Calkins H, el-Atassi R, Leon A, Kalbfleisch S, Borganelli M, Langberg J, Morady F
University of Michigan Medical Center, Division of Cardiology, Ann Arbor 48109-0022.
Pacing Clin Electrophysiol. 1992 May;15(5):771-8. doi: 10.1111/j.1540-8159.1992.tb06844.x.
Atrial arrhythmias occur frequently in the setting of increased atrial size and pressure. This may result from contraction-excitation feedback. The objective of this study was to investigate the effect of alterations in atrial pressure, induced by varying the atrioventricular (AV) interval, on atrial refractoriness, and on the frequency of induction of atrial fibrillation. Twenty-seven patients without structural heart disease participated in the study. In each patient the atrial effective (ERP) and absolute refractory period (ARP) were measured during AV pacing at a cycle length of 400 msec and AV intervals of 0, 120, and 160 msec. The ERP was defined as the longest extrastimulus coupling interval that failed to capture with an extrastimulus current strength of twice the stimulation threshold. The ARP was defined in a similar manner with an extrastimulus current strength of 10 mA. The ERP and ARP were determined during continuous pacing using the incremental extrastimulus technique. A subset of patients had the pacing protocol performed during autonomic blockade. As the AV interval was increased from 0 to 160 msec, the peak right atrial pressure decreased from 16 +/- 4 mmHg to 7 +/- 3 mmHg and the mean right atrial pressure decreased from 7 +/- 3 mmHg to 3 +/- 22 mmHg (P less than 0.001). The atrial ERP and ARP did not change with alterations in the AV interval. There was no difference in the frequency of induction of atrial fibrillation. Similar results were obtained during autonomic blockade. These findings suggests that the phenomenon of contraction-excitation feedback may not be of importance in the development of atrial arrhythmias in patients without structural heart disease.
心房颤动在心房大小和压力增加的情况下频繁发生。这可能是由收缩-兴奋反馈引起的。本研究的目的是探讨通过改变房室（AV）间期诱导的心房压力变化对心房不应期以及心房颤动诱发频率的影响。27例无结构性心脏病的患者参与了该研究。在每位患者中，在AV起搏时，以400毫秒的周期长度和0、120和160毫秒的AV间期测量心房有效（ERP）和绝对不应期（ARP）。ERP定义为在刺激阈值两倍的额外刺激电流强度下未能夺获的最长额外刺激耦合间期。ARP以类似方式定义，额外刺激电流强度为10毫安。使用递增额外刺激技术在连续起搏期间测定ERP和ARP。一部分患者在自主神经阻滞期间进行起搏方案。随着AV间期从0增加到160毫秒，右心房峰值压力从16±4毫米汞柱降至7±3毫米汞柱，右心房平均压力从7±3毫米汞柱降至3±2.2毫米汞柱（P<0.001）。心房ERP和ARP并未随AV间期的改变而变化。心房颤动的诱发频率没有差异。在自主神经阻滞期间获得了类似结果。这些发现表明，收缩-兴奋反馈现象在无结构性心脏病患者的心房颤动发生中可能并不重要。
