1073 An Unusual Case of AV Block Management with Armodafinil in a Narcolepsy Patient.

Abstract

Introduction: Narcolepsy is a sleep disorder of hypersomnia with typical features. Some narcolepsy patients may also have with autonomic dysfunction including bradycardia and hypotension1. We report a unique case where armodafinil was used to treat high-grade atrioventricular (AV) block in a narcolepsy patient. Report of Case: A 30 year-old woman presented with multiple events of transient dizziness, syncope, and excessive daytime sleepiness since age 16. Holter monitor demonstrated high-grade AV block with multiple sinus pauses up to 4-5 seconds in length. A tilt table test and EP study were negative. The patient was unable to tolerate a trial of theophylline due to tremors. Due to excessive daytime sleepiness, a sleep study was done which showed narcolepsy with cataplexy, and the patient was started on armodafinil. During follow-up, her syncope resolved, and repeat holter monitoring showed no more evidence of AV block or sinus pauses. Two years later, the patient stopped armodafinil, because she wanted to become pregnant. However, her syncope and arrhythmias recurred, and a pacemaker was implanted at the recommendation of her cardiologist. Conclusion: Armodafinil is the (R)-enantiomer of the wakepromoting compound modafinil with a longer half-life2. The α-1-adregnergic agonist properties of modafinil may promote wakefulness but appears to lack peripheral sympathomimetic effects seen with amphetamines2. Modafinil is known to increase norepinephrine in hypothalamus, and may also have a slight role on cardiac α1-B receptors. Similarly noradrenaline4 may have played a role in the stimulation of cardiac alpha receptor signal transduction pathways, leading to resolution of a high grade AV block with armodafinil. While armodafinil is not typically used to manage arrythmias, it may be used in highly select cases.