A Monitoring Catheter for Dynamic Cardiomyoplasty

Measurement of the pressure developed between a dynamic Cardiomyoplasty (DCMP) wrap and the myocardium was evaluated as a possible method for monitoring skeletal muscle contractile force and the synchronization of the myostimulator-induced DCMP contraction in relation to the heart cycle. A newly designed implantable monitoring catheter was tested in goats (n = 3) for a six-month duration. A small fluid-filled balloon attached to a monitoring catheter was placed between the myocardium and the DCMP wrap. The catheter ended in a subcutaneous access port used for pressure monitoring. Sharp pressure signals produced by the contracting DCMP were obtained in all animals at the beginning of the study. An 86% reduction of the initial amplitude of the pressure curve occurred after six months of stimulation in two goats. In the third goat, no contraction could be verified, and the DCMP was considered failed. Pressure signals transferred from the contracting myocardium could be characterized into defined segments of contraction, ejection and filling. This information allows mechanical synchronization of the DCMP contraction with the desired period of the heart cycle. The DCMP monitoring catheter successfully tranferred signals relating to the functional state of the DMCP wrap and its mechanical coupling to the heart cycle. We expect that with the use of this catheter we can better understand and optimize DMCP as a therapy for end-stage heart failure.