Heart rate stability in a clinical setting and after a short exercise in healthy male volunteers.

INTRODUCTION: Limited data exists on heart rate stabilization in the domiciled nature of phase I clinical studies, particularly when frequent measurements of QT intervals are involved. The present analysis aimed to evaluate heart rate stability in the domiciled nature of, and stabilization after a short exercise.

METHODS: 56 healthy male subjects were included in this analysis. Data during a domiciled clinical setting and after a short exercise were analyzed. Mean values of 30 second intervals of collected electrocardiographical data (PR, RR, QT and QTcF intervals) during a 10-minute supine resting period in a domiciled nature or after walking up and down three stories (100 steps) were compared to baseline values using paired t-tests or compared to the intrasubject standard deviation.

RESULTS: Stable heart rates and stable QTcF intervals observed immediately upon assuming a supine position in the domiciled clinical setting. After the short exercise, PR interval and RR interval were significantly (p<0.05) shorter for up to 120 seconds (mean value -9.8 ± 7.2 ms) and 30 seconds (-160 ± 165 ms, p<0.05), respectively. QT and QTcF intervals were significantly (p<0.05) shorter for up to 90 and 120 seconds post exercise, respectively. Both QT and QTcF intervals stabilized after 2 minutes, but QT interval remained prolonged while QTcF interval returned to baseline levels.

CONCLUSION: In a clinical setting, male volunteers do not require a waiting period for electrocardiographic parameter normalization. However, accurate measurement of these parameters following a short exercise necessitates a minimum two-minute resting interval. This article is protected by copyright. All rights reserved.