Non ECG gated supine to prone left ventricular volume ratio: a novel marker for myocardial ischemia.

Transient ischemic dilation (TID), a marker of severe coronary artery disease (CAD), is the post-stress to rest left ventricular (LV) volume ratio quantified using non ECG gated single photon emission computerized tomography (SPECT). Although prone positioning causes physiological reduction of LV volume in normal subjects, we hypothesize this may not occur in TID with underlying severe CAD as cardiac hemodynamics worsen when prone. We aim to evaluate the utility of the non ECG gated supine to prone LV volume ratio (SPLVr) for identifying severe CAD.