美托洛尔测定心脏固有心率的临床观察

目的　探讨 β1 受体阻滞剂——美托洛尔替代普奈洛尔测定心脏固有心率 (IHR)的可行性。方法　 6 0例受检者根据静息状态下的基础窦性心率分为 2组 :窦性心动过缓组 (心率低于 6 0次 / min,n=35 ) ;窦房结功能正常组(心率≥ 6 0次 / min,n=2 5 )。两组病人均以美托洛尔 5 mg与阿托品 2 mg混合一次性静脉注射测定 IHR,同时应用经食管心房调搏方法测定阻断自主神经前后的窦房结恢复时间 (SNRT)和校正窦房结恢复时间 (SNRTc)。结果　正常组的 IHR为 90 .2± 8.7次 / min;在窦缓组中 ,2 1例 SNRT和 SNRTc异常者 (窦缓 A组 )的 IHR为 6 7.1± 7.9次/ m in,14例 SNRT和 SNRTc正常者 (窦缓 B组 )的 IHR为 84.2± 16 .2次 / m in,A、B两亚组之间的 IHR值有显著性差异 (P<0 .0 1)。结论　美托洛尔与阿托品混合静脉注射能够理想地阻断自主神经系统对窦房结的影响 ,真实显示窦房结固有的自律性功能。

The clinical observation of measuring intrinsic heart rate by metoprolol

Objective To investigate the feasibility of β 1-blocker Metoprolol in measuring intrinsic heart rate (IHR). Methods 60 adult patients were divided into two groups, bradycardiac group (HR<60 bpm, n=35) and normal group (HR≥60 bpm, n=25), according to rest heart rate(HR). IHR was measured after Metoprolol (5mg) and Atropin(2mg) were intravenously injected. Sinus node recovery time (SNRT) and corrected SNRT (SNRTc) were measured using trans-esophageal atrial pacing. Results IHR was 90.2±8.7 bpm in normal group. In bradycardiac group, IHR was 67.1±7.9 bpm in 21/35 cases with abnormal SNRT and SNRTc (sub group A). IHR was 84.2±16.2 bpm in 14/35 patients with normal SNRT and SNRTc (sub group B). There were significant differences between sub group A and B (P<0.01). Conclusion Administration of intravenous Metoprolol and Atropin may properly block effects of autonomic nervous system on sinus node and truly indicate automobility of sinus node.