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An Overview of Heart Disease in Women

Paula Kinnunen, MD, treating a patient

Cardiovascular disease is the leading cause of death for American women, accounting for 45 percent of all fatalities. Although the prevalence of symptomatic coronary disease is higher in men in every age group except the elderly, an equal number of men and women die each year from heart disease, due to the higher mortality rate in women.

A quarter of a million women die each year from heart attacks - far outnumbering deaths from cancer - but awareness of heart disease as a potential health risk in women has lagged behind awareness of other health problems, such as breast cancer. This gap is due, in part, to women developing heart disease at an older age than men, and to the focus on male cardiac patients in most clinical trials to-date.

Gender Differences in Heart Disease

Studies reporting separate data for female and male participants have indicated that women typically are older than men by 10 to 20 years when they first present with coronary artery disease. According to the Framingham Heart Study, mortality after a heart attack is significantly higher for women. In addition, more recent data indicate that the risk of dying in the hospital after a heart attack is significantly higher for young women compared to men of the same age, debunking the myth that women's poorer prognosis is due to older age when symptoms first present.

Once diagnosed with heart disease, women fare worse than their male counterparts, which is reflected in poorer overall survival rates. One explanation for this difference includes the fact that therapeutic interventions such as coronary angioplasty or stenting, thrombolytic therapy, and coronary artery bypass graft surgery all carry higher complication and mortality rates for women.

Women's hearts also differ electrically from men's. Beginning at puberty, women have longer QT intervals, which represent the time for both ventricular contraction (stimulation) and ventricular relaxation (recovery), than men. This makes women more susceptible to potentially lethal ventricular arrhythmias as a complication of therapy with certain drugs. Female family members with inherited long QT syndrome are more vulnerable to sudden cardiac death.

In addition, female hormones affect cardiac electrical properties, and fluctuations in these hormone levels during pregnancy, the menstrual cycle, and menopause may predispose women to develop supraventricular arrhythmias (abnormal heart rates that originate above the ventricles, within the sinus node or atrium).

Hormone Therapy & Heart Disease Prevention in Women

Several recent, large-scale studies such as the Women's Health Initiative (WHI), the Postmenopausal Estrogen and Progestin Interventions (PEPI) and the Heart and Estrogen/Progestin Replacement Study (HERS) have shed light on the role of hormone therapy in coronary disease prevention in women. These studies have also highlighted the need for clinical trials regarding cardiovascular disease therapy specific to women.

The recently published HERS study showed that estrogen plus progesterone did not provide cardiac protection for women with known coronary disease, despite favorable effects on lipid profiles. In addition, the WHI prematurely terminated its study of postmenopausal estrogen plus progesterone therapy because of an increase in adverse cardiac events in the group receiving therapy. Given these reported poorer outcomes, coronary prevention has become recognized as a crucial public health issue for women, in addition to being extremely important for individual patients regardless of gender.

Heart Disease Risk Factors in Women

Recognized coronary risk factors in women include hyperlipidemia, hypertension, diabetes and a family history of premature coronary disease. With respect to the prevention of coronary artery disease, lipid profiles need to be interpreted with knowledge of the patient's sex: in men, LDL (bad) cholesterol is the primary determinant of coronary risk, whereas HDL (good) cholesterol levels are the most important determinant of subsequent coronary risk for women. Increased risk for women begins with HDL levels of less than 50.

Systolic hypertension is more prevalent in women, with a marked increase in incidence with age. Adequate blood pressure control significantly reduces the risk of both stroke and coronary artery disease. Smoking, another modifiable coronary risk factor, is actually increasing in young women. And, young women who smoke and take oral contraceptives are at an extremely high risk of heart disease compared to their nonsmoking peers.

Recognition of coronary risk factors - and their modification, if possible - should be a part of every woman's health evaluation, including measurement of blood pressure, lipid levels, blood glucose, and determination of smoking status and family history of heart disease. Newer markers of coronary risk such as C-reactive protein and homocysteine also should be measured on a case-by-case basis.

Diagnosing Heart Disease in Women

The diagnosis of coronary disease is also more difficult in female patients. Parameters for exercise stress testing were initially developed for male patients, so there are more frequently false positive tests in females due to circulating estrogen. Exercise imaging tests using current methods, however, are equally accurate in male and female patients.

Important gender differences also exist for patients with congestive heart failure (CHF). CHF in male patients is more frequently due to impaired systolic (pumping) function, whereas women are much more likely to have CHF due to abnormal diastolic (filling) function, a condition less well understood.

Treating Women with Heart Disease at Lahey Clinic

Women with heart disease can receive comprehensive cardiac care at Lahey Clinic. Our extensive services and capabilities include (among other elements):

Senior staff physicians with clinical expertise in women's cardiac issues
A full range of diagnostic cardiac testing, interventional cardiology and electrophysiology services
Access to a Lipid Clinic, where patients receive thorough evaluation and expert advice regarding management of their lipid abnormalities
Published works by staff physicians on gender differences in cardiovascular disease (i.e., male versus female responses to hypertension and aortic stenosis)

Further Information

For further information on Lahey's services for female cardiac patients, please contact the Department of Cardiovascular Medicine at 781-744-8460.

Women & Heart Disease: Gender Differences in Cardiovascular Health