Hemodynamical Comparison Of Right Ventricular Outflow Pacing And Right Ventricular Apical Pacing

Hemodynamical effects of right ventricular outflow pacing were studied in 13 patients (69.8 +/- 8.2 years old). When the pacing site was changed from apex to outflow, Cardiac output( CO) increased from 3.3 +/- 0.6 to 3.4 +/- 0.5 l/min (p<0.001), Pulmonary capillary wedge pressure (PCWP) decreased from 9.3 +/- 1.9 to 8.8 +/- 2.0 mmHg (p<0.05) during right ventricular pacing in 11 patients, and CO increased from 3.9 +/- 0.4 to 4.0 +/- 0.4 l/min (p<0.05), PCWP decreased from 7.1 +/- 2.3 to 6.6 +/- 2.1 mmHg (p<0.05) during AV sequential pacing in 8 patients. When the pacing site was changed from apex to right outflow, CO increased from 3.6 +/- 0.5 to 3.7 +/- 0.4 l/min (p<0.05) in 7 patients (EF>55%), and CO also increased from 2.9 +/- 0.4 to 3.0 +/- 0.4 l/min (p<0.01) in 4 patients (EF<55%). In conclusion, cardiac function is improved by right ventricular outflow pacing compared to apical pacing regardless of the pacing mode or the cardiac function.