ADVERSE PACEMAKER HEMODYNAMICS EVALUATED BY PULMONARY VENOUS FLOW MONITORING

The pacemaker syndrome refers to symptoms and signs in the pacemaker p atient caused by an inadequate timing of atrial and ventricular contra ctions. The lack of normal atrioventricular synchrony may result in a decreased cardiac output and venous cannon A waves. The objective of t his study was to define the left atrial and pulmonary venous flow resp onse to ventricular pacing in a group of 14 unselected consecutive pat ients with total heart block and sinus rhythm. Pulmonary venous flow w as assessed by transesophageal pulsed Doppler echocardiography in the VVI and DDD pacing modes. An inappropriate atrial timing caused a mark ed augmentation of the normally small pulmonary venous z wave in all p atients (''negative atrial kick,'' peak z wave in DDD pacing 14.5 +/- 4.6 cm/s, VVI pacing 51.8 +/- 15.0 cm/s). Restoration of AV synchrony (DDD pacing, AV interval 100 ms) abolished these ''cannon z waves'' in all patients, and a normal pattern of pulmonary venous flow was achie ved. Abnormal pulmonary venous flow characteristics were observed in 2 of 14 patients during DDD pacing with short AV intervals (100 ms). Th e Doppler pattern was similar to She findings seen in VVI pacing. Asse ssment of pulmonary venous flow by transesophageal pulsed Doppler echo cardiography may provide a simple, sensitive, and relatively noninvasi ve technique to evaluate patients with suspected pacing induced advers e hemodynamics.