Correlated study on cardiac contractility change trend and oxygen uptake and heart rate in human

Introduction

Using phonocardiography to evaluate the variation of cardiac contractility and cardiac contractility reserve have been proved that the amplitude of first heart sound directly reflect the variation of cardiac contractility, which has high correlated with the ventricle pressure. However, the relationship of cardiac contractility with oxygen uptake and heart rate were seldom studied. This study was designed to study the relationship of cardiac contractility change trend (CCCT) with oxygen uptake and heart rate during the exercise to provide a new noninvasive approach to measure and evaluate athletes′cardiac contractility and cardiac reserve.

Methods

The different grades athletes (n=20) and common college students (n=15) were randomly chosen as the subjects. They performed on Monark 830E Computerized Ergometer with increasing loads until fatigue. At the same time to get their cardiac contractility change trend (CCCT), peak heart rate and VO2max the Exercise Cardiac Contractility Monitor (ECCM) was put into use to detect the amplitude of first heart sound of the subjects during the different exercise stage, with respect to the amplitude of the first sound recorded at rest was defined as CCCT. The MAXⅡ Exercise Cardiopulmonary Function Monitor and Polar Heart Rate Monitor were applied to monitor the oxygen uptake and heart date. The data were analyzed by SPSS11.0.

Results

Cardiac contractility change trend was correlated highly with oxygen uptake(r=0.589～0.978)and heart rate (r=0.739 0.986)during exercise and convalescence. The correlation coefficients were analyzed (rCCCT-HR=0.935, rCCCT-VO2=0.90) through one sample T test by SPSS11.0.

Discussion / Conclusions

There was a closely correlation between cardiac contractility change and oxygen uptake, heart rate respectively. Therefore, CCCT could be used to measure cardiopulmonary function of athletes and ordinary people. Also it could be applied to monitor exercise process and evaluate fatigue. This noninvasive method is worth studying further.