A Heart Attack is the popular term for an acute failure of the pumping action of the heart, accompanied by lung congestion and the accumulation of fluid in the dependent parts of the body. The symptoms of a heart attack include coughing, copious frotiiy spittie, discomfort when lying down, labored breatiiing, rapid heart action, blueness of the skin and lips, swelling of the legs, and fatigue. Heart attacks are a leading cause of death, particularly among men, and more than 500,000 people in the United States die from heart attacks every year.
Causes of Heart Attacks
A major cause of heart fadure is coronary thrombosis. In this disorder, a blood clot in one of the small coronary arteries obstructs the delivery of blood to a portion of the heart. If the affected muscle segment dies, the heart may no longer be able to function properly. Odier leading causes of heart attacks include severe hypertension (excessively high blood pressure) and obstructions or leaks in one or more of the heart valves. Heart failure may occur widiin a few minutes after a coronary tiirombosis or may develop slowly over several weeks as when a valve is obstructed.
No matter what the underlying cause of heart failure may be, the heart's main pumping chamber, the left ventricle, becomes overburdened and cannot pump away the volume of blood tiiat returns to it. As a result, blood becomes dammed back in the left atrium and in the veins that drain the lungs, and as the pressure rises in the lung blood vessels, the distended lung capillaries protrude into the air spaces and become covered with fluid seeping out of tiiem, thereby diminishing the uptake of oxygen by the blood. The excess fluid in the lungs causes coughing, air hunger, and resdessness. Fluid may also accumulate in the chest cavity, sometimes causing a lung to collapse.
Once the lungs are congested with blood, the blood pressure in the lung arteries rises, overloading the right ventricle and sometimes causing it to fail. The pressure tiien rises in the large veins that empty into the right atrium. This elevated venous pressure increases the pressure in the capillaries throughout the body, and fluid seeps out of them, especially into the dependent parts of the body. When the patient is lying down, the fluid accumulates in the area of the sacrum; when he is standing, it accumulates in the legs. As much as 10 liters (over 10 quarts) excess of fluid may accumulate in the body. When the patient goes to bed, much of this fluid is returned to the blood and is transferred to the lungs. Widiin an hour after going to bed, the lung congestion causes labored breathing and fits of coughing, which often awaken the patient. If he gets out of bed and walks around, he experiences relief because the fluid becomes redistributed to his legs.
Treatment of Heart Attacks
Heart failure is treated with bed rest, usually in a sitting position, removal of excess blood from the circulation (by bleeding or by temporary tourniquets at the extremities), and the administration of oxygen, morphine, and heart stimulants. Fluid loss is encouraged by drugs that increase urine output and by a low sodium thet that reduces the body's tendency to retain fluids. After acute symptoms are relieved, the specific cause of the attack is diagnosed and, if possible, treated.