Heart Attack Medical Tests & Diagnosis - OmniMedicalSearch.com (Myocardial Infarction)

Conditions & Diseases: Cardiovascular System

Heart Attack (Myocardial Infarction)

Heart Attack Medical Tests & Diagnosis

A heart attack is a process that spans over several hours and a fast diagnosis can increase the chance of survival and minimize the damages. A heart attack diagnosis involves a physical examination, a medical review of health problems, and diagnostic tests.

I. Physical examination. During a physical examination the medical team will check the pulse and blood pressure. The heart and lungs will be listen to with a stethoscope and the patient is usually hooked up to a heart monitor.

II. Medical review of health problems. During the medical health review, the doctor collects information regarding past medical problems such as a history of heart diseases in the family, past heart or blood vessel problems, a review of heart attack risk factors, and present symptoms.

III. Diagnostic tests. Diagnostic tests are divided in two categories: non-invasive tests and invasive tests.

The category of non-invasive tests includes:
1. Electrocardiogram (or EEG). Electrocardiogram is the first test done by the medical team to diagnose a heart attack. This test establishes whether a heart attack is in progress or has already occurred by recording the electrical activity of the heart. When the heart muscle has suffered injuries, it doesn't conducts electrical impulses normally, and a special device registers these changes through a set of electrical sensors (leads) attached to certain location on the arms, legs, and chest.

2. Echocardiogram. Echocardiogram is a non-invasive diagnostic test that can determine whether the heart muscle has suffered changes and detect blood clots. It is similar with an ultrasound producing visual images of the heart. This test can provide information regarding the heart's strength which is essential in determining the severity of the heart attack, which portion of the heart may have been affected, and what coronary artery is blocked . In normal conditions, approximately 60 percent of the blood in the left ventricle is pumped out each time the heart contracts. If echocardiogram reveals 40 to 45 percent of the blood is pumped out, the patient has suffered a minor heart attack. When 30 to 40 percent of the blood is pumped out, the patient has suffered a moderate to severe heart attack. When only 10 to 25 percent of the blood is pumped out, the patient has suffered a massive heart attack.

3. Chest x-ray. This is an additional test used to visualize the shape and size of the heart, the width of aorta, and the condition of the lungs.

The category of invasive tests includes:
1. Blood tests. Blood tests are performed to detect the death of myocardial cells. Normal functioning and healthy myocardial cells contain certain enzymes and proteins that are released in the bloodstream only when they die. The level of these enzymes in the blood helps to determine the size of the heart attack and when the necrosis (the sudden death of myocardial cells due to lack of oxygen) started.

2. Cardiac catheterization. This procedure is also known as cardiac cath or coronary catheterization (arteriogram). Cardiac catheterization is usually used during the first hour of a heart attack to visualize the inside of the blood vessels within the heart. It helps to determine which artery suffered an occlusion or blockage, which arteries are narrow, and to asses the damages resulted during the heart attack. This imaging test can be performed in the presents of a dye agent injected into the heart arteries through a catheter (placed in one of the leg or arm arteries). The infusion of the dye agent produces a "hot flash" sensation in the body that lasts between 10 and 15 seconds.

3. Transesophageal echocardiography. This is an additional imaging test that can be performed in heart attack patients. Transesophageal echocardiography uses an ultrasound device inserted into the body through the esophagus to create a clear image of the heart muscle and heart itself. This test provides information regarding the heart strength in pumping blood, the heart size, and the location and extent of the damaged tissue.

4. Thallium stress test. Thallium stress test is a nuclear scanning test effective in revealing how well the blood flows into the heart muscle. This test helps the medical team determine (1) the extent of the coronary artery blockage, (2) the cause of chest pain, and (3) the extent of heart damage. This test is usually performed at during an exercise stress test (when the patient is asked to exercise on the treadmill or bicycle). When the patient reaches the maximum level of exercise a small amount of thallium (a radioactive substance) is administrated. When the heart functions normally, thallium mixes with the blood and enters the myocardial cells. The damaged tissue can be identified due to the lack or less amount of thallium revealed by a special device (called gamma camera).

Article by Alina Morrow, MS
Medical Writer
OmniMedicalSearch.com