968 LYME CARDITIS: COMPLETE AV DISSOCIATION PRESENTING AS DYSPNEA IN THE EMERGENCY DEPARTMENT


 
 
 Lyme carditis (LC), an early disseminated manifestation of Lyme disease, has important clinical implications for patients. High-degree atrioventricular block is the most common presentation of LC, and usually resolves with antibiotic therapy.
 
 
 
 A 31 years-old man without remote pathological history and cardiovascular risk factors presents for resting dyspnea. In the EKG, findings of paroxysms third-degree atrioventricular block with a junctional escape rhythm were found. No abnormalities found on the transthoracic echocardiogram. After the tick bite reported about 1-2 months earlier, given the suspicion of Lyme carditis, serology for Borrelia Burgdoferi was tested, which was then positive, and empirical antibiotic therapy has been initiated. During the EKG monitoring, paroxysms of second-degree type I atrioventricular block and first-degree AVB were relevated. In few days, we assisted to a complete retrieval of normal atrioventricular conduction. Therefore, a loop recorder was implanted, cardiac resonance was performed and then discharged. About 4 weeks later the patient performed a stress test on the cycloergometer to identify frequency-dependent atrioventricular blocks, which was then negative.
 
 
 
 The suspicion and the early diagnosis of Lyme carditis is fundamental to identify this unusual transient condition, thus preventing unnecessary PM implantation in otherwise healthy young individuals.
