This study was performed to assess the effect of pacing-induced tachycardia in patients with aortic regurgitation. In 12 patients (5 men and 7 women with a mean age of 53 years) with aortic regurgitation, left ventricular end-diastolic and end-systolic volume indexes were measured with multigated equilibrium blood pool imaging, and forward cardiac index was determined with thermodilution, both at rest (mean heart rate ± standard deviation 72 ± 8 beats/min) and during atrial pacing at 100 and 120 beats/min. Pacing caused a decremental reduction in left ventricular end-diastolic and end-systolic volume indexes and radionuclide-determined stroke volume index but no change in radionuclide-determined cardiac index or left ventricular ejection fraction. Forward cardiac index increased incrementally from the baseline value at rest to that at 120 beats/min despite a decremental reduction in stroke volume index. There was a stepwise decrease in regurgitant volume/stroke (46 ± 20 ml/m2 at baseline, 27 ± 15 at 120 beats/min; p < 0.05) but no change in regurgitant volume/min (3.38 ± 1.80 Iiters/min per m2 at baseline, 3.22 ± 1.78 at 120 beats/min; difference not significant [NS]) or regurgitant fraction (0.54 ± 0.13 at baseline, 0.49 ± 0.13 at 120 beats/min; NS). Mean femoral arterial, pulmonary arterial and pulmonary capillary wedge pressures did not change with pacing.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine