The majority of scans are performed using a stress/rest protocol using adenosine as the stressor which acts to induce ischaemia in the myocardium by the coronary 'steal' phenomenon. Some centers use inotrope dobutamine to stress the heart and the images are interpreted in a similar fashion to dobutamine stress echocardiogram. This article concentrates on adenosine stress scans. Adenosine stress An intravenous infusion of adenosine is given at 140 µg/Kg/min for 3 minutes with continuous heart rate and blood pressure recording to induce hyperaemia (normally seen as a drop in systolic blood pressure of 10mmHg or a rise in heart rate of 10bpm). Following this, an intravenous bolus of 0.05 mmol/kg of a gadolinium chelate (such as gadodoteric acid) is administered via an antecubital fossa vein on the contralateral arm to the adenosine. The scan Typically, 3 short axis slices, each of 10mm thickness, are acquired per cardiac cycle, at the basal, mid papillary and apical levels of the left ventricle. A single shot prospectively gated, balanced TFE sequence is used with a typical resolution of 2.5 x 2.5mm. The patient is then allowed to rest until the haemodynamic effects of the adenosine have stopped (typically 5 minutes). The same scan protocol is then performed at rest. Image analysis The images are stored as video files and are analysed on a dedicated workstation. The majority of clinical scans are analysed qualitatively by visually comparing the stress and rest scans in parallel. In a normal scan, the wash in (1st pass) of gadolinium into the myocardium can be seen as the myocardium turning from black to mid grey uniformly throughout the whole of the left ventricle in both the stress and rest scans. In an abnormal scan an area of the myocardium will turn grey slower than the surrounding tissue as the blood (and hence gadolinium) enters more slowly due to a narrowing of the coronary artery supplying it. This is called a<unk>  defect and usually represents myocardial ischaemia. It may be seen on both the rest and stress scans in which case it is called a matched<unk>  defect and is probably due to an area or scar from a previous myocardial infarction. If it is only seen on the stress scan it is called an area of inducible<unk>  defect (ischaemia). The position in the left ventricle of the<unk>  defects are described using the AHA 17 segment model.
Cardiac magnetic resonance imaging perfusion
Coronary CT calcium scan
Coronary CT angiography
Pressure–volume loop analysis in cardiology
ST2 cardiac biomarker
Cardiac electrophysiology
Impedance cardiography
Pulmonary angiography