Luzza F, Consolo A, Oreto G
Cattedra di Cardiologia, Università degli Studi, Messina.
Cardiologia. 1994 Jul;39(7):517-9.
A patient with recent myocardial infarction presented with premature ventricular contractions (PVCs), couplets, and runs of ventricular tachycardia (VT). Two types of ectopic complexes, labeled A and B, were present. Isolated PVCs, as well as the first complex in a couplet, were always type A beats. In contrast, the second beat in a couplet was always a type B beat. Any run of VT was initiated by a type A beat. Monomorphic VT was made only of type B complexes, apart from the first one. Several episodes of VT, however, reflected an alternation of type A and type B complexes with alternating cycle length. This is a manifestation of extrasystolic ventricular bigeminy where any VT impulse (type B) is followed by an extrasystole (type A). In addition, extrasystolic impulses affect the tachycardia, resetting its cycle.
一名近期发生心肌梗死的患者出现室性早搏（PVC）、成对早搏及室性心动过速（VT）发作。存在两种类型的异位复合波，标记为A和B。孤立的室性早搏以及成对早搏中的第一个复合波总是A 型搏动。相比之下，成对早搏中的第二个搏动总是B型搏动。任何室性心动过速发作均由A型搏动起始。除第一个复合波外，单形性室性心动过速仅由B型复合波构成。然而，有几次室性心动过速发作表现为A型和B型复合波交替出现且周期长度交替变化。这是室性早搏二联律的一种表现，即任何室性心动过速冲动（B型）之后都跟随一个早搏（A型）。此外，早搏冲动会影响心动过速，重置其周期。
