Heart rate as a cardiovascular risk factor: Do women differ from men?

Considerable progress has been made in our understanding of the role of hig h heart rate in determining cardiovascular morbidity and mortality. However , whether the association between fast heart rate and cardiovascular diseas e is equally strong in males and females is still a matter far debate. In m ost studies, the predictive value of tachycardia for all-cause mortality ha s been found to be weaker in women than in men, and in some studies no asso ciation between heart rate and cardiovascular mortality was observed. In pa rticular, high heart rate appeared to be a weak predictor of death from cor onary heart disease in the female gender. Multiple mechanisms by which symp athetic overactivity could cause hypertension and the metabolic syndrome of insulin resistance have been documented. Recent results obtained at the An n Arbor laboratory from the analysis of four populations indicate that thes e mechanisms are operative mostly in males in whom tachycardia reflects a h eightened sympathetic tone. in women, fast heart rate would merely represen t the extreme of a normal distribution. However, tachycardia can also have a direct impact on the arterial wall, as demonstrated in laboratory studies , and can favour the occurrence of cardiac arrhythmias. The impact of these mechanisms may be similar in men and women and could explain why a high he art rate has been found to have a detrimental effect also in the female gen der. Pharmacological reduction of high heart rate is an additional desirabl e goal of therapy in several clinical conditions such as hypertension, myoc ardial infarction and congestive heart failure. Although a greater effect i s expected in men, cardiac slowing could counteract the detrimental haemody namic effect of tachycardia also in women.