Key Points: AV block refers specifically to delayed or failed conduction of impulses from the atria to the ventricles. AV block is classified by the ECG pattern of conduction: First-degree…
A 68-year-old man has syncope, then has a second syncopal episode while lying still on a stretcher during evaluation at an outpatient clinic. He is sent emergently to the ED….
Key Points: LVH reflects increased left ventricular muscle mass, usually from chronic pressure overload. Common causes include longstanding hypertension and aortic stenosis. ECG diagnosis is imperfect. Voltage criteria are specific…
A 49-year-old man arrives with palpitations and chest discomfort. The monitor shows an irregular, wide-complex tachycardia with varying morphology and rates nearing 250 to 300 bpm. The team debates polymorphic…
A 53-year-old man presents with palpitations and lightheadedness. The following ECG is obtained on arrival and appears very rapid and irregular with changing QRS morphologies. He starts showing signs of…
A young man with recurrent palpitations presents to the emergency department hemodynamically stable during an episode. The arrival ECG shows a wide complex, regular tachycardia and the computer interpretation calls…
Key Points: Appropriate discordance refers to the expected secondary ST segment and T wave pattern seen with abnormal ventricular depolarization, especially LBBB and ventricular-paced rhythm. The ST segment and T…
Key Points: Antidromic AVRT is an AV re-entrant tachycardia that conducts antegrade down the accessory pathway and returns retrograde through the AV node (or another pathway), producing a regular wide-complex…
Key Points: BiVT is a regular wide-complex tachycardia with strict beat-to-beat alternation of QRS axis and/or bundle-branch pattern (often an approximately 180° frontal-plane axis flip). In adults, assume digoxin toxicity…
A 43-year-old woman with sharp left-sided chest pain and minimal cardiac risk factors has an initial ECG that is not diagnostic for STEMI. She looks stable, but one feature on…
Key Points: VT is a ventricular-origin rhythm: ≥3 consecutive ventricular beats, QRS >120 ms, rate usually 120–250 bpm. Types include monomorphic VT, polymorphic VT, torsades (PMVT with long QT), ventricular…
Key Points: Defibrillation First, Minimal Pauses: pVT is rapidly fatal without immediate shocks and high‑quality CPR. Charge defibrillator during compressions and resume compressions immediately after each shock. pVT is a…
Key Points: Defibrillation First, Minimal Pauses: VF is rapidly fatal without immediate shocks and high‑quality CPR. Charge during compressions and resume compressions immediately after each shock. Chaotic Electrical Activity: VF…
Key Points: Definition: A malignant ventricular tachyarrhythmia with a regular, sine-wave–like waveform at ~250–350 bpm, no isoelectric baseline, and no discernible P/QRS/T distinction. Clinical importance: Rapidly degenerates into ventricular fibrillation…
Key Points: Intervene Immediately: Unstable tachyarrhythmias pose significant risk for rapid clinical deterioration that may lead to irreversible end-organ damage or cardiac arrest. Clinical Indicators of Instability: Altered Mental Status:…
Key Points: Premature complexes are early depolarizations arising from the atrium, AV junction, or ventricle which interrupt the expected sinus rhythm. Rapid classification by origin: look for a P wave…
Key Points An Osborn wave is a notch or slur at the J point that becomes more prominent as core temperature falls. Most visible in inferolateral and precordial leads; can…
Key Points PVCs are early ventricular depolarizations that produce a wide QRS with secondary ST-T changes and are usually followed by a full compensatory pause. No preceding P wave. A…
Key Points: Definition: AIVR is a transient, usually benign ventricular rhythm often seen after reperfusion of an acute myocardial infarction (AMI), whether spontaneous or post-intervention (PCI or thrombolysis). Rate Differentiation:…
Key Points: Definition: Wide complex tachycardia (WCT) = QRS >120 ms with a steady R-R interval. This section focuses on regular WCT (RWCT). Wide & irregular rhythms are covered separately…