Contractile performance of right ventricular myocardium of 34 patients transplanted for ischemic cardiomyopathy

Objectives: The clinical and scientific interest in ischemic cardiomyopathy was focussed on the left ventricle. This study attempts to analyze right ventricular performance. The experimental model of isolated right ventricular trabeculae was selected to allow the analysis by exclusion of pulmonary resistances, load conditions and the interference with left ventricular contractile behaviour. Material and Methods: Isolated trabeculae from the free right ventricular wall (0.3×4.0mm) were eletrically stimulated (range: 0.5–3Hz) while isometric force, resting force and contraction kinetics were analyzed as a function of stimulation frequency (n=34). Right ventricular specimen of normal donor hearts (n=16) were used as control. Trabeculae from the same patients were loaded with the calcium indicator FURAII to analyze electromechanical coupling. Using the ratio method (340nm/380nm at 250Hz) intracellular calcium, muscle length, force (systolic/diastolic), calcium (systolic/diastolic) were simultaneously recorded (measurement conditions: 37°C, oxygenated Krebs-Henseleit-Solution, supramaximal stimulation, optimal length). Results: Isometric force increased as a function of stimulation frequency up to an optimum in any preparation. However, the optimum was near 2.5Hz in NDH but near 1.5Hz in ICM (p1Hz. Diastolic calcium increased in ICM but not in NDH (p