Until recently, most cases of congestive heart failure were believed to occur when the heart weakens and becomes unable to pump effectively—a condition known more specifically as systolic heart failure (SHF).
Now: A review of nearly 4,600 heart failure cases treated at the Mayo Clinic shows that a long-overlooked form of congestive heart failure, called diastolic heart failure (DHF), is even more common than SHF and is just as deadly. In 15 years, the proportion of heart failure cases caused by diastolic dysfunction jumped from 38% to 54%.
The Aging Heart
Normally, the heart muscle contracts and relaxes with every beat. The contraction phase, when blood is pumped out to the body, is called systole...the relaxation phase, when the heart refills with blood, is called diastole. With age or disease, such as high blood pressure, diabetes or atherosclerosis (plaque buildup in the arteries), the heart muscle may become weak and unable to pump effectively, resulting in SHF...or rigid and unable to relax and fill properly, leading to DHF.
*Blood pressure measurement of the pressure of blood against the walls of the main arteries-is expressed in terms of systolic pressure the top number) and dia stolic pressure (the bottom number).
Both SHF and DHF are chronic, progressive and often fatal. They produce identical symptoms—shortness of breath...inability to exercise...and fatigue. They can lead to lung congestion (fluid backup in the lungs) or swelling in the abdomen, lower legs or feet, caused by fluid and water retention (edema).
Important: It's impossible to distinguish SHF and DHF with a physical exam, X-ray or electrocardiogram a recording of the electrical activity of the heart). To get a definitive diagnosis, you need an echocardiogram (an ultrasound of the heart, which shows pictures of the valves and chambers). If you have been diagnosed with heart failure, ask your doctor about receiving an echocardiogram.
There's evidence showing that the incidence of DHF is rising-perhaps because our aging population is living longer with hypertension, atherosclerosis, diabetes and other diseases that can compromise diastolic functioning (as well as systolic functioning). Most cases of DHF are diagnosed in people over age 70, and, for unknown reasons, a disproportionate number of them are women.
Best Treatment Options
Although researchers are now beginning to recognize the prevalence of DHF, the treatment approach is less well defined than that for SHF The goal is to help manage symptoms related to fluid retention, such as edema and shortness of breath, and treat underlying conditions, such as hypertension, atherosclerosis, atrial fibrillation (irregular heartbeat), diabetes or high cholesterol, with medication and/or lifestyle changes.
Treatments for DHF…
- Diuretics to reduce excess bodily fluid and prevent pulmonary congestion or edema.
- Angiotensin-converting enzyme (ACE) inhibitors or other vasodilators to relax and widen blood vessels and lower blood pressure.
- Beta-blockers to slow heart rate, giving the heart more time to fill with each beat. Although the use of beta-blockers is standard in SHF, they're not always appropriate for DHF. That's because beta-blockers not only slow heart rate, but also reduce the heart's ability to relax.
However, in the first major beta-blocker study to include some older DHF patients, participants taking the new beta-blocker nebivolol had a 4.2% lower risk for heart failure-related hospitalizations and a 2.3% lower risk for death than the placebo group. Still, more research is needed, and the decision to use beta-blockers for DHF must be made on an individual basis, weighing the potential risks and benefits for the particular patient.
Diet And Exercise
DHF patients--as well as people with SHFshould eat a heart healthy diet rich in whole grains as well as vegetables and fruits...reduce their intake of sodium (especially if they have hypertension) to 2 g daily...and limit saturated fats and avoid trans fats.
Exercise is difficult for heart failure patients because they may experience shortness of breath, but if they can manage 30 minutes daily of a low-intensity activity, such as walking, cycling or water aerobics, it can help maintain and perhaps improve heart functioning.
Also helpful: Yoga or tai chi. In an Italian study published in The Lancer, heart failure patients who practiced yoga-like breathing for one month had higher resting blood oxygen levels, slower normal breathing rates and more endurance for exercise-all signs of improved cardiopulmonary functioning. (To find a yoga teacher, contact the American Yoga Association at 941927-4977 or www.americanyogaassociation.org)
Meanwhile, in a recent Harvard Medical School study, heart failure patients who participated in a twice-weekly, hour-long tai chi class for three months in addition to taking medication) were able to walk longer distances without getting winded and reported feeling better overall. (To find a tai chi class near you, visit the Tai Chi and Health Information Center Web site, www.americantaicbi.net.)
On The Horizon
As DHF becomes more widely recognized, scientists are increasingly making it a focus of their research. Promising therapies…
- Angiotensin receptor blockers (ARBs). Studies have shown that these blood pressure-lowering medications are useful for treating SHF Now researchers at Georgetown University Hospital in Washington, DC, are investigating whether theses drugs also may benefit DHF patients.
- Alagebrium. This new drug reduces arterial stiffness. In a recent trial at Wake Forest University in Winston-Salem, North Carolina, it was shown to significantly improve diastolic function in patients with DHF. Study participants taking alagebrium reported having more physical energy for daily activities and improved mental functioning. Larger studies are under way to confirm the effectiveness of alagebrium.
- Aldosterone receptor antagonists. These drugs, which act as potassium-sparing diuretics (causing the kidneys to excrete excess fluid while retaining potassium), are typically prescribed for hypertension or edema and have been shown to help SHF patients. In August, the National Institutes of Health launched the first large-scale clinical trial to determine whether an aldosterone antagonist called spironolactone Aldactone) helps DHF patients.
- Sildenafil (Viagra). Brazilian researchers recently reported that this impotence drug may safely lower blood pressure as well as resting heart rate and improve exercise tolerance in men who have both erectile dysfunction (ED) and congestive heart failure.
Sildenafil is not FDA-approved for heart failure treatment, but that may change if current studies yield positive results.
- Cardiac resynchronization therapy (CRT). In about one-third of heart failure patients, the heart's ventricles fail to beat simultaneously, which reduces pumping efficiency. With CRT, a specialized pacemaker is implanted, which re-coordinates the action of the heart's right and left ventricles.
In a recent study, CRT combined with drug therapy reduced the risk for hospitalizations and fatalities among SHF patients by as much as 20%. Researchers are planning trials to determine whether it may offer similar benefits to DHF patients.
Multidetector computed tomography (MDCT) lets doctors see plaque in arteries with a 15-second scan in the emergency room. Chest pain from heart attacks and angina rarely occurs without plaque buildup. A few hospitals can do MDCT now, and more are expected to in the future.