The role of detailed medical history for the early diagnosis of familial bradycardia in a patient with associated atrial fibrillation: case report

Bradycardia represents a frequent reason for medical presentation and has a complex aetiology, including genetic disorders, like LMNA mutation. LMNA mutation is responsible for laminopathies, including LMNA -cardiomyopathy. Cardiac involvement is prevalent and is linked to dilated cardiomyopathy associated with conduction block, which is anticipated by bradyarrhythmia and supraventricular tachyarrhythmia. LMNA mutation carriers have higher risk for sudden cardiac death (SCD), malignant ventricular tachycardia, and extreme bradycardia.

A 48-year-old female presented for recurrent episodes of dizziness, lightheadedness, headache, and fatigue, occurring at rest. The past medical history was positive for hypertension and one episode of paroxysmal atrial fibrillation. The family medical history was positive; both children and the patient’s mother are known with bradycardia. The electrocardiogram showed sinus bradycardia, and the echocardiography revealed a mild concentric hypertrophy of the left ventricle, associated with impaired relaxation diastolic dysfunction. The 24 h Holter monitoring recorded sinus bradycardia, multiple pauses, paroxysmal atrial fibrillation, and multiple episodes of junctional rhythm. The positive family medical history suggested a genetic link. Further, genetic testing was performed, revealing a mutation of the LMNA gene.

Despite apparently benign at the initial presentation, the correct diagnosis and management required detailed medical history and extensive investigation of both the patient and the first-degree relatives. As the LMNA mutation carriers have a higher risk for SCD and have a mortality risk of 40% at 5 years, we emphasize the role of early diagnosis and periodic monitoring for preventing the worsening of the condition.