Ventricle-Specific Biomechanical Responses to Inotropic and Vasoactive Drugs in Human Myocardial Slices

This study aimed to compare baseline biomechanical contractile properties between right (RV) and left ventricular (LV) human living myocardial slices (LMS) and explore the effect of dobutamine, noradrenaline, adrenaline, levosimendan and enoximone in both ventricles. Sixty-three slices (33 RV, 30 LV) were produced from 5 explanted hearts. At baseline, RV LMS had a higher maximum contraction force, shorter contraction duration, time to peak and time to relaxation, steeper dF/dt and a larger peak area than LV LMS. Dobutamine administration had a larger effect in RV than LV LMS. Spontaneous, irregular contractions were observed after noradrenaline, adrenaline and dobutamine administration. In conclusion, RV LMS showed a stronger contraction with higher contraction velocity as compared to LV LMS and exhibited a greater response to dobutamine. These findings contribute to the understanding of the RV physiology as a separate entity, advocating for a different approach in treating RV or LV dysfunction.