Atrioventricular heart block and syncope coincident with diagnosis of systemic lupus erythematosus

Etiologies of atrioventricular block in young patients: A single-center study in China

BACKGROUND

Atrioventricular block (AVB) is common in the elderly and therefore considered to be a degenerative disease of the cardiac conduction system. However, there exist other etiologies contributing to AVB in young patients. This study aimed to determine the etiologies in patients aged before 60 years receiving their first pacemaker implantation for AVB in China.

METHODS AND RESULTS

Medical records and diagnostic tests of AVB patients were reviewed to identify the etiologies between 2010 and 2021 at Guangdong Provincial People's Hospital. Eight hundred and twenty-six patients (median age 47 years; 47.9% males) were included. The etiologies were identified in 336 (40.7%) cases, including complications to cardiac surgery (n = 190 [23.0%]), myocarditis (n = 57 [6.9%]), myocardial infarction (n = 25 [3.0%]), complications to catheter-based interventional procedures (n = 21 [2.5%]) and others (n = 43 [5.2%]). AVB caused by myocardial infarction was more common in men (5.8% vs. 0.5%, p < .001), while women received pacing treatment earlier (48 vs. 46 years, p = .019). Men were more likely to suffer from dilated cardiomyopathy (6.6% vs. 2.1%, p = .001) and atrial fibrillation/flutter (23.0% vs. 12.8%, p < .001). The number of first pacemaker implantation increased with age especially among patients with unclear etiologies.

CONCLUSION

The etiology of AVB was only determined in approximately 40% of patients receiving their first pacemaker implantation aged before 60 years. The predominance of AVB with unknown etiology and potential gender differences warrants further studies.

Systemic Diseases and Heart Block

Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.

Systemic Diseases and Heart Block

Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.

Systemic Diseases and Heart Block

Systemic diseases can cause heart block owing to the involvement of the myocardium and thereby the conduction system. Younger patients (<60) with heart block should be evaluated for an underlying systemic disease. These disorders are classified into infiltrative, rheumatologic, endocrine, and hereditary neuromuscular degenerative diseases. Cardiac amyloidosis owing to amyloid fibrils and cardiac sarcoidosis owing to noncaseating granulomas can infiltrate the conduction system leading to heart block. Accelerated atherosclerosis, vasculitis, myocarditis, and interstitial inflammation contribute to heart block in rheumatologic disorders. Myotonic, Becker, and Duchenne muscular dystrophies are neuromuscular diseases involving the myocardium skeletal muscles and can cause heart block.

Complete heart block in lupus

Conduction abnormalities are uncommon in adult patients with lupus. We present a young woman with recurrent syncope caused by third-degree atrio-ventricular block as the initial manifestation of lupus and review 31 additional cases of systemic lupus erythematosus patients that have been described previously with complete heart block. Heart blocks occurred almost exclusively in females. The median age was 37 years. In 24 cases heart blocks were diagnosed in patients with established lupus. In only five patients, including the patient presented here, heart blocks were diagnosed before the lupus diagnosis. Syncope was the most common presenting symptom of heart block. Electrocardiographic findings prior to heart block episodes were reported in 17 cases: eight had normal findings, but nine had already variant forms of atrioventricular or intraventricular conduction defects. Anti-nuclear antibody tests were reported in 25 cases and were all positive. Anti-DNA antibodies were also common and were positive in 16 of 19 cases (84%). Anti-La and anti-Ro antibodies were less common (13% and 35%, respectively). Three patients died, all prior to 1975. Heart block resolved in 10 cases. Follow-up was reported in four of these cases and heart block recurred in three of them. A permanent pacemaker was the eventual treatment in 22 cases. The etiology of lupus-associated complete heart block is not clear. It is probably variable, possibly related to effects of autoantibodies reacting with the conduction system, myocardial disease and adverse effects of antimalarials. Insertion of a permanent pacemaker seems to be the preferable method of treatment.

The Role of Contrast-Enhanced Cardiac Magnetic Resonance in the Assessment of Patients with Malignant Ventricular Arrhythmias

Cardiac magnetic resonance (CMR) imaging has gained significant traction as an imaging modality of choice in the evaluation of individuals with, or at risk for, heart failure. Ventricular arrhythmias, often malignant, may be sequelae of heart failure and arise from fibrosis. Late gadolinium enhancement evaluation by CMR has become a preferred modality to assess individuals at risk for malignant ventricular arrhythmias. A spectrum of various pathologies that predispose individuals to malignant ventricular arrhythmias, as well as the usefulness of CMR in their identification and prognostication, are reviewed.

Syncope caused by complete heart block and ventricular arrhythmia as early manifestation of systemic lupus erythematosus in a pregnant patient: a case report

Systemic lupus erythematosus (SLE) can affect all heart structures including the conduction system, with either reversible or permanent derangement. However, only a few cases of adult SLE and complete atrioventricular (AV) block have been reported. We describe a young pregnant woman who initially presented with complete AV block on electrocardiography before the diagnosis of SLE. Syncope subsequently developed during the postpartum period due to frequent nonsustained polymorphic ventricular tachycardia, suggesting lupus myocarditis. The ventricular arrhythmia was successfully treated by intravenous corticosteroids, lidocaine and implantation of a permanent pacemaker. This may represent the first report of complete AV block with polymorphic ventricular tachycardia, which was identified before the other clinical features of SLE fully manifested. SLE should be considered if a patient presents with complete AV block without other clinical features. It may warn for early diagnosis and appropriate treatment of SLE including lupus-related heart disease.

Role of Cardiac Magnetic Resonance in the Diagnosis and Prognosis of Nonischemic Cardiomyopathy

Cardiac magnetic resonance (CMR) is a valuable tool for the evaluation of patients with, or at risk for, heart failure and has a growing impact on diagnosis, clinical management, and decision making. Through its ability to characterize the myocardium by using multiple different imaging parameters, it provides insight into the etiology of the underlying heart failure and its prognosis. CMR is widely accepted as the reference standard for quantifying chamber size and ejection fraction. Additionally, tissue characterization techniques such as late gadolinium enhancement (LGE) and other quantitative parameters such as T₁ mapping, both native and with measurement of extracellular volume fraction; T₂ mapping; and T₂* mapping have been validated against histological findings in a wide range of clinical scenarios. In particular, the pattern of LGE in the myocardium can help determine the underlying etiology of the heart failure. The presence and extent of LGE determine prognosis in many of the nonischemic cardiomyopathies. The use of CMR should increase as its utility in characterization and assessment of prognosis in cardiomyopathies is increasingly recognized.

Severe brady-arrhythmias in systemic lupus erythematosus: prevalence, etiology and associated factors

Background

Severe brady-arrhythmias, requiring a permanent pacemaker (PPM), have been sparsely reported in systemic lupus erythematosus (SLE). The aim of this study was to describe the characteristics of such arrhythmias in a defined lupus cohort.

Patients and methods

The database of the Toronto Lupus Clinic ( n = 1366) was searched for patients who received a PPM. Demographic, clinical, immunological and therapeutic variables along with electrocardiographic (ECG) and echocardiographic findings (based on the last available test prior to PPM) were analyzed. Patients with a PPM (cases) were compared with age-, sex- and disease duration-matched patients without a PPM (controls). Analysis was performed with SAS 9.0; p < 0.05 was considered significant.

Results

Eighteen patients were identified, 13 (0.95%) with complete atrioventricular block and 5 (0.37%) with sick sinus syndrome. Disease duration at PPM implantation was 22 ± 12 years. Compared to controls, cases had more frequently coronary artery disease, hypertension, dyslipidemia and longer antimalarial (AM) treatment duration. The prevalence of first-degree atrioventricular block, right bundle branch block, left anterior fascicular block and septal hypertrophy was also higher. AM treatment was significantly associated with brady-arrhythmias (OR = 1.128, 95% CI = 1.003–1.267, p = 0.044). Nine patients had prior heart disease and one received a PPM two years after renal transplantation. Eight patients did not have any potential risk factors; prolonged AM therapy (mean 22 years) might have been the cause.

Conclusions

Apart from known causes, prolonged AM treatment may be associated with severe brady-arrhythmias in SLE. Certain ECG and echocardiographic characteristics may represent indicators of an ongoing damage in the conduction system.