Therapeutic Research

Abstract

67 year –old Japanese female with sarcoidosis and complete atrio –ventricular block status post ICD implantation had been followed by remote monitoring system（RMS） every week and at ICD clinic every four month. ICD（TELIGEN, Boston Scientific） was set at DDD 50/110. At ICD clinic she complained of faintness for a few seconds only after she ate food or kept a certain posture for a long time. RMS revealed no ventricular arrhythmia and showed good lead status with 1％ of atrial pacing and 90％ of ventricular pacing with frequent PVCs. Her 12 leads ECG showed atrial sensing followed by ventricular pacing without any problem, so we did not check ICD manually at clinic. Although her complaint was considered to be vasovagal or gastrointestinal, her gastrointestinal evaluation showed no abnormality. Four month later at ICD clinic she kept complaining of the same symptom and this time her ECG showed only one beat of atrial pacing after single PVC, which was not followed by any ventricular event. RMS this time again showed no ventricular arrhythmia and good lead status with 1 ％ of atrial pacing and 90％ of ventricular pacing and frequent PVCs. During manual ICD check, we made her drink water or change position to provoke the same symptom, which revealed no abnormality. When we started to check atrial lead pacing threshold, however, it revealed the markers of atrial pacing and ventricular sensing without any ventricular event. Because of atrial pacing spike, crosstalk inhibition happened and ventricular pacing was inhibited. Integrated bipolar lead used for a short female patient was suspected to be the cause of crosstalk inhibition. We lengthened ventricular blanking after atrial pacing from 65 ms to 85 Zms, changed the sensitivity of ventricle, decreased lower rate to prevent unnecessary atrial pacing, and decreased atrial output to eliminate crosstalk inhibition. After the adjustment, her symptom diminished. Although RMS is usually useful for the early detection of device trouble, this case had the opposite effect because of the omission of manual checking. Since this phenomenon was difficult to judge only by RMS, we should carefully listen to the patients and not to hesitate manual check even though RMS showed no abnormality.