Analysis of Left Ventricular Systolic, Diastolic Properties, and Left Atria Contribution during Acute Increase in Afterload in Normal Subjects : Assessment with Forward and Backward ECG Gating Radionuclide Ventriculography

The response of left ventricular systolic, diastolic properties and left atrial contribution during acute increase in afterload was evaluated in 10 normal subjects. Radionuclide ventriculography was performed befor and during angiotensin infusion. The systolic blood pressure was increased about 40mmHg with angiotensin infusion. The data was acquired in a list mode and left ventricular volume curves were constructed by forward and backward gating from the R wave of ECG. The systolic phase indexes : EF (ejection fraction), PER (peak ejection rate), 1/3%SV (first third % stroke volume), and TES (time to end-systole), and the early diastolic phase indexes : PFR (peak filling rate) and FF (filling fraction) were caluclated from the forward gating left ventricular volume curve. Left atrial contribution (AC/SV) was caluclated from the backward gating left ventricular volume curve. During acute increase in afterload, EF (59±5 to 48±6%