Heart Disease

CORONARY ARTERY DISEASE

Coronary artery disease (CAD), which results from atherosclerosis of the vessels that supply blood to the heart muscle, is a leading cause of death in industrialized countries (see Fig. 9-8). An early sign of CAD is the type of chest pain known as angina pectoris. This is a feeling of constriction around the heart or pain that may radiate to the left arm or shoulder, usually brought on by exertion. Often there is anxiety, diaphoresis (profuse sweating), and dyspnea (difficulty in breathing).

CAD is treated by control of exercise and administration of nitroglycerin to dilate coronary vessels. Other drugs may be used to regulate the heartbeat, strengthen the force of heart contraction, or prevent formation of blood clots. Patients with severe cases of CAD may be candidates for angioplasty, surgical dilatation of the blocked vessel by means of a catheter, technically called percutaneous transluminal coronary angioplasty (PTCA) (Fig. 9-10). If further intervention is required, the blocked vessel may be surgically bypassed with a vascular graft (Fig. 9-11). In this procedure, known as a coronary artery bypass graft (CABG), another vessel or a piece of another vessel, usually the saphenous vein of the leg or the left internal mammary artery, is used to carry blood from the aorta to a point past the obstruction in a coronary vessel.

CAD is diagnosed by electrocardiography (ECG), study of the electrical impulses given off by the heart as it functions, stress tests, coronary angiography (imaging), echocardiography, and other tests.

Angioplasty Catheter

Wall of coronary artery

- Plaque

Catheter in place; balloon deflated

Balloon inflated

Dashed lines indicate old plaque thickness

FIGURE 9-10. Coronary angioplasty (PTCA). (A) A guide catheter is threaded into the coronary artery. (B) A balloon catheter is inserted through the occlusion. (C) The balloon is inflated and deflated until plaque is flattened and the vessel is opened.

Wall of coronary artery

- Plaque

Catheter in place; balloon deflated

Balloon inflated

Plaque ^ expanded: catheter removed

Dashed lines indicate old plaque thickness

FIGURE 9-10. Coronary angioplasty (PTCA). (A) A guide catheter is threaded into the coronary artery. (B) A balloon catheter is inserted through the occlusion. (C) The balloon is inflated and deflated until plaque is flattened and the vessel is opened.

Right Coronary Bypass Catheter

FIGURE 9-11. Coronary artery bypass graft (CABG). (A) A segment of the saphenous vein carries blood from the aorta to a part of the right coronary artery that is distal to an occlusion. (B) The mammary artery is used to bypass an obstruction in the left anterior descending (LAD) coronary artery.

Left subclavian artery

Internal mammary artery

Anterior descending branch of the left coronary artery

FIGURE 9-11. Coronary artery bypass graft (CABG). (A) A segment of the saphenous vein carries blood from the aorta to a part of the right coronary artery that is distal to an occlusion. (B) The mammary artery is used to bypass an obstruction in the left anterior descending (LAD) coronary artery.

Degenerative changes in the arteries predispose a person to thrombosis and sudden occlusion (obstruction) of a coronary artery. The resultant area of myocardial necrosis is termed an infarct (Fig. 9-12), and the process is known as myocardial infarction (MI), the "heart attack" that may cause sudden death. Symptoms of MI include pain over the heart (precordial pain) or upper part of the abdomen (epigastric pain) that may extend to the jaw or arms, pallor (paleness), diaphoresis, nausea, and dyspnea. There may be a burning sensation similar to indigestion or heartburn.

FIGURE 9-12. Myocardial infarction.

FIGURE 9-12. Myocardial infarction.

And Ast Release From The Muscle

MI is diagnosed by electrocardiography, by measurement of certain enzymes (CK, LDH, AST) released into the blood from the damaged heart muscle and by a variety of other methods described later in this chapter.

Patient outcome is based on the degree of damage and early treatment to dissolve the clot and re-establish normal heart rhythm.

ARRHYTHMIA

Arrhythmia is any irregularity of heart rhythm, such as a higher- or lower-than-average heart rate, extra beats, or an alteration in the pattern of the beat. Bradycardia is a slower-than-average rate, and tachycardia is a higher-than-average rate. In cases of MI, there is often fibrillation, an extremely rapid, ineffective beating of the heart. MI may also result in heart block, an interruption in the electrical conduction system of the heart (Fig. 9-13). Cardioversion is the general term for restoration of a normal heart rhythm, either by drugs or application of electric current. Several devices are in use for electrical defibrillation. If, for any reason, the SA node is not generating a normal heartbeat, an artificial pacemaker (Fig. 9-14) may be implanted in the chest to regulate the beat.

HEART FAILURE

The general term heart failure refers to any condition in which the heart fails to empty effectively. The resulting increased pressure in the venous system leads to edema, often in the lungs (pulmonary edema), and justifies the description congestive heart failure (CHF). Other symptoms of congestive heart failure are cyanosis, dyspnea, and syncope. Heart failure is one cause of shock, a severe disturbance in the circulatory system resulting in inadequate delivery of blood to the tissues. Heart failure is treated with rest, drugs to strengthen heart contractions, diuretics to eliminate fluid, and restriction of salt in the diet.

Heart Nomenclature
FIGURE 9-13. Potential sites for heart block in the atrioventricular (AV) portion of the heart's conduction system.
Heart Valves And Conduction System
FIGURE 9-14. Placement of a pacemaker.

CONGENITAL HEART DISEASE

A congenital defect is any defect that is present at birth. The most common type of congenital heart defect is a hole in the septum (wall) that separates the atria or the ventricles. The result of a septal defect is that blood is shunted from the left to the right side of the heart and goes back to the lungs instead of out to the body. The heart has to work harder to meet the body's need for oxygen. Symptoms of septal defect include cyanosis (leading to the description "blue baby"), syncope, and clubbing of the fingers. Most such congenital defects can be corrected surgically.

Another type of congenital defect is malformation of a heart valve. Failure of a valve to open or close properly is evidenced by a murmur, an abnormal sound heard as the heart cycles.

Still other congenital defects result from failure of fetal modifications to convert to their adult form at birth. In patent ductus arteriosus (Fig. 9-15), a vessel present in the fetus to bypass the lungs fails to close at birth. Blood can then flow from the aorta to the pulmonary artery and return to the lungs.

RHEUMATIC HEART DISEASE

In rheumatic heart disease, infection with a specific type of streptococcus sets up an immune reaction that ultimately damages the heart valves. The infection usually begins as a "strep throat," and most often it is the mitral valve that is involved. Scar tissue fuses the leaflets of the valve, causing a narrowing or stenosis that interferes with proper function. People with rheumatic heart disease are subject to repeated infections of the valves and must take antibiotics prophylactically (preventively) before any type of surgery and before even minor invasive

A Closed ductus arteriosus

Patent Ductus Arteriosus Surgery Scar

Descending aorta

B Patent ductus arteriosus

Pulmonary Heart Disease

Pulmonary artery

Descending aorta

'Pulmonary artery

FIGURE 9-15. Patent ductus arteriosus. (A) Normal. (B) The ductus arteriosus fails to close.

procedures such as dental cleaning. Severe cases of rheumatic heart disease may require surgical correction or even valve replacement. The incidence of rheumatic heart disease has declined with the use of antibiotics.

Herbal Remedies For Acid Reflux

Herbal Remedies For Acid Reflux

Gastroesophageal reflux disease is the medical term for what we know as acid reflux. Acid reflux occurs when the stomach releases its liquid back into the esophagus, causing inflammation and damage to the esophageal lining. The regurgitated acid most often consists of a few compoundsbr acid, bile, and pepsin.

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