Impact of pacing and high-pass filter settings on ventricular bipolar electrograms in implantable cardioverter defibrillator systems: Implication of predictors for inappropriate therapy caused by oversensing of repolarization electrograms

Background: Predictors of T wave oversensing with implantable cardioverter-defibrillator (ICD) systems remains to be clarified. Methods and Results: Thirteen consecutive patients who underwent ICD implantations were included. The depolarization (R) and repolarization (T) of bipolar electrograms during baseline, AAI and DDD modes, and an isoproterenol (ISO) infusion were evaluated. The R wave amplitude during DDD was significantly lower as compared to that during the other conditions in all high-pass filter settings. In contrast, there was no significant difference in the T wave amplitude during the DDD as compared to the other conditions. With the DDD, there was a significantly higher incidence of a T/R ratio of greater than 0.25 as compared to that with the other conditions. T wave amplitude in Brugada syndrome was significantly higher than that in non-Brugada syndrome. The existence of Brugada syndrome and T/R ratio during the AAI with a high-pass filter setting of 10/20 Hz was an excellent predictor of T wave oversensing in the follow-up period. Conclusions: DDD had a significant impact on the R wave amplitude reduction and the T/R ratio during AAI can be predictors of T wave oversensing. These findings have important implications for inappropriate shocks due to T wave oversensing.