| 摘要 |
<p>In a dual chamber cardiac pacemaker, apparatus for determining an atrioventricular (AV) delay interval to maintain optimal left heart AV mechanical synchrony and function. When the intrinsic or paced atrial heart rate is stable, test AV delay intervals are selected and delivered as right ventricular absolute blood pressures (RVP) are measured at the opening of the pulmonary valve. The opening of the pulmonary valve is determined by the peak rate of change in the RVP (dP/dt) following depolarization of the right ventricle. The test AV delay interval providing the lowest amplitude RVP at the peak dP/dt, indicating the lowest pulmonary blood pressure, is selected as the optimal AV delay. The system may be fully contained in an implanted pacemaker system including a right ventricular absolute blood pressure sensor and automatically invoked to determine the optimum AV delay for the prevailing atrial heart rate at any time, or may be invoked at a predetermined time of day or may be invoked by a programmed-in command. The system may also be employed on a temporary basis in conjunction with an implanted dual chamber pacemaker and an external pacemaker programmer with a temporary absolute blood presure sensor to provide the blood pressure signals.</p> |
