EFFECT OF AGING ON MYOCARDIAL REPOLARIZATION

本研究的目的是探讨年龄对男女性自主神经阻滞前后QT间期和QT离散度的影响。 已经描述了原始AT逆变器随年龄增长的性别差异，但性别和年龄对QT离散度的相互作用尚不清楚。 将在西北纪念医院的综合临床研究中心对40名无结构性心脏病证据的年轻受试者和40名老年受试者进行评价。 受试者将接受筛选访视，以确保不存在禁忌自主神经阻滞的结构性心脏病或全身性疾病。 在随后的访视中，受试者将在几个阶段接受常规12导联ECG和体表标测：（1）休息时;（2）阶段性自行车运动试验期间;（3）双重自主神经阻滞方案的第一种药物（阿托品或普萘洛尔）后;（4）第二种药物（普萘洛尔或阿托品）后;（5）双重自主神经阻滞给药后的运动试验期间。 将以标准方式测量QT间期。 将使用先前开发的算法，通过手动和计算机化方法确定12导联EKG的QT离散度。 将使用定制设计的算法分析体表标测图上的QT离散度，该算法将作为研究的一部分开发。 重复测量方差分析将用于检查自主神经阻滞前后年轻人和老年人之间绝对QT间期和QT离散度的差异。 此外，还将审查性别影响。

The purpose of this study is to examine the effects of aging on the QT interval and QT dispersion in both genders before and after autonomic blockade. Gender differences in the raw AT inverval with aging have been described but the interaction of gender and aging on QT dispersion are unknown. Forty young and forty elderly subjects without evidence of structural heart disease will be evaluated in the General Clinical Research Center at Northwestern Memorial Hospital. Subjects will undergo a screening visit to ensure the absence of structural heart disease or systemic diseases which would contraindicate autonomic blockade. On a subsequent visit, subjects will undergo routine 12 lead ECG and body surface maps at several stages: (1) At rest; (2) During staged bicycle exercise testing; (3) After the first drug of a double autonomic blockade protocol (atropine or propranolol); (4) After the second drug (propranolol or atropine); (5) During exercise testing after the administration of double autonomic blockade. The QT interval will be measured in the standard fashion. QT dispersion on the 12 lead EKG will be determined by both manual and computerized methods using algorithms that have been previously developed. QT dispersion on body surface maps will be analyzed using custom designed algorithms which will be developed as part of the study. Repeated measures of analysis of variance will be used to examine differences in the absolute QT interval and in QT dispersion between the young and elderly before and after autonomic blockade. In addition, gender effects will also be examined.