Key result
Direct mechanical ventricular assistance boosts cardiac output ~27% and improves hemodynamics in acute heart failure.
Why the study?
Does direct mechanical ventricular assistance improve hemodynamics and regional myocardial function in a porcine model of acute heart failure?
Does direct mechanical ventricular assistance improve hemodynamics and regional myocardial function in a porcine model of acute heart failure?
Direct mechanical ventricular assistance improves hemodynamics and regional myocardial function in a porcine model of acute heart failure, suggesting potential for myocardial recovery.
DMVA effects on RMF in porcine acute HF are hypothesis-generating; leaves open translation to human therapy.
Direct mechanical ventricular assistance (DMVA) improves hemodynamics in failing hearts without complications associated with a blood/device interface. Epicardial Doppler displacement transducers provide exact measurements of tissue displacement and regional myocardial function (RMF). An in vivo porcine model of acute heart failure was used to examine the effects of DMVA on RMF, which have not been reported before. In 8 anesthetized pigs cardiac output (CO), left ventricular pressure (LVP), aortic blood pressure (BP), systolic contractility (dp/dt max), and systolic wall thickening fraction (WT%) were measured. A multichamber pump system (IMPS) surrounding the left ventricle was implanted and the measurements were repeated. Then acute heart failure was induced by beta-blockade, resulting in a decline of all measured parameters to more than 30% compared to baseline values. In the further course of the experiment, repeated measurements were taken at several intervals with and without DMVA by the implanted device. The IMPS implantation caused no significant hemodynamic changes. Under conditions of acute heart failure DMVA improved LVP (46 +/- 7 to 81 +/- 9 mm Hg), dp/dt max (532 +/- 207 to 744 +/- 361 mm Hg/s), CO (1.5 +/- 0.1 to 1.9 +/- 0.5 L/min) and WT% (19 +/- 7% to 32 +/- 8%). Left ventricular myocardium not directly assisted by external pressure application showed improved regional myocardial function during DMVA. We conclude that DMVA is capable of improving hemodynamics due to extrinsic compression. It also enhances the remaining myocardial function of the failing heart, which might lead to myocardial recovery. These synergistic effects are considered responsible for the high efficiency shown by the IMPS in previous investigations.
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Kaczmarek et al. (2003) studied acute heart failure (n=8). Direct mechanical ventricular assistance (DMVA) vs. without DMVA was evaluated on hemodynamics and regional myocardial function. Direct mechanical ventricular assistance improved left ventricular pressure (46 to 81 mm Hg), cardiac output (1.5 to 1.9 L/min), and wall thickening (19% to 32%) in acute heart failure.