High resting pulse increases risk of MI, coronary death in women

Moral of the story: know your risk factors. Are you female? Do you have a resting heart rate higher than 75 bpm? Then you are at an increased risk for MI (heart attack) and coronary disease/death. Make sure to take especially good care of your heart if you fall into both of those categories

Heartwire
Clinical cardiology
High resting pulse increases risk of MI, coronary death in women
February 4, 2009

Washington, DC - A high resting heart rate is associated with an increased risk of MI or coronary death in females, a new analysis from the Women's Health Initiative (WHI) shows [1]. Dr Judith Hsia (AstraZeneca, Wilmington, DE, who was at George Washington University when this research was done) and colleagues report the findings online February 3, 2009 in BMJ.

"Multiple studies in men have previously shown that a high heart rate, after adjustment for other potential confounders such as blood pressure and cholesterol, is associated with an increased risk of heart attack and coronary death," Hsia explained to heartwire. "But this is the first demonstration in women that having a high heart rate increases this risk."

She points out that it was only women in the highest quintile (with a heart rate of 76 bpm or higher) who had a significantly increased risk and that there was no relationship between high resting pulse and risk of stroke in this cohort.

In terms of implications for doctors, Hsia says, as physicians already check resting pulse as part of their global cardiovascular risk assessment, "they may just consider this in addition to the factors they already use when deciding how aggressively people need to be managed. If, for example, you have a patient who is reluctant to take something for their blood pressure or cholesterol, maybe they should think again if they have a high resting heart rate."

Association present across ethnic groups, strongest in younger women

In their analysis, Hsia et al identified 2281 women with MI or coronary death and 1877 with stroke over a mean of 7.8 years of follow-up among 129 135 postmenopausal women in the WHI with no history of cardiovascular events. They evaluated associations between resting heart rate and cardiovascular events in Cox regression models adjusted for multiple covariates. Hsia points out that the WHI is one of the few studies to have detailed information on physical activity, which was also adjusted for.

Higher resting heart rate was independently associated with a 26% increased risk of coronary events (hazard ratio 1.26 for highest quintile [>76 bpm] vs lowest quintile [<62 bpm]; p=0.001), but not with stroke (HR 1.01).

The relation between resting pulse and risk of coronary events was stronger in younger postmenopausal women (aged 50 to 64) than in older ones (65 and over), and heart rate was similarly predictive for coronary events across all ethnic groups included in the study, Hsia said.
What's attractive about this analysis is that heart rate is such a low-tech assessment.
The strength of this association, from lowest to highest quintile of heart rate, is less than the association with cigarette smoking or diabetes mellitus, Hsia and colleagues add, but they say it "might be large enough to be clinically meaningful," and they stress that it is independent of physical activity.

"We don't know exactly why this higher heart rate is associated with increased heart-attack risk," Hsia told heartwire. "Heart rate is thought to reflect a balance between the adrenaline side of the system and the vagal side, so it may be that the 'thermostat' is set on the high side for adrenaline in those women who have a higher heart rate.

"What's attractive about this analysis is that heart rate is such a low-tech assessment" compared with more elaborate, time-consuming, and expensive methods to assess autonomic tone, she concludes.

Source
Hsia J, Larson JC, Ockene JK, et al. Resting heart rate as a low tech predictor of coronary events in women: prospective cohort study. BMJ 2009; DOI:10.1136/bmj.b219. Available at: http://www.bmj.com.