Brief Notes on Electrocardiograms, February 27, 1985

Brief Notes on Electrocardiograms, February 27, 1985

When the sinoatrial node’s automatic rhythm function declines, due to physiological protective mechanisms, impulses are generated at the atrioventricular junction or within the ventricles, resulting in ectopic rhythms. Rhythms originating at the atrioventricular junction are called junctional escape beats: ① After a relatively long P-P interval, a set of QRS-T complexes appears, with a morphology indistinguishable from normal waves. ② In excessively long intervals, the QRS complex may lack a sinus P wave, or even show a retrograde P wave before the QRS complex. ③ In cases of sinus bradycardia, sinus arrest, compensatory pauses following junctional, atrial, or ventricular premature beats, prolonged pauses after termination of tachycardia, and excessively long pauses following second- or third-degree atrioventricular block, junctional escape beats may occur.