DIAGNOSIS IN HEART DISEASE

Diagnosis because heart attack is a process that actually occurs over several hours, diagnosis must be made as quickly as possible to minimize permanent damage. Diagnosis involves physical examination, medical history (including history of symptoms related by the patient or a bystander), and diagnostic tests (e.g., blood tests, chest x-ray, electrocardiogram, echocardiogram). Blood tests include the following: Complete blood count (CBC), Chemistry and electrolytes, Clotting function (coagulation), Enzyme levels (elevated levels of certain enzymes are released into the bloodstream during heart attack) Chest x-ray may be performed to detect abnormalities in the size and shape of the heart and to detect the accumulation of fluid in the lungs, which may indicate decreased blood flow. During an echocardiogram, a microphone-like device (transducer) is used to transmit and receive ultrasonic waves that travel through the chest wall to the heart and are reflected back to the transducer.

An electrocardiogram (ECG or EKG) is a noninvasive test used to measure electrical activity in the heart. Electrical sensors (called leads) are attached to predetermined positions on the arms, legs, and chest to record electrical activity and help diagnose heart attack. ECG is not conclusive and the test is repeated in most cases. Echocardiogram (cardiac echo) is an ultrasound examination of the heart that produces detailed images of the organ. It can be used to detect abnormalities in the structure of the heart and blood clots that may cause additional damage. Echocardiogram also is used to measure the strength of the heart (called ejection fraction), which is an important factor in determining treatment.

Normally, approximately 60% of the blood in the left ventricle is ejected each time the heart beats (contracts). Patients with ejection fractions of approximately 40–45% have mildly depressed ejection fractions, which may indicate a relatively minor heart attack; patients with ejection fractions of about 30–40% have moderately depressed ejection fractions, which may indicate moderate or severe heart attack; and patients with ejection fractions in the 10–25% range have severely depressed ejection fractions, which may indicate a massive heart attack, several mild heart attacks, or other heart conditions. During an echocardiogram, a microphone-like device (transducer) is used to transmit and receive ultrasonic waves that travel through the chest wall to the heart and are reflected back to the transducer.

Cardiac catheterization involves passing a catheter (i.e., a thin flexible tube) through an artery or a vein to the heart, and into a coronary artery. This procedure produces angiograms (i.e., x-ray images) of the coronary arteries and the left ventricle, the heart's main pumping chamber, and also can be used to measure pressures in the pulmonary artery and to monitor heart function, usually in critically ill patients (called right heart catheterization).In most cases, cardiac catheterization is recommended when a partial or complete arterial blockage is suspected. It is used to evaluate how well the heart is functioning and to obtain information about blockages. Cardiac catheterization is performed in a hospital. Usually, the procedure takes 2 to 3 hours to perform and patients are required to remain immobile for 4 to 6 hours following cardiac catheterization.