Cardiac stress determination or stress echo is done to investigate underlying coronary artery disease. It helps determine blood flow and the pumping rate of the heart. The preliminary tests performed before stress echocardiography include the assessment of ventricular function, wall motion thickness and aortic root. These tests indicate cardiac conditions along with ischemic heart disease and other cardiac conditions. Stress echocardiography is recommended over pharmacological assessment, because of its advantage in describing the cardiac performance during the test through images. Pictures are taken of your heart before and after exercise to check the efficiency of the heart.
Stress echocardiography is carried out on a treadmill or by a bicycle in a supine position. A work load of 25W is given initially with subsequent rise in intensity. Stress echocardiography also determines the aerobic capacity. The use of bicycle exercise has an advantage as it gives the Doppler information of the test. This provides information about the blood flood through the heart's pumping chambers and valves. Stress echocardiography has been extensively used in the risk evaluation for coronary artery disease even in patients who are asymptomatic. The usual protocol followed for the test is fasting for at least three hours before the test is performed.
Before commencing the stress test, your blood pressure and electrocardiogram (EKG) is also done. The stress echo is taken during the rest phase, stress phase and a repeat when the heart is still beating fast. Pregnant women are not advised to undergo this test. You will be connected to an ECG monitor to record the heart activity through small electrodes. Stress echocardiography is beneficial for physicians to determine the treatment options for asymptomatic conditions pertaining to coronary artery disease. It also aids the detection of angina or chest pain in the patients and also conditions like cardiomegaly and myocardial infarction.
Cardiac Stress Test
A cardiac stress test aids in assessing how the heart can cope during exercise, especially when the body need for oxygen puts extra demands on the heart. A cardiac stress test is called a graded test or exercise tolerance test, exercise stress test or exercise electrocardiography. It helps to primarily evaluate the heart and vascular systems during the exercise. In fact, the American Heart Association has recommended the Cardiac stress test (EKG treadmill in particular) as the first choice to be tried on patients with medium risk of coronary heart disease and who exhibit certain risk factors of smoking, family history of coronary stenosis, high blood pressure, and high cholesterol.
- It helps to determine whether coronary arteries are clogged or blocked.
- To find the cause of chest pain.
- To assess the heart's capability after a heart attack or heart surgery.
- To discover the presence of any heart disease.
- To set limits on a person's exercise.
- To detect arrhythmia, that is extra heart beats, during the exercise.
- To assess the capacity of medicine used to control chest pain or extra beats during exercise.
The cardiac stress test can be done in a clinic or a hospital. The patient may be asked to exercise using a bicycle, treadmill or arm ergometer. The patient is attached to an ECG machine. The blood pressure cuff is placed on any one arm. The patient's heart is usually monitored using a 12 - lead EKG or ECG machine. A heart monitor may be used during and after exercise. After a baseline ECG is obtained, the patient begins to perform a low level of exercise, either by walking on a treadmill or pedaling on a stationary bicycle.
At each stage of the exercise, the pulse, the blood pressure and ECG are recorded along with any symptoms that the patient may be experiencing.
The level of exercise is gradually increased until the patient cannot keep up any longer because of fatigue or until symptoms like chest pain, shortness of breath or lightheadedness prevent further exercise. The goal of this stress test is to diagnose the presence or absence of coronary artery disease. In a sub maximal stress test, the patient exercises only until a pre-determined level of exercise is attained. These tests are used in patients with known coronary artery disease, to measure whether the patient can perform a specific level of exercise with relative safety.
The side effects of a cardiac stress test also include palpitation, chest pain, and shortness of breath, headache, nausea and fatigue. The hypertension caused by stress testing is always considered abnormal and it may lead to severe coronary disease. In stress tests, false positive results are not uncommon. There can be occasions when the patient's ECG changes could suggest ischemia, even in the absence of coronary artery disease. Similarly, in stress test, false negatives are also not uncommon. In some patients, no significant ECG changes will be seen even in the presence of coronary artery disease. Presently, a new concept called nuclear perfusion study is added to the stress test. This factor has helped to minimize the limitations and improve the diagnostic capability of stress tests.
Angina or chest pain is a typical symptom associated with coronary artery disease. Angina is a sign that the heart is not getting sufficient blood flow. This is usually due to narrowing of the arteries (atherosclerosis. It can also be the result of extreme hypertension, hypertrophic Cardiomyopathy or valvular heart disease. Stable angina is a pain that occurs when there is extra load on the heart and occurs in a regular pattern. This type of angina pain can be tackled with medication and rest. On the other hand, unstable angina can be dangerous as it may the precursor to a heart attack. The pain in such a case is more prolonged and severe. Prinzmetal's angina or variant angina pectoris occurs due to transient spasm of the coronary artery. This does not get triggered due to physical exertion.
The pain associated with angina is uncomfortable pressure and squeezing on the chest. There is pain or discomfort in the neck, shoulder and arms. But not all chest pains are signs of angina. ECG (electrocardiograph) helps in tracing heart activity. Exercise-ECG assesses your heart condition when you are on a treadmill. Beta-blocker drugs help prevent angina pain. Potassium channel blockers and calcium channel blockers aid in improving blood flow to the coronary arteries. Glyceryl Trinitrate or GTN tablets work instantaneously by relaxing blood vessels and easing the blood flow to the heart muscles. Aspirin is prescribed to reduce the probability of blood clots and reducing blood viscosity. Statin medicines are prescribed to reduce cholesterol levels. Angioplasty involves passing a tiny balloon into a large artery and then blowing it up inside to widen the artery. Bypass surgery is done to bypass the narrowed section of arteries and provide the heart with blood vessels that are not obstructed. Angina can be controlled with medication and lifestyle changes in diet and exercise.
- Quit smoking
- Control cholesterol levels
- Control blood pressure levels
- Regular exercise regimen
- Nutritious diet - low in fat, high in fibers, rich in fruits, vegetables and oily fish
- Maintain healthy body weight