Fluoroscopic determination of latissimus dorsi muscle shortening fraction after dynamic cardiomyoplasty.
Optimization of the skeletal muscle contraction during cardiac assist is important to achieve maximal cardiac assist and yet avoid overstimulation that may injure skeletal muscle. Dynamic cardiomyoplasty suffers from lack of an objective, reproducible, and accurate technique to measure skeletal muscle shortening fraction after wrap and training of the muscle. A recruitment curve is considered the best way to select the proper stimulation level to achieve supramaximal contraction without overstimulating the muscle. A fluoroscopic technique of determining latissimus dorsi recruitment curve was evaluated in five goats undergoing dynamic cardiomyoplasty with an anterior cardio-subcutaneous wrap. Two pairs of stainless steel targets (0.5 and 1 cm of diameter) were implanted on each side of the muscle wrap. One pair of sonomicrometer crystals was also implanted. Displacement of the targets was measured under fluoroscopy at five different stimulation levels. Correlation coefficients between targets on the inside surface of the wrap and the sonomicrometer crystals, and targets on the outside surface of the wrap and the sonomicrometer crystals were 0.71 (P < 0.05) and 0.60 (P < 0.05), respectively. Targets on the inside surface of the wrap were more accurate than targets on the outside surface of the wrap for measurement of skeletal muscle shortening fraction and establishment of a recruitment curve. Adverse effects from the targets were not observed.
Monnet
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E
Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
Orton
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EC
Jacobs
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G
Metelman
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L
D000818:Animals; D018421:Cardiomyoplasty; D005471:Fluoroscopy / Q000295:instrumentation*; D006041:Goats; D006439:Hemodynamics / Q000502:physiology; D009200:Myocardial Contraction / Q000502:physiology*; D011183:Postoperative Complications / Q000503:physiopathology*; D019736:Prostheses and Implants; D012680:Sensitivity and Specificity