Salutary Effects of Short-Term Non–Blood-Contacting Ventricular Actuation Versus Left Ventricular Assist in Chronic Heart Failure

Mechanical circulatory support (MCS) restores flow using blood pumps with ventriculoarterial (VA) uncoupling and unloading. Blood contact contributes to bleeding, thromboembolism, and infection. Direct mechanical ventricular actuation (DMVA) maintains VA coupling and augments ventricular expansion and end-diastolic geometry. These effects differ from conventional MCS. This study evaluated postsupport cardiac function following DMVA compared with a clinically available left ventricular assist device (LVAD) in a chronic heart failure (HF) model. Chronic HF was induced in adult canines using rapid ventricular pacing or serial coronary microembolization. Animals were assigned to 2 hours of DMVA or LVAD. Hemodynamic measurements, pressure–volume analyses, and dobutamine stress responses were assessed postsupport. Support was successfully maintained in all animals. After device removal, DMVA was associated with significant improvements in preload-recruitable stroke work and end-diastolic pressure–volume relationships. Dobutamine responsiveness was preserved after DMVA but blunted following LVAD. No postsupport improvements in systolic or diastolic function were observed after LVAD support. Direct mechanical ventricular actuation resulted in salutary effects on systolic and diastolic function in chronically failing hearts, whereas LVAD support did not. Unlike LVAD support, DMVA maintains VA coupling and exerts salutary effects on the failing heart, notably improving diastolic function. Synchronous DMVA support may further enhance these effects.