Heart Failure: The Price of Success

In 1953, surgeon John Gibbon undertook the first successful open heart surgery using a heart-lung machine, a pump that performs both heart and lung functions while the heart is stopped for repairs.  The pump ushered in a new era of cardiac surgery and made it possible to correct heart problems that had up until then caused premature disability and death.

In the years that followed Dr. Gibbon’s groundbreaking surgery, materials science, technology and pharmacology advanced rapidly, allowing surgery and medication to be used to treat a wider variety of heart problems, including heart attacks. Today we live in an age of coronary artery bypass surgery, clot-busting drugs,  and stents that prop open diseased coronary arteries. Advancements such as these have reduced death rates from heart attacks substantially; nonetheless, heart disease remains the number one killer of men and women in the United States, and heart failurethe constellation of symptoms that come from poorly contracting heart muscle –  is now the leading cause of hospitalization for patients over the age of sixty-five. With all of the progress that has been made in cardiovascular care, how can this be?

Why is there more heart failure now than in the past?

The answer is simple. Mortality rates are lower in the immediate aftermath of heart attacks because of the ability to dissolve clots and prop arteries open. Drugs and lifestyle management may be slowing the progression of the coronary artery disease that causes heart attacks. As a result of these advances, people no longer die as often in the earlier phases of a very long disease process which often ends in failure of the heart muscle to contract as strongly as it needs to.

If you liken cardiovascular care to home repairs, then the major advances in care ­­­have taken place in areas roughly equivalent to plumbing and electrical maintenance. Angioplasties, coronary artery bypasses, and stents are used to keep the pipes open; electronic pacemakers provide power, triggering muscle contractions in an organized fashion, while defibrillators restart the power when there are outages. A house with functional plumbing and electrical systems remains habitable remains habitable long enough for the underlying structural elements of the building, like the roof, ceilings, walls, and floors, to begin to fail. In the heart, the underlying structural element is muscle. When the muscular structure of the heart begins to fail, the signs and symptoms of heart failure appear.

Signs and symptoms

Heart muscle fibers that begin to contract less efficiently reduce the heart’s pumping capacity, preventing adequate blood flow to the major organs. The body reacts to this deficient blood flow by increasing the volume of blood in the body. It accomplishes this by retaining more salt and water, but when this happens, the blood’s increased volume stretches the failing heart muscle and damages it even further. The more the heart stretches, the less efficiently it pumps; the less efficiently it pumps, the more the body tries to boost blood flow by retaining fluids.

This vicious cycle results in what is known as congestion. Congestion occurs when the tissues, including the lungs, becoming filled with excess fluid. This fluid buildup causes swelling in the legs and abdomen and a shortness of breath. Fatigue and an inability to tolerate exercise are the heart failure patient’s constant companions. Gravity causes fluid to collect in the lower half of the body while the patient is standing or sitting, and when he lies down, it becomes redistributed, accumulating in the lungs where it can cause a telltale shortness of breath that is symptomatic of a deteriorating heart.

Causes

Age is an important contributing factor in the development of heart failure because the longer people live, the more time there is for coronary artery disease and the problems that contribute to it to take their toll on the heart muscle. Coronary artery disease deprives areas of the heart of blood and oxygen, leaving behind damaged muscle that contracts poorly and moves blood inefficiently. Smoking, excessive alcohol use, diabetes, hypertension, obesity, and lack of exercise contribute not only to coronary artery disease, but also to weakening the heart muscle directly. Less common factors involved in heart failure include viral infections that affect the heart and a variety of rare metabolic conditions that disrupt heart muscle fibers. Heart valve disease, when left untreated, can ultimately damage the heart by dilating it or causing it to thicken. However, valve disease is much less prevalent since the development of successful antibiotic treatments for childhood streptococcus infections.

Treatment

The quality and length of life heart failure patients can expect depends on how closely they adhere to the treatment plans provided by their doctors. Salt-restricted diets are a very important part of a heart failure treatment plan, and the mainstays of drug treatment plans are medications that prevent salt retention, get rid of excess water, improve the ability of the heart muscle to contract, and decrease blood pressure. Heart failure treatment treads a fine line between causing the patient’s body to retain too much and too little fluid. Drying a heart failure patient out too much can push the kidneys into failure. Too little and the lungs are liked soaked sponges, unable to exchange carbon dioxide for oxygen efficiently.  The margin of error in fluid balance gets smaller and smaller as the disease progresses and this tightening window contributes to high hospital readmission rates for congestive heart failure patients.  Physicians must monitor their patients’ weight, symptoms, electrolytes, and kidney functions more and more closely and start adding tests like chest X-rays and echocardiograms.

A variety of innovative devices and surgical procedures have been designed to cinch up dilated, failing hearts but have not succeeded in producing adequate results. Some success is being reported from the use of multiple pacemakers, which allow different segments of the heart to be stimulated in a defined order that improves the sequence of muscular contraction enough to generate greater cardiac output. Currently, bi-ventricular pacing—the separate pacing of both sides of the heart–is the most promising addition to the heart failure treatment arsenal. Cardiac transplantation remains the most difficult, expensive, and uncommon solution for a heart that has reached the end of its functional life.

Heart failure may eventually be overcome by artificial pumping devices or methods of stimulating the production of new cardiac muscle, but in the meantime, prevention is still the most desirable treatment option. Not smoking, maintaining a healthy weight and good exercise habits, sticking to a balanced diet of fresh foods, getting adequate sleep, and managing stress well are all cheap and valuable ways to invest in your heart’s health.

 

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