Some studies have demonstrated that synergistic activation of the two ventricles is also necessary besides atrioventricular synchronisation for the maintenance of cardiac function at an optimum level. In this study, it has been investigated whether the effects of implantation of a pacemaker electrode in the right ventricular outflow tract (RVOT) instead of the classical right ventricular apical (RVA) position can preserve better left ventricular function or not. For this purpose, a temporary pacemaker electrode was placed firstly into the RVOT and pacing was performed at 10 beats/minute more than the intrinsic heart rate in 17 patients (8 men and 9 women, mean age 53.23 ± 10.11). Cardiac output (CO) and cardiac index (CI) were measured by the thermodilution method. Secondly, the electrode was placed in the RVA for similar pacing and CO and CI measurements were made in the same manner. CO and CI measurements from RVOT pacing were significantly higher than RVA pacing (5.57 ± 1.9 litres/min and 4.95 ± 1.77 litres/min, p < 0.02; 3.16 ± 0.85 litres/min/m2 and 2.82 ± 0.82 litres/min/m2, p < 0.01 respectively). In women and patients with coronary artery disease RVOT pacing was found to provide better haemodynamic parameters than the RVA pacing. In conclusion, the data obtained suggests that implantation of a ventricular pacemaker electrode into RVOT instead of RVA may provide better cardiac performance
