Protocols for High-Risk Pregnancies. Группа авторов
measurementsEnd‐diastolic ventricular diameter just inferior to the atrioventricular valve leaflets in the short or long axis viewThickness of the ventricular free walls and interventricular septum in diastole just inferior to the atrioventricular valvesAdditional measurements if clinically relevant, including:systolic ventricular dimensions (short or long axis views)transverse atrial dimensionsbranch pulmonary artery diametersCardiac function assessment (if clinically relevant) Fractional shorteningVentricular strainMyocardial performance index
Management
When a cardiac anomaly is found, a full detailed fetal scan to detect any other extracardiac anomalies is mandatory. Many fetal syndromes include cardiac anomalies, and accurate counseling requires complete enumeration of associated anomalies. Fetal karyotype testing should be offered to the parents, as chromosome abnormalities are seen in a large segment of fetuses with congenital heart disease. Additional testing for a microdeletion of chromosome 22q11 can be helpful in fetuses with conotruncal malformations (e.g., tetralogy of Fallot, truncus arteriosus). As for all fetal anomalies, microarray testing for microdeletions and microduplications has also become routine. In selected cases specific gene sequencing or even whole exome or genome sequencing is indicated.
Overall survival once a cardiac lesion is found depends on the nature of the cardiac problem, the presence of extracardiac anomalies, the karyotype, and the presence of fetal hydrops. Fetal hydrops in association with structural heart disease is virtually universally fatal. Aneuploid fetuses may have dismal prognoses even in the absence of heart disease; for example, fetal trisomy 18 may make repairing even a straightforward ventricular septal defect inadvisable.
Lesions that can be repaired into a biventricular heart carry a better long‐term prognosis than those that result in a univentricular heart. In general, infants known to have congenital heart disease prenatally do better than those whose cardiac defects are only found after birth.
Fetal arrhythmias
Diagnosis and management
The largest group of fetal arrhythmias are intermittent and due to atrial, junctional or ventricular extrasystoles. They carry a small risk of co‐existent structural abnormality. A greater risk exists of an unrecognized tachyarrhythmia, or the development of a tachyarrhythmia later in gestation. Atrial extrasystoles predispose the fetus to development of reentrant atrial tachycardia, which can lead to fetal hydrops. We recommend weekly auscultation of the fetal heart, along with avoidance of caffeine or other sympathomimetics, until resolution of the arrhythmia.
Fetal tachycardias represent a management challenge, because determination of the precise electrophysiological cause of the arrhythmia is essential to any rational management strategy, but fetal electrocardiography is not yet clinically practical in the presence of intact membranes. The differential diagnoses of fetal tachycardias include reentrant atrial tachycardia, atrial flutter, and ventricular tachycardia. The treatment of these disorders differs significantly, and appropriate medications for one may be contraindicated for another. The correct diagnosis, which should be based on combinations of M‐mode, Doppler and color Doppler–M‐mode imaging, is essential to appropriate therapy.
If there is a fetal bradycardia, the first step is to determine if there is a regular or an irregular atrial rate. If the atrial rate is regular and slow, that is, below 100 beats per minute, there may be sinus bradycardia, which should prompt a complete evaluation of fetal well‐being. The most common clinically important fetal bradycardia results from complete heart block, which will demonstrate a normal regular atrial rate with a slower ventricular rate whose beats do not occur in conjunction with atrial beats. In structurally normal hearts this is usually caused by maternal antibodies associated with lupus erythematosus and Sjögren syndrome, termed SSA/Ro and SSB/La. A smaller group of patients, without maternal antibodies, may present with congenital complete heart block in a setting of complex congenital heart disease involving the central fibrous body of the heart (e.g., left atrial isomerism, corrected transposition of the great arteries). In these patients, the prognosis is directly related to the complexity of the heart disease and the association with congestive heart failure.
A more benign cause of fetal bradycardia, which may be mistaken for 2:1 heart block, is blocked atrial bigeminy. In such cases the atrial rate is not regular, but rather demonstrates paired beating in which a premature atrial beat follows closely after a normal atrial beat with no ventricular response to the premature beat. This arrhythmia has no significance beyond that of isolated atrial extrasystoles.
Follow‐up
The fetus with congenital heart disease should be carefully followed by ultrasound up to delivery. Structural lesions may evolve prenatally even as they do postnatally. It is particularly important to evaluate areas of potential obstruction, and the relationships of the great arteries to the ventricles. Fetuses with significant arrhythmias (including reentrant tachycardias, atrial flutter, and complete heart block) should also be followed at a center with experience in the prenatal medical management of fetal arrhythmias, by a team that includes perinatologists, pediatric cardiologists, and adult electrophysiologists. Delivery need not be by cesarean except in the presence of selected fetal arrhythmias that do not permit adequate fetal heart rate monitoring. For fetuses with lesions that are expected to render the neonate dependent on ductus arteriosus patency for systemic or pulmonary perfusion, prostaglandin E1 should be available in the nursery at the time of delivery to keep the ductus open.
Suggested reading
1 American Institute of Ultrasound in Medicine. AIUM Practice Guideline for the Performance of Obstetric Ultrasound Examinations. www.aium.org/resources/guidelines/obstetric.pdf
2 American Institute of Ultrasound in Medicine. AIUM Practice Parameter for the Performance of Fetal Echocardiography. https://doi.org/10.1002/jum.15188
3 Bahtiyar MO, Dulay AT, Weeks BP, Friedman AH, Copel JA. Prenatal course of isolated muscular ventricular septal defects diagnosed only by color Doppler sonography: single‐institution experience. J Ultrasound Med 2008; 27:715–20.
4 Copel JA, Liang RI, Demasio K, Ozeren S, Kleinman CS. The clinical significance of the irregular fetal heart rhythm. Am J Obstet Gynecol 2000; 182:813–17.
5 Copel JA, Tan AS, Kleinman CS. Does a prenatal diagnosis of congenital heart disease alter short‐term outcome? Ultrasound Obstet Gynecol 1997; 10:237–41.
6 Donofrio MT, Moon‐Grady AJ, Hornberger LK, et al. Diagnosis and treatment of fetal cardiac disease: a scientific statement. Am Heart Assoc Circ 2014; 129:2183–242.
7 Kleinman CS, Copel JA. Electrophysiological principles and fetal antiarrhythmic therapy. Ultrasound Obstet Gynecol 1991; 4:286–97.
8 Miller A, Riehle‐Colarusso T, Alverson MS, et al. Congenital heart defects and major structural noncardiac anomalies, Atlanta, Georgia, 1968 to 2005. J Pediatr 2011; 159:70–8.
9 Pierpont ME, Brueckner M, Chung WK, et al. Genetic basis for congenital heart disease: revisited. A scientific statement from the American Heart Association. Circulation 2018: 138:e653–e711.
10 Silverman NH, Kleinman CS, Rudolph AM, et al. Fetal atrioventricular valve insufficiency associated with nonimmune hydrops: a two‐dimensional echocardiographic and pulsed Doppler study. Circulation 1985; 72:825–32.
11 Todros T, Faggiano F, Chiappa E, Gaglioti P, Mitola B, Sciarrone A. Accuracy of routine ultrasonography in screening heart disease prenatally. Gruppo piemontese for prenatal screening of congenital heart disease. Prenatal Diag 1997; 17:901–6.
PROTOCOL 7 Clinical Use of Doppler
Henry L. Galan
Department