Correlation between time-domain measures of heart rate variability and scatterplots in patients with healed myocardial infarcts and the influence of metoprolol.
Keeley EC, Lange RA, Hillis LD, Joglar JA, Page RL. Correlation between time-domain measures of heart rate variability and scatterplots in patients with healed myocardial infarcts and the influence of metoprolol. Am J Cardiol. 1997 Feb 15; 79(4):412-4.