Fetal Bradycardia. A Practical Approach (original) (raw)
Congenital Heart Disease, 2021
Fetal arrhythmias reach up around 10% of the total third-level perinatal cardiology references. Sustained bradycardia is defined as a baseline fetal heart rate (FHR) of less than 110 bpm sustained for at least 10 min. The overall incidence of malignant fetal bradyarrhythmias, such as complete atrioventricular block (AVB) and channellopathies, is relatively rare, 1:5000 pregnancies, but represents a serious emergency for the gynecologist, neonatologists, and pediatric cardiologists. Fetal complete AVB is strongly associated with maternal connective tissue disease, but it can be also associated with congenital heart disease and usually with a poorer prognosis with high risk of fetal hydrops and abortion. Currently, the treatment of severe fetal bradyarrhythmias is principally pharmacological and aims to increase the FHR, besides an early resolution of underlying causes, when possible, and a promptly management of fetal heart failure. Intrauterine electrostimulation nowadays is an experimental pioneering method, reserved for limited selected cases.
Fetal Arrhythmia and Related Fetal and Neonatal Outcome
Donald School Journal of Ultrasound in Obstetrics and Gynecology, 2021
The evolution of fetal echocardiography (Motion and pulsed Doppler modes) has made possible the antenatal diagnosis of cardiac rhythm anomalies. Fetal cardiac arrhythmias are common anomalies, 20% of which are potentially dangerous. M-mode (motion-mode) echocardiography recording of the fetal heart cannot identify electrical events in the heart, but does depict the mechanical events that succeed them. Pulsed Doppler echocardiography identifies possible arrhythmias over a period of time, allowing for the measurement of these time intervals, a parameter absolutely necessary for the classification of various types of cardiac arrhythmias. Irregular cardiac rhythm (premature atrial contraction, premature ventricular contractions) is the most common disorder seen in practice in specialized fetal echography. These anomalies are usually benign and resolve spontaneously until delivery, thus do not require treatment. Fetal tachyarrhythmia (increased heart rate of 160-189 bpm) is detected by echocardiography, with a wide range of rhythm disorders. It is imperative to understand the mechanism of tachyarrhythmia, so that an accurate and rational management strategy can be formulated in each case. Fetal bradyarrhythmia is characterized by frequent irregular rhythm, low sustained heart rate (10 seconds-few minutes), below 110 bpm, or a combination of both. The diagnosis of the specific bradycardia depends on the echocardiogram findings and the atrioventricular conduction pattern.Once fetal bradycardia is noted, a quick fetal ultrasonographic examination should be performed to assess the normal fetal movements, fetal tone, thus contributing to the diagnosis of fetuses in distress, who require emergency delivery by cesarean section. This paper is an update of the diagnostic approaches in the current practice for different types of fetal heart rhythm disorders, the impact on the fetus and the newborn and their management.
Fetal arrhythmia: An institutional experience
Journal of neonatal-perinatal medicine, 2011
Fetal arrhythmias occur commonly, but most are benign. Clinically significant arrhythmias should be distinguished and managed. Supraventricular tachycardia (SVT) and severe bradycardia from complete heart block (CHB) can progress to heart failure and hydrops fetalis. This retrospective review of 2042 fetal echocardiograms aims to characterize an institutional experience with fetal arrhythmias. 131 fetuses were referred for arrhythmia evaluation. Premature atrial contractions (PACs) were found in 67 (51%) of which a third had a prominent atrial septal aneurysm. 49 (37%) had sinus rhythm (no noted arrhythmia). 15 (11%) had hemodynamically significant arrhythmias, which included fetal tachycardias in 12 (9%) and CHB in 3 (2%). All fetuses with tachycardia had structurally normal hearts. 10 had fetal SVT (3 with hydrops and 7 without hydrops) and 2 had atrial flutter (1 with hydrops and 1 without hydrops). All fetuses in tachycardia were converted to sinus rhythm and 2 required antiarrhythmic treatment after birth. CHB was found in 3 fetuses. Major cardiac malformations and hydrops were noted in 2 of these fetuses, both resulting in fetal demise. The third fetus with CHB had a structurally normal heart, was associated with maternal systemic lupus erythematosus (positive SS-A, SS-B antibodies), and required a pacemaker after birth. PACs and sinus rhythm were the most common diagnosis in fetuses referred for arrhythmia evaluation. Despite the presence of hydrops, SVTs responded well to maternal administration of antiarrhythmic therapy and were successfully converted to sinus rhythm. CHB can be associated with maternal autoimmune disease and certain cardiac malformations. The prognosis of CHB in the presence of cardiac disease is poor.
Current Opinion in Pediatrics, 2008
Purpose of review-Though fetal arrhythmias account for a small proportion of referrals to a fetal cardiologist, they may be associated with significant morbidity and mortality. The present review outlines the current literature with regard to the diagnosis and, in brief, some management strategies in fetal arrhythmias. Recent findings-Advances in echocardiography have resulted in significant improvements in our ability to elucidate the mechanism of arrhythmia at the bedside. At the same time, fetal magnetocardiography is broadening our understanding of mechanisms of arrhythmia especially as it pertains to ventricular arrhythmias and congenital heart block. It provides a unique window to study electrical properties of the fetal heart, unlike what has been available to date. Recent reports of bedside use of fetal ECG make it a promising new technology. The underlying mechanisms resulting in immune-mediated complete heart block in a small subset of 'at-risk' fetuses is under investigation. Summary-There have been great strides in noninvasive diagnosis of fetal arrhythmias. However, we still need to improve our knowledge of the electromechanical properties of the fetal heart as well as the mechanisms of arrhythmia to further improve outcomes. Multiinstitutional collaborative studies are needed to help answer some of the questions regarding patient, drug selection and management algorithms.
Fetal cardiac arrhythmias: Current evidence
Annals of pediatric cardiology
This article reviews important features for improving the diagnosis of fetal arrhythmias by ultrasound in prenatal cardiac screening and echocardiography. Transient fetal arrhythmias are more common than persistent fetal arrhythmias. However, persistent severe bradycardia and sustained tachycardia may cause fetal hydrops, preterm delivery, and higher perinatal morbidity and mortality. Hence, the diagnosis of these arrhythmias during the routine obstetric ultrasound, before the progression to hydrops, is crucial and represents a challenge that involves a team of specialists and subspecialists on fetal ultrasonography. The images in this review highlight normal cardiac rhythms as well as pathologic cases consistent with premature atrial and ventricular contractions, heart block, supraventricular tachycardia (VT), atrial flutter, and VT. In this review, the details of a variety of arrhythmias in fetuses were provided by M-mode and Doppler ultrasound/echocardiography with high-quality i...
The effect of early second stage bradycardia on newborn status
European Journal of Obstetrics & Gynecology and Reproductive Biology, 1997
In the present study 45 patients with intrapartum cardiotocograms showing prolonged fetal bradycardia during the early second stage of labor were included. Bradycardia persisted for 180 s or more with either rapid or prolonged return to baseline, without loss of variability and rise of baseline fetal heart rate (FHR). The mean duration of bradycardia was 5.0 + 1.3 min. In the group with normal EHR tracings the rate of normal delivery (73.3%) was significantly higher than that of the group with fetal bradycardia (26.7%, P < 0.0001). We also noted a significantly higher rate of cesarean section (44.4%) in patients with abnormal FHR tracings, compared to that (11.1%) of parturients with normal FHR tracings (P < 0.001). In all cases blood samples were obtained from the umbilical cord artery, immediately after delivery. Only in two cases with abnormal FHR tracing umbilical cord artery was the pH less than 7.20. We conclude that in most cases, prolonged fetal bradycardia in the early second stage with the characteristics described above is well tolerated by a mature fetus. (~ 1997 Elsevier Science Ireland Ltd.
Recognition of fetal arrhythmias by echocardiography
Journal of Clinical Ultrasound, 1985
Fetal arrhythmias were detected in 331198 high risk pregnancies from 21 weeks to term. Using the two-dimensional echocardiographic image of the fetal heart as a guide, the M-mode beam was directed to define the motion of the ventricular and atrial walls and atrioventricular valve or semilunar valves. Atrial contraction was defined either by the atrial wall motion or from the A-point of the atrioventricular valve. Ventricular contraction was defined by closure of the atrioventricular valve (Cpoint), the onset of ventricular wall contraction, or from the semilunar valve opening. Ladder diagrams of the sequence of atrial and ventricular activation were constructed to define the temporal sequence of these events. Premature atrial contractions were present in 12. In one fetus this arrhythmia converted into supraventricular tachycardia while in the other 11 fetuses the course was benign. Two fetuses had premature ventricular contractions. Supraventricular tachycardia was noted in five fetuses. One with hydrops at 29 weeks returned to sinus rhythm following maternal administration of procainamide. A second hydropic fetus with paroxysmal atrial tachycardia and hydrops failed to respond to digitalis, propranolol, procainamide, verapamil, or amiodarone, and died shortly after cesarean section. Two mature fetuses had tachycardia close to term and were treated after cesarean section. One fetus with runs of atrial tachycardia died in utero. Three fetuses had complete heart block, two of whom were from mothers with connective tissue diseases. In four fetuses, there was bradycardia of less than 1001 minute lasting more than 30 seconds, but these episodes disappeared in 2 minutes. One fetus with fetal hydrops and bradycardia died. The fourth, with a complex arrhythmia and a basic rate of 80lminute, 2 : 1 atrioventricular block, premature ventricular contractions, and severe structural heart disease died after delivery. Indexing Words:
Diagnosis, Treatment and Follow-up of Fetal Cardiac Arrhythmia
The Journal of Pediatric Research, 2021
Currently, echocardiography represents the most widely used tool for diagnosis and follow-up of fetal arrhythmias in clinical practice. Although non-invasive techniques to record electrophysiological signals from the fetal heart have been
Detection and management of life threatening arrhythmias in the perinatal period
Early Human Development, 2008
The management of tachyarrhythmias and bradyarrythmias in the fetus requires a team approach with careful monitoring of fetal well-being as well as care in establishing a precise diagnosis with use of m-mode and Doppler echocardiography to determine the atrial and ventricular rate. A persistent fetal heart rate less than 80 beats per minute (bpm) suggests complete atrioventricular block. A persistent fetal heart rate over 180 bpm suggests pathological tachycardia, most of which are a supraventricular tachycardia mediated via an accessory pathway. However, around 20% are due to atrial flutter, and this review highlights why medical management should be different for these cases, and for those with hydrops or cardiac failure. It also illustrates which fetus or infant may be at particular risk, and illustrates key features in their management before and after birth.