"
   • PA: High systolic, higher diastolic than RV (15-30/8-15 mmHg) - dicrotic notch appears
   • PCWP: Low, atrial-like waveform (mean 6-12 mmHg) - balloon wedged
5. Balloon deflated after PCWP recording; catheter remains in PA
6. All pressures recorded; blood samples drawn for oxygen saturation run
7. Cardiac output measured by thermodilution

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Pressure Waveforms During Flotation

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Complications

1. Pneumothorax (subclavian/jugular access)
2. Pulmonary artery rupture (over-wedging with balloon inflated too long)
3. Arrhythmias (catheter tip in RV - PVCs, VT)
4. Pulmonary infarction (catheter migrates distally and wedges permanently)
5. Catheter knotting in RV
6. Infection - catheter-related bloodstream infection

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Clinical Applications of RHC Data

• Pulmonary hypertension: mPAP >25 mmHg; PVR calculated
• Mitral stenosis: Elevated PCWP; transmitral gradient
• Cardiac tamponade: Equalization of RA, RV diastolic, PA diastolic, PCWP
• Constrictive pericarditis: Equalization + dip-and-plateau pattern in RV
• Cardiogenic shock: Low CO, high PCWP, high SVR

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Conclusion

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2. Fundamentals of Pacemaker

Introduction

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Indications for Pacing

1. Complete heart block (3rd degree AV block)
2. Symptomatic sinus bradycardia not responding to medication
3. Sick sinus syndrome
4. 2nd degree AV block (Mobitz type II)
5. Bifascicular and trifascicular block with symptoms
6. Neurocardiogenic syncope (vasovagal)
7. Hypertrophic obstructive cardiomyopathy (HOCM) - dual chamber pacing

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Types of Pacemakers

• Used in emergencies (acute heart block, post-cardiac surgery)
• Transvenous: Lead placed via femoral/subclavian vein into RV
• External (transcutaneous): Pacing pads on chest wall; painful; emergency only
• Generator external; connected to bedside pacemaker box

• Implanted subcutaneously below left or right clavicle
• Generator (battery) placed in subcutaneous pocket
• Lead(s) tunneled through subclavian/cephalic vein to heart

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Types of Permanent Pacemakers

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Pacemaker Code (NBG Code - 5 letters)

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Pacemaker Parameters

• Rate: Usually set 60 ppm (beats per minute) as lower rate limit
• Output (mA): Energy delivered; usually 2-3x threshold
• Sensitivity (mV): How well pacemaker detects native beats
• AV delay (in DDD): Time between atrial and ventricular pacing (usually 150-200 ms)

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Setting Up Lab for Permanent Pacing

1. Sterile operative field; lead apron for radiation protection
2. Fluoroscopy C-arm positioned for AP and LAO views
3. Pacing system analyser (PSA) connected to measure thresholds
4. Temporary pacing backup ready
5. Defibrillator on standby
6. Instruments: Pacemaker generator, leads (active/passive fixation), introducer set, pocket tools

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Pacemaker Follow-up

• Check at 1 month, 3 months, then every 6 months
• Parameters checked: Sensing, pacing threshold, impedance, battery status
• Battery life: 7-12 years depending on usage

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Conclusion

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3. Ventricular Assist Device (VAD)

Introduction

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Indications

1. Cardiogenic shock after myocardial infarction
2. Bridge to transplant (BTT) - keeping patient alive until heart transplant
3. Bridge to recovery (BTR) - myocarditis, post-cardiotomy shock
4. Destination therapy (DT) - permanent use in patients not eligible for transplant
5. Bridge to decision - while assessing transplant eligibility

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Types of VAD

• Draws blood from LV apex → pumps to ascending aorta
• Bypasses the failing left ventricle
• Used in left heart failure

• Draws blood from RA → pumps to pulmonary artery
• Used in right heart failure

• Both LVAD + RVAD together
• Used in total cardiac failure

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Types by Mechanism

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IABP (Intra-Aortic Balloon Pump) - Simplest VAD

• Balloon catheter inserted via femoral artery; tip in descending aorta
• Counterpulsation principle:
  • Balloon inflates during diastole → increases coronary perfusion pressure
  • Balloon deflates just before systole → reduces afterload; LV ejects more easily
• Timing: Triggered by ECG (R wave) or arterial pressure waveform
• Indications: Cardiogenic shock, pre-PTCA in high-risk patients, post-cardiac surgery low output
• Contraindications: Aortic regurgitation, aortic dissection, severe peripheral vascular disease

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Complications of VAD

1. Bleeding (anticoagulation needed)
2. Stroke (thromboembolism)
3. Device infection
4. Device malfunction/pump failure
5. Right heart failure (after LVAD - increased preload to RV)
6. Hemolysis (red cell destruction by pump)

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Conclusion

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4. Preparing the Cath Lab for a Diagnostic Study / Lab Setup

Introduction

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Pre-procedure Lab Checklist

• X-ray system (fluoroscopy + cine): Tested and functioning
• Image intensifier (II) / flat panel detector: Calibrated
• Table: Functional movements (longitudinal, lateral, height, tilt)
• Hemodynamic monitoring system: Transducers connected, zeroed, calibrated
• Power injector: Loaded with contrast, pressure tested
• Defibrillator: Charged, pads connected, tested
• Emergency cart (crash cart): Fully stocked - drugs, airway equipment

• Sterile drapes placed on procedure table
• Sterile gown and gloves for operator
• Sterile field prepared with:
  • Catheter tray (catheters, guidewires, sheaths)
  • Manifold assembled and de-aired
  • Contrast syringes filled
  • Heparinized saline flush bowls
  • Needles, scalpel, sutures

• Non-ionic contrast (Iohexol/Omnipaque) drawn into labeled syringes
• Contrast warmed to body temperature (reduces viscosity and patient discomfort)
• Contrast volume documented

• Transducers connected to monitoring system
• Zero reference set at phlebostatic axis (mid-chest level)
• Calibration verified against known pressure
• All channels labeled (RA, RV, PA, Ao, LV)

• Lead aprons worn by all staff
• Thyroid collars and lead glasses available
• Ceiling-mounted shield positioned
• Dosimeters worn by all personnel
• Image intensifier positioned correctly

• Patient transferred to cath table; identity verified
• ECG leads connected; continuous monitoring started
• Blood pressure cuff on arm; pulse oximeter attached
• Groin or wrist prepped and draped
• IV line patency checked
• Sedation given if prescribed

• Patient details entered into cath lab computer (DICOM system)
• Study type selected (diagnostic / PTCA / EP study)
• Radiation dose tracking started

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Post-procedure Lab Cleanup

1. Used catheters and sharps disposed in sharps container
2. Table cleaned with disinfectant
3. Reusable equipment sent for sterilization
4. Contrast syringes and tubing discarded
5. Radiation dose recorded in log
6. Images archived to PACS (Picture Archiving System)

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Conclusion

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5. Equipment Used in Arrhythmia Induction and Mapping (EP Study)

Introduction

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Equipment List

• Records electrical signals (electrograms) from multiple intracardiac catheters simultaneously
• Displays local electrograms alongside surface ECG leads
• Measures conduction intervals (PA, AH, HV intervals)
• Examples: GE CardioLab, Bard LabSystem Pro, Prucka CardioLab

• Delivers precisely timed electrical stimuli to heart through EP catheters
• Used for:
  • Programmed Electrical Stimulation (PES): S1-S2-S3 extra stimuli to induce tachycardia
  • Burst pacing: Rapid pacing to initiate atrial flutter/AF/VT
  • Overdrive suppression: Pacing faster than tachycardia to terminate it
• Parameters set: Cycle length, number of stimuli, output (mA), coupling intervals

• Delivers RF current (300-500 kHz) to ablation catheter tip
• Heats tissue to 50-60°C for controlled ablation
• Monitors tip temperature, impedance, and power in real-time
• Safety cutoff if temperature exceeds limit or impedance rises suddenly (steam pop)
• Examples: Biosense Webster Stockert generator, Medtronic RF generator

• Creates a 3-dimensional map of the heart chamber
• Catheter tip position tracked by magnetic or electrical field
• Two types:
  • CARTO (Biosense Webster): Magnetic field-based mapping
  • EnSite NavX / Precision (Abbott): Electrical field-based mapping
• Color-coded map shows:
  • Voltage map (scar vs. normal tissue)
  • Activation map (timing of electrical activation)
  • Propagation map (direction of wavefront)

• Ultrasound catheter placed inside heart (usually RA)
• Real-time visualization of cardiac structures during EP procedure
• Used for transseptal puncture guidance, catheter positioning, monitoring for complications

• Confirms catheter positions in AP, LAO, RAO views
• Used alongside mapping systems

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Conclusion

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3 MARK ANSWERS (Half Page)

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1. Principles of Oximetry

• Oxygenated hemoglobin (HbO₂) and deoxygenated hemoglobin (Hb) absorb light at different wavelengths
• HbO₂ absorbs more infrared light (940 nm)
• Hb (deoxygenated) absorbs more red light (660 nm)
• Ratio of red to infrared absorption calculated → gives SpO₂ %

1. Pulse oximeter: Non-invasive; probe on finger/ear; measures SpO₂ continuously
2. Co-oximeter (lab): Measures actual SaO₂ from arterial blood sample

• Oxygen saturation measured from blood samples at different cardiac chambers
• Step-up in saturation identifies level of intracardiac shunt (ASD/VSD/PDA)
• Normal saturations: SVC 70%, RA 75%, RV 75%, PA 75%, Aorta 98%

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2. ECM - External Cardiac Massage (CPR Basics)

1. Patient flat on hard surface; call for help
2. Heel of hand placed on lower half of sternum
3. Compress chest 5-6 cm depth at rate of 100-120 per minute
4. Allow full chest recoil between compressions
5. Ratio: 30 compressions : 2 rescue breaths (30:2)

• Cardiac arrest can occur due to arrhythmia, contrast reaction, or perforation
• Cath table lowered flat immediately
• CPR started; defibrillator charged
• ACLS protocol followed
• Adrenaline 1 mg IV every 3-5 minutes

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3. Table and Image Intensifier Movements

1. Longitudinal (cranial-caudal): Moves patient head-to-foot; used to position area of interest under X-ray beam
2. Lateral (left-right): Side-to-side movement for centering
3. Height: Raises/lowers table to optimize geometry
4. Tilt: Trendelenburg (head down) in hypotension; reverse Trendelenburg (head up) if needed

1. RAO (Right Anterior Oblique): C-arm rotates to patient's right side
2. LAO (Left Anterior Oblique): C-arm rotates to patient's left side
3. Cranial: II tilts toward patient's head; opens up inferior structures
4. Caudal: II tilts toward patient's feet; opens up superior structures
5. AP (Anterior-Posterior): Straight frontal view; zero angulation

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COMPLETE TOPIC COVERAGE SUMMARY

✅ NOW ALL TOPICS COVERED:

10 Mark (Essays - 3 questions):

1. ✅ Coronary Angiography
2. ✅ Cardiac Output (Thermodilution + Fick)
3. ✅ Pressure Recording + Waveforms + Gradients

5 Mark (Short Notes - 8 questions):

1. ✅ Radiation Protection
2. ✅ Sterilization Methods
3. ✅ Left Ventriculography
4. ✅ Right Heart Catheterization
5. ✅ Fundamentals of Pacemaker
6. ✅ Ventricular Assist Device / IABP
7. ✅ Cath Lab Setup / Lab Preparation
8. ✅ EP Study Equipment + RFA

3 Mark (Short Answers - 10 questions):

1. ✅ Seldinger Technique
2. ✅ Allen Test
3. ✅ TIMI Grades
4. ✅ Manifold
5. ✅ Contrast Nephropathy
6. ✅ Cardiac Index
7. ✅ Thermodilution Curve
8. ✅ Principles of Oximetry
9. ✅ ECM / CPR
10. ✅ Table and II Movements

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