HEALTH; Personal Health
By Jane E. Brody
Published: May 11, 1989
The last two decades have seen a dramatic improvement in the ability to prevent and treat life-threatening heart disease. Changes in living habits, like eating less fat, stopping smoking and getting more exercise, are stemming the epidemic of coronary deaths. And the lives of those already afflicted with heart disease are being prolonged by coronary care units, pacemakers, bypass surgery and drugs that stimulate the heart, thin the blood and lower cholesterol and blood pressure.
But many heart problems remain unconquered, and one of them, wildly erratic heart rhythms, costs hundreds of thousands of American lives each year. Although significant progress has been made in controlling these arrhythmias, the new techniques have not yet reached the vast majority of potential beneficiaries.
For many victims, the rapid-fire, ineffectual beating of their hearts that leads to circulatory collapse and death is their first sign of cardiac trouble.
Often these victims have what cardiologists call ''hearts too good to die.'' The muscle itself is strong. Perhaps 15 to 20 percent have no evidence of coronary heart disease and half have no coronary risk factors like smoking or high cholesterol. The problem is an electrical aberration in the heart. If it was detected and controlled in time, they might live for years as if nothing had happened.
For others, unstable and potentially lethal heart rhythms occur repeatedly, causing dizziness, even loss of consciousness, and cumulative damage to heart muscle. In effect, they have time bombs in their chests.
Arrhythmias cause at least 400,000 sudden deaths each year, or more than two-thirds of the nation's heart-related fatalities, said Jeffrey Rothfeder, a medical writer who spent four years studying the problem.
Only 100,000 of those whose hearts leap into a lethal rhythm are resuscitated fast enough to survive. And only about 3,000 people prone to arrhythmias are being treated at medical centers that are expert in diagnosing and treating the electrical instability, said Mr. Rothfeder, the author of ''Heart Rhythms,'' recently published by Little, Brown ($17.95)
Causes of Arrhythmia: Nearly everyone has experienced an occasional brief arrhythmia, the heart skipping a beat. Such benign, self-correcting palpitations might be set off by a near-accident, too much caffeine, the sight of a former lover, or nothing at all.
Life-threatening arrhythmias are like a chain of skipped beats. Electrical impulses in the heart's main pumping chambers, the ventricles, fire so fast and irregularly that the heart muscle cannot contract effectively to pump blood to the rest of the body.
These misfirings often do not reverse themselves and instead deteriorate into ventricular fibrillation - impulses so rapid that the heart can only twitch, not pump. The brain, deprived of oxygen-containing blood, loses consciousness. After several minutes of disrupted circulation, the person in cardiac arrest dies.
Cardiopulmonary resuscitation, administered when a person stops breathing and collapses with no detectable pulse, can temporarily maintain blood flow to the brain until advanced equipment can shock a fibrillating heart back to a normal rhythm.
Potentially fatal arrhythmias can be triggered by damage to the heart muscle, such as when a blocked coronary artery cuts circulation to part of the heart. One prime benefit of a coronary care unit in a hospital is the ability to detect and rapidly reverse erratic heart rhythms in people recovering from a myocardial infarction, or clot-caused heart attack.
Scars on the heart muscle left by a previous heart attack, including ''silent'' atttacks that slip by undetected, can also become focal points for aberrant rhythms. Even a brief disruption in blood flow to part of the heart can cause arrhythmias.
The role of emotional distress in arrhythmia is controversial, but doctors and patients alike have described thousands of cases in which fatal arrhythmias occurred after extreme emotional distress, like fear, depression or anger. Experts believe that the chemicals released under stress send conflicting signals to the heart, causing fibrillation in hearts already affected by disease.
In still other cases, there may be no identifiable physical or emotional cause of arrhythmia. But whatever the reason, patients saved from one episode of ventricular fibrillation are highly susceptible to a recurrence, usually within months.
Treatments: Before 1960, people prone to episodes of abnormally rapid ventricular contractions, called tachyarrhythmias, faced a 50 to 80 percent risk of dying suddenly within six months of the start of the abnormality.
Through various devices that monitor heart rhythms, like the portable Holter monitor that records the heart's electrical rhythms in the course of daily living, patients at risk of developing ventricular fibrillation can often be identified in time to introduce preventive therapy.
In the last three decades various treatments have been introduced that can reduce the risk of rhythmic aberrations or abort those that occur. The field is still evolving and current treatments are far from perfect. But when they work, they can save many hearts. Mr. Rothfeder, an editor at Business Week who is also a medical science writer, outlines these approaches in his book: