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.

Fetal hearing.

The fetus can hear during the last trimester of pregnancy. Consistent responses to acoustic stimuli have been observed from 28 weeks onwards. Animal experiments as well as investigations in the human lead to the conclusion that sounds from outside the mother are attenuated, but rarely by more than 30 decibels; external conversations are audible. Only 30% of the phonetic information is available to the fetus, but intonation is almost perfectly transmitted to the amniotic sac. Evidence is accumulating that the mother's voice or different sound patterns from the same voice are learnt by the fetus. Thus there are indications that short-term auditory memory may be present by the end of pregnancy.

[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.

[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)

[Reaction of the newborn infant less than 2 hours after birth to the maternal voice]. / Réactivité du nouveau-né de moins de deux heures de vie à la voix maternelle.

Our group provided in 1981 evidence of a transmission of external voices, particularly the mother's voice, into the pregnant uterus in the human. The present study was carried out in order to investigate the actual perception and memorisation of this particular feature of the fetal environment. 25 infant newborns, 20 within the first hour of life and 5 during the second hour, with no post-natal experience of the mother's voice, were submitted to five females voices. The mother's voice rank was determined by randomization. The stimulus consisted in the first name of the newborn, repeated three times, with no associated visual or tactile perception. The behavior of the newborn was studied on videotapes by three of the investigators, without knowledge of the rank of the mother. Three levels of response were determined: no reaction, weak response (segmental movement) and complete response (orienting movement). The behavioral responses to the mother's voice were significantly different (p less than 0.01). The mother induced 36% of complete responses, when the unknown voices induced only 12% (p less than 0.001). Because the intonation of the mother was found, as expected, significantly warmer, this factor had to be controlled. After exclusion of cold voices, a significant difference persisted (45% of complete responses to the mother versus 16% to the other women, p less than 0.02). A fetal perception of external sounds in demonstrated. Moreover, evidence of a prenatal experience of the mother's voice, possibly involved in the process of attachment, is provided.

[Intra-amniotic transmission of the human voice]. / La transmission intra-amniotique des voix humaines.

New acoustic measurements in amniotic environment permit to specify the conditions of transmission of human voices: voices emerge, incompletely covered by a low background noise, but however higher pitched near the placenta. The recognition of phonemes in utero is rather weak, approximately 30 per cent and appreciably identical for all voices and different mode of emission. Therefore this type of recognition is likely to play a minor role: the voices are evenly toneless by lack of high-pitch, and there is no obvious superiority of the intelligibility of direct maternal voice. The recognition of vowels by their second forming, as well as the emergence (demonstrated with special microphones) of impulse noises with very high-pitch components and of synthetic speech, confirm the possibility of transmission of frequencies exceeding 1,500 Hz to the intra-amniotic environment. On the contrary, melody recognition is excellent: probably major role of this factor. The loudness of the maternal voice transmitted to the uterus exceeds markedly that of outside voices, and this voice is certainly accessible to the fetus, most of the time. The demonstration of the transmission to the amniotic fluid of noises and voices enables to consider the possibility of perception.