[Atrioventricular delay and diastolic mitral regurgitation in patient with DDD pacemaker implantation, and cardiac...

We examined the mitral valve motion, the mitral valve flow pattern, and changing atrioventricular (AV) delay in 34 patients with DDD pacemaker implantation, using M-mode echocardiography and pulse Doppler echocardiography. In 28 patients, B-B' step and diastolic mitral regurgitation (DMR) were induced by extending the AV delay. 8 of 12 patients who showed B-B' step and DMR with the AV delay less than or equal to 165 mS had heart failures. In such patients, P-B-B' step (DMR) interval was 174 +/- 31 mS shorter than the other patients (216 +/- 26 mS, p less than 0.001), and Q-C interval was 131 +/- 26 mS longer than the other patients (63 +/- 31 mS, p less than 0.001). The minimal value of the AV delay that induces B-B' step and DMR can be decided under the influence of cardiac functions, and this echocardiographic examination is useful, giving us information about the cardiac function of the patients with DDD-PM. B-B' step is the mitral valve motion that corresponds with the DMR, so we can check the DMR through the B-B' step easily.