Conduction and rhythm disturbances following Direct current cardioversion

Introduction: Atrial fibrillation (AF) is one of the most common arrhythmias with life threatening complications. Direct-current cardioversion (DCCV) constitute an integral part of AF management. The study aims to assess the frequency of rhythm and conduction disturbances after DCCV and predict risk factors for post cardioversion cardiac arrhythmia

Methods: This is a single-center prospective study including 56 patients who underwent DCCV for AF or atrial flutter (AFL). Electrocardiograms before the procedure, immediately after and 24 hours later, were analyzed

Results: A total of 56 patients were assessed. All patients had AF/AFL for more than 72 hours. 11 patients have previously implanted pacemaker or ICD. Patients demographics and medical history are presented in table 1.

96% of patients has cardiac arrhythmia following DCCV, most commonly AV block mainly first degree AV block (32%) and sinus bradycardia (35%), but none required urgent medical therapy or pacing .second and third degree AV block were not recorded. Among patients with sinus bradycardia and AV block 65 % received beta blockers as compared to 35% who didn`t (p=0.197). 10 patients (17.8%) had QTc prolongation ≥480 ms following DC. 2 patients (3%) developed new RBBB. APCs (18%) ,VPCs (16%) and NSVT (3/6%) were also recorded. Two patients had Ventricular tachycardia requiring intervention and special observation following DCCV. One with HOCM and implanted ICD requiring anti-tachycardia pacing (ATP) to end the VT. A second patient with Torsades de pointes due to QT prolongation was transformed to the Intensive cardiac care unit for observation.

Conclusion: DCCV is a safe procedure, but relatively high percentage of patient having asymptomatic bradycardia following CV especially in patients with beta-blockers. QTc prolongation after DC is not infrequent , especially on antiarrhythmic drugs, but can be fatal and needs to be closely monitored.