Office versus ambulatory heart rate in the prediction of the cardiovascular risk.
Numerous studies have shown that a high heart rate is associated with high blood pressure and various metabolic abnormalities, and that it is prospectively related to the development of hypertension and atherosclerosis. Almost all these data have been obtained from resting heart rate measured in the clinic, which is a highly variable clinical parameter. Ambulatory heart rate might afford greater precision of measurement than can be achieved using clinic measurement, as is suggested by recent data obtained in our laboratory. However, the lack of association of ambulatory heart rate with blood pressure and metabolic abnormalities suggests that it might be less predictive of cardiovascular morbidity than is clinic heart rate. A high heart rate might also induce the development of atherosclerotic lesions via hemodynamic disturbances. In this respect, heart rate recorded over the 24 h should be more representative of the whole-day arterial stress than are casual measurements. However, recent data indicate that the progression of coronary lesions in patients who have suffered myocardial infarction is predicted by the minimum heart rate rather than by average 24 h values. Only prospective studies based on the measurement both of clinic and of ambulatory hearft rates will clarify the respective roles of these two clinical entities.
Palatini
P
Department of Clinical and Experimental Medicine, University of Padova, Italy.