Reproducibility of heart rate measured in the clinic and with 24-hour intermittent recorders

This study was undertaken to assess the reproducibility of office versus ambulatory heart rates in 839 hypertensive subjects participating in the Hypertension and,Ambulatory Recording Venetia Study (HARVEST). A 24-hour heart rate was recorded twice; this procedure was repeated three months later. Reproducibility was better for ambulatory than for office measurement, and was greater for 24-hour than for daytime heart rate, and lowest for night-time heart rate. Reproducibilty of office heart rate was impaired above 85 bpm, and was poorer in subjects with more severe office hypertension. A small but significant decrease in average daytime (-1 bpm, P < 0.0001) and virtually no change in night-time heart rate (-0.3 bpm, NS) were observed at repeat recording. Heart rate reproducibility indices were related to the extent of the heart rate and blood pressure white-coat effect, but did not vary according to age, gender, body mass index, day-night blood pressure difference, or alcohol or tobacco use, Results indicate that heart rate recorded over the 24 hours has a better reproducibility than office heart rate, and could thus be a better prognostic indicator than traditional measurement of resting heart rate in the hospital setting. Am J Hypertens 2000; 13:92-98 (C) 2000 American Journal of Hypertension, Ltd.