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Pressure/volume ratio and pressure/volume ratio exercise quotient: an echocardiographic comparative study of left
Abstract:
Noninvasive evaluation of left ventricular function (LVF) has been performed with two-dimensional echocardiography (TDE). Ejection fraction (EF), end systolic volume index (ESVI) and systolic blood pressure/end systolic volume index ratio (PVR)--an indicator which is independent of preload and afterload changes in a wide physiologic range--were assessed at rest and after exercise. Twenty-seven postmyocardial infarction (MI) patients were compared to 27 normal controls in an attempt to examine the above parameters of LVF in each group, measured by TDE. Correlation of TDE EF with radionuclide angiography EF proved the reliability of TDE. Rest and postexercise values of EF and PVR showed highly significant differences between the two groups. Using ESVI, a relatively lesser significant difference was found. PVR values at rest were 4.86 mm Hg/ml/m2 in the study group and 9.51 in the control group. These values increased to 5.34 and 15.15, respectively, after exercise. The ratio of PVR after exercise to PVR at rest, expressed as percentage change (PVREQ), seemed to be an additional tool in separating between both groups. This indicator merges pressure, volume, and the influence of exercise on both; a PVREQ of at least 145% correlated well with absence of MI in most of our patients.