Efficacy and Mechanisms of Biventricular and Left/Right Direct Cardiac Compression in Acute Heart Failure Sheep

Abstract

Direct cardiac compression (DCC) with implanted heart patches has previously demonstrated efficacy of biventricular (BiV) support in acute heart failure (HF) sheep. We hypothesized that this was primarily due to a left ventricular (LV) effect. This study compared BiV, LV, and right ventricular (RV) assists in terms of hemodynamic and energetic response. Ten sheep underwent instrumentation and device implantation at least 1 week prior to study. HF (50% reduction in cardiac output) was maintained with intravenous esmolol infusion. BiV, LV, and RV assists were activated randomly with intervening stable HF periods. BiV assist was more effective than either LV or RV assist in restoring hemodynamic parameters; however, there was no difference in efficacy of LV and RV support. RV assist preserved left coronary flow patterns and chamber geometry compared to other assist conditions, but increased LV preload. These results suggest that LV and RV support each make a significant contribution to the efficacy of BiV assist, albeit through different mechanisms.

Nonsurround, nonuniform, biventricular-capable direct cardiac compression provides Frank-Starling recruitment independent of left ventricular septal damage

“…17 After 4 weeks of recovery, the RV hemodynamic and dimensional changes were measured in response to custom-designed HeartPatch DCC placement and its actuation in 5 modes: no device use, passive placement of the DCC device, and LV, RV, or biventricular actuation. 15,18…”

“…Furthermore, the heart-surrounding configuration of such devices is likely to constrain ventricular filling and impair early diastolic relaxation. To overcome such shortcomings, we used a novel design consisting of independent nonsurround RV-and LV-apposed pumping chambers (HeartPatch-DCC device; Heart Assist Technologies, St Leonards, NSW, Australia; Figure 1), which has been shown to have potent ability to increase cardiac output 15 and restore myocardial efficiency during pharmacologically induced heart failure. 16 This device was implanted in sheep hearts with septal pathologic features, as previously described, 17 to compare the RV in-series, load-independent, and geometric responses to that of previously studied inline mechanical LVAD unloading.…”

The Right Heart and Its Distinct Mechanisms of Development, Function, and Failure

“…If maximum medical therapy fails to relieve symptoms of right heart failure, patients may require placement of a right ventricular assist device, a biventricular assist device, or orthotopic cardiac transplantation [99]. Left ventricular assist devices and intra-aortic balloon pumps have not proven beneficial for right heart failure [100].…”

Artificial Organs 2007: A Year in Review

“…Gabrielle L. Gallagher et al. (10) of the University of Sydney at Royal North Shore Hospital (Sydney, Australia) studied the efficacy and mechanisms of biventricular (BiV) and left/right direct cardiac compression in acute heart failure sheep. BiV assist was more effective than either left ventricular (LV) or right ventricular (RV) assist in restoring hemodynamic parameters.…”