Heart Diseases

-A-

Aneurysm-This term refers to a localized dilation of an artery or chamber of the heart. The behavior and prognosis for aneurysms varies, depending on their size and location. Aneurysms of the heart are usually the result of a prior heart attack. They generally don't require surgical resection. They may result in congestive heart failure and arrhythmias. Aneurysms of the main artery of the body, the aorta, generally require resection once they reach a certain size-anywhere from 4.5 to 6.0 centimeters in diameter. Aneurysms of the blood vessels in the brain can lead to catastrophic cerebral hemorrhages. Prophylactic surgical resection may be recommended based on their size and location.

Angina Pectoris-This is simply Latin for "pain in the chest" but is used to refer to any symptom caused by a temporary reduction in oxygen supply (ischemia) to the muscle of the heart (myocardium). The most common cause is coronary artery disease whereby atherosclerosis narrows the interior of the coronary arteries. At times when the heart has to work harder and requires more oxygen, the blood flow cannot increase as it normally does through these narrowed arteries, resulting in myocardial ischemia. This most typically occurs with physical exertion but can also happen with emotional stress, after meals, in association with noncardiac diseases stressing the heart and sometimes for no apparent reason.

The symptoms can occur in the chest, shoulders, either arm, back, upper stomach, neck or jaw in variable combinations. It is typically described as a heaviness, tightness, constriction, squeezing, dull ache, indigestion or gas pain. It may be associated with shortness of breath, sweating, weakness or nausea. Sometimes it manifests only as one of these associated symptoms, such as shortness of breath, without any chest pain or discomfort. The angina attack generally resolves within several minutes. In some people, the angina may resolve even if they continue what they were doing to provoke it (known as "walk-through" angina) but more commonly patients will need to stop, rest and possibly take nitroglycerin. Note that noncardiac causes of chest discomfort may mimic angina and may also respond to nitroglycerin. Severe angina is known as unstable angina.

The diagnosis of whether a patient's symptoms are from the heart (angina) or not (noncardiac chest pain) is determined by evaluating the patient's risk of having coronary artery disease and the characteristics of the symptoms. Diagnostic testing is carried out most commonly by stress tests as well as coronary angiograms. Ultrafast CT scans can also be used. The determination of whether testing should be done and which test is the best to start with is made by the physician based on the patient's risk factors and the nature of the symptoms.

Most patients with coronary artery disease are treated with an antiplatelet agent and risk factor modification. These decrease the risk of serious complications like a heart attack.

Symptom control is achieved by risk factor modification, antianginal agents, coronary angioplasty and stents or bypass surgery. The latter two are more effective than antianginal medications in controlling symptoms. For certain patients with multiple severe coronary narrowings, bypass surgery also prolongs survival. Experimental procedures include transmyocardial laser revascularization, enhanced external counter pulsation and spinal cord stimulation.

Antibiotic Prophylaxis-Certain types of valvular and congenital heart diseases can become infected at the site of the defect if bacteria get into the bloodstream. Patients with these conditions are advised to take antibiotics one hour before any medical or dental procedure that may introduce bacteria into the bloodstream.

Aorta-The main artery of the body. The heart pumps all the blood into the aorta. Branches from the aorta brings blood to all parts of the body.

Aortic Dissection-This used to be called a dissecting aneurysm. It refers to a tear in the wall of the aorta. It can be caused by inherited disorders of connective tissue, high blood pressure and atherosclerosis as well as blunt chest trauma and rapid decelerations typical of automobile accidents. It is characterized by severe, sharp chest pain radiating through to the back. It can be diagnosed by transesophageal echocardiography, MRI, CT scans and cardiac catheterization.The acute treatment includes beta blockers as well as additional intravenous medicine to rapidly reduce the blood pressure if it is elevated. Surgery is recommended for dissections involving the beginning part of the aorta and for dissections involving the more distant segments of the aorta that do not respond to medical therapy.

Aortic Valve-One of the four valves in the heart. It is composed of three cusps. The main pumping chamber of the heart, the left ventricle, ejects blood through this valve into the body's main artery, the aorta, during the portion of the cardiac cycle called systole. During the other part of the cardiac cycle, called diastole, the aortic valve closes so that blood does not leak backwards from the aorta to the left ventricle and the left ventricle fills with blood again from the left atrium for the next heart beat.

Aortic Valve Regurgitation-In this condition, the aortic valve does not close properly. It can be caused by congenital abnormalities of the valve, rheumatic heart disease, aneurysms of the aorta, high blood pressure or excessive build-up of calcium over time. Blood leaks back from the body's main artery (the aorta) to the the main pumping chamber of the heart (the left ventricle). If the leakage becomes severe enough, the left ventricle may dilate and weaken. Eventually, symptoms of shortness of breath (heart failure) occur particularly with exertion or when lying flat. Chest discomfort, swelling of the feet and weakness can also occur.

The diagnosis can be made by the physician noting a characteristic murmur and a change in the quality of the pulse. The diagnosis can be confirmed by echocardiography and/or cardiac catheterization. Definitive treatment is open heart surgery to replace the valve. This is indicated when symptoms occur or if the left ventricle is sufficiently weakened or dilated even in the absence of symptoms. Severe regurgitation that doesn't yet require surgery is managed by medications such as certain calcium channel blockers (nifedipine) or angiotensin converting enzyme inhibitors.

Aortic Valve Stenosis-In this condition,