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: Early post-ROSC ECGs often mislead. Obtain the first ECG immediately after ROSC, but treat it as an early snapshot, not the entire story. Post-arrest physiology, defibrillation, acidosis, and…
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…
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 PJCs are premature impulses from ectopic foci in or near the AV junction. ECG hallmark is a narrow premature beat with an absent or retrograde P wave. Retrograde…
Key Points The J point is the junction where QRS ends and the ST segment begins. It is a location, not a waveform. ST deviation is judged at the J…
Key Points Definitions: The J point is the QRS–ST junction (a location). A J wave is an added deflection at or just after that point (notch or slur). Why it…
Key Points Severe hypothermia causes rate- and temperature-dependent ECG changes that signal high arrhythmia risk. Recognition guides safe rewarming and prevents iatrogenic VF. Osborn (J) waves may appear and typically…
Key Points SCAD Definition: A spontaneous, non-atherosclerotic tear in the coronary artery wall, often affecting young, otherwise low-risk women (including peripartum patients). SCAD presents similarly to ACS and is an…
Key Points A diagnostic 12‑lead ECG is only as good as your electrode placement. Misplacement can mimic MI, BBB, or poor R‑wave progression and trigger unnecessary workups. A standard 12‑lead…
Key Point Cannabis use is rising across recreational and medical contexts. Causation is not proven, but multiple contemporary studies associate cannabis with acute cardiovascular events, including MI, stroke, arrhythmias, and…
Key Points Definition and mechanics: Genetic hypertrophic cardiomyopathy with asymmetric LV hypertrophy, typically septal, causing dynamic LVOT obstruction from systolic anterior motion (SAM) of the mitral valve. Gradient worsens when…
Key Points Definition and mechanics: Hypertrophic cardiomyopathy variant with maximal hypertrophy at the LV apex (apical HCM, ApHCM). LVOT is often not obstructed at rest; some patients have mid-ventricular obstruction…
Key Points: ECG and monitor early: First-time seizure, near-syncope, unexplained LOC, or syncope all get a 12-lead now and continuous telemetry. Repeat ECG during symptoms or after another event. History…
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: Syncope and the ECG: Syncope is a transient loss of consciousness and postural tone, characterized by rapid onset, brief duration, and spontaneous recovery without medical intervention. Cardiac syncope…
Key Points BRASH is a synergistic spiral: bradycardia, renal failure, therapeutic AV-nodal blockade, shock, and hyperkalemia. The signature clue is disproportionate brady-shock despite only modest potassium elevation. Do not be…
Key Points Tension pneumothorax is a clinical diagnosis—ECG changes are nonspecific but can provide supportive evidence in the right context. Electrical changes are primarily due to mechanical effects of air…
Key Points: Aortic dissection or aneurysm can produce ischemic‑appearing ECGs due to coronary malperfusion, most often right coronary involvement causing inferior changes. Pseudo‑infarction patterns, ST‑deviation, and conduction blocks can occur…
Key Points Definition: The ST segment runs from the J point (end of QRS) to the start of the T wave, the interval between ventricular depolarization and repolarization. Normal: Usually…