Differences in pacing from the atrial appendage and the lateral atrial free wall on left ventricular filling and haemodynamics during DDD pacing

Introduction Atrio ventricular sequential pacing involves stimulation from electrodes in the right atrium, generally the atrial appendage (RAA) and th e right ventricular apex. The appendage, however, may be unsuitable if a st able position cannot be achieved. The aim of this study was to assess the h aemodynamic consequences of different atrial stimulation sites during DDD p acing. Methods In 12 consecutive patients (mean age 67+/-7 years) who underwent DD D pacemaker implantation, an additional temporary bipolar pacing electrode was positioned on the right atrial free wall. Pacing was performed alternat ing from the two locations at 85, 100 and 120 beats per minute (bpm). Paced atrioventricular delay was set at 180 ms. Cardiac output and mitral inflow measurements were performed using Doppler echocardiography. Results Pacing at 85 and 100 bpm resulted in a significantly higher A-peak velocity from the RAA compared with the right atrial free wall. Cardiac ind ex was consistently higher from the RAA location (2.4 +/- 1.2 vs 2.1 +/- 0. 91. min(-1) m(-2) at 85 bpm, 2.71 +/- 1.4 vs 2.35 +/- 1.11. min(-1) m(-2) a t 100 bpm and 2.94 +/- 1.5 vs 2.61 +/- 1.41. min(-1) m(-2) at 120 bpm. P<0. 05). Conclusion Stimulation from the RAA was superior to stimulation from the ri ght atrial free wall with respect to left ventricular filling and cardiac o utput. Compared with stimulation from the right atrial free wall, RAA pacin g resulted in an increase of 10-15% in cardiac output. (Europace 2001; 3: 5 2-55) (C) 2001 The European Society of Cardiology.