Symptomatic Bradycardia in a KCNQ1 Patient

Background: This case report is about a female that presented with severe weakness due to episodic bradycardia. The patient has a history of familial atrial fibrillation (FAF) from a KCNQ1 mutation treated with ablation in 2008. Is this presentation secondary to known FAF, a result of the ablation, or another unrelated disease process? Case Information: A 38-year-old Caucasian female presented to a standalone ED reporting sudden weakness and fatigue. She was at home when the symptoms caused her to sit on the kitchen floor. During the episode she had no syncope, chest pain, or shortness of breath. The patient's FAF has caused her no symptoms since 2008, when ablation through pulmonary vein isolation occurred. At the ED, ECG revealed sinus bradycardia. All other vitals were normal and chest x-ray was insignificant. CBC, CMP, and troponins were within normal limits, except for low Vitamin D. Cardiology placed a cardiac loop recorder which recorded symptomatic episodes of bradycardia and intermittent pauses. A pacemaker is scheduled for placement. Conclusions: Atrial fibrillation commonly presents with symptomatic tachycardia rather than bradycardia. The KCNQ1 mutation is not known to cause bradycardia. Additionally, bradycardia after a cardiac ablation is more likely to present acutely after the procedure. Evidence of post ablation bradycardia presenting years after the procedure is sparse. Perhaps this presentation is a separate undiagnosed disease entity that may or may not be related to prior treatment and/or as a result of this patient's cardiac history.