ABSTRACT
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.
Subject(s)
Cardiac Catheterization/methods , Cardiomyoplasty , Catheterization/methods , Animals , Female , Goats , Monitoring, Physiologic/methods , Muscle Contraction/physiology , Muscle, Skeletal/pathology , Muscle, Skeletal/physiology , Myocardial Contraction/physiology , Pressure , Swine , Time FactorsABSTRACT
Sodium-potassium cotransport activity is thought to be defective in essential hypertension and could be a useful genetic marker for susceptibility to essential hypertension. In this study cotransport activity in subjects with hypertension was compared with that in normotensive controls. The effects of ethnic differences, environment, and antihypertensive drugs were also studied. Mean cotransport activity was lower in hypertensive subjects than in controls of the same ethnic groups. There was, however, a large overlap between controls and hypertensive subjects. No ethnic or environmental influences were found. The large overlap found suggests that sodium-potassium cotransport activity is not a useful genetic marker in essential hypertension.
