Alteration of systolic time intervals in right ventricular failure

Systolic time intervals (STI) were measured in matched patients with and without right ventricular failure (RVF). STI were calculated from branchial arterial pressure tracings obtained at cardiac catheterization in four groups of patients: controls, without RVF; acute pulmonary embolism with and without acute RVF; mitral stenosis, with and without chronic RVF; primary pulmonary hypertension, with chronic RVF. In patients with pulmonary embolism without acute RVF, STI were normal. However, patients with acute RVF due to pulmonary embolism had significantly shortened left ventricular ejection times (LVETc) and significantly increased pre ejection periods (PEPc) and increased PEPc/LVETc ratios (P<0.05, P<0.001, P<0.001 respectively). Similar results were obtained in patients with chronic RVF. In patients with mitral stenosis without RVF, STI were normal. However, in patients with chronic RVF due to mitral stenosis or primary pulmonary hypertension, PEPc and PEPc/LVETc ratios were lengthened and LVETc was shortened (P<0.003, P<0.005, and P<0.001 respectively). PEPc/LVETc ratios increased as stroke index decreased (r=-0.55). There was also an association between PEPc/LVETc and right atrial mean pressure (r=0.70). These data demonstrate that patients with acute and chronic right ventricular failure have abnormal systolic time intervals possibly secondary to left ventricular dysfunction.