Sinus Bradycardia and QT Interval Prolongation in West Nile Virus Encephalitis: A Case Report

Abstract

Cardiac arrhythmias were reported in cases of West Nile Virus (WNV) encephalitis; however, the underlying pathophysiology remains incompletely understood. We present a 67-year-old male with altered mental status, later diagnosed with WNV encephalitis. Hospital course was complicated by progressive sinus bradycardia and corrected QT (QTc) prolongation. These findings persisted despite the absence of classical causes and resolved only after improvement of the underlying encephalitis. After excluding classical causes, autonomic dysfunction is one of the proposed mechanisms behind cardiac arrhythmias in WNV encephalitis. Resolution of arrhythmias is expected after the improvement of underlying encephalitis and should be taken into consideration before proceeding for pacemaker placement or other cardiac intervention. Furthermore, this case highlights the importance of continuous cardiac monitoring in WNV encephalitis patients.

Keywords: arrhythmia; sinus bradycardia; west nile virus encephalitis.

Figure 1. Initial EKG on day one showing normal sinus rhythm and normal QTc interval (426 millisecond); indicated between two green arrows

Figure 2. EKG on day five showing first-degree AV block (PR interval of 240 ms, indicated between two blue arrows) and prolonged QTc of 525 ms (between two green arrows)

EKG: electrocardiogram, AV: atrioventricular, QTc: corrected QT

Figure 3. EKG showing resolution of the bradycardia and restoration of normal QTc (439 ms, indicated between two green arrows)

EKG: electrocardiogram, QTc: corrected QT