These disorders are grouped according to whether they affect primarily the heart or the blood vessels. In some cases, the underlying cause of a heart ailment is a blood vessel disorder.
Arrhythmia, or dysrhythmia, refers to an abnormal heartbeat. It may be caused by a number of factors, including damage to the heart conduction system, drugs, electrolyte imbalance, or a diminished supply of blood via the coronary arteries. In addition to irregular heartbeats, arrhythmia includes
- Bradycardia-a slow heart rate of less than 60 beats per minute. Note that the bradycardia in well- trained athletes is a healthy condition because it saves energy during resting heart contraction and has a greater potential to increase cardiac output.
- Tachycardia-a fast heart rate of over 100 beats per minute.
- Heart flutter-a very rapid heart rate of 200 to 300 beats per minute.
Fibrillation-a very rapid heart rate in which the contractions are uncoordinated so that blood is not pumped from the ventricles. Ventricular fibrillation is usually fatal without prompt treatment.
Congestive heart failure (CHF) is the acute or chronic inability of the heart to pump out the blood returned to it by the veins. Symptoms include fatigue; edema (accumulation of fluid) of the lungs, feet, and legs; and excess accumulation of blood in internal organs. CHF may result from atherosclerosis of the coronary arteries, which deprives the myocardium of adequate blood.
Heart murmurs are unusual heart sounds. They are usually associated with defective heart valves, which allow a backflow of blood. Unless there are complications, heart murmurs have little clinical significance.
Myocardial infarction (mf-o-kar’-de-al in-fark’-shun) is the death of a portion of the myocardium due to an obstruction in a coronary artery. The obstruction is usually a blood clot that has formed as a result of atherosclerosis. This event is commonly called a “heart attack,” and it may be fatal if a large portion of the myocardium is deprived of blood.Pericarditis is the inflammation of the pericardium and is usually caused by a viral or bacterial infection. It may be quite painful as the inflamed membranes rub together during each heart cycle.
Blood Vessel Disorders
An aneurysm (an’-yu-rizm) is a weakened portion of a blood vessel that bulges externally, forming a balloonlike sac filled with blood. Rupture of an aneurysm in a major artery may produce a fatal hemorrhage.
Arteriosclerosis (ar-te”-rfo-skle-ro ‘-sis) is hardening of the arteries. It results from calcium deposits that accumulate in the tunica media of arterial walls and is usually associated with atherosclerosis.
Atherosclerosis is the formation of fatty deposits (cholesterol and triglycerides) along the tunica intima of arterial walls. The atherosclerotic plaques reduce the lumen of the arteries and increase the probability of blood clots being formed. Such deposits in the coronary, carotid, or cerebral arteries may lead to serious circulatory problems.
Hypertension refers to chronic high blood pressure. It is the most common disease affecting the heart and blood vessels. Blood pressure that exceeds 140/90 mm Hg is indicative of hypertension. A systolic blood pressure of 120 to 139 mm Hg and a diastolic blood pressure of 80 to 89 mm Hg is considered to be prehypertension. Hypertension may be caused by a variety of factors, but persistent stress and smoking are commonly involved.
Phlebitis (fle-bi’-tis) is inflammation of a vein, and it most often occurs in a lower limb. If it is complicated by the formation of a blood clot, it is called thrombophlebitis.
Varicose veins are veins that have become dilated and swollen because their valves are not functioning properly. Heredity seems to play a role in their occurrence. Pregnancy, standing for prolonged periods, and lack of physical activity reduce venous return and promote varicose veins in the lower limbs. Chronic constipation promotes their occurrence in the anal canal, where they are called hemorrhoids (hem ‘o-royds).