Heart rate and systolic blood pressure response during the early exercise test and cardiovascular mortality after myocardial infarction

Abstract

Exercise cardiography still remains the cornerstone of noninvasive evaluation of functional status of cardiovascular system and is almost uniformly performed after myocardial infarction. The patients after myocardial infarction can be divided into relative high- and low-risk groups for subsequent cardiac events if all information available on the exercise test is used. Objective. The aim of this study was to evaluate the prognostic significance of the shape of heart rate and systolic blood pressure curves (their dynamic characteristics) during the early exercise testing and after it and to design the prognostic system capable to recognize patients with a high risk of coronary death during 2 years after myocardial infarction. Material and methods. The submaximal exercise testing within 3 weeks of acute myocardial infarction was performed on 894 patients. Cases of noncardiac deaths or patients subjected to coronary bypass surgery were excluded from the further analysis. At the end of 2 years after myocardial infarction, there were 426 survivors and 42 cases of cardiac death. At 2-year follow-up after infarction in the nonsurvivor group, there were only 42.2% of patients with exercise-induced ST segment depression. This shows that prognostic importance of ST depression is insufficient and demands research of more consistent signs. Results. The cardiovascular response to exercise was interpreted as transiting process of self-regulation of cardiovascular system, and the new predictive signs were found based on the curves of heart rate and systolic blood pressure during the exercise and after it. The prognostic value of these signs was established. The combined use of both the new predictive signs and usual data of early exercise test shows the high predictive possibility of test – the early cardiac death was predicted in 80% of cases. Conclusion. The combined use of both, the widely accepted data of early exercise test after myocardial infarction and dynamic characteristics of heart rate and systolic blood pressure, increased the predictive power of the test.