28An unusual case of stroke and atrial fibrillation in a 23 year-old

Abstract

Introduction and case report description: A 23-year-old man presented with difficulty speaking and right-sided weakness. He had a reported history of spinal muscle atrophy (SMA) type III diagnosed by muscle biopsy and clinical manifestations at an outside institution at age 4. He was not on any medication. He smoked marijuana occasionally, but denied other drug or alcohol use. Description of the problem, procedures, techniques and/or equipment used: Head CT angiography showed a left middle cerebral artery (MCA) stroke. His physical exam was significant for truncal weakness, significant contractures at the elbows, and he was noted to walk on his toes which was lifelong (Figure 1, panel A and B). Heart exam was notable for a regular bradycardia. His electrocardiogram (ECG) demonstrated atrial fibrillation with a slow ventricular response (Figure 1, panel C), at times with regularization consistent with complete heart block and a junctional escape (Figure 1, panel D). Transthoracic echocardiogram showed a normal ejection fraction with no valvular disease. The MCA stroke was felt to be a thromboembolic complication of atrial fibrillation, eventhough CHA2DS2-VASc score was 0. He was treated upon presentation with thrombolytic therapy (tPA) with complete resolution of symptoms. Questions, problems or possible differential diagnosis: The above mentioned findings on physical exam and cardiac manifestations of atrial fibrillation, stroke and conduction disease were more congruent with a neuromuscular disorder (NMD), specfically Emery Dreifuss muscular dystrophy (EDMD) rather than his reported history of SMA. EDMD is typically characterized by a classic triad of early joint contractures, slowly progressive muscle weakness and wasting, and cardiac disease, typically AV conduction abnormalities and atrial arrhythmias. Answers and discussion: His ongoing evaluation and management included a cardiac MRI which showed biatrial enlargement and preserved left and right ventricular function without late gadolinium enhancement. He was anticoagulated with rivaroxaban and a TEE was initially performed to guide cardioversion. After we excluded left atrial appendage thrombus, two successive cardioversions were performed in the electrophysiology laboratory and were each accompanied by 5 second pauses with early recurrence of atrial fibrillation. While briefly in sinus rhythm, the AH interval was measured at 230 ms and the HV interval at 55 ms. Atrial electrograms were small and the atrial tissue in multiple sites was unable to be paced consistent with an atriopathy. Genetic testing showed mutations in Figure 1 LMNA (c. 122G>A p. Arg41His), known to be mutants in EDMD and Lamin A/C. A single chamber ICD was implanted given the risk of ventricular arrhythmias in addition to conduction disease associated with EDMD with Lamin A/C mutation. Conclusions and implications for clinical practice: This case highlights the electrophysiological manifestations in one of the neuromuscular disorders, specifically EDMD. A multidisciplinary approach for early diagnosis of these neuromuscular disorders, given the risk of sudden cardiac death and other findings like embolic stroke, is of paramount importance. Genetic testing is also important in cases of NMD. If testing reveals a LMNA mutation, there is a role for routine cardiac monitoring including ECG and echocardiogram given the high rate of cardiac manifestations and sudden cardiac death in EDMD. (Figure Presented).