Cardiac
Rhythm Recognition & 12-Lead ECG Interpretation
Matching rate, regularity, waveforms, and ST-segment patterns to rhythm diagnoses and STEMI localization clues.
Rhythm analysis sequence
Start with rate and regularity, then P waves, PR interval, QRS width, and relationship between P and QRS. Narrow-complex tachycardia with absent P waves suggests SVT or atrial fibrillation depending on irregularity. Wide-complex tachycardia is ventricular tachycardia until proven otherwise—treat per unstable tachycardia algorithm.
The NHLBI describes heart attack as blocked coronary blood flow; prehospital 12-lead acquisition identifies ST-elevation myocardial infarction patterns that activate cath lab teams.1 Compare current ECG to prior when available; new ST elevation or new bundle branch block may meet STEMI criteria even with nonspecific symptoms.
STEMI patterns and mimics
ST elevation in anatomically contiguous leads localizes infarct territory—anterior (V1–V4), inferior (II, III, aVF), lateral (I, aVL, V5–V6). Reciprocal depression supports acute ischemia. The CDC notes heart disease remains a leading killer; rapid recognition shortens door-to-balloon time.2
Mimics include benign early repolarization, pericarditis, hyperkalemia peaked T waves, and paced rhythms. Hyperacute T waves may precede ST elevation—serial 12-leads during transport capture evolution. Document rhythm, rate, and STEMI alert transmission time on the PCR.
Practice this skill
Apply what you read with a hands-on Rhythm Recognition & 12-Lead ECG drill — instant feedback on every scenario.
