New method for monitoring the functional state of a dynamic cardiomyoplasty

Objective: To assess the impact of a dynamic cardiomyoplasty on failing hearts, it is essential to estimate the contraction force of the skeletal muscle and how its contraction is synchronized with the heart cycle. Methods: In a 6-month study a small fluid-filled, balloon-mounted catheter was placed between the myocardium and the muscular wrap in five adult female Boor goats and two female domestic pigs. The catheter was connected to a subcutaneous measuring chamber whereby pressure monitoring could be accomplished. Distinct pressure signals as a result of function of the dynamic cardiomyoplasty and the heart were detected initially in all animals. Results: Maximal relative pressure from the dynamic cardiomyoplasty was calculated as 336.2% ± 69.4% on day 24 ± 6.1 ( n = 7) and end-stage pressure as 59.8% ± 9.7% on day 174.6 ± 13.1 ( n = 4). A functional loss of pressure signals from the dynamic cardiomyoplasty was correlated to severe histologic muscle damage ( n = 3). Pressure signals transferred from the contracting myocardium to the catheter showed defined segments of contraction, ejection, and filling periods, allowing a mechanical synchronization of the dynamic cardiomyoplasty to the heart cycle. Conclusions: This monitoring catheter enabled the assessment of the functional state of the dynamic cardiomyoplasty and allowed a synchronization to the heart cycle. It will promote understanding and might help to avoid muscle damage in dynamic cardiomyoplasty for an improved outcome of the surgical treatment of end-stage heart failure. (J Thorac Cardiovasc Surg 1997;114:1097-106)