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 Heart Health - Detail

Heart Failure

Dr. Raymond Dong, Cardiologist

Heart failure can be simply defined as a condition in which the heart muscle pump cannot provide sufficient output to meet the needs of the rest of the body. The cardiac cycle has two main phases, consisting of systole (during which the pump pushes blood forward), and diastole (during which the heart muscle actively relaxes and fills with blood). Patients with heart failure can have isolated systolic failure, or they can have mostly diastolic dysfunction (where forward pumping remains intact). Many patients have a combination of both of these elements.

The number of people in Canada with heart failure is rising each year. There are approximately 600,000 such individuals at present. The causes of heart failure are many, and the most common of these include coronary artery disease, hypertension, and diabetes. Our ability to intervene early in the setting of acute heart attack has improved survival, but many of these patients have had some degree of damage to their ventricles (heart muscle pumps). Uncontrolled high blood pressure causes the heart muscle to become thick and stiff, leading to abnormal relaxation of the muscle, which causes impaired filling of the pump.

Other causes of heart failure include heart valve dysfunction (either reduced opening or incomplete closure), primary heart muscle diseases (cardiomyopathies), and metabolic conditions such as hyperthyroidism. Patients who drink excessive amounts of alcohol, or use illicit drugs such as cocaine are also more susceptible to developing heart failure. Less frequent causes of heart failure include sustained rapid heart rhythms, HIV, and certain congenital heart abnormalities.

Heart failure symptoms can be subtle or very obvious. Most patients will report shortness of breath, especially on exertion. There usually is weight gain due to fluid retention, and this can manifest as cough, inability to lie flat in bed, and waking up late at night with sudden shortness of breath. There may generalized fatigue, increased abdominal girth, and swelling of the lower body, starting at the ankles and progressing upwards. Depending on the cause of the heart failure, patients may also report effort-induced chest discomfort, and palpitations, lightheadedness and dizzy spells.

There are a number of steps that can be taken by doctors to arrive at a diagnosis and specific treatment plan for patients with heart failure. The first and most basic step is the taking of the medical history and the physical examination. Once the diagnosis of heart failure is suspected, the doctor will then proceed with a chest X-tray, an electrocardiogram, and some blood tests. A particularly useful blood test is the BNP (brain natriuretic peptide) which is a protein that is released from heart muscle tissue when the heart s pumping less than optimally. Also important are the serum electrolytes (sodium and potassium) and measures of kidney function. Further evaluation of heart function is usually done by echocardiography (which uses ultrasound to image the heart). Echocardiography is a powerful tool as it allows objective assessment of heart muscle size, pump function, and cardiac valve structure and function. Serial studies can be done for follow-up evaluation. Depending on the treatment plan, patients may also undergo cardiac catheterization (to assess the pressures inside the heart directly, and to visualize the coronary artery anatomy), and cardiac MRI, nuclear cardiac imaging, and even cardiac muscle biopsy.

Treatment of heart failure can be divided into an acute phase of management, wherein symptom relief is the primary goal, followed by a longer-term strategy of reducing morbidity and mortality. As patients report shortness of breath initially, removal of the excess retained fluid is accomplished with diuretics (which rid the body of salt and water). Early treatment with beta-blockers, and ACE inhibitors are equally important as these medications have been shown in large clinical trials to be of benefit. The severity of the heart failure can be clinically graded according to the patient’s exercise capacity. Some of the more severely affected patients may need other medications such as spironolactone, hydralazine, long-acting nitroglycerin and digoxin. Specific approaches to further management depend greatly on the cause of the heart failure. For example, patients with symptomatic coronary artery disease may require coronary artery angioplasty or bypass grafting, and those with leaking or narrowed heart valves may need valve replacement or repair..

When optimal medical therapy has been reached, there may be some patients who will benefit from additional therapies such as devices, or cardiac transplantation. These patients usually have remained very symptomatic and may receive biventricular pacing (where both the left and right ventricles are “resynchronized” to pump more effectively together). Severely compromised heart muscle pumps are more prone to develop serious cardiac dysrhythmias, and as such, an implantable cardioverter-defibrillator (ICD) may be prophylactically implanted to reduce the risk of sudden cardiac death. Newer technologies include left ventricular assist devices (mechanical miniature pumps that help to improve cardiac output) which can serve to stabilize a patient enroute to cardiac transplant, or if transplant is not an option, can serve as permanent destination therapy over a longer term.

Needless to say, with a chronic condition such as heart failure, the patient is always an active participant in his or her care. Heart function clinics specialize in caring for, and educating patients and their families as to how to live with their condition. Lifestyle changes with regards to salt and water management, monitoring of daily weights and learning how to recognize the signs and symptoms of worsening heart failure help to reduce the need for hospital admission. Cardiac exercise programs specifically designed for the heart failure patient improve quality of life and help reduce the fatigue that can develop as the rest of the body tries to adapt to a decrease in cardiac output.

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