Can AV dissociation masquerade as junctional rhythm?

Abstract

CAN AV DISSOCIATION MASQUERADE AS JUNCTIONAL RHYTHM L. R. is a 76-year-old Caucasian male with CAD s/p CABG in 1977 and 2004, atrial fibrillation (AF), s/p AF ablation, in 2002. Recurrence of AF prompted a failed direct current cardioversion and subsequent reablation of the pulmonary veins. The postoperative course was complicated by left femoral and right neck hematoma. This prompted hospital readmission 5 days post-procedure. The night of the admission patient awoke with palpitations and the electrocardiogram showed AF at a rate of 90 to 110 bpm with stable blood pressures. The patient was given Metoprolol 5 mg IV, subsequently started on a BID course of Metoprolol 25 mg PO, and IV Amiodarone was also initiated as an anti-arrhythmic. The patient converted to sinus rhythm but had postconversion pauses up to 6.8 seconds, followed by junctional bradycardia (Figure 1). Not long after the conversion, the patient became hypotensive with SBP in the70s and developed shortness of breath, nausea, and diaphoresis. IV Amiodarone was immediately discontinued and the patient was given 1/2-amp of Atropine, with noted improvement of the heart rate into the 40s.