Complete ECG Topics - Everything You Need to Know

1. Foundations and Basic Science

1. History of electrocardiography
2. Basic electrophysiology of cardiac cells
3. Resting membrane potential
4. Action potential - phases 0 to 4
5. Depolarization and repolarization
6. Automaticity and pacemaker cells
7. Ion channels - sodium, potassium, calcium currents
8. The Frank-Starling mechanism and its ECG relevance
9. Concept of a dipole and electrical vectors

2. Cardiac Anatomy Relevant to ECG

1. Structure of the heart - atria, ventricles, valves
2. The conduction system:
   • Sinoatrial (SA) node
   • Atrioventricular (AV) node
   • Bundle of His
   • Right and left bundle branches
   • Left anterior and posterior fascicles
   • Purkinje fibers
3. Normal conduction sequence

3. ECG Equipment and Technique

1. The ECG machine - how it works
2. ECG paper - grid, speed (25 mm/sec), calibration (1 mV = 10 mm)
3. Standard electrode placement - limb and precordial electrodes
4. Lead systems:
   • Standard limb leads (I, II, III)
   • Augmented leads (aVR, aVL, aVF)
   • Precordial/chest leads (V1-V6)
   • Right-sided leads (V3R, V4R)
   • Posterior leads (V7, V8, V9)
5. 12-lead ECG recording
6. Artifacts and technical errors (loose leads, muscle tremor, AC interference, baseline wander)

4. The Normal ECG Waveforms

1. The P wave - atrial depolarization, normal morphology
2. The PR interval - AV conduction time
3. The QRS complex - ventricular depolarization, normal duration and morphology
4. Q waves - normal vs. pathological
5. R wave progression across precordial leads
6. The ST segment - isoelectric baseline
7. The T wave - ventricular repolarization, normal orientation
8. The U wave - significance and origin
9. The QT interval - total ventricular repolarization
10. QTc (corrected QT) - Bazett's and Fridericia's formulas

5. Normal Intervals and Measurements

1. Normal P wave duration and amplitude
2. Normal PR interval (120-200 ms)
3. Normal QRS duration (<120 ms)
4. Normal QT and QTc values
5. Normal R wave amplitude in limb and chest leads

6. Electrical Axis

1. Concept of mean electrical axis
2. Hexaxial reference system
3. Normal axis (0° to +90°)
4. Left axis deviation (LAD) - causes
5. Right axis deviation (RAD) - causes
6. Extreme (northwest) axis deviation
7. Calculating axis from leads I and aVF
8. Calculating axis from any two leads

7. Systematic Approach to ECG Interpretation

1. Rate - calculating heart rate (large box method, 1500 method)
2. Rhythm - regular vs. irregular
3. P wave morphology and relationship to QRS
4. PR interval assessment
5. QRS duration and morphology
6. ST segment - elevation, depression, morphology
7. T wave changes
8. QT interval assessment
9. Overall interpretation / clinical correlation

8. Atrial Abnormalities

1. Left atrial enlargement (P mitrale) - broad, notched P in II, biphasic P in V1
2. Right atrial enlargement (P pulmonale) - tall, peaked P in II
3. Biatrial enlargement

9. Ventricular Hypertrophy

1. Left ventricular hypertrophy (LVH):
   • Sokolow-Lyon criteria
   • Cornell voltage criteria
   • Romhilt-Estes scoring system
   • Strain pattern (ST depression + T wave inversion)
2. Right ventricular hypertrophy (RVH):
   • Right axis deviation
   • Dominant R in V1
   • Strain pattern
3. Biventricular hypertrophy

10. Bundle Branch Blocks

1. Right bundle branch block (RBBB) - complete and incomplete (RSR' in V1, wide S in I/V6)
2. Left bundle branch block (LBBB) - complete and incomplete
3. Clinical significance and causes of each
4. LBBB and diagnosing ischemia/infarction
5. Left anterior fascicular block (LAFB) - left axis deviation, small Q in I/aVL
6. Left posterior fascicular block (LPFB) - right axis deviation
7. Bifascicular block (RBBB + LAFB or RBBB + LPFB)
8. Trifascicular block
9. Nonspecific intraventricular conduction delay (IVCD)

11. Pre-excitation Syndromes

1. Wolff-Parkinson-White (WPW) syndrome - delta wave, short PR, widened QRS
2. Types of accessory pathways (manifest vs. concealed)
3. WPW and SVT risk
4. Lown-Ganong-Levine syndrome
5. Clinical management and ECG recognition

12. AV Conduction Abnormalities (Heart Blocks)

1. First-degree AV block - prolonged PR >200 ms
2. Second-degree AV block:
   • Mobitz type I (Wenckebach) - progressive PR lengthening then dropped beat
   • Mobitz type II - sudden dropped beat without PR change
3. 2:1 AV block - distinguishing Mobitz I vs. II
4. High-degree (advanced) AV block
5. Third-degree (complete) AV block - AV dissociation
6. AV dissociation (non-complete block)
7. Junctional vs. ventricular escape rhythms in complete block

13. SA Node and Sinus Rhythms

1. Normal sinus rhythm
2. Sinus bradycardia
3. Sinus tachycardia
4. Sinus arrhythmia (respiratory)
5. Sinus pause and sinus arrest
6. Sinoatrial exit block (1st, 2nd, 3rd degree)
7. Sick sinus syndrome (SSS) / Tachy-Brady syndrome

14. Supraventricular Arrhythmias

1. Premature atrial contractions (PACs) - morphology, blocked PACs
2. Atrial tachycardia (focal and multifocal)
3. AV nodal re-entrant tachycardia (AVNRT) - typical and atypical
4. AV re-entrant tachycardia (AVRT) - orthodromic and antidromic
5. Atrial flutter - sawtooth waves, 2:1 / 4:1 block patterns, typical vs. atypical
6. Atrial fibrillation - irregularly irregular, absent P waves, rate classification
7. Junctional rhythms - junctional escape, accelerated junctional, junctional tachycardia
8. Multifocal atrial tachycardia (MAT)
9. Narrow complex tachycardia - differential diagnosis approach

15. Ventricular Arrhythmias

1. Premature ventricular contractions (PVCs) - morphology, unifocal vs. multifocal
2. Bigeminy, trigeminy, quadrigeminy
3. Ventricular couplets and runs
4. Accelerated idioventricular rhythm (AIVR)
5. Ventricular tachycardia (VT):
   • Monomorphic VT
   • Polymorphic VT
   • Torsades de pointes (TdP)
6. Ventricular flutter
7. Ventricular fibrillation (VF)
8. Wide complex tachycardia - differential diagnosis (VT vs. SVT with aberrancy)
9. Brugada criteria for VT vs. SVT
10. Atrioventricular dissociation as a criterion for VT

16. Ischemia and Infarction

1. Pathophysiology of ECG changes in ischemia vs. injury vs. infarction
2. Zones of infarction, injury, and ischemia
3. Hyperacute T waves - earliest sign
4. ST segment elevation (STEMI): - Convex (tombstone) morphology - Localization by leads
5. ST segment depression - subendocardial ischemia, NSTEMI
6. T wave inversion - patterns and causes
7. Q wave formation - pathological Q wave criteria
8. R wave loss / poor R wave progression
9. Localization of infarction by territory: - Anterior (V1-V4) - LAD territory - Inferior (II, III, aVF) - RCA territory - Lateral (I, aVL, V5-V6) - LCx territory - Posterior (tall R in V1-V2, V7-V9) - Right ventricular infarction (V3R, V4R elevation)
10. Wellens' syndrome (LAD critical stenosis patterns)
11. De Winter T waves
12. Sgarbossa criteria - STEMI diagnosis in LBBB
13. Reciprocal changes and their significance
14. Pseudo-infarction patterns (LVH, LBBB, WPW, Brugada, HCM, ARVC)
15. Left main coronary artery occlusion - ST elevation in aVR

17. Repolarization Abnormalities and ST-T Changes

1. Early repolarization - J-point elevation, slurred J wave
2. Brugada syndrome - Type 1, 2, 3 patterns (coved vs. saddle-back)
3. Long QT syndrome (LQTS) - congenital (LQT1, LQT2, LQT3) and acquired
4. Short QT syndrome
5. J wave syndromes (Brugada, early repolarization, hypothermia)
6. Osborn (J) waves in hypothermia
7. Digitalis effect ("Salvador Dali" ST, scooped ST) vs. digitalis toxicity
8. Drug-induced QT prolongation

18. Electrolyte and Metabolic Effects

1. Hyperkalemia - peaked T waves, widened QRS, sine wave, asystole
2. Hypokalemia - flat T waves, prominent U waves, QU prolongation
3. Hypercalcemia - shortened QT
4. Hypocalcemia - prolonged QT (specifically QTc)
5. Hypermagnesemia and hypomagnesemia
6. Acidosis and alkalosis effects
7. Hypothyroidism (low voltage, bradycardia, flat T waves)
8. Hyperthyroidism (sinus tachycardia, atrial fibrillation)

19. ECG in Specific Cardiac Conditions

1. Hypertrophic cardiomyopathy (HCM) - LVH, deep Q waves in lateral leads
2. Dilated cardiomyopathy - LBBB, non-specific ST-T changes
3. Arrhythmogenic right ventricular cardiomyopathy (ARVC) - epsilon wave, T inversion V1-V4
4. Acute pericarditis - diffuse saddle-shaped ST elevation, PR depression
5. Pericardial effusion / cardiac tamponade - low voltage, electrical alternans
6. Myocarditis - non-specific ST-T changes, conduction abnormalities
7. Pulmonary embolism (PE) - S1Q3T3, sinus tachycardia, RBBB, right axis deviation
8. Chronic obstructive pulmonary disease (COPD) - P pulmonale, right axis, low voltage, S1S2S3
9. Acute cor pulmonale

20. Special Populations and Situations

1. Pediatric ECG - normal values by age, differences from adults
2. Neonatal ECG - right ventricular dominance
3. Athlete's heart ECG - physiological changes (sinus bradycardia, LVH, early repolarization)
4. ECG in pregnancy
5. ECG in the elderly
6. ECG changes in COVID-19

21. Pacemaker ECGs

1. Pacing spikes - atrial, ventricular, dual chamber
2. Single-chamber pacemaker (AAI, VVI)
3. Dual-chamber pacemaker (DDD) - modes and programming
4. Biventricular pacemaker / CRT (cardiac resynchronization therapy)
5. Pacemaker-mediated tachycardia
6. Failure to pace, failure to capture, failure to sense
7. Fusion and pseudofusion beats
8. Diagnosing ischemia in paced rhythm (Sgarbossa modified criteria)
9. Implantable cardioverter-defibrillator (ICD) - rhythm detection on ECG

22. Exercise ECG (Stress Testing)

1. Principles of exercise stress testing
2. Normal ECG response to exercise
3. Positive criteria - horizontal/downsloping ST depression ≥1 mm
4. Upsloping ST changes
5. Duke treadmill score
6. False positives and negatives
7. Post-exercise ECG analysis
8. ST elevation during exercise

23. Ambulatory and Long-term ECG

1. Holter monitoring (24-72 hour)
2. Event monitors and loop recorders
3. Implantable loop recorders (ILR)
4. Patch monitors
5. Indications (syncope, palpitations, cryptogenic stroke, AF detection)
6. Remote ECG telemetry
7. Wearable ECG devices (smartwatch ECG, single-lead monitoring)

24. Signal-Averaged ECG and Advanced ECG

1. Signal-averaged ECG (SAECG) - late potentials, VT risk
2. QT dispersion
3. T-wave alternans
4. Heart rate variability (HRV)
5. High-frequency ECG analysis
6. Vectorcardiography (VCG)
7. Computerized ECG interpretation - capabilities and pitfalls

25. Clinical Approach and Differential Diagnosis Frameworks

1. Approach to narrow complex tachycardia
2. Approach to wide complex tachycardia
3. Approach to bradycardia
4. Approach to irregular rhythms
5. Approach to syncope and ECG
6. Approach to sudden cardiac death - ECG screening
7. Approach to chest pain and ECG
8. ECG in acute coronary syndromes (STEMI vs. NSTEMI vs. UA)
9. Conditions that mimic STEMI (STEMI mimics) - early repolarization, pericarditis, LVH, LBBB, Brugada, de Winter, Takotsubo
10. ECG in cardiac arrest - shockable vs. non-shockable rhythms (VF, VT vs. PEA, asystole)

26. ECG Eponyms and Named Patterns

1. Wenckebach phenomenon
2. Brugada sign/pattern
3. Wellens' sign
4. De Winter T waves
5. Osborn (J) wave
6. Epsilon wave (ARVC)
7. Delta wave (WPW)
8. Lambrinudi sign / Sgarbossa criteria
9. Dressler beat (fusion beat)
10. Marriott criteria
11. Bifid P wave (P mitrale)
12. Terminal force in V1