A 60-year-old woman presents with palpitations and an irregular wide-complex tachycardia. The computer calls atrial fibrillation with a left bundle branch block, but a subtle clue in the precordial leads…
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: Left ventricular hypertrophy (LVH) with strain is one of the most common and dangerous STEMI mimics, particularly in the anterior leads, and is a frequent cause of false-positive…
Key Points: LBBB and ventricular-paced rhythms can hide acute coronary occlusion because abnormal depolarization creates expected secondary ST-T changes. Occlusion MI can still be recognized when those ST changes are…
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: WPW alters ventricular depolarization, producing secondary repolarization abnormalities that can mimic or mask myocardial infarction. ST-segment deviation in WPW is often non-ischemic, driven by abnormal activation via the…
A 68-year-old man is brought to the emergency department by EMS with acute chest discomfort. The following prehospital ECG was obtained and shows concave ST elevation across multiple leads. The…
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: The ECG’s primary role in ACS is detecting acute coronary occlusion. Acute coronary occlusion myocardial infarction (OMI) is a time-critical diagnosis that requires immediate reperfusion. Time is myocardium….
Key Points: Traditional STEMI criteria miss many acute coronary occlusions. A substantial proportion of true OMIs do not meet classic millimetric STEMI thresholds. OMI is a pathophysiologic diagnosis, not an…
Key Points: Baseline ECG abnormalities do not protect patients from occlusion MI. They increase miss rates because they distort the ST segment and T waves. The core question is not…
Key Points: Lateral and high-lateral STEMI often present with subtle ST elevation and are commonly missed or labeled as nonspecific ST-T changes. Small-appearing ECG changes may represent true coronary occlusion…
Key Points: Inferior STEMI is the most common STEMI subtype and is frequently complicated by right ventricular and posterior involvement. Inferior occlusion may present with classic ST elevation, subtle ischemic…
Key Points: Anterior STEMI represents large myocardial territory at risk and carries the highest mortality among STEMI subtypes. Early recognition and reperfusion are critical. LAD occlusion may present with classic…
Key Points: Definition: A true LV aneurysm is a chronic, post transmural MI complication from scarred myocardium with akinetic or dyskinetic (paradoxical) wall motion. ECG hallmark: Persistent ST elevation in…
Key Points: ST elevation describes an ECG finding, not a diagnosis. It reflects abnormal ventricular repolarization and can arise from ischemic, structural, metabolic, electrical, or extracardiac processes. Occlusion MI is…
Key Points: High risk of missed diagnosis. Isolated posterior occlusion MI is frequently missed because ST elevation is absent on the standard 12-lead ECG. Instead, posterior infarction most often presents…
Key Points: LV aneurysm pattern is a post MI scar pattern with persistent ST elevation in the prior infarct territory, usually with pathologic Q waves and a stable, non evolving…
Key Points: ST elevation is a pattern, not a diagnosis. STEMI represents one cause of ST elevation and requires correlation with ECG morphology, distribution, evolution, and clinical context. Most ED…
Key Points: Severe hyperkalemia is a true ECG chameleon. It can produce ST elevation, wide QRS complexes, axis shifts, and conduction blocks that closely mimic STEMI or ventricular tachycardia. New…