الفهرس 
The Helical Ventricular Myocardial Band of Torrent-Only 14 pages are availabe for public view
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Abstract
Chest pain may be associated with coronary arteries that appear normal. Normal angiography in patients with chest pain is more common in women than in men. Among patients with chest pain and normal angiography, an unknown number are suffering from cardiac pain of ischemic origin[1].
No single underlying mechanism has been identified for the angina like chest pain with normal coronary angiographic findings, Small vessel coronary artery disease, abnormal coronary vascular resistance, and subendocardial ischemia have been invoked as possible mechanisms, although none of these factors is universally accepted.
Several studies have found abnormalities consistent with myocardial perfusion in patients with CSX using positron emission tomography, scintigraphic myocardial perfusion imaging[143],and nuclear magnetic resonance imaging[144].
Echocardiography is a versatile imaging modality for the management of patients with chest pain and assessment of left ventricular systolic function, diastolic function, and even myocardial and coronary perfusion and is, therefore, useful in the diagnosis and triage of patients with acute chest pain or dyspnea[2] .
This echo technique has its limitations, with relatively high for both intra-observer and interobserver variability[3],and the limited ability of the human eye to resolve rapid and short-lived myocardial motion[4].Of note, visual evaluation of wall motion only assesses radial deformation of the myocardium, and it is well known that myocardial contractility consists of thickening, shortening, and twisting.