Should the heart rate of hypertensive patients influence clinical decisions?

Abstract

Although heart rate (HR) is commonly recorded multiple times when blood pressure (BP) is measured, particularly when automatic devices are doing it in the clinic, at home, or during 24-hour ambulatory blood pressure monitoring (ABPM), many clinicians tend to ignore the HR unless it is extremely high or low. But perhaps this is inappropriate, because there is a great deal of information accumulating that indicates that HR is a significant predictor of cardiovascular risk. There are at least 2 prognostic issues that might be predicted by a rapid HR that could in theory affect how aggressively we treat our patients. The first is that in younger persons with borderline hypertension, a high HR may predict the development of sustained hypertension, and the second is the prediction of cardiovascular events in older persons. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) acknowledged this with the following statement: ‘‘Data from epidemiologic studies and clinical trials have demonstrated that elevations in resting HR and reduced HR variability are associated with higher cardiovascular risk. In the Framingham Heart Study, an average resting HR of 83 beats ⁄min was associated with a substantially higher risk of death from a cardiovascular event than the risk associated with lower HR levels.’’ This statement was based on a Framingham report that used HRs taken during routine clinic visits in patients with less severe hypertension who were not originally on treatment and that concluded that a big difference in HR (40 beats ⁄min) was associated with a doubling of mortality. There has been much interest in the variability of HR, which reflects the degree of autonomic control, and as also mentioned in JNC 7, reduced HR variability has also been associated with increased cardiovascular morbidity. However, it is of course not part of any routine clinical examination, so it need not be further discussed here. One issue that is critical is how and when the HR should be measured for clinical use. This is discussed below.