Key Points: Short QT Syndrome (SQTS) is a rare condition characterized by a shortened QT interval on the ECG, increasing the risk of atrial and ventricular arrhythmias, including sudden cardiac…
Key Points: Definition and measurement: The P wave is atrial depolarization. Measure duration from initial deflection to return to baseline and amplitude from baseline to peak. Normal values: Duration <120…
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…
Key Points: Definition: QT is measured from QRS onset to T-wave end. It reflects total ventricular depolarization plus repolarization. Use QTc: QT varies with heart rate. Interpret QTc, not the…
Key Points: Every ECG tracing is built from waveforms (deflections), segments (baseline portions between waveforms), and intervals (time that include waveforms plus segments). Waveforms describe electrical events (depolarization or repolarization)….
Why ECG Interpretation Matters: The ECG is one of the fastest, highest-impact diagnostic tests in acute care. When interpretation is rapid and accurate, patients get timely reperfusion, pacing, defibrillation, antidotes,…
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 Reperfusion after fibrinolysis is a bedside diagnosis using a bundle of findings: symptoms, ECG trend, and hemodynamic/electrical stability. Best ECG marker of successful fibrinolysis: at least 50% ST-segment…
Key Points: Reperfusion and re-occlusion can occur spontaneously or after therapy. The ECG often reflects these changes earlier than symptoms. Most useful bedside ECG marker of reperfusion is ST-segment resolution…
Key Points: Mechanical artifact caused by an ECG electrode sitting on top of a strong arterial pulse. Seen frequently in dialysis patients with AV fistulas. Can mimic serious pathology including…
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 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 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 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: Small, low-amplitude positive deflections at the terminal QRS or very early ST segment, caused by delayed right ventricular activation through diseased myocardium. Association: Highly specific for arrhythmogenic…
Key Points Definition: Chronic pressure/volume overload → thickened RV (pulm HTN, congenital lesions, pulmonary disease). ECG signature: Rightward axis, dominant R in V1, deep S in V5–V6, with possible right-sided…
Key Points Definition and Measurement: A Q wave is the first negative deflection of the QRS. Measure width in ms from the onset below baseline to its return to baseline;…
Key Points: Definition and measurement: The QRS complex is ventricular depolarization, measured from the earliest ventricular deflection (Q or R) to the latest S return to baseline in any lead….
Key Points Definition: The R wave is the first positive deflection of the QRS complex, reflecting early ventricular depolarization, predominantly of the left ventricle. Normal progression: Precordial R amplitude increases…