Fetal treatment of congenital heart block ascribed to anti-SSA antibody: case reports with observation of cardiohemodynamics and review of the literature

Clinical course and outcome of antenatally detected atrioventricular block: experience of a single tertiary centre and review of the literature

OBJECTIVE

The objective is to study the course and outcome of fetuses with congenital atrioventricular block (AVB) in a single centre.

METHODS

Retrospective analysis of cases diagnosed prenatally with second and third degree AVB. The clinical characteristics and outcome of fetal AVB were evaluated including in utero treatment.

RESULTS

Sixty-two cases were studied. AVB was associated with a congenital heart defect (CHD-AVB) in 17 cases (27%), whereas it was isolated (i-AVB) in 45 (73%), 42 of which were associated with maternal antibodies. There were nine (52.9%) live births in the CHD-AVB group, five of which (55%) resulted in infant deaths. In the i-AVB group, there were 40/45 (88.9%) live births and 1/40 (2.5%) infant death; 36 (90%) babies required a permanent pacemaker. The only factor predictive of postnatal death was the presence of CHD (5/9 vs 1/39 or 48.7 [3.6; 1457.7], p < 0.001). Nineteen fetuses (40.5%) with i-AVB received steroids in utero. No difference in outcome was found between the AVB treated in utero versus the no-treatment group in terms of permanent pacemaker placement, postnatal death or development of dilated cardiomyopathy.

CONCLUSION

The most important prognostic factor for congenital AVB is the association with CHD. In utero treatment remains questionable.

Atrioventricular block during fetal life

Congenital complete atrioventricular (AV) block occurs in approximately 1 in 20,000 live births and is known to result in significant mortality and morbidity both during fetal life and postnatally. Complete AV block can occur as a result of an immune or a non-immune mediated process. Immune mediated AV block is a multifactorial disease, but is associated with the trans-placental passage of maternal autoantibodies (anti-Ro/SSA and/or anti-La/SSB). These autoantibodies attach to and subsequently damage the cardiomyocytes and conduction tissue in susceptible fetuses. In this report, we examine the evidence in reference to means of assessment, pathophysiology, and potential prenatal therapy of atrioventricular block.

Neonatal lupus erythematosus in Japan: a review of the literature

Neonatal lupus erythematosus (NLE) is an autoimmune disease associated with maternal anti-SS-A/Ro and anti-SS-B/La antibodies. NLE is characterized by cutaneous erythema, congenital heart block (CHB), hepatic dysfunction and hematological abnormalities. CHB is irreversible, usually requiring a pacemaker, but other symptoms are reversible and most disappear within 6 months in parallel with declining antibody levels. In Japan, 193 cases of NLE were reported between 1971 and 2008. Most showed erythema, and only 23% of cases presented with CHB. Conversely, antibody status had not been examined in many infants presenting with CHB during the same period. Most pregnant woman with anti-SS-A/Ro and anti-SS-B/La antibodies are asymptomatic, and antibody status is first indicated when their child shows symptoms of NLE. These women show a greater risk of delivering an infant with CHB than normal. CHB is important because the main morbidity and mortality of NLE is from CHB. All clinicians should be familiar with the characteristics of NLE. We believe all pregnant women should be screened for anti-SS-A/Ro and anti-SS-B/La antibodies.

Perinatal Outcome of Fetal Atrioventricular Block

Background— Fetal atrioventricular (AV) block is an uncommon lesion with significant mortality. Because of the rarity of this disorder, the natural course, extensive evaluation of untreated fetuses, and late follow-up remain unclear.

Methods and Results— Of the 116 consecutive cases of fetal AV block studied from 1988 to 2006, only 1 was terminated, and 75% were live births. Fifty-nine cases of AV block were associated with major structural heart disease, mainly left atrial isomerism (n=40), with only 26% of neonatal survivors. Of the 57 fetuses with normal cardiac anatomy, 41 (72%) were positive for maternal antinuclear antibodies, and 32 of these seropositive mothers did not receive any treatment. This untreated group had live-birth and 1-year infant survival rates of 93% and 90%, respectively. Five fetuses from seronegative mothers showed regression to sinus rhythm during pregnancy. The presence of major structural heart disease, hydrops, an atrial rate ≤120 bpm, and a ventricular rate ≤55 bpm were identified as risk factors for mortality. Logistic regression analysis of the whole group showed that the presence of structural heart disease was the only independent predictor of death ( P <0.001).

Conclusions— This long-term study confirms that fetal AV block has a poor outcome when associated with structural heart disease and that spontaneous regression of AV block is possible in seronegative forms. The survival rate of >90% of our untreated patients with isolated forms of AV block raises concerns about any decision to intervene with immunosuppressive agents.

Transient heart block in a neonate associated with previously undiagnosed maternal anti-Ro/SSA and anti-La/SSB antibodies

This report presents the case of an infant who was born with transient complete heart block. The cardiac rhythm converted to normal sinus rhythm within 12 hours of life. Following the diagnosis in this infant of congenital heart block, both the mother and the infant were tested for autoantibodies. Both were found to be strongly positive for anti-Ro/SSA antibodies. The infant was also weakly positive for the anti-La/SSB antibodies and her mother moderately positive for the same. Congenital heart block associated with these maternal antibodies is well documented in the literature; however, this is the only reported case that documents a transient nature of the complete heart block.

Doppler echocardiographic and electrocardiographic atrioventricular time intervals in newborn infants: evaluation of techniques for surveillance of fetuses at risk for congenital heart block

OBJECTIVE

To evaluate one novel and two previously reported Doppler flow velocimetric techniques to estimate atrioventricular (AV) time intervals, suggested to be useful for early identification of fetuses at risk for congenital heart block.

METHODS

In 22 newborn infants, Doppler tracings were obtained from the mitral valve/aortic outflow and the superior vena cava/ascending aorta, as an ECG was recorded simultaneously. AV time intervals were measured using the onsets of the mitral A-wave/aortic outflow (MV-Ao), superior vena cava a-wave/aortic flow (SVC-Ao), and mitral A-wave/mitral valve closure (MV) as indirect markers of electrical atrial/ventricular activation.

RESULTS

Close positive linear relationships to the electrocardiographic PR interval were demonstrated for the MV-Ao (r = 0.82, S(y/x) = 7.4 ms), SVC-Ao (r = 0.85, S(y/x) = 6.8 ms), and MV (r = 0.92, S(y/x) = 3.8 ms) approaches. Both techniques using the aortic flow to indicate ventricular activation overestimated the PR interval: the MV-Ao by + 32 +/- 7.7 ms (mean +/- SD) and the SVC-Ao approach by + 22 +/- 7.0 ms. The new MV approach using mitral closure for the same purpose did not overestimate the PR interval, but there was a trend towards underestimation of the PR intervals as time intervals increased.

CONCLUSIONS

When systematic differences between echocardiographic and electrocardiographic AV time intervals are compensated for, all three techniques are useful to get indirect estimates of the PR interval. As MV recordings only need insonation of a single valve, and are thus easier to obtain, this technique may be of value as a first screening method to identify fetuses in need for further surveillance. In cases with AV time prolongation the SVC-Ao method seems superior.

Increased Expression of Vascular Endothelial Growth Factor in Cardiac Structures of Fetus with Hydrops as Compared to Nonhydropic Controls

OBJECTIVE

The hypothesis that severe fetal hydrops is caused by an excess of vascular endothelial growth factor (VEGF), mainly produced in the fetal heart, is tested.

METHODS

Immunohistochemical VEGF-stained postmortem biopsies from the right ventricle and right atrium of 8 hydropic fetuses were compared to those of 8 nonhydropic fetuses. The endocardium, myocardium, epicardium, endothelium, and vascular smooth muscle cells were scored on intensity of VEGF-staining. The Mann-Witney test was used to test for significancy (p < 0.05) of the differences in staining. Increased vascularization as a result of VEGF was measured in both groups by standard randomization count.

RESULTS

The endocardium, epicardium and endothelium of the coronary vessels showed significantly (p < 0.05) more intense VEGF-staining in the hydrops group than in the control group. The atria showed more intense staining than the ventricles in both groups. The hydropic fetuses showed a significantly increased number of coronary vessels in the myocardium. These vessels contained more blood cells than the coronary vessels in nonhydropic fetuses.

CONCLUSION

The fetal heart appears to be a major source of excess VEGF in fetal hydrops.

Atrioventricular block detected in fetal life: associated anomalies and potential prognostic markers

OBJECTIVES

To assess the spectrum of anomalies associated with fetal heart block and to identify possible prognostic markers.

METHODS

Retrospective review of all cases of second- or third-degree heart block identified in two tertiary referral centers in Germany (Bonn and Lübeck) and one in the USA (Baltimore).

RESULTS

Sixty fetuses with heart block were identified in the study period. Thirty-two had complex cardiac malformations, 31 of them associated with left isomerism. The outcomes of these fetuses were 22 terminations of pregnancy (TOP), three intrauterine fetal deaths (IUFD), three neonatal deaths (NND), two childhood deaths (CD) and there were two survivors. In 20 cases without complex cardiac malformations maternal antinuclear-antibodies were detected. Their outcomes were 2 TOP, 1 IUFD, 1 NND and 16 survived. The remaining eight cases had neither complex cardiac malformations nor associated maternal antibodies. Their outcomes were 1 TOP, 2 IUFD, 2 NND and 3 survived. After exclusion of terminated cases, hydrops as well as the presence of cardiac defects was significantly associated with non-survival (P < 0.01). The cardiothoracic circumference ratio was significantly higher in hydropic fetuses and significantly negatively correlated with survival in immune-mediated cases (P < 0.01). Atrial and ventricular frequencies and their evolution did not accurately predict fetal or neonatal outcome. Sympathomimetic treatment in seven cases was not associated with favorable fetal outcome in cases of hydrops or cardiac malformations.

CONCLUSIONS

The most important marker predicting adverse outcome in cases of heart block is fetal hydrops, followed by the association with complex cardiac malformations. Cases without cardiac malformations have a significantly better prognosis, especially in the absence of severe cardiomegaly.

Fetal Doppler echocardiographic diagnosis and successful steroid therapy of Luciani-Wenckebach phenomenon and endocardial fibroelastosis related to maternal anti-Ro and anti-La antibodies

BACKGROUND

Complete fetal heart block (HB) and endocardial fibroelastosis (EFE) are known to be associated with maternal anti-Ro and anti-La antibodies. Complete fetal HB is irreversible.

OBJECTIVES

We sought to (1) assess the value of the superior vena cava/ascending aorta Doppler approach in the early detection of abnormal delay in the fetal atrioventricular (AV) time of conduction, before appearance of complete fetal HB; and (2) report the effect of prenatal steroid therapy on EFE, HB, or both.

RESULTS

The clinical history, echocardiographic, and Doppler investigations of 3 fetuses and children born to mothers positive for anti-Ro and anti-La antibodies are reported. Two fetuses presented with EFE either isolated (29 weeks) or associated with AV block (25 weeks). In this last case, the superior vena cava/ascending aorta approach allowed the identification of a Luciani-Wenckebach phenomenon. In a third fetus, 2:1 AV block was noted at 23 weeks of gestation. Dexamethasone (4 mg/day) was administered to all 3 patients. Complete regression of the EFE and conduction abnormalities was documented in all cases.

CONCLUSION

Early prenatal detection of abnormal delay in fetal AV time conduction is possible with the Doppler superior vena cava/ascending aorta approach. Steroid therapy can cure fetal EFE and AV conduction delays associated with maternal anti-Ro and anti-La antibodies.

Autoimmune-associated Congenital Heart Block: Treatment of the Mother With Immunoadsorption

Autoimmune-associated congenital heart block (CHB) is a rare complication of pregnancy in mothers with Anti-Ro/SSA antibodies (SSA-abs), resulting in fetal myocarditis, atrioventricular block, hydrops fetalis and/or intrauterine fetal death. As these antibodies are supposed to be directly involved in the pathogenesis of CHB, their removal should be associated with an improved clinical course. Extracorporeal immunoadsorption (IA) is the most efficient method to remove IgG-immunoglobulins like SSA-abs selectively. Two women with high titers of those auto-antibodies [mothers serum 615 and 612, respectively (normal range <3.0 IU/mL)] were treated with IA two to three times per gestation week in the outpatient department of the University of Rostock. In both patients, the mean removal of IgG (65 +/- 6%) to a target near 2.0 g/L after IA was successful. The SSA-abs were reduced from mean 328 +/- 138 and 247 +/- 105 pre IA to 88 +/- 124 and 98 +/- 42 post IA, respectively. One child received a pacemaker due to the persisting atrioventricular block grade III after birth. The second was unaffected. The removal of highly elevated SSA-antibodies by immunoadsorption is a possible treatment option in pregnant woman with high titers of those antibodies and/or a positive history of clinical complications. Further clinical studies are necessary.

Treatment of fetal heart block with maternal steroid therapy: case report and review of the literature

The presence of maternal autoantibodies to SS-A/Ro and/or SS-B/La is associated with the development of fetal heart block. There are data suggesting that maternal treatment with steroids might reverse heart block. We report on a pregnancy in a mother with secondary Sjögren syndrome and systemic lupus erythematosus with presence of autoantibodies to SS-A/Ro and SS-B/La, which was complicated by the development of incomplete fetal heart block. Oral dexamethasone treatment could not prevent progression to complete heart block and was associated with a number of complications.A review of the literature revealed 19 studies (including ours) in which 93 cases of fetal heart block were treated with maternal steroid therapy. Complete heart block proved irreversible in all cases; and of 13 fetuses with incomplete heart block which received maternal steroid therapy, three had a reduction in their degree of block and one reverted to sinus rhythm. Maternal steroid therapy, initiated early in pregnancy and potentially preventing the onset of heart block, did not decrease the incidence of heart block in nine studies with 43 cases. Furthermore, the literature review revealed numerous serious side effects of maternal steroid administration during pregnancy. Data on these potential side effects are lacking in the 28 studies discussed in this review. Maternal dexamethasone therapy to prevent or treat fetal heart block remains, in our opinion, a questionable intervention and can as yet not be recommended in the clinical situation.

Signs of first-degree heart block occur in one-third of fetuses of pregnant women with anti-SSA/Ro 52-kd antibodies

OBJECTIVE

To prospectively investigate the development of fetal heart block in anti-SSA/Ro 52-kd-positive women, and to evaluate the usefulness of serial Doppler echocardiography in detecting early signs of congenital heart block.

METHODS

Twenty-four women with anti-SSA/Ro 52-kd antibodies and consequently increased risk for fetal heart block were followed up weekly, between 18 and 24 weeks of gestation, with two Doppler echocardiographic methods designed to estimate the time delay between hemodynamic events caused by atrial and ventricular depolarizations. Two hundred eighty-four women with normal pregnancies served as controls. Anti-Ro 52-kd, anti-Ro 60-kd, and anti-La antibodies were investigated by immunoblotting and enzyme-linked immunosorbent assay using recombinant proteins.

RESULTS

In anti-Ro 52-kd-positive women, fetal atrioventricular (AV) time intervals were longer and heart rates were slightly lower compared with those in controls. Eight of 24 fetuses had signs of first-degree block. One of these fetuses had progression to complete block, and another showed recovery from second-degree block to first-degree block with betamethasone treatment. In the remaining 6 fetuses, spontaneous normalization occurred before or shortly after birth. Fetuses with normal AV time intervals at 18-24 weeks had normal electrocardiographic results at birth.

CONCLUSION

Anti-Ro 52-kd-positive pregnant women frequently carry fetuses with Doppler echocardiographic signs of first-degree AV block. These blocks revert spontaneously in the majority of fetuses, but progression to a more severe degree of block may occur in some. Serial Doppler echocardiographic measurement of AV time intervals is suggested as a useful method for surveillance of these high-risk pregnancies.

The monolithic fetal pacemaker: prototype lead design for closed thorax deployment

Prenatal sudden cardiac death and hydrops fetalis are often due to complete heart block. However, no pacing modality exists for intrauterine application for fetal bradycardia. A prototype lead for a novel fetal pacemaker has been developed and used in a direct pacing model. It has been demonstrated that the lead can be safely and successfully deployed using a hypochondriac and transdiaphragmatic or subxiphoid approach. Pacing with ventricular capture was evident with the widening of QRS duration from 50.2 +/- 9.8 to 95.1 +/- 12.8 ms (P = 0.0001). Further studies by echocardiogram revealed an increase in the pulse with pacing, confirming pacing. This study documents proof-of-concept for closed thorax over-the-wire deployment of a novel lead design applicable to fetal pacing. By combining the lead design with microcircuitry and a small power source, it is possible to create a monolithic fetal pacemaker system capable of being deployed in utero.

Fetal cardiology

The prevalence of congenital heart disease increases with increasing NT, and many defects can be detected by echocardiography performed by a specialist at 13 to 17 weeks. There is increasing evidence that a prenatal diagnosis improves fetal outcome. Physiology and pathophysiology of the human fetal pulmonary circulation play an important role in the fetal circulation, and recent studies about the reactivity of these vessels in the third trimester have contributed to increase our understanding. The main issue in fetal arrhythmias (brady- and tachycardia) is the correct indication, efficacy, and safety of treatment.