High Blood Pressure + High Heart Rate = Increased MI Risk

Some weeks ago I reported that a high heart rate in women is as risky for heart attack as it is in men.  While a high heart rate (called tachycardia) is an independent risk factor, if it occurs in someone with high blood pressure the risk is probably even greater.  This was the finding reported at the American Society of Hypertension meeting in New York. 

Ann Arbor researchers analyzed data from a large anti-hypertension study, the VALUE trial, which included 15,245 patients from 30 countries; the study compared outcomes between two drugs: a calcium-channel blocker (amlodipine), and valsartan (an angiotensin receptor blocker, Diovan®).  As there was no significant differences between the two drugs in their outcomes, results from all the patients were pooled for this current analysis.

Each 10 beats per minute increase in baseline heart rate was linked with a 16% greater risk of cardiovascular death or illness. This relationship was maintained even in those patients whose blood pressure was controlled to below 140/90 mm Hg.  Moreover, analyses showed that baseline heart rate predicted events in both the early and the late stages of the study (an average of 4 years); this is considered important, because if a cardiovascular condition was responsible for the tachycardia, the frequency of events would have fallen off after the first two years.  Confirming this, the association was similar for heart rate measurements made during the course of the study.

The problem is, although tachycardia is an independent risk factor, it behaves a bit differently.  Lowering heart rate (with drugs and/or exercise) doesn’t always improve the outcome, according Dr Messerli, a New York hypertension expert.  So it’s not the same as other so-called independent risk factors, like glucose, lipids, blood pressure, where correcting them leads to a lower likelihood of a cardiovascular ‘event’, such as heart attack, stroke, severe angina, or cardiac death.  Maybe we should think about lowering heart rate by other means, such as mindfulness meditation?