Dynamic cardiomyoplasty: a surgical approach for ventricular assistance.
Dynamic cardiomyoplasty involves the use of an electrically stimulated skeletal muscle wrapped around part of the heart to restore or augment myocardial contractility. In our approach, a Latissimus Dorsi muscle flap (LDMF) is transferred to the heart via a partial resection of the second rib, and sutured around the ventricles. The muscle flap is stimulated in synchrony with the heart contractions with bursts of impulses delivered by a "Cardio-Myostimulator" implantable pulse generator via intramuscular electrodes. The object of this study was to identify features of muscle stimulation and to measure the efficacy of L.D. cardiomyoplasty in increasing cardiac output, using an ultrasonic Doppler technique. This report shows the results obtained for goats in which such procedures were performed. Ultrasonic measurements were recorded at the time of cardiomyoplasty and 3-6 months later, during which period the muscle was put progressively into use by slowly increasing the burst frequency content, number of pulses as well as the heart-muscle contraction ratio (3:1, 2:1, 1:1). This postoperative muscle stimulation protocol takes into account the delay of gradual conversion of fast-twitch glycolytic muscular fibers into slow-twitch oxidative, fatigue-resistant fibers, as well as the healing time after cardiomyoplasty required for the muscle flap to recover collateral blood circulation and to adhere to the heart. Results show that synchronous burst stimulation of the muscle flap increases the blood peak velocity in the descending aorta (+36 +/- 8%) and increases the left ventricular stroke volume (+70 +/- 14%).(ABSTRACT TRUNCATED AT 250 WORDS)
Chachques
J C
JC
Department of Cardiovascular Surgery, Hôpital Broussais, Paris, France.
Grandjean
P
P
Nataf
P
P
Mihaileanu
S
S
Perier
P
P
Bourgeois
I
I
Carpentier
A
A
D000818:Animals; D001783:Blood Flow Velocity; D006348:Cardiac Surgical Procedures / Q000379:methods*; D004562:Electrocardiography; D005260:Female; D006041:Goats; D009206:Myocardium / Q000473:pathology; D013318:Stroke Volume; D013524:Surgical Flaps