Validity of standard deviation and maximum: Minimum ratio in quantifying cardiac autonomic function following acute unilateral brachial artery occlusion

Objective The clinical utility of analysis of heart rate variability is currently under research. We evaluated the validity of time domain measures of heart rate variability parameters in appraising the impact of acute unilateral brachial artery occlusion on cardiac autonomic control in healthy subjects. Methods In 11 healthy female volunteers aged between 20-25 years, R-R intervals and blood pressure were recorded for 30 s under resting condition and during occlusion of left brachial artery. Heart rate variability was quantified by time domain method. Mean differences in values of measured parameters were compared between resting and during brachial artery occlusion employing paired 't' test. Results Systolic and diastolic blood pressure increased significantly during occlusion phase compared to resting state (P < 0. 05, P < 0. 01 respectively). Among the measured time domain heart rate variability parameters, standard deviation of mean R-R interval (SDNN) and maximum; minimum ratio de -creased significantly during occlusion phase compared to baseline (t = 2. 36, P < 0. 05; t = 2. 76, P < 0. 05 respectively). Conclusion Acute unilateral brachial artery occlusion induced transient cardiovascular changes on cardiac autonomic control is better reflected in maximum; minimum ratio and SDNN.