Initial experience with a new discrimination algorithm in dual chamber ICDs

Inappropriate therapy, due to poor discrimination of SVT and VT remains a major problem in patients with an ICD. Theoretically, the addition of atrial sensing in detection algorithms should improve this differentiation. Twenty-six patients received a nonthoracotomy ICD system (Phylax AV, Biotronik, Germany) with a new tachycardia discrimination algorithm, SMART Detection(TM). During a mean follow-up of 8 months, a total number of 139 events with stored electrograms were recorded in 12/26 patients. The final diagnosis was VF/VT (n=89), SVT (n=26), other ventricular arrhythmia (n=3) and T wave oversensing (n=21). In 6 episodes a dual tachycardia was present. Considering SVT episodes, inappropriate therapy occurred in 5 cases. With the SMART Detection(TM) algorithm, discrimination of VT from SVT achieved a sensitivity of 100%, with an accuracy of 95,6% for all ventricular arrhythmias