9[2]Ambepitiya G, Roberts M, Raniadayalan K, et al. Silent exertional myocardial ischemia in the elderly: A quantitative analysis of anginal perceptual threshold and the influence of autonomic function[J]. J Am Geriater Soc,1994, 42:732 - 737
10[3]Kleiger RE, Miller JP, Bigger JT, et al. Decreased heart rate variability and its association with increased mortality after acute myocardial infarction[J ]. Am J Cardiol, 1987, 59:256 - 262