胎儿心律失常的超声心动图检测及其临床意义

目的 探讨超声心动图检测对胎儿心律失常的诊断价值及临床意义。方法 采用超声心动图对725例胎龄16-41周临床疑诊为心律失常或存在其他异常的胎儿进行检测。结果 共检出胎儿心律失常90例。其中,期前收缩72例(房性期前收缩65例,室性期前收缩7例),心动过缓9例,心动过速6例,2:1房室传导阻滞2例,心房扑动1例。4例心动过缓胎儿并发先天性心血管畸形患者,2例在随访过程中死于宫内(尸体解剖证实为单心室伴肺动脉瓣狭窄1例,心脏横纹肌瘤1例),2例终止妊娠(尸体解剖证实为二尖瓣闭锁1例,共同房室通道1例)。1例胎龄38周心房扑动胎儿经吸氧及严密监护24h后,心律失常无缓解,立即行剖宫产术,出生后应用西地兰后心律转为窦性。其余85例胎儿心律失常均为阵发性,不伴有胎儿心脏形态、结构畸形及胎儿水肿,均足月出生,出生后听诊均未闻及心脏杂音及心律失常。结论 胎儿超声心动图是产前检查胎儿心律失常的可靠的无创性影像技术,其应用有助于早期检出并指导心律失常胎儿的处理。     

Fetal complete heart block: antenatal diagnosis, significance and management

Complete heart block was diagnosed prenatally in 21 fetuses. Associated structural cardiac defects were present in 18 fetuses, in particular complete atrioventricular canal with atrial isomerism (5 cases), and 'corrected' transposition of the great arteries (4 cases). Maternal systemic lupus erythematosus was proved in only one case. In 11 fetuses, intra-uterine congestive heart failure with the signs of non-immune hydrops fetalis occurred. In all 11 fetuses, the hydrops was associated with a cardiac defect, in particular complete atrioventricular canal with atrial isomerism in 5 cases. A review of the literature confirms that only the association of complete heart block and cardiac malformation can cause intra-uterine congestive heart failure, whereas in the case of fetal complete heart block without cardiac malformation or with prenatally hemodynamically insignificant cardiac malformation, congestive heart failure is rare. Only 30% of newborns with complete heart block have associated cardiac malformations. In our series, however, 86% of the fetuses with complete heart block had cardiac malformations. The most important reason for this percentage discrepancy is that almost all fetuses with associated severe cardiac defects, in particular atrioventricular canal defects, develop heart failure which frequently results in prenatal death. Thus, fetal deaths are not included in pediatric statistics. Nevertheless, fetuses with isolated complete heart block generally do not develop heart failure and in almost all of the cases are born alive.     

Fetal tachyarrhythmia--current state of knowledge

Fetal tachyarrhythmia occurs in approximately 10% of all fetal arrhythmias. The majority of fetal tachyarrhythmias occur due to atrioventricular reentrant type of supraventricular tachycardia. A fetal tachycardic heart is at risk of developing low cardiac output, hydrops and ultimately fetal death or significant neurological morbidity. Reliable diagnosis of fetal tachyarrhythmia is possible by echocardiography and is crucial for a managed therapeutic approach. The goals of therapy for fetal tachyarrhythmias are to restore sinus rhythm, resolve heart failure and postpone delivery before term. A review of fetal tachyarrhythmias has been reported in our work.     

Right Fetal Cardiac Axis: Clinical Significance and Associated Findings

Objective: To ascertain the clinical significance of right fetal cardiac axis.Methods: Fetal cardiac axis was assessed prospectively in ultrasound examinations of 16,562 fetuses over a 6-year period.Results: Twenty-two fetuses had a right cardiac axis. When classified by ventricular and atrial configuration, six fetuses had mirror-image hearts with situs inversus, 12 had rotation of the heart axis alone, and four had inversion of the ventricles. Fourteen of the 22 had underlying structural cardiac defects, most of which were atrioventricular septal defects, double outlet right ventricles, or common atria. The chromosomes and/or phenotypes of all 22 were normal. All four fetuses with polysplenia and asplenia died. Major extracardiac defects were few (two) but lethal.Conclusion: Right cardiac axis in the fetus is associated with a high incidence of structural cardiac defects. In the absence of severe extracardiac defects, polysplenia, or asplenia, neonatal outcome was good.     

Management strategy for fetal tachycardia

OBJECTIVE: To develop a management strategy for fetal tachycardia. METHODS: Forty-four fetuses (20-40 weeks' gestation) with nonsinus tachycardia were divided into three groups based on duration of tachycardia and degree of heart failure. Fetuses with intermittent tachycardia were treated expectantly. Fetuses with sustained tachycardia were treated with transplacental antiarrhythmic agents alone if heart failure was mild to moderate, and with direct intramuscular therapy if heart failure was severe. Degree of heart failure was determined by echocardiographic variables of ventricular function, atrioventricular valve insufficiency, and hydrops. Fetal well-being and response to treatment were evaluated by daily heart rate surveillance and frequent fetal echocardiograms and ultrasounds. RESULTS: Fifteen fetuses with intermittent tachycardia (n = 15, group 1) did not progress to sustained tachycardia or heart failure. Fetuses with sustained tachycardia and mild-to-moderate heart failure (n = 14, group 2) were cardioverted or rate controlled with transplacental agents (n = 9); three term fetuses were delivered electively without treatment and two progressed to severe heart failure and were treated in group 3. Seventeen fetuses (15 initially, two progressing) with severe heart failure were cardioverted (in 0. 25-21 days; mean 4.3 days) with fetal intramuscular plus transplacental antiarrhythmic therapy (group 3). Overall, 43 of 44 fetuses were delivered at 32 to 41 (mean 37) weeks with minimal morbidity and a mortality rate of 2.2% (95% confidence interval 0. 06%, 12.0%). CONCLUSION: Perinatal mortality and morbidity were low after following a management strategy based on duration of tachycardia, degree of heart failure, and biophysical profile combined with vigilant ongoing fetal surveillance.     

Long-term outcome in fetuses with cardiac arrhythmias

OBJECTIVE: The objectives of this follow-up study of 292 fetuses with various cardiac arrhythmias were to estimate the incidence of structural heart defects and fetal compromise, to investigate the effects of antiarrhythmic medication, and to evaluate perinatal mortality and morbidity and long-term outcome. METHODS: The arrhythmias were classified into atrial extrasystoles (n = 200), atrial tachycardias (n = 35), atrioventricular block (n = 36), sinus bradycardia (n = 14), and ventricular extrasystoles (n = 7), and outcome of the infants was analyzed. RESULTS: The incidence of cardiac anomalies was 12% in the study population. In utero cardiac failure was noted in 11%. Among fetuses with atrial extrasystoles, 1% developed supraventricular tachycardia after birth. During antiarrhythmic therapy, sinus rhythm was achieved in 92% of nonhydropic and in 63% of hydropic fetuses. The latter had higher mortality and risk for neurologic morbidity than did nonhydropic fetuses; 38% versus 3.7% and 40% versus 12%, respectively. Among fetuses with atrioventricular block only, the survival rate was 82%, with a heart defect, prognosis was poor: 50% survived. Sinus bradycardia and ventricular extrasystoles were associated with survival rates of 75% and 67%. In the follow-up of the whole study population lasting a median 5 years, 93% are alive and 3% have a neurologic disorder. CONCLUSION: All fetal arrhythmias except atrial extrasystoles were associated with a moderately high risk for fetal distress. In cases of compromise, fetal and neonatal prognosis was poor and was an indication for perinatal medication. After the newborn period, the prognosis has been good. However, the risk for neurologic morbidity must be taken into consideration.     

Prenatal diagnosis and treatment of fetal long QT syndrome: a case report

We report a case of a fetus presenting with bradycardia, intermittent atrioventricular (AV) block, ventricular tachycardia (VT) and the signs of fetal congestive heart failure (ascites and scrotal hydrocele) during mid-gestation. Prenatal treatment with beta-adrenergic blocker (propranolol) and digitalis glycosides was prescribed because of suspicion of long QT syndrome occurring with fetal congestive heart failure. The male baby was born at 39 weeks of gestation and showed a prolonged QT interval (QTc = 492 ms) and frequent variable AV block or alternating left and right bundle branch block, depending on the atrial rate. Prenatal administration of lidocaine failed to correct the fetal VT. Conversely, propranolol decreased the attack frequency of fetal VT. Postnatal administration of the K(+) channel opener (nicorandil) successfully shortened the QT interval and improved the outcome.     

Fetal bradycardia in the first trimester: an unusual presentation of atrial extrasystoles

We report a fetus with fetal bradycardia at 13 weeks of gestation secondary to atrial extrasystoles. The fetus subsequently developed paroxysmal supraventricular tachycardia and hydrops fetalis. The cardiac arrhythmia recovered spontaneously without any medical intervention. This case illustrates that atrial ectopic beats can present in the first trimester with fetal bradycardia. Rapidly evolving hydrops fetalis secondary to supraventricular tachycardia can develop, warranting close monitoring with weekly heart rate assessment. Fetal bradycardia secondary to atrial extrasystole should be differentiated from first trimester sinus bradycardia and those associated with major structural cardiac abnormality, which have a high fetal loss rate.     

Fetal Arrhythmias: A 3-Year Experience*

Eight cases of fetal arrhythmia were seen over a 3-year period. Two had atrial and/or ventricular extrasystoles, 1 had complete atrioventricular block and 5 had tachyarrhythmias--3 supraventricular tachycardia, 1 atrial flutter and 1 ectopic atrial tachycardia. All had structurally normal hearts. Nonimmune hydrops fetalis was the initial presentation in 3 of the 5 cases with tachyarrhythmias. There were 2 deaths--a stillbirth and a neonatal death, while 2 others required neonatal intensive care. The 6 survivors have remained well and are now off treatment. The diagnosis, careful assessment and management of a fetal arrhythmia may lead to a successful outcome. The complexity of the problems experienced may warrant early referral to a tertiary centre where the overall management of the mother, fetus and neonate, may be undertaken.     

Role of fetal echocardiography in the management of isolated fetal heart block with ventricular rate <55 bpm.

Persistent bradycardia is an uncommon cardiac problem in fetuses but carries a high mortality in those with a ventricular rate <55 bpm. Fetal heart block is one of the most common causes of persistent fetal bradycardia (PFB). An optimal method for assessing and monitoring cardiovascular compensation in the setting of PFB due to heart block has not been fully established. We report the application of two-dimensional and Doppler echocardiography in close monitoring of cardiac function and hemodynamics in a third-trimester fetus with a ventricular rate <55 bpm due to heart block, which assisted in successful management of the pregnancy to term. Hemodynamic and cardiac adaptive changes in compromised fetuses, particularly due to heart block, are discussed.     

Perinatal outcome of fetus with isolated congenital second degree atrioventricular block without maternal anti-SSA/Ro-SSB/La antibodies

OBJECTIVE: We determined the perinatal outcomes of fetuses with isolated congenital second degree atrioventricular block detected in utero and born to mothers seronegative for anti-SSA/Ro-SSB/La antibodies. METHODS: Isolated second degree atrioventricular block was defined as second degree atrioventricular block detected in utero without the accompanying structural cardiac anomaly, tachyarrhythmia, non-conducted premature atrial beats or long QT syndrome. We review our own cases and search from Medline using keywords such as atrioventricular block, arrhythmia, bradycardia and congenital to collect cases of congenital isolated second degree atrioventricular block. RESULTS: Two cases were from our institution and five cases from a Medline search; in total seven cases of isolated second degree atrioventricular block without maternal anti-SSA/Ro-SSB/La antibodies were analyzed. Six of the seven fetal arrhythmias reverted to sinus rhythm by delivery and did not recur during the follow-up period. The prognosis of the fetus with isolated second degree atrioventricular block without maternal anti-SSA/Ro-SSB/La antibodies is better than that of the fetus with maternal anti-SSA/Ro-SSB/La antibodies or the fetus of congenital long QT syndrome with second degree atrioventricular block detected in utero. CONCLUSION: The fetus with isolated congenital second degree atrioventricular block carries a good prognosis in the absence of maternal anti-SSA/Ro-SSB/La antibodies.     

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.     

Prenatal diagnosis of arrhythmias and conduction disturbances

OBJECTIVES AND DESIGN: Cardiac arrhythmias are one of the most frequent indications for the fetal echocardiographic assessment. The objective of this work is to present our own results of diagnosing and treating the fetuses with arrhythmias. MATERIALS AND METHODS: The 1485 prenatal echocardiographic examinations were performed in 1302 fetuses. The 109 of fetuses suffered from arrhythmias. RESULTS: 68 fetuses (62.8%) in the analysed group presented with arrhythmias in the form of extra-systoles, 19 fetuses (17.4%) with tachycardia and 22 (20.2%) with a complete atrioventricular block. CONCLUSIONS: We concluded, that arrhythmias can be diagnosed precisely in the early prenatal period, which enables the introduction of the adequate pharmacological treatment and the coexistence of the fetal complete a-v block and structural heart defect in a fetus is associated with poor prognosis.     

Prenatal diagnosis of asplenia/polysplenia syndrome

Complex congenital heart disease with atrioventricular block was detected prenatally in two fetuses at 34 and 28 weeks' gestation. The spleen was not seen on ultrasonographic examination in either fetus, suggesting polysplenia/asplenia syndrome. Both infants died shortly after delivery and the autopsies confirmed this diagnosis. Recommendations for sonographic screening of the fetal spleen in cases of prenatal detection of complex heart disease or cardiac dysrhythmia are discussed.     

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.     

Transient non-autoimmune fetal heart block

OBJECTIVES: Fetal heart block is a rare and irreversible condition associated with structural heart defects or maternal autoantibodies (SS-A/Ro and SS-B/La) resulting in permanent damage of the atrioventricular (AV) node. This is the first report of 4 cases with a transient fetal heart block in structurally normal hearts without maternal autoantibodies. METHODS: A report on 4 patients seen within a 14-year period at one center with fetal heart block without intracardiac abnormalities or maternal autoantibodies. RESULTS: Three patients were referred to our center with a fetal bradycardia (heart rate 70-85 bpm), between 20 and 33 weeks' gestational age, and 1 for a 'triple' test at 16 weeks' gestational age. Echocardiography showed a complete heart block in 2 fetuses, and a second-degree AV block in the other 2. Heart block had completely resolved at all following visits. Postnatal ECG recordings showed normal sinus rhythm in all patients. Echocardiographic evaluation at presentation and follow-up showed normal cardiac anatomy, without signs of hydrops or cardiac decompensation in all patients. All mothers tested negative on SS-A/Ro and SS-B/La autoantibodies. CONCLUSIONS: Fetal heart block can occur in the absence of structural heart defects and maternal autoantibodies to SS-A/Ro and SS-B/La. The origin of such heart block is unknown, but its course seems benign: none of the patients ever showed ventricular heart rates <55 bpm, signs of congestive heart failure or fetal hydrops. Heart block resolved spontaneously in all patients.     

Fetal Echocardiography: An 8-Year Experience

Over 8 years, 680 fetuses in 521 gestations underwent echocardiography. Indications included genetic or teratogenic risk, arrhythmias, diabetes, collagen vascular disease, hypertension, growth retardation, and hydrops. Most studies were normal. Eight fetuses had structural heart disease, 31 had benign atrial or ventricular premature beats, five had benign unsustained arrhythmias, three had heart block associated with maternal autoantibodies, and one had sustained supraventricular tachycardia with hydrops. Eight had suspected hydrops, fetal demise, or molar pregnancy. There were 19 cases of abnormal umbilical artery Doppler waveforms and three with pathologic cerebral artery waveforms.

Fetal echocardiography is a valuable noninvasive diagnostic tool in selected cases with a high sensitivity and specificity for serious hemodynamic problems.     

Combined echocardiographic and Doppler assessment of fetal congenital atrioventricular block

Fetal heart rate monitoring was combined with fetal echocardiography for examination of atrial reactivity during labour in five fetuses with second or third degree heart block. Alterations in vagal tone accompanying uterine contraction influence atrial rate, even when the ventricle is not under atrial 'control'. Fetal echocardiography enabled diagnosis of the underlying basis of the arrhythmia and located the optimal position for recording atrial activity with an external heart rate monitor. External and internal monitoring of atrial activity demonstrated reactivity during labour. Two patients were delivered vaginally after monitoring throughout labour. One mother preferred elective caesarean delivery. Caesarean section was required in another for cephalopelvic disproportion and in the remaining woman for late decelerations. These monitoring techniques provide an assessment of fetal well-being in the presence of fetal bradycardia due to variable degrees of heart block.     

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.     

Combined echocardiographic and Doppler assessment of fetal congenital atrioventricular block

Summary. Fetal heart rate monitoring was combined with fetal echocardiography for examination of atrial reactivity during labour in five fetuses with second or third degree heart block. Alterations in vagal tone accompanying uterine contraction influence atrial rate, even when the ventricle is not under atrial'control'. Fetal echocardiography enabled diagnosis of the underlying basis of the arrhythmia and located the optimal position for recording atrial activity with an external heart rate monitor. External and internal monitoring of atrial activity demonstrated reactivity during labour. Two patients were delivered vaginally after monitoring throughout labour. One mother preferred elective caesarean delivery. Caesarean section was required in another for cephalopelvic disproportion and in the remaining woman for late decelerations. These monitoring techniques provide an assessment of fetal well-being in the presence of fetal bradycardia due to variable degrees of heart block.