A new method to select stimulus strength after cardiomyoplasty.
At present, there is no technique available for the determination of optimal stimulus strength in patients after cardiomyoplasty. To stimulate the latissimus dorsi (LD) muscle, we implanted Itrel stimulators in two goats and cardiomyostimulators in three goats following the routine cardiomyoplasty procedure. During the following 3 months, these LD muscles were conditioned at 2.5-4.0 volts (V). After conditioning, LD muscle shortening was measured on x-ray films using the distance between two stimulation electrodes as references. LD muscle shortening increased rapidly at higher stimulus strength and reached 13% +/- 2% at 2.0 V. Shortening was calculated in one patient at 4, 6, and 9 weeks following surgery. The increase in the number of pulses per burst (2, 3, and 6, respectively) had a positive effect on muscle shortening between the two stimulation electrodes (10%, 14%, and 20%, respectively). Also, muscle shortening was measured between two clips attached to the distal part of the LD muscle. Muscle shortening in the area wrapped around the left ventricle was 15% after 9 weeks. In a second patient, shortening between the electrodes was 16% at 14 months after surgery, and distal muscle shortening was 11%. We concluded that optimal stimulation after cardiomyoplasty could be detected more accurately by measurement of LD muscle shortening using the stimulation electrodes or surgical clips as markers.
van der Veen
F H
FH
Department of Cardiology, University of Limburg, Maastricht, The Netherlands.
Lucas
C
C
Lorusso
R
R
van der Nagel
T
T
Penn
O C
OC
Wellens
H J
HJ
D000818:Animals; D001243:Assisted Circulation; D009202:Cardiomyopathies / Q000601:surgery*; D004558:Electric Stimulation / Q000379:methods*; D004566:Electrodes; D005500:Follow-Up Studies; D006041:Goats; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D013524:Surgical Flaps / Q000502:physiology*