CASE PRESENTATION
A 38-year-old woman was referred to our institution due to skipped beats and general fatigue. Atrial bigeminy was recorded on a surface electrocardiogram (Fig. 1). Although the detailed morphology of premature atrial contractions (PACs) was difficult to discern due to its overlap with T waves, positive P waves in inferior leads and lead V1 suggested that PACs were originated from the left atrium close to the right superior pulmonary vein (PV).1 In a 24-hour Holter electrocardiogram, premature atrial contractions (PACs) occurred at a frequency of 30,880 beats per day. Although 1.25 mg of bisoprolol reduced the PAC burden, it had to be discontinued due to sinus bradycardia. Given the severity of her symptoms, we decided to perform catheter ablation for PACs. The activation map of PACs was created on a high-density mapping system (CARTO 3 mapping system, Biosense-Webster, Inc., Diamond Bar, CA). After transeptal puncture, sequential contact mapping of the left atrium was performed using a multispline mapping catheter (Pentaray; Biosense Webster, Inc.). The activation map showed a centrifugal activation with a widespread breakthrough on the anterior wall (Fig. 2A). Local potentials recorded in the earliest activation site preceded the distal coronary sinus potential, which served as a reference, by 110 ms (Fig. 2B). In contrast, the local potentials recorded in the right pulmonary vein were only 10 ms earlier than the reference (Fig. 2C). Where is the origin of the PACs? What is the optimal ablation strategy for this case?