Echocardiography including Stress Echocardiography and TEE
An echocardiogram is a key test used by cardiologists to diagnose a number of heart conditions. Painless and non-invasive, echocardiography uses ultrasound to create a moving picture of the beating heart. A transducer that emits sound waves is placed on the chest and aimed at different parts of the heart to determine the size of the heart chambers, wall thickness, and valve and heart function. The procedure is used to detect among other conditions blood clots in the heart, rheumatic valvular disease, tumors, fluid around the heart, and congenital abnormalities such as a hole between the heart chambers.
The transthoracic echocardiogram (TTE) is the most common type of echocardiogram. Others include a stress echocardiogram that determines cardiac function when the heart is beating quickly during a stress test; transesophageal echocardiogram (TEE) where the heart is seen from a small scope inside the esophagus for better image resolution; and Doppler echocardiogram which measures and evaluates blood flow.
A stress echocardiogram is mainly used to find blockages in coronary arteries that are often not detectable when a patient is at rest. First, the patient undergoes a standard echocardiogram used as a basis for comparison. To achieve rapid heart rate levels, the patient either walks on a treadmill or pedals on a bicycle while hooked up to an EKG and blood pressure monitor. The exercise pace is increased to elevate the heart rate. Physicians evaluate the symptoms, the EKG, and the results of the echocardiogram during the stress procedure. Blocked arteries of the heart that do not supply enough blood flow to the heart muscle can be detected.
Patients with medical conditions that prevent them from exercising can undergo a dobutamine stress echocardiogram. This uses dobutamine, an intravenous medication, to increase the heart rate, thus mimicking the same effect on the heart as exercise.
A transesophageal echocardiogram (TEE) images the heart through a scope that is inserted into the mouth and passed down into the esophagus. TEE results in clearer pictures because the probe is closer to the heart, and because sound waves do not have to penetrate the lungs or chest wall. For this procedure, physicians will relax the gag reflex with an anesthetic agent (spray or lozenge), and patients will also receive a sedative similar to Valium. Patients may experience some discomfort during the test, as well as possible side affects afterwards, including throat ache, nausea, possible bleeding and trouble breathing.
A Doppler echocardiogram monitors the movement of blood through the heart chambers and valves, and is used to detect valve abnormalities and estimate pressures in the heart. A Doppler echocardiogram is often performed in conjunction with a TTE, TEE or stress echocardiogram.