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Occlusion MI Patterns in Left Bundle Branch Block

Key Points LBBB Does Not Exclude Acute Coronary Occlusion: LBBB alters ventricular activation, leading to expected secondary ST/T abnormalities. However, acute occlusion myocardial infarction (OMI) can and must still be…

Modified Sgarbossa Criteria

Key Points Wide QRS Rhythms Can Mask OMI: Left bundle branch block (LBBB) and right ventricular (RV)-paced rhythms alter ventricular depolarization, producing expected secondary ST/T changes. However, acute occlusion MI…

Hyperkalemic Periodic Paralysis (Impressive Syndrome)

Key Points What It Is: A rare autosomal dominant sodium channelopathy that leads to episodic muscle weakness or paralysis in the setting of elevated serum potassium. Named after “Impressive,” the…

Catecholaminergic Polymorphic VT (CPVT)

Key Points Definition: CPVT is a rare hereditary form of polymorphic ventricular tachycardia (VT) that is often triggered by emotional or physical stress, leading to potentially fatal arrhythmias such as…

Sinus Node Dysfunction (Sick Sinus / Brady–Tachy Syndrome)

Key Points Spectrum, not one rhythm: Look for sinus brady, pauses, arrest, alternating atrial tachyarrhythmias (AF, flutter, ATach). Symptoms matter: Syncope, presyncope, fatigue usually come from cerebral/systemic hypoperfusion, especially after…

Wellens Syndrome

Key Points Diagnosis: Wellens syndrome is a clinical diagnosis that requires more than just the presence of Wellens waves; it necessitates a thorough history and consideration of other potential causes…

Slow Atrial Fibrillation

Key Points Definition: Atrial fibrillation with a slow ventricular response, usually < 60 bpm. ECG: Irregularly irregular rhythm, no discrete P waves, slow R-R intervals. Common causes: AV-nodal blockers (digoxin,…

Aslanger Pattern (OMI Pattern)

Key Points STEMI Diagnosis and Contiguous Leads: While current guidelines typically require ST elevation (STE) in at least two contiguous leads for the diagnosis of STEMI, this practice is not…

Precordial Swirl (OMI Pattern)

Key Points Definition: The precordial swirl sign refers to a rotational pattern of ST-segment abnormalities across the precordial leads, suggesting a dynamic and evolving occlusion myocardial infarction (OMI). It is…

RV Outflow Tract Tachycardia (RVOT)

Key Points Origin: RVOT tachycardia is a monomorphic ventricular tachycardia (VT) that arises from the right ventricular outflow tract or tricuspid annulus. Population: Most commonly idiopathic, occurring in patients without…

High-Risk Pulmonary Embolism

Key Points The ECG can provide early, life-saving clues in the diagnosis of high-risk PE. Right Heart Strain: ECG signs of right heart strain in acute PE can predict which patients…

ST Elevation in aVR with Diffuse ST Segment Depression

Key Points Pattern: ST elevation in aVR (≥1 mm), often with ST elevation in V1 and widespread ST depression (≥1 mm in ≥6 leads). Mechanism: Reflects global subendocardial ischemia, often…

Pericardial Tamponade

Key Points Beyond Electrical Alternans: Although classically linked to tamponade, electrical alternans is present in fewer than 30% of confirmed cases. It’s abscence should never rule out tamponade. Low Voltage…

Post-Cardiac Arrest ECGs

Key Points Coronary Occlusion After Shockable Arrest: ~30% of patients resuscitated from ventricular fibrillation (VF) arrest have an acute coronary occlusion and present with STEMI on ECG. Among patients without…

Electrical Alternans

Key Points Classically associated with pericardial tamponade but seen in fewer than 30% of confirmed cases. Combination of low-voltage QRS + sinus tachycardia strongly suggests pericardial effusion/tamponade. Always perform rapid…

Torsades de Pointes (TdP)

Key Points Definition: TdP is a specific subtype of polymorphic ventricular tachycardia associated with a prolonged QTc interval. It often presents with a “twisting” pattern on ECG but can be…

Polymorphic Ventricular Tachycardia (PMVT)

Key Points Definition: PMVT is a ventricular tachycardia characterized by beat-to-beat variations in QRS morphology, axis, and duration, reflecting multiple ventricular foci or reentrant circuits. Clinical Importance: PMVT is often…

Posterior STEMI Criteria

Key Points High Risk of Missed Diagnosis: Isolated posterior occlusion MI is frequently missed due to the absence of ST elevation on standard 12-lead ECG. Instead, ST depression in V1–V3…

Ventricular Fibrillation (VF)

Key Points Rapidly Fatal Rhythm: VF is the most critical shockable cardiac arrest rhythm, requiring immediate defibrillation and high-quality CPR to prevent sudden cardiac death within minutes. Chaotic Electrical Activity:…

ST Depression V1-V4 (Posterior OMI Pattern)

Key Points Most Missed STEMI: Isolated posterior MI is the most commonly missed occlusion MI due to the absence of ST elevation on standard 12-lead ECG. ECG Pattern of Posterior…

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