Association of latissimus dorsi muscle expansion with electrostimulation before cardiomyoplasty.

BACKGROUND: The principle of cardiomyoplasty is chronic electrostimulation of the latissimus dorsi muscle (LDM) flap wrapped around the heart to obtain a phasic activity that can be integrated to ventricular kinetics. In clinical cardiomyoplasty procedures, a complete wrap of both ventricles by the LDM cannot always be obtained in cases of extremely dilated hearts. This is due to the limited LDM length available for wrapping. In most of these cases, benefits of cardiomyoplasty are very limited. We have investigated the feasibility of progressive LDM expansion associated with electrostimulation. The aim was to increase the muscle area before cardiomyoplasty, while preserving the electrophysiologic characteristics of muscle fibers. METHODS: In 5 goats, a silicone LDM expander with two incorporated muscular pacing electrodes was inserted deep into the LDM through a paravertebral incision along the posterior edge of the muscle. The pacing leads were connected to a myostimulator implanted in a subcutaneous pocket. The expander was progressively inflated over 8 weeks, up to 500 mL. Simultaneously the LDM was electrostimulated. RESULTS: At 2 months planimetric studies demonstrated an increase of the LDM surface from 175 +/- 12 to 229 +/- 17 cm2 (+31% +/- 4%; p < 0.05). The expanded LDM showed preserved electrophysiologic characteristics. The analysis of biopsy samples revealed histologic integrity of muscle fibers and preservation of their mean diameter. CONCLUSIONS: Potential benefits of this procedure are (1) increase of muscle surface, (2) training of muscular fibers and preservation of muscular tone, and (3) division of the distal vascular supply at implantation, which may potentiate vascularization from the LDM main pedicle. An LDM expansion could be considered before cardiomyoplasty in cases of significant heart dilatation. This device was successfully implanted in 2 patients, 2 months before cardiomyoplasty. Cardiomyoplasties were performed without difficulty, and a complete biventricular wrap was obtained in both patients in spite of massive cardiomegaly.

[Diagnostic evaluation of fetal distress during pregnancy by a sound stimulation test]. / Evaluation diagnostique de la souffrance foetale pendant la grossesse au moyen d'un test de stimulation sonore.

A vibro-acoustic stimulus induces in the human fetus over 28 weeks of gestational age some modifications of the fetal heart rate. Absence of response, as a single test, has been used to suggest the diagnosis of fetal jeopardy (Read and Miller, Trudinger and Boylan). In this series, the pronostic value of the sound stimulation test (SST) was evaluated in association with the results of the widely used non stress test (NST). In 78 patients, 93 pathological NST, quantified by means of the Fischer's score, were assessed by SST. The results showed a good correlation between NST and SST : SST appears to be negative (no fetal response) in respectively 10%, 48% and 100% of NST tracings with Fischer score of 7, 6 or less than or equal to 5. Thus, when the basal Fischer score indicates fetal distress, no complementary test is needed (all 11 infants showed low Apgar score or acidosis). On the other hand, when the NST is less severely abnormal (score 6 or 7), the SST allows a good discrimination of the risk of neonatal distress. Among 62 cases explored less than one week before birth, a 27% (17/62) overall probability of neonatal depression (low Apgar score at 5 minutes and/or acidosis in the umbilical artery at birth) was noticed. The SST was interpreted as reactive in 44 cases of this group, with only 8 depressed neonates (18.2%). In the other 18 cases, a negative SST was followed by birth of 9 depressed infants (50%). The difference is statistically significant (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

[Auditory perception and fetal reaction to react to sound stimulation (author's transl)]. / Perception auditive et réactivité foetale aux stimulations sonores.

The confirmation of techniques used to stimulate the fetus in utero led us to an exhaustive study of spontaneous intra-uterine noises and those modified by different stimuli (while evaluating the diagnosis of fetal distress with flat cardiac rhythm during pregnancy). By the use of elaborate techniques simultaneously we could appreciate the signal and analyse the information obtained and we able to show incontrovertibly that over and above the basal sound that the fetus could hear it could appreciate the mother's voice and other voices, which were perfectly audible to it but lacking in tone because the sharp frequencies were absorbed. The first results of stimulation using calibrated sounds seem to confirm that the fetus does not react to a sound stimulus when it is in a state of fetal distress, but when there is no fetal distress it does react immediately by change in the heart rate, often associated with movements. This technique, incidentally, can be used to show if the fetus can hear well in the uterus in cases of family deafness or of rubella associated with pregnancy.