Therapeutic Research

Abstract

A 78–year –old woman was implanted with a pacemaker because of sick sinus syndrome after catheter ablation of paroxysmal atrial fibrillation. Initially it was considered only atrial pacing was needed to just sustain a narrow QRS. The pacing mode was changed from AAI to DDIR and antiarrhythmic drugs were prescribed for an atrial tachycardia occurring after four months. She was admitted to a nearby hospital for a heart failure exacerbation after 1 month. It was believed that mitral regurgitation （MR） caused by an increasing frequency of ventricular pacing had worsened. It was considered that the CRT–P upgrade performed at our hospital worsened the heart failure due to MR.Echocardiography confirmed that the MR had increased more during the ventricular paced rhythm than during the intrinsic QRS. At a later date in order to add a left ventricular lead, we changed the pacing mode for the CRT–P. The MR then decreased with the CRT–P, and made satisfactory progress. The change in the left ventricular contraction pattern associated with right ventricular pacing, was one factor that would not seem to have been predicted an increase in the MR.