Unveiling Asymptomatic Atrioventricular Reciprocating Tachycardia in a Patient With Wolff-Parkinson-White Syndrome and Multiple Sclerosis

Background Multiple sclerosis (MS) is an immune-mediated disorder of the central nervous system characterized by demyelination, leading to various neurological deficits, including sensory disturbances and autonomic dysfunction. These disruptions can obscure the recognition of critical physiological symptoms including arrhythmias. Wolff-Parkinson-White (WPW) syndrome, characterized by an accessory atrioventricular conduction pathway, predisposes patients to supraventricular tachycardia (SVT), most commonly atrioventricular reentrant tachycardia (AVRT). While AVRT typically manifests as palpitations, dizziness, or syncope, sensory and autonomic pathway disruptions in MS may diminish symptom perception. This case highlights the diagnostic challenges posed by the coexistence of MS and WPW syndrome, emphasizing the need for heightened clinical awareness in such patients. Case Presentation : Our case is a 54 year-old female with a history of secondary progressive multiple sclerosis (SPMS), WPW pattern, toxic thyroid adenoma, and paroxysmal atrial fibrillation admitted for complicated Eschierichia coli cystitis with concern for bacteremia. Initial labs were significant for leukocytosis and hypokalemia, as well as elevated liver function tests and a euthyroid state. ECG on admission showed sinus tachycardia with a right bundle branch block. Due to concern for sepsis, she received appropriate fluid resuscitation and was started on IV ceftriaxone. Patient continued to be tachycardic, so she received an additional liter of Lactated Ringer’s and was placed on telemetry. She subsequently developed worsening hypokalemia in addition to hypomagnesemia and subclinical hypothyroidism. Further telemetry monitoring revealed an episode of asymptomatic AVRT at a rate of 220 BPM with concomitant hypotension. She was transferred to the ICU for direct current cardioversion and sinus tachycardia was achieved on the third shock. She underwent subsequent electrophysiology study with successful ablation of a left-sided anterolateral accessory pathway. Conclusion This case highlights the importance of close monitoring for arrhythmias in patients with MS, particularly in patients with MS who may have diminished symptom awareness. We recommend a comprehensive approach to management of MS patients with risk factors for arrhythmias, including routine cardiac telemetry, electrolyte monitoring, and a low threshold for obtaining diagnostic tests in patients that may show discreet signs of arrhythmias.