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The electrocardiogram in fetal asphyxia
CORRESPONDENCE
The electrocardiogram
in fetal
asphyxia
To the Editors: We wish to comment on the electrocardiograph tracings in Figs. 13, 14, and 15 of Dr. Ronald E. Myers’1 article on “Two patterns of perinatal brain damage and their conditions of occurrence.” Attention has been focused on the P wave as an aid to assessment in respiratory distress in the human neonate.2-4 Emphasis was placed on the contour of this wave in the right precordial leads. The serious prognostic significance of notching, especially when associated with a dominant S wave, was stressed. While not wishing to detract from the electrocardiograph changes specifically mentioned by the author, we note that here too the described P wave patterns apply and are particularly well shown on Fig. 13. With progressive recovery from anoxia, the P wave from being notched becomes narrower based and peaked. Incidentally, the text indicates that the upper tracing in Fig. 13 shows T wave inversion. This is manifestly an error.
correct in that the upgoing T wave in this tracing would be considered normal in the adult. HOWever, I refer the correspondents to the fact that a true inversion or reversal of T wave polarity does occur as the animal emerges from deep asphyxia going toward a more normal state of oxygenation (read the tracings from above down). Thus, the upgoing T wave in the upper tracings becomes downgoing in the lower tracings. Much of this confusion in nomenclature is derived from the fact that the rules governing the reading of the electrocardiogram in the adult lying supine must be modified when applied to the fetus in utero. The latter exhibits a highly variable positioning of his body parts and partictularly of their relation to one another. There also occurs a variable positioning of the relatively oversized fetal heart within the thoracic cavity which, in turn, contains uninflated lungs. The fetus in utero maintains an open ductus arteriosus. This also affects the behavior
FMBP
Gerald J. &tin, M.R.C.P.(Edin.) Senior Lecturer and Paediatrician H. de Villiers Heese, M.D., F.R.C.P.Ed. Professor of Paediatrics and Child Health University of Cape Town Department of Paediatrics and Child Health Medical School Observatory Cape Cape Town, South Africa
I
38
43 REFERENCES
1. 2. 3. 4.
Myers, R. E.: AM. J. OBSTET. GYNECOL. 112: 246, 1972. Sutin. G. J.. and Heese, H. de V.: Lancet 2: 532, ‘1964.” ’ Sutin, G. J., Homer, R., Heese, H. de V., and Malan. A. F.: Arch. Dis. Child. 40: 402. 1965. Sutin, G. J.: Lancet 1: 1273: 1966. .
Reply To
to Drs. Sutin
and
Heese
the Editors: Drs. Sutin and Heese disagree with the designation of the upper tracing of my Fig. 13 as showing T wave inversion. Technically, they are
/
+ 34
41 -.
Fig. 13. Fetal ECG recovery after release of maternal aorta from an artificial Type II dip produced by maternal aortic constriction. The recording above is taken at the depth of the period of fetal asphyxia while the successive recordings show stages in the recovery from the abnormal pattern. FHR = Fetal heart rate. FMBP = Fetal mean blood pressure. ( Mueller-Heubach, Myers, and Adamsons: Unpublished data.)
The electrocardiogram
in fetal
asphyxia
To the Editors: We wish to comment on the electrocardiograph tracings in Figs. 13, 14, and 15 of Dr. Ronald E. Myers’1 article on “Two patterns of perinatal brain damage and their conditions of occurrence.” Attention has been focused on the P wave as an aid to assessment in respiratory distress in the human neonate.2-4 Emphasis was placed on the contour of this wave in the right precordial leads. The serious prognostic significance of notching, especially when associated with a dominant S wave, was stressed. While not wishing to detract from the electrocardiograph changes specifically mentioned by the author, we note that here too the described P wave patterns apply and are particularly well shown on Fig. 13. With progressive recovery from anoxia, the P wave from being notched becomes narrower based and peaked. Incidentally, the text indicates that the upper tracing in Fig. 13 shows T wave inversion. This is manifestly an error.
correct in that the upgoing T wave in this tracing would be considered normal in the adult. HOWever, I refer the correspondents to the fact that a true inversion or reversal of T wave polarity does occur as the animal emerges from deep asphyxia going toward a more normal state of oxygenation (read the tracings from above down). Thus, the upgoing T wave in the upper tracings becomes downgoing in the lower tracings. Much of this confusion in nomenclature is derived from the fact that the rules governing the reading of the electrocardiogram in the adult lying supine must be modified when applied to the fetus in utero. The latter exhibits a highly variable positioning of his body parts and partictularly of their relation to one another. There also occurs a variable positioning of the relatively oversized fetal heart within the thoracic cavity which, in turn, contains uninflated lungs. The fetus in utero maintains an open ductus arteriosus. This also affects the behavior
FMBP
Gerald J. &tin, M.R.C.P.(Edin.) Senior Lecturer and Paediatrician H. de Villiers Heese, M.D., F.R.C.P.Ed. Professor of Paediatrics and Child Health University of Cape Town Department of Paediatrics and Child Health Medical School Observatory Cape Cape Town, South Africa
I
38
43 REFERENCES
1. 2. 3. 4.
Myers, R. E.: AM. J. OBSTET. GYNECOL. 112: 246, 1972. Sutin. G. J.. and Heese, H. de V.: Lancet 2: 532, ‘1964.” ’ Sutin, G. J., Homer, R., Heese, H. de V., and Malan. A. F.: Arch. Dis. Child. 40: 402. 1965. Sutin, G. J.: Lancet 1: 1273: 1966. .
Reply To
to Drs. Sutin
and
Heese
the Editors: Drs. Sutin and Heese disagree with the designation of the upper tracing of my Fig. 13 as showing T wave inversion. Technically, they are
/
+ 34
41 -.
Fig. 13. Fetal ECG recovery after release of maternal aorta from an artificial Type II dip produced by maternal aortic constriction. The recording above is taken at the depth of the period of fetal asphyxia while the successive recordings show stages in the recovery from the abnormal pattern. FHR = Fetal heart rate. FMBP = Fetal mean blood pressure. ( Mueller-Heubach, Myers, and Adamsons: Unpublished data.)