Assessment of atrial capture in committed atrioventricular sequential (DVI) pacing systems

Two patients with committed dual unipolar AV sequential pacing systems are presented in whom atrial capture was unable to be demonstrated on the surface electrocardiogram. The bedside examination is proposed as a means of identifying the presence or absence of atrial capture with subsequent confirmation by M-mode echocardiographs and jugular venous pulse tracings. Mode, rate, and output programmability may aid in the evaluation of these pacing systems. Intentional reduction of the ventricular output to subthreshold levels in pacemakers capable of this degree of programmability will permit the rapid bedside confirmation of atrial capture without the need for expensive and time-consuming noninvasive tests.