1007-17 Demonstration of Pericardial Constraint in Chronic Heart Failure

Pericardial constraint may be an important feature in chronic heart failure (CHF). We hypothesized that baseline pericardial constraint could be inferred if left ventricular end-diastolic volume (LVEDV) paradoxically increased during lower body negative pressure (LBNP), as a consequence of abolition of constraint with an increase in the left ventricular transmural and transseptal pressure gradients.Methods11 patients with CHF and left ventricular ejection fraction <35% (age 34–82, mean 51.5 years; 8 male, 3 female) were compared with 6 healthy controls (age 31–61, mean 50.5 years; all male). Radionuclide ventriculography was performed before and during application of 30mmHg LBNP. Left ventricular end-diastolic counts were corrected for time decay and tissue attenuation. LVEDV was then calculated with reference to an externally counted blood sample taken during each of the acquisitions.Results(expressed as mean±SD): Comparing baseline with 30mmHg LBNP, LVEDV changed by –4.5 to -26.3ml (mean–14.2±8.6ml) in controls vs. -24.4 to +62.1ml (mean +8.2±23.5ml) in CHF patients (p=0.041) The % change in LVEDV with LBNP (mean±SD) is shown in the figure. There was a linear correlation between change in LVEDV and baseline pulmonary capillary wedge pressure (b-PCWP) in CHF patients (r=0.68; p=0.031)ConclusionsBaseline pericardial constraint is demonstrated in the 4 patients with CHF in whom LVEDV increased during LBNP, a response associated with higher b-PCWP. In patients with attenuated reductions in LVEDV, abolition of baseline constraint and impaired myocardial compliance are both possible explanations