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Cardiac magnetic resonance imaging perfusion (cardiac MRI perfusion, CMRI perfusion), also known as stress CMR perfusion, [1] is a clinical magnetic resonance imaging test performed on patients with known or suspected coronary artery disease to determine if there are perfusion defects in the myocardium of the left ventricle that are caused by narrowing of one or more of the coronary arteries.
A cardiac stress test is a cardiological examination that evaluates the cardiovascular system's response to external stress within a controlled clinical setting. This stress response can be induced through physical exercise (usually a treadmill) or intravenous pharmacological stimulation of heart rate. [1]
Dobutamine is a direct-acting agent whose primary activity results from stimulation of the β 1-adrenoceptors of the heart, increasing contractility and cardiac output. Since it does not act on dopamine receptors to inhibit the release of norepinephrine (another α 1 agonist), dobutamine is less prone to induce hypertension than is dopamine.
Rate pressure product is a measure of the stress put on the cardiac muscle based on the number of times it needs to beat per minute (HR) and the arterial blood pressure that it is pumping against (SBP). It will be a direct indication of the energy demand of the heart and thus a good measure of the energy consumption of the heart.
The Harvard step test, in scientific literature sometimes referred to as the Brouha Test, is a type of cardiac stress test for detecting and diagnosing cardiovascular disease. It is also a good measurement of fitness and a person's ability to recover after a strenuous exercise by checking the recovery rate.
Angina index will be zero if no pain appears during the exercise, one if the pain is limited to the exercise period but the patient can continue the exercise (typical angina), and two if a limiting pain occurs which is a reason to stop the exercise test. [2] [3] Duke treadmill scores typically range from -25 (highest risk) to +15 (lowest risk).
The modified Bruce Protocol is an alteration in the protocol so that the treadmill is initially horizontal rather than uphill, with the 1st few intervals increasing the treadmill slope only. [3] The Bruce treadmill test estimates maximum oxygen uptake using a formula and the performance of the subject on a treadmill as the workload is increased ...
Because of this, the valve area may be erroneously calculated as stenotic if the flow across the valve is low (i.e. if the cardiac output is low). The measurement of the true gradient is accomplished by temporarily increasing the cardiac output by the infusion of positive inotropic agents, such as dobutamine.