Large animal ex vivo biventricular working hearts are a recent breakthrough in the scientific experimental community. This model allows a greater insight into intrinsic cardiac electrophysiology and hemodynamic function without interference from autonomous nervous system.

Perform a comparative study between different perfusion mediums and their impact on intrinsic hearts hemodynamics.

Pig hearts were excised with the pericardium. Cardiac arrest was induced in vivo by infusion of cold cardioplegic solution into the aortic root, followed by a rapid excision and immersion in a cold 0.9% saline solution. Some hearts were perfused with autologous blood (1.5 diluted in 10L Tyrode's solution). The aorta, pulmonary artery, pulmonary veins and vena cava were cannulated and remaining vessels were sutured. Hearts were placed on the setup and perfused at fixed pre- and afterloads. All hearts were perfused with Tyrode's solution with BSA and fatty acids (FA) (group 1), or BSA/FA and blood (group 2) or blood (group 3).

An increased aortic flow was observed in hearts perfused with blood without (+110%, P<0.05) and with BSA/FA (+50%, non-significant) compared to BSA/FA group. A drop was noted in LV and RV minimum pressure (−75 to 100%), end diastolic pressure (−40 to 80%) and dP/dtmin (−50%) in hearts perfused with blood±BSA/FA compared to BSA/FA only. dP/dtmax did not change in LV, but increased in the RV (+120–60% in blood±BSA/FA groups). All hearts perfused with BSA/FA±blood displayed a lower heart rate than hearts perfused with blood without BSA/FA (P<0.05).

This study shows significant advantages the addition of blood has on the ex vivo heart hemodynamics, especially for diastolic parameters, leading to a better maintenance of function during perfusion. Limitation of edema and a better oxygen carrying capacity of blood help reduce localised ischemia by improving the overall perfusion of the myocardium.