A 23-year-old woman presents with palpitations and lightheadedness after a spontaneous episode of regular wide complex tachycardia. Her post-conversion ECG shows anterior T wave inversions with a subtle abnormality hiding…
A 63-year-old man presents with shortness of breath. His ECG shows an unusual rhythm with repetitive groups of two beats separated by pauses.
Key Points: Definition: Slow VT refers to ventricular tachycardia occurring at an unusually low ventricular rate, often near or even below the conventional tachycardia threshold. There is no universally accepted…
Key Points: Default assumption: A regular wide-complex tachycardia should be considered VT until another diagnosis is more likely. Rate modifies the differential, not the diagnosis. Typical monomorphic VT is often…
A 34 year old man presents with acute chest pain radiating to the left arm associated with diaphoresis. He has hyperlipidemia and a family history of early coronary disease. The…
Key Points: LBBB does not exclude acute coronary occlusion. LBBBs produce abnormal depolarization and expected secondary ST-T changes, which can mask or mimic ischemia. Acute occlusion MI can still be…
A 72-year-old man is brought to the ED after a witnessed out-of-hospital cardiac arrest. Bystander CPR is started quickly, EMS finds a non-shockable rhythm, and ROSC is achieved after one…
A 44-year-old man with severe cardiomyopathy, an LVAD, chronic amiodarone therapy, and an AICD presents with palpitations. His ECG shows a regular wide-complex tachycardia, but the rate is only 135….
Key Points: RBBB delays right ventricular activation. The left ventricle depolarizes normally through the left bundle, while the right ventricle is activated late by slow myocardial spread. ECG hallmark: QRS…
Key Points: LBBB delays left ventricular activation. The RV activates first through the intact right bundle, then the impulse spreads slowly from right to left across the septum and LV…
Key Points: In a patient with ischemic symptoms, new RBBB + LAFB should raise concern for proximal LAD or septal ischemia until proven otherwise, especially if the patient has ongoing…
Key Points: A QRS duration greater than 120 ms reflects delayed or abnormal ventricular depolarization. A wide QRS may be chronic and benign in context, or it may be the…
Key Points: Unstable bradyarrhythmias cause poor perfusion which can rapidly progress to shock, irreversible organ injury, or cardiac arrest. Priority: Do not treat the heart rate alone. Treat clinical instability….
Key Points: Definition: Polymorphic ventricular tachycardia is VT with beat-to-beat variation in QRS morphology, axis, and amplitude. Clinical significance: PMVT is electrically unstable and can rapidly deteriorate into ventricular fibrillation…
Key Points: Definition: Nonsustained ventricular tachycardia is 3 or more consecutive ventricular beats lasting less than 30 seconds and terminating spontaneously. Rate: VT is usually faster than 120 bpm, but…
Key Points: Wide QRS rhythms distort repolarization. Bundle branch block and ventricular pacing create secondary ST-T changes even without occlusion MI. Appropriate discordance is expected. ST segments and T waves…
Key Points: Ventricular paced rhythms can mask acute coronary occlusion. Pacing alters depolarization and produces expected secondary ST-T abnormalities, so standard STEMI criteria are unreliable. Appropriate discordance is expected in…
Key Points: Ventricular pacing changes depolarization and repolarization, so ST-T segments often look abnormal. In most paced rhythms, some discordant ST deviation is expected and should not be mistaken for…
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….