Saul D. Larks

Wave forms of the electrohysterogram in pregnancy and labor

Abstract The existence of the repetitive uterine electrical wave form as previously described is confirmed in this report. Simultaneous multichannel recording shows that the appearance of the wave varies depending on the location of the electrodes. Repetitive, symmetrical wave forms can be understood only as correlates of propagated events, arising in definite foci. As judged by the earlier onset of fast activity as well as earlier onset of the U b −U c deflection, it appears most reasonable to assume that the focus is on the right side. The hypothesis is presented that the human uterus in labor behaves like a large auricle, i.e., as a single-chambered organ in which excitation spreads radially over the surface from a single dominant pacemaker.

The fetal electrocardiogram in multiple pregnancy

Abstract 1. 1. The fetal electrocardiogram is shown to be a useful tool in the study of multiple pregnancy. 2. 2. Recordings from 9 sets of twins, one set of triplets, and one set of quadruplets are presented. 3. 3. Diagnosis of a twin pregnancy at 16 weeks is demonstrated. 4. 4. The possibility of studying the presentation of the fetuses is discussed. 5. 5. The fetal electrocardiogram is suggested as an alternate method of diagnosis when x-ray technique may not be desired.

Experiences in the diagnosis of fetal life with the fetal electrocardiogram.

Abstract 1. Twenty-five instances in which the technique of fetal electrocardiography was used for the diagnosis of fetal life, because fetal heart tones could not be heard, are presented and discussed. 2. It was shown that the positive fetal electrocardiograms which could be expected in a number of these instances were evidence for the existence of fetal life. 3. The significance of negative findings is discussed. It is suggested that the negative fetal ECG has no meaning prior to 18 weeks, and in the epoch of low accuracy from the twenty-fifth to the thirty-second week. 4. In the epochs of high accuracy from the eighteenth to the twenty-fourth week, and again toward term, a negative fetal ECG can raise a presumption as to the absence of fetal life. Even at these times, however, there are about 3 per cent false-negatives.

THE HUMAN ELECTROHYSTEROGRAM: ELECTRICAL EVIDENCE FOR THE EXISTENCE OF PACEMAKER FUNCTION IN THE PARTURIENT UTERUS*

originated at either or both cornua. In rabbits Reynolds (1939) observed contraction waves originating in the tubes, some of which were transmitted to the uterus resulting in contraction of its musculature. Steer (1954), studying the fast electrical pulses, felt that one of his records suggested propagation, but that evidence for pacemaker activity which was present in early labour disappeared as labour progressed. Alvarez and Caldeyro-Barcia (1954), utilizing intramuscular balloons, stated that a pacemaker exists at both cornua, although their published records in normal labour showed the contraction waves originating near the right cornu only. In this report evidence for the existence of pacemaker function in the parturient uterus will be examined, on the basis of our studies on the

Observations on electrical activity of the pregnant uterus, not in labor

Abstract 1.1. Electrical activity associated with the uterus can be demonstrated in pregnancy prior to labor. 2.2. In late pregnancy, from the thirty-fifth week onward, a high level of electrical activity is reached, signaling the approaching onset of labor. 3.3. The very great variability and relative lack of pattern may suggest multiple foci and localized events, or sporadic pacemaker activity. 4.4. Appearance of major diphasic slow waves probably indicates the conduction and spread of excitation waves. 5.5. It appears that, toward the end of gestation, pacemaker activity, conduction of the excitation waves, and muscular response are activated in that order. 6.6. From the thirty-fifth week onward, this epoch electrically speaking may have the physiologic function of preparation for the end of gestation by means of favoring activation of pacemaker, conduction, and response, and possibly the establishment of the hegemony of a single pacemaker.

Predictive Obstetrics: Relative Significance of Absence of Fetal Heart Tones and Absence of the Fetal Electrocardiogram Complex

ON THE BASIS of the biomathematical approaches being developed by this laboratory *• 5 and the work of others, l a kind of predictive obstetrics may emerge. Thus, it has been shown that prenatal prediction of the state of the infant at birth is possible, * and early perinatal identification of factors associated with congenital heart disease and with malformation may be made. Such approaches not only serve to identify significant factors but also make possible the evaluation of the quantitative contribution of each factor. In this report these quantitative approaches will be used for the purpose of evaluating the relative significance of absence of the fetal heart tones (FHT) and absence of the fetal electrocardiogram (FECG) complex as these factors affect a predicted Apgar score, i.e. the condition of the infant at birth.