AUTONOMIC MECHANISMS AND SUDDEN-DEATH - NEW INSIGHTS FROM ANALYSIS OF BARORECEPTOR REFLEXES IN CONSCIOUS DOGS WITH AND WITHOUT A MYOCARDIAL-INFARCTION
AUTONOMIC MECHANISMS AND SUDDEN-DEATH - NEW INSIGHTS FROM ANALYSIS OF BARORECEPTOR REFLEXES IN CONSCIOUS DOGS WITH AND WITHOUT A MYOCARDIAL-INFARCTION
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DOI：
10.1161/01.cir.78.4.969
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发表时间：
1988-10-01
期刊：
影响因子：
37.8
通讯作者：
FOREMAN, RD
中科院分区：
文献类型：
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作者：
SCHWARTZ, PJ;VANOLI, E;FOREMAN, RD
我们认为，在前壁心肌梗塞（MI）愈合的清醒狗中，压力屈肌敏感性（BRS）降低在与运动负荷测试相关的短暂缺血发作期间发生心室颤动的风险较高。我们之前的研究结果的临床和病理生理学意义促成了本研究，该研究解决了三个主要问题：1）MI后BRS分析确实是猝死风险分层的特异性和敏感标记吗？ 2）MI会修改BRS吗？ 3) MI 前的 BRS 分析是否提供有关 MI 后缺血发作期间结果的信息？在 301 只狗中产生了前壁心肌梗死，4 周后，可以在 192 只狗中进行从运动压力测试的最后一分钟开始的 2 分钟冠状动脉闭塞。 106 只（55%）狗（易猝死）发生心室颤动，而 86 只（45%）狗（不易猝死）幸存。 BRS 通过去氧肾上腺素方法进行评估，并通过将 RR 间隔与血压变化相关的回归线表示。易感犬中的 BRS 显着低于耐药犬（9.1.+-.6.0 与 17.7.+-.6.5 毫秒/毫米汞柱，p < 0.0001）。猝死风险从 BRS 大于 15 毫秒/毫米汞柱的 20%（73 只狗中的 15 只）增加到 BRS 小于 9 毫秒/毫米汞柱的 91%（68 只狗中的 62 只）（p < 0.001）。对 55 只动物进行的内部对照研究表明，与对照条件相比，MI 后 4 周，BRS 降低（13.5 .+-. 6.7 对比 17.8 .+-. 6.6 毫秒/毫米汞柱，p < 0.001），并且 73% 的动物出现降低。易感犬和 MI 后自然死亡的犬甚至在 MI 之前就具有较低的 BRS（16.2 .+-. 5.9 与 22.2 .+-. 6.2 毫秒/毫米汞柱，p < 0.001）。 MI 之前 BRS 大于 20 毫秒/毫米汞柱，MI 后猝死的风险从 35%（26 只狗中的 9 只）增加到 MI 之前 BRS 小于 14 毫秒/毫米汞柱的 85%（20 只狗中的 17 只）（p < 0.001）。这项研究表明，BRS 减少与随后缺血发作期间心室颤动的敏感性增加有关。对于大多数狗来说，MI 后 BRS 会降低。对 192 只具有治愈的 MI 的意识清醒的狗进行的结果表明，BRS 分析不仅是 MI 发生后甚至是 MI 发生前风险分层的有力工具。
We have suggested that among conscious dogs with a healed anterior wall myocardial infarction (MI) a depressed baroflex sensitivity (BRS) carries a higher risk of developing ventricular fibrillation during a brief ischemic episode associated with an exercise stress test. The clinical and pathophysiological implications of our previous findings prompted the present study, which addressed three major questions: 1) Is, indeed, analysis of BRS after MI a specific and sensitive marker for sudden death-risk stratification? 2) Does MI modify BRS? 3) Does analysis of BRS before MI provide information about outcome during ischemic episodes occurring after MI? An anterior MI was produced in 301 dogs, and 4 weeks later, a 2-minute coronary artery occlusion beginning during the last minute of an exercise stress test could be performed in 192 animals. Ventricular fibrillation occurred in 106 (55%) dogs (susceptible to sudden death), whereas 86 (45%) dogs (resistant to sudden death) survived. BRS was assessed by the phenylephrine method and was expressed by the regression line relating RR intervals to blood-pressure changes. BRS was significantly lower among susceptible than among resistant dogs (9.1 .+-. 6.0 vs. 17.7 .+-. 6.5 msec/mm Hg, p < 0.0001). The risk for sudden death increased from 20% (15 of 73 dogs) for a BRS greater than 15 msec/mm Hg to 91% (62 of 68 dogs) for a BRS less than 9 msec/mm Hg (p < 0.001). An internal control study in 55 animals showed that BRS was reduced 4 weeks after MI compared with control conditions (13.5 .+-. 6.7 vs. 17.8 .+-. 6.6 msec/mm Hg, p < 0.001) and that a reduction occurred in 73% of animals. Susceptible dogs and those that spontaneously died after MI had a lower BRS even before the MI (16.2 .+-. 5.9 vs. 22.2 .+-. 6.2 msec/mm Hg, p < 0.001). The risk for sudden death after MI increased from 35% (nine of 26 dogs) for a BRS before MI greater than 20 msec/mm Hg to 85% (17 of 20 dogs) for a BRS before MI less than 14 msec/mm Hg (p < 0.001). This study demonstrates that the presence of a reduced BRS is associated with a greater susceptiblility to ventricular fibrillation during subsequent ischemic episodes. In the majority of dogs, BRS is reduced after an MI. The results in 192 conscious dogs with a healed MI indicate that analysis of BRS is a powerful tool for risk stratification not only after, but even before, the occurrence of an MI.