Ishikawa T, Sumita S, Kimura K, Kikuchi M, Kosuge M, Nakagawa T, Matsushita K, Usui T, Umemura S
Second Department of Internal Medicine, Yokohama City University School of Medicine, Yokohama, Japan.
Jpn Circ J. 2000 Aug;64(8):579-82. doi: 10.1253/jcj.64.579.
The efficacy of a short atrioventricular (AV) delay in patients with dilated cardiomyopathy has been reported, but there are deleterious effects of right ventricular pacing. Diastolic mitral regurgitation (MR) is observed in patients with elevated left ventricular end-diastolic pressure and can be induced by prolonging the AV delay in patients with DDD pacemakers. The critical PQ interval that induces diastolic MR may represent the upper limit of the optimal PQ interval. The efficacy of AV sequential pacing and diastolic MR were studied in 11 patients (68.3+/-13.7 (SD) years old) with intrinsic AV conduction and with implanted DDD pacemakers. Cardiac output (CO) and pulmonary capillary wedge pressure (PCWP) were measured by Swan-Ganz catheter and transmitral flow was recorded by pulsed Doppler echocardiography. AV delay was prolonged stepwise by 25 ms starting from 65 ms. Pacing rate was fixed at 70-80 beats/min. In 6 of the 11 patients, diastolic MR was observed under atrial pacing and the critical PQ interval for the appearance of diastolic MR was 0.22+/-0.04 s. CO was increased from 3.8+/-0.8 to 4.3+/-0.9 L/min (p<0.05) and PCWP was decreased from 7.5+/-2.8 to 5.5+/-1.6 mmHg (p<0.05) by shortening the AV delay till the diastolic MR disappeared. On the other hand, in 5 of the 11 patients, diastolic MR was not observed, and CO (4.2+/-0.5 to 4.3+/-0.5L/min, ns) and PCWP (5.8+/-4.6 to 5.4+/-3.9 mmHg, ns) were not improved by AV sequential pacing. In conclusion, cardiac function may be improved by AV sequential pacing and setting the AV delay under the critical PQ interval for the appearance of diastolic MR when the diastolic MR is observed. However, AV sequential pacing may be either ineffective or even deleterious for patients in whom diastolic MR is not observed.
已有报道指出短房室（AV）延迟对扩张型心肌病患者具有疗效，但右心室起搏存在有害影响。在左心室舒张末期压力升高的患者中可观察到舒张期二尖瓣反流（MR），并且在植入DDD起搏器的患者中，延长AV延迟可诱发舒张期二尖瓣反流。诱发舒张期MR的临界PQ间期可能代表最佳PQ间期的上限。我们对11例（年龄68.3±13.7（标准差）岁）存在自身房室传导且植入DDD起搏器的患者进行了房室顺序起搏疗效及舒张期MR的研究。通过Swan - Ganz导管测量心输出量（CO）和肺毛细血管楔压（PCWP），并用脉冲多普勒超声心动图记录二尖瓣血流。从65毫秒开始，AV延迟以25毫秒的步长逐步延长。起搏频率固定为70 - 80次/分钟。11例患者中有6例在心房起搏时观察到舒张期MR，出现舒张期MR的临界PQ间期为0.22±0.04秒。通过缩短AV延迟直至舒张期MR消失，CO从3.8±0.8升/分钟增加至4.3±0.9升/分钟（p<0.05），PCWP从7.5±2.8毫米汞柱降至5.5±1.6毫米汞柱（p<0.05）。另一方面，11例患者中有5例未观察到舒张期MR，房室顺序起搏后CO（4.2±0.5至4.3±0.5升/分钟，无显著差异）和PCWP（5.8±4.6至5.4±3.9毫米汞柱，无显著差异）未得到改善。总之，当观察到舒张期MR时，通过房室顺序起搏并将AV延迟设置在出现舒张期MR的临界PQ间期以下，心脏功能可能会得到改善。然而，对于未观察到舒张期MR的患者，房室顺序起搏可能无效甚至有害。
