the reason a small HRT also predicts a likelihood of death from non-cardiac causes as well as from cardiac causes. See also Heart rate variability References Further reading Georg Schmidt, "Heart-rate turbulence after ventricular premature beats as a predictor of mortality after acute myocardial infarction. Lancet 1999; Vol. 353; No. 9162; 1390-96" Mari Watanabe, "Heart Rate Turbulence: a Review", Indian Pacing Electrophysiol. J. 2003;3(1):10 Cardiology Cardiac electrophysiology