When atrioventricular block paves the way to a more severe diagnosis: a case report

Systemic sclerosis (SSc) is an autoimmune connective tissue disease characterized by widespread fibrosis of skin and internal organs. Cardiac involvement is common but often subclinical, and advanced conduction abnormalities such as complete atrioventricular block are rarely the initial manifestation.

A 42-year-old man presented with fatigue and episodes of syncope. Electrocardiography confirmed complete AV block. Physical examination revealed diffuse skin tightening and Raynaud's phenomenon. Immunological testing detected high-titre antinuclear antibodies and anti-topoisomerase I, confirming diffuse cutaneous SSc. Further evaluation disclosed multiorgan involvement: high-resolution CT showed pulmonary fibrosis and right heart catheterization confirmed severe precapillary pulmonary hypertension. The patient underwent permanent dual-chamber pacemaker implantation and was started on immunosuppressive therapy and pulmonary vasodilators. On follow-up, his bradycardia resolved and exercise tolerance improved, indicating partial clinical improvement.

This case highlights an atypical cardiac onset of diffuse SSc with high-grade conduction disease. It underscores the importance of considering systemic autoimmune disorders in patients with unexplained high-degree AV block, especially in the presence of characteristic skin findings. Comprehensive assessment revealed concurrent pulmonary and gastrointestinal involvement, reflecting the multisystem nature of SSc. Early recognition allowed a coordinated multidisciplinary treatment strategy, including device implantation and disease-modifying therapy, which ultimately stabilized the patient's condition. This case emphasizes the need for early diagnosis and integrated management of cardiac, pulmonary, and gastrointestinal complications in SSc. Although SSc is generally progressive, prompt recognition and treatment of organ involvement may significantly improve patient outcomes and quality of life.