HEART RATE VARIABILILTY AND SUDDEN CARDIAC DEATH

心源性猝死通常是由恶性心室 心律不齐 恶性室性心律失常，冠心病 疾病，是由于基质之间的相互作用（疤痕 心室），触发事件（自发性心室 心律失常）和自主神经系统。 无创 需要有方法来评估风险的这三个组成部分， 以制定全面的检测和预防方案。 有合理的非侵入性筛选试验， 致心律失常底物（左心室射血分数和 信号平均心电图），以及用于触发事件 （24小时连续ECG记录）。 我们认为， 心率或心动周期变异性可以提供用于 自主神经系统活动的非侵入性评估。 我们 已经发现，一个宽频带的测量心脏周期的变异性， 在一个连续的时间序列中，所有正常R-R间期的标准差 24-在心肌梗死后11 ± 3天进行1小时ECG记录 梗死，预测死亡率在随后的2至4年 独立于左心室功能障碍和自发性 室性心律失常 我们建议评估各种 测量时间内的心率或周期变异性， 在心肌梗死后早期， 预测死亡的准确性（总死亡、心源性死亡、猝死和 死亡）。 我们将比较短和长的测量结果- 术语心率和心动周期变异性。 我们将确定 我们的日常可重复性和变化的时间过程 心率变异性和心率变异性的测量 在心肌梗死后晚期测量随后的死亡率 和恶性室性心律失常的发展。 我们将 对比心率和心动周期变异性结果， 年龄和性别匹配的正常人心肌梗死 受试者和恶性心室肌纤维化患者的研究 心律不齐 我们将在几个大型的 既往心肌梗死患者样本或 恶性室性心律失常和正常 科目 我们希望开发新的、改进的非侵入性方法 用于检测那些最有可能发展为恶性肿瘤的患者 室性心律失常和心源性猝死， 以改进对心脏性猝死的检测和预防。

Sudden cardiac death usually is caused by malignant ventricular arrhythmias. Malignant ventricular arrhythmias, in coronary heart disease, are due to an interplay among substrate (scarred ventricles), triggering events (spontaneous ventricular arrhythmias), and the autonomic nervous system. Non-invasive methods are needed to evaluate these three components of risk in order to develop comprehensive detection and prevention programs. There are reasonable non-invasive screening test for the arrhythmogenic substrate (left ventricular ejection fraction and signal averaged electro-cardiograms), and for triggering events (24-hour continuous ECG recordings). We believe that measures of heart rate or heart period variability may provide the means for non-invasive assessment of autonomic nervous system activity. We have found that a broad band measure of heart period variability, the standard deviation of all normal R-R intervals in a continuous 24-hour ECG recording made 11 plus/minus 3 days after myocardial infarction, predicts mortality in the subsequent two to four years independently of left ventricular dysfunction and spontaneous ventricular arrhythmias. We propose to evaluate various measurements of heart rate or period variability in the time and frequency domains made early after myocardial infarction for their accuracy in predicting death (total, cardiac, sudden, and arrhythmic death). We will compare measurements of short and long- term heart rate and heart period variability. We will determine the day-to-day reproducibility and the time course of change of our measures of heart rate variability and heart rate variability measured late after myocardial infarction for subsequent mortality and development of malignant ventricular arrhythmias. We will contrast the heart rate and heart period variability findings after myocardial infarction with those in age and sex matched normal subjects and with those made in patients with malignant ventricular arrhythmias. We will conduct these analyses in several large samples of patients with previous myocardial infarction or malignant ventricular arrhythmias and in a sample of normal subjects. We hope to develop new, improved non-invasive methods for detecting those patients most likely to develop malignant ventricular arrhythmias and sudden cardiac death and point the way to improved detection and prevention of sudden cardiac death.