Fetale Tachyarrhythmien

Fetal tachyarrhythmias are rare events which can cause neurological impairment and even intrauterine fetal death because of cardiac insufficiency. The initial tachycardia is followed by hydrops fetalis, polyhydramnios, and thickened placenta. Diagnosis can be made by fetal echocardiography using the M-mode. Heart size, the presence of AV valve insufficiency, and venous blood flow velocity waveforms are useful for fetal surveillance. Especially after conversion into sinus rhythm, the latter can be utilised for the evaluation of the grade of myocardial dysfunction. In non-hydropic fetuses, digoxin is still the drug of choice, whereas in hydropic fetuses additional medication (flecainide, amiodarone; in atrial flutter also sotalol) is mandatory. Successful therapy improves the prognosis, but the presence of hydrops fetalis, onset of tachyarrhythmia in early pregnancy, and preterm delivery worsen the outcome.     

Aetiology of non-immune hydrops: the value of echocardiography

Forty-eight pregnancies, five of them multiple, were referred for fetal cardiac assessment following the detection of non-immune hydrops fetalis; there were 52 hydropic fetuses in total. A cardiovascular aetiology was found in 21 of these 52 (40%); structural heart disease was present in 13, tachyarrhythmia in the remaining eight. The accurate delineation of these causes was possible using fetal echocardiography, and enabled rational management to be instituted. This included termination of pregnancy, pharmacological control of arrhythmias and appropriate timing of delivery.     

Aetiology of non-immune hydrops: the value of echocardiography

Summary. Forty-eight pregnancies, five of them multiple, were referred for fetal cardiac assessment following the detection of non-immune hydrops fetalis; there were 52 hydropic fetuses in total. A cardiovascular aetiology was found in 21 of these 52 (40%); structural heart disease was present in 13, tachyarrhythmia in the remaining eight. The accurate delineation of these causes was possible using fetal echo-cardiography, and enabled rational management to be instituted. This included termination of pregnancy, pharmacological control of arrhythmias and appropriate timing of delivery.     

Fetal atrial tachycardia diagnosed by magnetocardiography and direct fetal electrocardiography. A case report of treatment with propranolol hydrochloride

At 26 weeks of gestation, fetal tachyarrhythmias (about 250 bpm) and ascites were detected by ultrasonography, and oral treatment with propranolol (30 mg/day) was commenced. Within 10 h, the fetal heart rate changed to approximately 85 bpm. The averaged fetal magnetocardiogram triggered by R peaks showed P wave and QRS complexes and an extra P wave. In addition, many extra nonconducted P-waves were detected in a fetal direct electrocardiogram. At 27 weeks of gestation, fetal tachycardia occurred again, and arrhythmia was diagnosed as the result of a blocked premature atrial contraction (PAC) with intermittent atrial tachycardia by fetal electrocardiogram. Administration of transplacental propranolol (90 mg/day) resolved the fetal tachyarrhythmias and ascites. Further studies are required to evaluate the efficacy and adverse effects of propranolol for fetal atrial tachycardia.     

Transplacental digoxin therapy for fetal tachyarrhythmia with multiple evaluation systems

Background.?Sustained fetal tachyarrhythmia may result in congestive heart failure, hydrops fetalis, and fetal/neonatal death, which requires timely and appropriate therapy.

Aim.?To determine the value of transplacental digoxin therapy for fetal tachyarrhythmia with multiple evaluations.

Methods.?Four cases of fetal tachyarrhythmia were diagnosed with fetal echocardiography and treated with transplacental digoxin therapy with an initial dosage of 0.25?mg qd. Fetal echocardiography and measurement of maternal serum digoxin concentrations were performed every 5–7 days. Echocardiographic information was further used for the calculation of three evaluation systems including, Tei index, cardiovascular profile score (CVPS), and umbilical artery resistance index (UARI). The dosage of digoxin was adjusted according to the serum concentration, as well as results from three evaluation systems.

Results.?During the course of digoxin treatment, our patients show an increase of CVPS and decrease of Tei index and UARI, suggesting the recovery of heart function. Sinus rhythm was restored in 3–10 days in three cases and 42 days in one case. At the time of delivery, the placental transportation efficiency (neonate/mother ratio of serum digoxin concentration) was 76.45–84.31%. Following delivery, the general conditions of neonates were favorable. During the 4- to 14-month follow-up, reoccurrence of arrhythmia, neurological deficit, and retarded growth and development were not observed.

Conclusions.?Transplacental digoxin therapy with combined evaluation of Tei index, CVPS, and UARI systems is useful for treating fetal atrial flutter (AF) and supraventricular tachycardia (SVT).     

Fetal arrhythmias case series: Experiences from a fetal screening center in Taiwan

ObjectiveFetal arrhythmias are common and in rare cases can be associated with severe mortality and morbidity. Most existing articles are focused on classification of fetal arrhythmias in referral centers. Our main objective was to analyze types, clinical characteristics, and outcomes for arrhythmia cases in general practice.Case reportWe retrospectively reviewed a case series of fetal arrhythmias in a fetal medicine clinic between September 2017 and August 2021.Fetal arrhythmias in our sample presented byEctopies (86%, n = 57), bradyarrhythmias (11%, n = 7), and tachyarrhythmias (3%, n = 2). One tachyarrhythmia case was associated with Ebstein's anomaly. Two cases of second-degree AV block received transplacental fluorinated steroid therapy with recovery of fetal cardiac rhythm in later gestation. One case of complete AV block developed hydrops fetalis.ConclusionDetection and careful stratification of fetal arrhythmias in obstetric screening is crucial. While most arrhythmias are benign and self-limited, some require prompt referral and timely intervention.     

Fetal dysrhythmias

Fetal cardiac dysrhythmias are potentially life-threatening conditions. However, intermittent extrasystoles, which are frequently encountered in clinical practice, do not require treatment. Sustained forms of brady- and tachyarrhythmias might require fetal intervention. Fetal echocardiography is essential not only to establish the diagnosis but also to monitor fetal response to therapy. In the last decade, improvements in ultrasound methodology and new diagnostic tools have contributed to better diagnostic accuracy and to a greater understanding of the electrophysiological mechanisms involved in fetal cardiac dysrhythmias. The most common form of supraventricular tachycardia - that caused by an atrioventricular re-entry circuit - should be differentiated from other forms of tachyarrhythmias, such as atrial flutter and atrial ectopic tachycardia. Ventricular tachycardia is rare in the fetus. Sustained tachycardias, intermittent or not, might be associated with the development of congestive heart failure and hydrops fetalis. Prompt treatment with either anti-arrhythmic drugs or delivery must be considered. Persistent fetal bradycardias associated with complete heart block are also potentially dangerous, whereas bradyarrhythmia due to blocked ectopy is well tolerated in pregnancy. Heart block can be associated with maternal anti-Ro/La autoantibodies or develop in fetuses with left atrial isomerism or with malformations involving the atrioventricular junction. The treatment of fetuses with immune-mediated heart block remains debatable. The use of antenatal steroid therapy is not widely accepted and there is concern over the risks and benefits of its use in the fetus. Direct fetal cardiac pacing has rarely been attempted.     

Arrhythmias in perinatal period and neonatal outcome--analysis of own experiences

OBJECTIVE: The paper presents review of different kinds of fetal arrhythmias, diagnosed in our centres. DESIGN: The aim of our study was to analyse results of echocardiographic examinations of 141 fetuses with diagnosed arrhythmias referred for fetal cardiac examination in years VI. 1996-V. 2001 and neonatal outcome. RESULTS: Premature contractions were recognised in 113 (80%) fetuses, tachyarrhythmias in 7 (5%) cases and complete atrioventricular block in 5 (4%). Heart defects were diagnosed in three cases. Three fetuses developed congestive heart failure (2x SVT, 1x HLHS + block a-v III*). From all group 6 newborns died. CONCLUSION: In case of fetal arrhythmias echocardiography should be widely applied in order to evaluate the kind of arrhythmia, sufficiency of circulation and coexistence of heart defects or functional abnormalities with arrhythmia in fetal circulation.     

Intrauterine therapy of fetal tachyarrhythmias: intraperitoneal administration of antiarrhythmic drugs to the fetus in fetal tachyarrhythmias with severe hydrops fetalis

In cases of fetal tachyarrhythmia with congestive heart failure accompanied by signs of non-immune hydrops fetalis, the transplacental treatment of the fetus with antiarrhythmic agents by administration of drugs to the mother is only rarely successful. In the two cases reported, the cardioversion of a supraventricular tachycardia to a sinus rhythm or a constant 2:1 AV conduction block to a 1:1 AV conduction with atrial flutter could only be achieved after additional antiarrhythmic treatment directly administered to the fetus using ultrasound guidance. Drugs used include: beta-methyldigoxin, verapamil, propafenon, and they were administered according to the dosing amounts for intravascular injections. This was carried out 12 times in case 1 by the intraperitoneal route into the fetal ascites and twice in case 2. This led in both cases to varying durations of a sustained sinus rhythm after 5-15 minutes. This technically relatively simple procedure affords the option of rapidly achieving high concentrations, even when antiarrhythmic agents are administered which do not adequately cross the placenta. This direct treatment is indicated in cases of tachyarrhythmia with advanced signs of non-immune hydrops fetalis as a supplement to the high-dose transplacental therapy using antiarrhythmic agents.     

Fetus with long QT syndrome manifested by tachyarrhythmia: a case report.

We encountered a fetus who exhibited transient (at most 30 s), repeated episodes of tachyarrhythmia (240 bpm). This female neonate was born at 36 weeks of gestation and showed a markedly prolonged QT interval and transient, repeated episodes of polymorphic ventricular tachycardia. Congenital long QT syndrome was diagnosed. Retrospective analysis of the videotape showing fetal cardiac movement revealed that atrio-ventricular dissociation was present prenatally and thus, the fetal tachyarrhythmia was due to ventricular tachycardia. To our knowledge, there are few reports of a fetus with the long QT syndrome who exhibited ventricular tachycardia in utero. In the presence of unexplained fetal tachyarrhythmia, long QT syndrome should be considered as a possible underlying cause disorder. The presence of atrio-ventricular dissociation may be useful in prenatal diagnosis of long QT syndrome.     

Spectral analysis of fetal heart rate variability in fetuses with supraventricular extrasystoles

OBJECTIVE: Fetal heart rate (FHR) variability is an important indicator of fetal well-being. In fetal tachyarrhythmias, however, visual analysis of FHR variability is limited. We therefore applied power spectral analysis of FHR to evaluate the fetal state. METHODS: Fetal R-R intervals were detected by means of an external ECG in 3 fetuses with supraventricular extrasystoles after cardiac malformations had been excluded by fetal echocardiography. Using an autoregressive model, power spectral densities were calculated from 20 consecutive 256-beat segments for the following frequency bands: <0.03 Hz (very low frequency), 0.03-0.069 Hz (low frequency; LF), 0.07-0.129 Hz (mid-frequency) and 0.13-1.0 Hz (high frequency; HF). RESULTS: The FHR variability in fetal supraventricular extrasystoles mainly resulted from the HF component (63.91 +/- 6.97%). The sympatho-vagal balance (LF/HF) was decreased in the tracings with extrasystoles (0.13). CONCLUSION: The analysis of FHR variability in fetal supraventricular extrasystoles revealed an imbalance between sympathetic and parasympathetic regulation.     

Prenatal diagnosis of slow-rate ventricular tachycardia using fetal electrocardiography

OBJECTIVES: We report a case in which fetal ventricular tachycardia (VT) could be diagnosed, in utero, using a transabdominal fetal electrocardiogram (fECG) with motion-mode (M-mode) echocardiography. METHODS: The fetus was referred at 32 weeks' gestation due to tricuspid atresia. The fetal cardiotocogram demonstrated paroxysmal tachycardia with a ventricular rate of 155 to 160 bpm within the confines of normal sinus rhythm. RESULTS: M-mode echocardiography showed atrioventricular dissociation with a rather slow ventricular rate. To identify the level of the ectopic focus for tachyarrhythmias, we attempted to detect the electrical signals of the fetal heart and succeeded in recording the fECG. Morphological assessment of the fECG allowed for the extraction of both the normal QRS complex and apparently dissimilar ectopic QRS beat, which has a different polarity despite a relatively similar width. CONCLUSION: Consequently, the case proved to have VT at a slow rate, probably originating from the focus near the atrioventricular junction inside the ventricle.     

Fetal supraventricular tachycardias: diagnosis and management

In the majority of cases, the diagnosis of an isolated fetal tachyarrhythmia results in a favorable perinatal outcome. Although there is general consensus on the management of fetal extrasystoles, refractory supraventricular tachycardia, and atrial flutter and fibrillation, the optimal approach to supraventricular tachycardia without hemodynamic compromise remains uncertain. The benefits of conservative management without antiarrhythmic therapy must be weighed carefully against the lack of reliable predictors for the development of fetal hydrops and associated neurologic complications.     

Simultaneous supraventricular tachycardias in both fetuses of a twin gestation

Background Fetal supraventricular tachycardia confers an increased risk of cardiac failure, hydrops, and eventual intrauterine death. Although protocols for prenatal anti-arrhythmic treatment are now well established, few published reports discuss this condition in the setting of multiple pregnancies.Case report A 20-year-old primigravida woman with a twin pregnancy presented at 31 weeks of gestation for routine obstetrical check-up which revealed simultaneous supraventricular tachycardia in both fetuses. She was treated with oral digoxin, resulting in successful cardioversion in both of the fetuses, which was maintained until they were delivered by caesarian section at 38 weeks gestation. However, several hours after birth, tachyarrhythmias recurred in each of the infants. Combined disopyramide therapy with digoxin was necessary to control their heart rates.Conclusion The treatment of arrhythmia in fetuses of a multiple gestation presents unique issues, particularly when diagnosed prior to fetal lung maturity.     

Pregnancy complicated by chronic cardiomyopathy and an automatic implantable cardioverter defibrillator.

The dismal prognosis of dilated cardiomyopathy and its resulting tachyarrhythmias has recently been improved by technical advances such as the automatic implantable cardioverter defibrillator. We report a successful pregnancy in a patient with chronic cardiomyopathy and malignant tachyarrhythmias necessitating use of this device, with a documented defibrillator discharge and monitored fetal response.     

Intravenous Adenosine for the Treatment of Maternal Paroxysmal Supraventricular Tachycardia

Intravenous adenosine is being used for the treatment of paroxysmal supraventricular tachycardia and paroxysmal junctional tachyarrhythmia in nonpregnant patients. In the cases presented here, intravenous adenosine rapidly terminated maternal paroxysmal supraventricular tachycardia in pregnant patients without maternal or fetal complications. Its potential advantages over other antiarrhythmics are discussed.     

Fetal heart rate monitoring: is it salvageable?

Fetal heart rate monitoring was introduced in the 1960s. After a number of randomized controlled trials in the mid 1980s, doubt arose regarding the efficacy of fetal heart rate monitoring in improving fetal outcome. The potential reasons why fetal heart rate monitoring has not been shown to be efficacious are (1) use of an outcome measure that is not related to variant fetal heart rate monitoring patterns, (2) lack of standardized interpretation of fetal heart rate patterns, (3) disagreement regarding algorithms for intervention of specific fetal heart rate patterns, and (4) the inability to demonstrate the reliability, validity, and ability of fetal heart rate monitoring to allow timely intervention. A recent National Institutes of Health committee proposed detailed, quantitative, standardized definitions of fetal heart rate patterns, which can serve as a basis for determining whether fetal heart rate monitoring is reliable and valid. In this article we examine reasons why fetal heart rate monitoring did not live up to its original expectations and why the randomized controlled trials did not demonstrate efficacy, and we make suggestions for determining whether electronic fetal heart rate monitoring should be abandoned.     

胎儿心律失常的产前诊断和宫内治疗进展

胎儿心律失常的正确诊断对其治疗至关重要,可根据心律失常类型对胎儿进行个体化治疗,积极改善胎儿预后,提高胎儿存活率,避免不明原因胎儿宫内死亡的发生。临床上胎儿心律失常可分为3种类型：心脏节律不规则、快速心律失常和缓慢心律失常。诊断方式包括胎儿心电图、心磁图、脉冲多普勒及M型超声心动图。大部分胎儿心律失常为良性,通常不需要治疗,但需要密切随访。而对于伴随心功能不全或胎儿水肿的持续性胎儿心律失常,则需要宫内治疗。综述不同类型的胎儿心律失常的诊断方法、病因及治疗方案,加强胎儿宫内管理,改善胎儿围生结局。