Neonatal lupus with congenital atrioventricular block and myocarditis

Anatomical and pathological findings in hearts from fetuses and infants with cardiac manifestations of neonatal lupus

OBJECTIVE

The autopsy and clinical information on children dying with anti-SSA/Ro-associated cardiac manifestations of neonatal lupus (cardiac NL) were examined to identify patterns of disease, gain insight into pathogenesis and enhance the search for biomarkers and preventive therapies.

METHODS

A retrospective analysis evaluating reports from 18 autopsies of cardiac NL cases and clinical data from the Research Registry for Neonatal Lupus was performed.

RESULTS

Of the 18 cases with autopsies, 15 had advanced heart block, including 3 who died in the second trimester, 9 in the third trimester and 3 post-natally. Three others died of cardiomyopathy without advanced block, including two dying pre-natally and one after birth. Pathological findings included fibrosis/calcification of the atrioventricular (AV) node, sinoatrial (SA) node and bundle of His, endocardial fibroelastosis (EFE), papillary muscle fibrosis, valvular disease, calcification of the atrial septum and mononuclear pancarditis. There was no association of pathology with the timing of death except that in the third-trimester deaths more valvular disease and/or extensive conduction system abnormalities were observed. Clinical rhythm did not always correlate with pathology of the conduction system, and the pre-mortem echocardiograms did not consistently detect the extent of pathology.

CONCLUSION

Fibrosis of the AV node/distal conduction system is the most characteristic histopathological finding. Fibrosis of the SA node and bundle of His, EFE and valve damage are also part of the anti-Ro spectrum of injury. Discordance between echocardiograms and pathology findings should prompt the search for more sensitive methods to accurately study the phenotype of antibody damage.

Atrial and ventricular rate response and patterns of heart rate acceleration during maternal-fetal terbutaline treatment of fetal complete heart block

Terbutaline is used to treat fetal bradycardia in the setting of complete heart block (CHB); however, little is known of its effects on atrial and ventricular beat rates or patterns of heart rate (HR) acceleration. Fetal atrial and ventricular beat rates were compared before and after transplacental terbutaline treatment (10 to 30 mg/day) by fetal echocardiography in 17 fetuses with CHB caused by immune-mediated damage to a normal conduction system (isoimmune, n = 8) or a congenitally malformed conduction system associated with left atrial isomerism (LAI, n = 9). While receiving terbutaline, 9 of the 17 fetuses underwent fetal magnetocardiography (fMCG) to assess maternal HR and rhythm, patterns of fetal HR acceleration, and correlation between fetal atrial and ventricular accelerations (i.e., AV correlation). Maternal HR and fetal atrial and ventricular beat rates increased with terbutaline. However, terbutaline's effects were greater on the atrial pacemaker(s) in fetuses with isoimmune CHB and greater on the ventricular pacemaker(s) in those with LAI-associated CHB. Patterns of fetal HR acceleration also differed between isoimmune and LAI CHB. Finally, despite increasing HR, terbutaline did not restore the normal coordinated response between atrial and ventricular accelerations in isoimmune or LAI CHB. In conclusion, the pathophysiologic heterogeneity of CHB is reflected in the differing effect of terbutaline on the atrial and ventricular pacemaker(s) and varying patterns of HR acceleration. However, regardless of the cause of CHB, terbutaline augments HR but not AV correlation, suggesting that its effects are determined by the conduction system defect rather than the autonomic control of the developing heart.

Dilated Cardiomyopathy Associated with Dual-Chamber Pacing in Infants:. Improvement Through Either Left Ventricular Cardiac Resynchronization or Programming the Pacemaker Off Allowing Intrinsic Normal Conduction

The etiology of dilated cardiomyopathy associated with congenital complete AV block has not yet been clarified. Two infants with AV block of autoimmune and surgical etiology, respectively, had received a dual-chamber right ventricular-based pacemaker and developed dilated cardiomyopathy with severe septal to left ventricular free-wall dyssynchrony 3.4 (0.9) years later. After 4 weeks of biventricular pacing and spontaneous junctional narrow QRS rhythm, respectively, both children showed significant improvement in left ventricular function along with reverse remodeling. Thus, electromechanical dyssynchrony associated with conventional right-ventricular-based DDD pacing may play a significant role in the development of dilated cardiomyopathy in the young.

Congenital atrioventricular block: histological aspects

It is known that maternal immunological factors such as systemic disease are involved in the genesis of cardiac conduction problems in the fetus but the histologic changes in the conduction system are less documented. We report the case of a 33-year-old woman with no significant medical history. Her first pregnancy was induced by Clomifene. At 17 weeks of gestation, the fetus presented sonographic abnormalities characteristic of a complete atrioventricular block. Biological investigations found anti-SSA and -SSB antibodies. Clinical history search for systemic disease was positive for photosensitivity, lasting 10 years, suggesting the diagnosis of systemic lupus erythematosus. The patient was treated with prednisone 20 mg per day but fetal death occurred at 29 weeks of gestation. Histological examination of the fetal heart showed an altered atrioventricular node and bundle of His with fibrosis, calcifications, endocardial fibroelastosis and mononucleated inflammatory cells. The search for these specific lesions can be determinant in establishing the disease pathogenesis; also, it is important to eliminate this diagnosis in an unexplained fetal death.

Congenital heart block: development of late-onset cardiomyopathy, a previously underappreciated sequela

OBJECTIVE

We report 16 infants with complete congenital heart block (CHB) who developed late-onset dilated cardiomyopathy despite early institution of cardiac pacing.

BACKGROUND

Isolated CHB has an excellent prognosis following pacemaker implantation. Most early deaths result from delayed initiation of pacing therapy or hemodynamic abnormalities associated with congenital heart defects.

METHODS

A multi-institutional study was performed to identify common clinical features and possible risk factors associated with late-onset dilated cardiomyopathy in patients born with congenital CHB.

RESULTS

Congenital heart block was diagnosed in utero in 12 patients and at birth in four patients. Ten of 16 patients had serologic findings consistent with neonatal lupus syndrome (NLS). A pericardial effusion was evident on fetal ultrasound in six patients. In utero determination of left ventricular (LV) function was normal in all. Following birth, one infant exhibited a rash consistent with NLS and two had elevated hepatic transaminases and transient thrombocytopenia. In the early postnatal period, LV function was normal in 15 patients (shortening fraction [SF] = 34 +/- 7%) and was decreased in one (SF = 20%). A cardiac pacemaker was implanted during the first two weeks of life in 15 patients and at seven months in one patient. Left ventricular function significantly decreased during follow-up (14 days to 9.3 years, SF = 9% +/- 5%). Twelve of 16 patients developed congestive heart failure before age 24 months. Myocardial biopsy revealed hypertrophy in 11 patients, interstitial fibrosis in 11 patients, and myocyte degeneration in two patients. Clinical status during follow-up was guarded: four patients died from congestive heart failure; seven required cardiac transplantation; one was awaiting cardiac transplantation; and four exhibited recovery of SF (31 +/- 2%).

CONCLUSIONS

Despite early institution of cardiac pacing, some infants with CHB develop LV cardiomyopathy. Patients with CHB require close follow-up not only of their cardiac rate and rhythm, but also ventricular function.

Successful implantation of a bipolar epicardial lead and an autocapture pacemaker in a low-body-weight infant with congenital atrioventricular block: report of a case

A permanent pacemaker system was successfully implanted into a low-body-weight infant with congenital atrioventricular (AV) block, using a bipolar epicardial CapSure Epi lead and an autocaptured Pacesetter Solus-micro VVIR pacemaker. The calculated life span of the pacemaker generator is 5 years with a heart rate of 120/min and an output of 1.2 V (0.31 ms), and fortunately, its threshold was autocaptured. Thus, we can conclude that the combination of a steroid-eluted bipolar epicardial lead and the smallest possible autocaptured pacemaker generator is most suitable for a neonate or young infant.

Neonatal lupus erythematosus

Neonatal lupus erythematosus (NLE) is an autoimmune disease whose major findings are subacute cutaneous lupus erythematosus (SCLE) skin lesions and congenital heart block. Babies have maternal anti-Ro/SSA, anti-La/SSB, or anti-U1RNP autoantibodies. Anti-Ro/SSA are the predominant autoantibodies, having been found in about 95% of cases. The autoantibodies pass through the placenta from mother to child. Skin disease resolves at about the time that maternal autoantibodies can no longer be detected in the baby. NLE therefore provides the strongest clinical evidence that autoantibodies are involved in at least some manifestations of lupus erythematosus, but there is as yet no definitive evidence implicating autoantibodies in the disease process. Skin disease usually begins after birth, is transient, and does not result in scarring. Cardiac disease begins in utero, and the heart block is almost always permanent. Many babies require pacemakers, and about 10% die from complications related to cardiac disease. In some cases, transient liver disease or thrombocytopenia have been observed. Individuals who had NLE usually have healthy childhoods but may develop autoimmune disease in adulthood. Whether the later development of autoimmune disease is a common or an unusual event is not yet known. Mothers of babies with NLE may be asymptomatic initially, but with time usually develop symptoms of autoimmune disease. The most typical constellation of symptoms in our group of approximately 30 mothers of babies with NLE is that of Sjögren's syndrome. Most babies exposed to anti-Ro/SSA autoantibodies during gestation will not develop NLE. There is no test to determine prospectively which babies will be affected. Treatment during gestation is still controversial and, if attempted, should be reserved for fetuses with potentially life-threatening disease. Treatment after birth consists of topical management for skin disease and pacemaker implantation, if necessary, for heart block. Systemic steroids may be given for serious internal disease.

Maternal autoantibodies and pregnancy--II: The neonatal lupus syndrome

NLE is manifested most typically as transient subacute cutaneous lupus lesions or isolated complete congenital heart block. Babies with NLE have maternal anti-Ro/SSA, anti-La/SSB, or anti-U1RNP autoantibodies. It is presumed, but not proven, that transmission of these autoantibodies through the placenta to the baby has resulted in disease. However, other factors such as inflammatory cells or complement activation may be necessary for disease to be expressed. About half of babies reported with NLE have had heart disease and about half have had skin disease. There have been a few reports of liver disease and a few of thrombocytopenia. Any combination of these findings is possible in a given infant. Possibly, other haematologic abnormalities, pneumonitis or neurological disease could occur, but the evidence that these other abnormalities are part of NLE is scant. Mortality in NLE has occurred in babies with severe cardiac disease. It is estimated that 10% or more of babies with cardiac NLE die in infancy. Of the remainder, perhaps half will require permanent pacemaker implantation. Thus, there is substantial morbidity and mortality with cardiac NLE. The skin disease, by contrast, is not serious and typically leaves little or no residua. Individuals who have had NLE may develop connective tissue disease in adulthood. Whether this is a common or an unusual occurrence is not yet known, since a large cohort of individuals with NLE has not yet been followed into adulthood. Mothers of babies with NLE are often initially asymptomatic. With time, they frequently develop connective tissue disease symptoms. In our experience, these have been largely symptoms of Sjögren's syndrome and have generally not been debilitating. Most babies of mothers with anti-Ro/SSA, anti-La/SSB, or anti-U1RNP autoantibodies do not develop NLE. There is no way to determine prospectively which fetus or infant will be affected and which of those affected will have life-threatening disease. Systemic therapies should be reserved for those infants who have life-threatening manifestations of NLE. It is not yet known whether treatment of the mother during gestation will be beneficial or harmful to fetuses with severe NLE cardiac disease.