Right ventricular performance and contractile reserve in patients with severe heart failure. Assessment by pressure-area relations and association with outcome

Abstract

Background: Right ventricular (RV) performance appears to be important in patients with severe heart failure. Although clinical assessments of RV function previously have been limited to load-dependent ejection phase indices, a new method has been developed using the relatively load-insensitive concepts of pressure-volume relations with automated echocardiographic measures of RV cross-sectional area as a surrogate for volume.

Methods and results: Sixteen patients with New York Heart Association functional class IV heart failure and group mean left ventricular ejection fraction of 20 +/- 5% were studied. RV pressure-area loops were recorded on-line from echocardiographic measures of RV area and high-fidelity pressure during transient inferior, vena caval balloon occlusions. RV contractile reserve was assessed as its functional response to an increase in dobutamine from 5.7 +/- 4.1 to 13.1 +/- 4.7 micrograms/kg per minute. Complete data sets were available in 13 patients. Group mean RV end-systolic elastance (E'es) and maximal elastance (E'max) increased with augmented dobutamine infusion (2.9 +/- 1.5 to 5.5 +/- 3.3 mm Hg/cm2 and 3.3 +/- 1.6 to 6.4 +/- 3.9 mm Hg/cm2, respectively; P < .01 versus baseline), although individual responses were variable. During a 30-day follow-up, 9 patients remained unstable, requiring continuous intravenous inotropic therapy; 6 of these had profound deterioration requiring mechanical circulatory support. The remaining 4 patients had a comparatively good short-term outcome with clinical stability. A 100% increase in RV E'es or E'max was associated with a good short-term outcome (P < .05).

Conclusions: RV performance can be assessed by pressure-area relations in patients with heart failure. RV contractile reserve in response to increases in dobutamine was associated with a good short-term outcome and may be of prognostic value in patients with severe heart failure.