Results of estimation of variability of cardiac rhythms in patients with coronary heart disease during coronary artery bypass surgery are presented. The aim of the study was to search for innovative methods for the assessment of the patients' conditions as a criterion for their rational choice for cardiosurgical intervention to enable adequate anesthesiological support and postoperative follow-up. We revealed additional characteristics of cardiac rhythm variability facilitating such choice and predictors of the risk of life-threatening heart arrhythmias. It is shown that high-resolution analysis of cardiac rhythms allows such peculiarities of dynamics of patient's conditions to be revealed that can not be exposed by the existing standard methods.