AGE-ASSOCIATED CHANGES IN CARDIAC RHYTHM AND CONDUCTION

a.确定与以下疾病相关的PR间期延长部位： 老化，我们进行了信号平均高分辨率表面心电图在161 临床健康的巴尔的摩老龄化纵向研究（BLSA）志愿者 房室传导正常PR间期延长 随着年龄的增长，发现在两种性别，并定位于近端的希氏 束除极，但远的P波铭文，表明 房室结内阻滞;类似的定性相似，但更多 在7名老年男性中，在希氏束近端观察到明显的延迟， 一度房室传导阻滞。 B。我们已经确定了运动诱发的 频繁或重复的室性异位搏动（VEB）， BLSA志愿者。在1974年至1984年期间，1160个这样的国家中有80个国家 无症状受试者发生频繁的VEB（> 10%）或齐射（> 3例， 行）在至少一个最大跑步机运动测试中。这80个主题 明显比没有这种 运动诱发的VEB（63.8 +/-12.5 vs 50.0 +/-16.1，p <.0001）。中只有9 80例（11%）表现出缺血性ST段对运动的反应。通过 平均随访4.6年;仅发生8例心脏事件，而10例 在80名年龄和性别匹配的对照受试者中， 运动诱发VEB（p = NS）。 C. 24小时动态心电图记录的预后意义是 在100名> 60岁的健康BLSA志愿者中进行评估。在平均 随访10年，10例患者发生冠状动脉事件（CE）。的 室上性（SV）和室性（V）的患病率和复杂性 异位搏动在有和没有CE的组中相似。然而，CE ST段平坦或下斜的5例受试者中有2例（40%）发生 ST段压低≥ 1.0 mm，而无ST段压低的95例患者中仅有8例（8%）。

A. To determine the site of the PR interval prolongation associated with aging, we performed signal averaged high resolution surface ECGs in 161 clinically healthy Baltimore Longitudinal Study of Aging (BLSA) volunteers with normal atrioventricular (AV) conduction. An increase in PR interval with age was found in both sexes and was localized proximal to the His bundle depolarization but distal to the P wave inscription, suggesting block within the AV junction; a similar qualitatively similar but more pronounced delay was noted proximal to the His bundle in 7 older men with first degree AV block. B. We have determined the prevalence and significance of exercise-induced frequent or repetitive ventricular ectopic beats (VEB) in apparently healthy BLSA volunteers. Between 1974 and 1984, 8O of 1160 such asymptomatic subjects developed frequent VEB (> 10%) or salvos (> 3 in a row) on at least one maximal treadmill exercise test. These 80 subjects were significantly older than the larger group without such exercise-induced VEB (63.8 +/- 12.5 vs 50.0 +/- 16.1, p<.0001). Only 9 of 80 (11%) demonstrated an ischemic ST segment response to exercise. Over a mean followup of 4.6 years; only 8 cardiac events have occurred versus 10 events in 80 age- and sex-matched control subjects without such complex exercise-enduced VEB (p = NS). C. The prognostic significance of 24-hr ambulatory ECG recordings was assessed in 100 healthy BLSA volunteers > 60 years old. Over a mean followup of 10 years, coronary events (CE) developed in 10 subjects. The prevalence and complexity of both supraventricular (SV) and ventricular (V) ectopic beats were similar in the groups with and without CE. However, CE occurred in 2 of 5 subjects (40%) with flat or downsloping ST segment depression > or = 1.0 mm versus only 8 of 95 (8%) without such ST changes.