Congenital heart block is defined as the presence of atrioventricular block and heart damage between 16-24 weeks of gestation. Structural cardiac abnormalities and maternal autoimmune disorders are the key events in pathogenesis. The diagnosis can be made perinatally or postnatally. Treatment often mandates pacemaker implantation, but mortality rates may be very high in severe forms of the condition.
The clinical presentation of a complete heart block (CHB) may significantly vary, depending on the severity of the block (first degree, second degree, or complete heart block) and presence of additional structural heart disorders, such as congenital - corrected transposition of the great arteries and heterotaxia have been associated with this condition . CHB develops between 16-24 weeks of gestation, and symptoms may start during fetal life. Numerous cardiac rhythm abnormalities are described, including atrial flutter, the presence of both atrial and ventricular ectopic beats, sinus node dysfunction, and ectopic tachycardia (both ventricular and junctional)  . Bradycardia, however, is also documented and carries the poorest prognosis . CHB may also lead to myocardial fibrosis and myocarditis, which often presents as cardiomyopathy, pericarditis or pericardial effusion, both prenatally and postnatally  . In fact, dilated cardiomyopathy is the most important complication in the first year of life, as mortality rates reaching up to 40% . Although only 1-2% of fetuses are born to mothers carrying anti–SSA/Ro-SSB/La antibodies , they encompass between 60-90% of all cases reported in the literature   . For this reason, CHB is often accompanied by various non-cardiac symptoms - liver failure, transient thrombocytopenia, neutropenia, neonatal hyperbilirubinemia, and cholestasis, as well as annular erythematous plaques on the skin . The term neonatal lupus is used to describe CHB when it appears along with these findings
- Heart Disease
No reports of congenital heart disease among the children of mothers with connective tissue disease fit this description. [ncbi.nlm.nih.gov]
In cases where congenital heart disease is not present, congenital heart block is almost always secondary to maternal connective tissue disease (anti SSA/Ro antibodies). [pedecho.org]
- Skipped Beats
Atrioventricular block For 1st-degree block, conduction is slowed without skipped beats. All normal P waves are followed by QRS complexes, but the PR interval is longer than normal ( > 0.2 sec). [msdmanuals.com]
In the Wenckebach or Mobitz I type, there is a progressive delay between heartbeats until a beat is dropped or skipped. [rarediseases.org]
- Slow Pulse
This condition, however, must be seriously considered in a child with a slow pulse rate when a history of acquired disease, such as diphtheria, rheumatic fever, syphilis or severe pyogenic infection is not obtained. [jamanetwork.com]
This may predispose the infant to transient hydrocephalus, seizures, or vascular myelopathy. The infant's posture and muscle tone, primitive reflexes, and Babinski reflex should be assessed. [nursingcenter.com]
- Behavior Problem
Children should also be monitored for neuropsychiatric and behavioral problems and attention deficit disorder. [nursingcenter.com]
Auscultation of the heart during prenatal or postnatal assessment is the key step in the detection of cardiac abnormalities and may provide sufficient clinical suspicion for a more detailed evaluation. Obstetrical ultrasonography, maternal-fetal monitoring, or fetal echocardiogram with Doppler techniques are useful during the perinatal period, while standard echocardiography is the mainstay of diagnosis in neonates and infants . Patent ductus arteriosus (PDA), atrial septal defects (ASDs), ventricular septal defects (VSDs), as well as dysplasia, stenosis or regurgitation of either atrioventricular and/or semilunar valves may be identified . Decreased contractility is one of the main findings pointing myocarditis . Moreover, tricuspid regurgitation, ventricular inversion, and other structural heart anomalies are seen in some cases . The detection of heart blocks, however, is the most important finding that can lead to the diagnosis of CHB, which is detected by observing the length of the PR interval, but QT prolongation is also noted   . The wider the PR interval, the more severe the block.
- Wide QRS Complex
Mechanical ventricular dyssynchrony is not synonymous with a wide QRS EKG complex. [ecrjournal.com]
Wenckebach block is usually due to block within the AV node, with a narrow QRS complex. On the other hand, Mobitz II is generally associated with a wide QRS complex, due to infranodal disease. [thecardiologyadvisor.com]
Provided that the pre-paced rhythm is not complete heart block with a wide QRS complex, the 12-lead ECG should give the diagnosis before the patient enters the pacing theatre! If not, fluoroscopy will suggest the abnormality ( figure 1 ). [bjcardio.co.uk]
Intrauterine steroid treatment in the presence of fetal hydrops and congenital heart block is discussed. [ncbi.nlm.nih.gov]
In a case of fetal heart block, maternal administration of ritodrine may be a therapeutic intervention to improve the fetal and neonatal prognosis. [ncbi.nlm.nih.gov]
We discuss the 2 major etiologies of congenital heart block and the implications in subsequent pregnancies. [ncbi.nlm.nih.gov]
Interestingly, two cases of fetal congenital heart block occurred in women without known risk factors (eg, positive anti-Ro/SSA antibody, previous pregnancy with congenital heart block).  Many times, no clear etiology is determined for isolated CAVB [emedicine.medscape.com]
Etiology: 1. Autoimmune antibodies. 2. Structural heart abnormalities due to congenital heart disease (eg-L-TGA, Endocardial cushion defects, syndromic ASD) 3. Idiopathic familial congenital CHB 21. [slideshare.net]
(First-degree heart block) Introduction Clinical definition an impairment of the electrical transmission from the atria to the ventricles Etiology idiopathic (most common) e.g., fibrosis and sclerosis of the conduction system ischemic heart disease (2nd [step2.medbullets.com]
In this Review, we discuss the epidemiology, classification and management of women whose pregnancies are affected by autoimmune CHB, with a particular focus on the autoantibodies associated with autoimmune CHB and how we should test for these antibodies [ncbi.nlm.nih.gov]
pathophysiology, classification & diagnosis of bradyarrhythmias suitabe for permanent cardiac pacing therapy Persitent bradycardia Intermittent (documented) bradycardia Suspected (undocumented) bradycardia Indications for cardiac resynchronization Epidemiology [escardio.org]
Neonatal lupus: Epidemiology, pathogenesis, clinical manifestations, and diagnosis [visitado 2017 Nov 21]. Disponible en: https://www.uptodate.com/contents/neonatal-lupus-epidemiology-pathogenesisclinical-manifestations-and-diagnosis. [revista.fecolsog.org]
Epidemiologic studies suggest that a genetic or environmental cause for CHD is identifiable in approximately 20%–30% of cases, with 3%–5% of CHD due to a detectable single-gene disorder. [invitae.com]
References 1 Epidemiology, etiology, detection, and treatment of autoantibody-associated congenital heart block in neonatal lupus, Curr Rheumatol Rep, 2007, vol. 9 (pg. 101 - 8 ) 2 Congenital heart block risk to newborns of mothers with anti-Ro/SSA antibodies [academic.oup.com]
The possible pathophysiological mechanisms underlying CHB associated with 1 degrees SS are discussed. [ncbi.nlm.nih.gov]
Presentation Published in 2013 Reference CP Published in 2013 Reference Addenda -Eur Heart J - doi:10.1093/eurheartj/eht180 Table of contents: Full Text (ESC Clinical Practice Guidelines) Preamble Indications for pacing Epidemiology, natural histroy, pathophysiology [escardio.org]
Grasp the full scope of the pathophysiology of CHD with well-organized, expert guidance. Quickly search the contents online, download images in JPG or PPT format, and view 70 echocardiogram videos at expertconsult.com. [books.google.ro]
[…] lesions with secondary collagen degeneration and fibrosis of AV and SA nodes. 4– 6 One study shows that anti-Ro antibody positive adults with SLE are more likely to have conduction defects than anti-Ro negative patients. 7 This may provide a clue to the pathophysiology [ard.bmj.com]
Preventive treatment during pregnancy, however, before the critical period of cardiac development, can prevent the development of CHB. [ncbi.nlm.nih.gov]
- Capone C, Buyon JP, Friedman DM, Frishman WH. Cardiac Manifestations of Neonatal Lupus: A Review of Autoantibody Associated Congenital Heart Block and its Impact in an Adult Population. Cardiol Rev. 2012;20(2):72-76.
- Brucato A. Prevention of congenital heart block in children of SSA-positive mothers. Rheumatology (Oxford). 2008;47(3):iii35-37.
- Friedman D, Duncanson L, Glickstein J, Buyon J. A review of congenital heart block. Images Paediatr Cardiol. 2003;5(3):36-48.
- Gordon PA. Congenital heart block: clinical features and therapeutic approaches. Lupus. 2007;16(8):642-646.
- Friedman DM, Kim MY, Copel JA, et al. Utility of cardiac monitoring in fetuses at risk for congenital heart block: the PR Interval and Dexamethasone Evaluation (PRIDE) prospective study. Circulation. 2008; 117:485-93.