Significance of Chronic Sinus Bradycardia in Elderly People
Significance of Chronic Sinus Bradycardia in Elderly People
复制标题
慢性窦性心动过缓对老年人的意义
DOI：
10.1161/01.cir.46.5.924
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发表时间：
1972
期刊：
影响因子：
37.8
通讯作者：
N. Fowler
中科院分区：
文献类型：
--
作者：
N. S. Agruss;Elaine Y. Rosin;R. Adolph;N. Fowler
由于窦性心率低于50次/分可能随年龄增长而正常发生，因此可能难以评价老年人的窦性心动过缓。7名无症状心动过缓受试者（心率41-51次/分），年龄67-79岁，无心脏功能受损证据，未服用药物，与4名年龄匹配的对照组（心率60-84次/分）进行比较。通过Valsalva动作、吸入亚硝酸戊酯、静注甲氧胺、头高位倾斜和静脉注射阿托品（2 mg）检测自主神经功能。心动过缓受试者静息心脏指数正常（2.4 ± 0.1 SEM）;心脏每搏输出量（SV）增加补偿了心率减慢。在仰卧位自行车运动中，每增加100 ml耗氧量，心输出量增加在心动过缓患者中是正常的（885 ± 60 ml，而对照组为907 ± 171 ml）。这种运动反应主要是通过心动过缓者的SV增加和对照者的心率增加来实现的。在心动过缓患者中，阿托品和心房起搏均可显著增加心输出量，但在对照组中无此现象。未发现自主神经功能损害。心率对运动和被动倾斜反应较低提示心搏过缓者迷走神经张力增加。因此，老年人心率低于50次/分并不一定表明心脏功能低下。进一步评估这些受试者心动过缓的重要性需要长期观察。
It may be difficult to evaluate sinus bradycardia in the elderly since sinus rates below 50 beats/min may occur normally with aging. Seven asymptomatic bradycardic subjects (heart rates 41-51 beats/min), ages 67-79 years, with no evidence of impaired cardiac performance and taking no drugs, were compared with four age-matched controls (heart rates 60-84 beats/min). Autonomic function was tested with the Valsalva maneuver, amyl nitrite inhalation, methoxamine infusion, head-up tilt, and atropine intravenously (2 mg).Cardiac index at rest was normal in bradycardic subjects (2.4 ± 0.1 SEM); increased cardiac stroke volume (SV) compensated for the slow heart rate. With supine bicycle exercise, increase in cardiac output per 100 ml increase in oxygen consumption was normal in bradycardics (885 ± 60 ml compared to 907 ± 171 ml in controls). This exercise response was achieved mainly by increased SV in bradycardics and by increased heart rate in controls. Significant increases in cardiac output occurred with both atropine and atrial pacing in bradycardics, but not in controls. Autonomic impairment was not found. Increased vagal tone in bradycardics was suggested by a lesser heart rate response to exercise and passive tilting.Hence, a heart rate below 50 beats/min in elderly people does not necessarily indicate depressed cardiac performance. Further evaluation of the significance of bradycardia in these subjects requires long-term observation.