RESUMEN
Efficacy of short atrioventricular (AV) delay and diastolic mitral regurgitation (MR) were studied in 16 patients (70.2 mais ou menos 10.5 SD years old) with implanted DDD pacemakers. AV delay was set at 0.215 and 0.115 sec. In 10 of the 16 patients, diastolic MR was not observed when the AV delay was set at both 0.215 and 0.115 sec. Cardiac output (CO) and pulmonary capilary wedge pressure (PCWP) did not change.In 6 of the 16 patients, diastolic MR was observed when the AV delay was set a 0.215 se However, diastolic MR was not observed when the AV delay was set at 0.115 sec. CO increased from 3.6 mais ou menos 0.7 to 3.9 mais ou menos 0.8 I/min (p menor que 0.05). PCWP was decreased in 5 of the 6 patients (83 por cento, p menor que 0.05 vs. 10 por cento in patients without diastolic MR at 0.215 sec of AV delay). Cardiac function may be improved by shortening AV delay when the diastolic MR was observed. On the other hand, short AV delay may not be effective for patients in whom diastolic MR was ntobserved.