Clinical ECG Interpretation
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Introduction to ECG Interpretation6 Chapters
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Cardiac electrophysiology and ECG interpretation
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Cardiac electrophysiology: Action potential, automaticity and vectors
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The ECG leads: Electrodes, limb leads, chest (precordial) leads and the 12-Lead ECG
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The Cabrera format of the 12-lead ECG and inverted lead aVR
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ECG interpretation: Characteristics of the normal ECG (P-wave, QRS complex, ST segment, T-wave)
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How to interpret the ECG: A systematic approach
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Cardiac electrophysiology and ECG interpretation
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Arrhythmias and arrhythmology24 Chapters
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Mechanisms of cardiac arrhythmias: from automaticity to re-entry (reentry)
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Aberrant ventricular conduction (aberrancy, aberration)
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Premature ventricular contractions (premature ventricular complex, premature ventricular beats)
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Premature atrial contraction (premature atrial beat / complex): ECG and clinical implications
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Sinus rhythm: physiology, ECG criteria & clinical implications
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Sinus arrhythmia (respiratory sinus arrhythmia)
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Sinus bradycardia: definitions, ECG, causes and management
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Chronotropic incompetence (inability to increase heart rate)
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Sinoatrial arrest & sinoatrial pause (sinus pause / arrest)
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Sinoatrial block (SA block): ECG criteria, causes and clinical features
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Sinus node dysfunction (SND) and sick sinus syndrome (SSS)
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Sinus tachycardia & Inappropriate sinus tachycardia
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Atrial fibrillation: ECG, classification, causes, risk factors & management
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Atrial flutter: classification, causes, ECG criteria and management
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Ectopic atrial rhythm (EAT), atrial tachycardia (AT) & multifocal atrial tachycardia (MAT)
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Atrioventricular nodal reentry tachycardia (AVNRT): ECG features & management
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Pre-excitation, Atrioventricular Reentrant (Reentry) Tachycardia (AVRT), Wolff-Parkinson-White (WPW) syndrome
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Junctional rhythm (escape rhythm) and junctional tachycardia
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Ventricular rhythm and accelerated ventricular rhythm (idioventricular rhythm)
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Ventricular tachycardia (VT): ECG criteria, causes, classification, treatment
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Long QT (QTc) interval, long QT syndrome (LQTS) & torsades de pointes
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Ventricular fibrillation, pulseless electrical activity and sudden cardiac arrest
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Pacemaker-mediated tachycardia (PMT): ECG and management
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Diagnosis and management of supraventricular and ventricular tachyarrhythmias: Narrow complex tachycardia & wide complex tachycardia
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Mechanisms of cardiac arrhythmias: from automaticity to re-entry (reentry)
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Myocardial Ischemia & Infarction22 Chapters
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Introduction to Coronary Artery Disease (Ischemic Heart Disease)
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Classification of Acute Coronary Syndromes (ACS) & Acute Myocardial Infarction (AMI)
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Clinical application of ECG in chest pain & acute myocardial infarction
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Diagnostic Criteria for Acute Myocardial Infarction: Cardiac troponins, ECG & Symptoms
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Cardiac troponin I (TnI) and T (TnT): Interpretation and evaluation in acute coronary syndromes
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Myocardial Ischemia & infarction: Cellular changes, ECG and symptoms
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The left ventricle in myocardial ischemia and infarction
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Factors that modify the natural course in acute myocardial infarction (AMI)
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ECG in myocardial ischemia: ischemic changes in the ST segment & T-wave
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ST segment depression in myocardial ischemia and differential diagnoses
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ST segment elevation in acute myocardial ischemia and differential diagnoses
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ST elevation myocardial infarction (STEMI) without ST elevations on 12-lead ECG
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T-waves in ischemia: hyperacute, inverted (negative), Wellen's sign & de Winter's sign
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ECG signs of myocardial infarction: pathological Q-waves & pathological R-waves
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Other ECG changes in ischemia and infarction
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Supraventricular and intraventricular conduction defects in myocardial ischemia and infarction
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ECG localization of myocardial infarction / ischemia and coronary artery occlusion (culprit)
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The ECG in assessment of myocardial reperfusion
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Approach to patients with chest pain: differential diagnoses, management & ECG
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Stable Coronary Artery Disease (Angina Pectoris): Diagnosis, Evaluation, Management
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NSTEMI (Non-ST Elevation Myocardial Infarction) & Unstable Angina: Diagnosis, Criteria, ECG, Management
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STEMI (ST Elevation Myocardial Infarction): Diagnosis, ECG, Criteria, and Management
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Introduction to Coronary Artery Disease (Ischemic Heart Disease)
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Conduction Defects11 Chapters
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Overview of atrioventricular (AV) blocks
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First-degree AV block (AV block I, AV block 1)
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Second-degree AV block: Mobitz type 1 (Wenckebach) & Mobitz type 2 block
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Third-degree AV block (3rd degree AV block, AV block 3, AV block III)
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Management and treatment of AV block (atrioventricular blocks)
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Intraventricular conduction delay: bundle branch blocks & fascicular blocks
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Right bundle branch block (RBBB): ECG, criteria, definitions, causes & treatment
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Left bundle branch block (LBBB): ECG criteria, causes, management
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Left bundle branch block (LBBB) in acute myocardial infarction: the Sgarbossa criteria
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Fascicular block (hemiblock): Left anterior & left posterior fascicular block
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Nonspecific intraventricular conduction delay (defect)
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Overview of atrioventricular (AV) blocks
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Cardiac Hypertrophy & Enlargement5 Chapters
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Atrial and ventricular enlargement: hypertrophy and dilatation on ECG
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ECG in left ventricular hypertrophy (LVH): criteria and implications
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Right ventricular hypertrophy (RVH): ECG criteria & clinical characteristics
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Biventricular hypertrophy ECG and clinical characteristics
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Left atrial enlargement (P mitrale) & right atrial enlargement (P pulmonale) on ECG
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Atrial and ventricular enlargement: hypertrophy and dilatation on ECG
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Drugs & Electrolyte Imbalance3 Chapters
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Genetics, Syndromes & Miscellaneous7 Chapters
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ECG J wave syndromes: hypothermia, early repolarization, hypercalcemia & Brugada syndrome
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Brugada syndrome: ECG, clinical features and management
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Early repolarization pattern on ECG (early repolarization syndrome)
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Takotsubo cardiomyopathy (broken heart syndrome, stress induced cardiomyopathy)
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Pericarditis, myocarditis & perimyocarditis: ECG, criteria & treatment
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Eletrical alternans: the ECG in pericardial effusion & cardiac tamponade
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Long QT Syndrome (LQTS)
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ECG J wave syndromes: hypothermia, early repolarization, hypercalcemia & Brugada syndrome
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Exercise Stress Testing (Exercise ECG)6 Chapters
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Introduction to exercise stress testing (treadmill test, exercise ECG)
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Indications, Contraindications, and Preparations for Exercise Stress Testing
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Exercise stress test (exercise ECG): protocols, evaluation & termination
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Exercise stress testing in special patient populations
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Exercise physiology: from normal response to myocardial ischemia & chest pain
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Evaluation of exercise stress test: ECG, symptoms, blood pressure, heart rate, performance
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Introduction to exercise stress testing (treadmill test, exercise ECG)
Other ECG changes in ischemia and infarction
Pathological R-wave progression
Normal R-wave progression implies that the R-wave amplitude increases gradually from V1 to V5 and then diminishes again in V6. Refer to Figure 1. Abnormal R-wave progression implies that the gradual increase from V1 to V5 is absent. It may be broken, as in Figure 1. Any type of infarction may cause pathological R-wave progression. However, the specificity for pathological R-wave progression is considerably lower than pathological Q-waves and guidelines do not state any ECG criteria specific to R-wave progression.

U-wave changes
New U-waves (in absence of bradycardia) may indicate ischemia. If U-waves were present on previous recording, the amplitude must be increased in order to suggest ischemia. Inverted U-waves are even more typical of ischemia (but the sensitivity is low). U-wave changes always accompany other ischemic ST-T changes. They may occur in both NSTEMI and STEMI.
QTc prolongation
The QT (QTc) interval may be prolonged, shortened or unchanged in ischemia.
R-wave amplitude
Acute transmural ischemia may transiently increase the amplitude of the R-waves. This is believed to be due to delayed (and thus electrically unopposed) depolarization in the ischemic area.
Fragmented QRS complex
The definition of fragmented QRS complexes (Figure 2) are as follows:
- QRS complex with more than 1 R wave and/or
- notch in the descending limb of the R-wave and/or
- notch in the descending limb of the S-wave
In case of complete/incomplete bundle branch block or pacemaker rhythm, >2 notches are required in the S-wave or R-wave.
Fragmented QRS complexes are indications of previous myocardial infarction. There are imaging studies demonstrating that QRS fragmentation is more common than the development of pathological Q-waves after infarction. The sensitivity of fragmented QRS for myocardial infarction was 86%, as compared with 36% for pathological Q-waves. However, the specificity was lower for fragmented QRS (89% vs 99%). The absence of fragmented QRS has a high negative predictive value (93%) for myocardial infarction. Moreover, fragmented QRS is associated with an increased risk of sudden cardiac death and ventricular arrhythmias.
