16-60: A New Approach to analyze ICD therapy Efficacy. Single-Centre Experience of Discovery™ Link TachyMed (Medtronic, USA)

Abstract

The goal: to analyze an ICD therapy efficacy using an application Discovery™ Link TachyMed (Medtronic, USA). Materials and Methods: We enrolled 154 patients connected to the remote monitoring network Carelink (Medtronic, USA) who had an implanted dual (46) and triple chamber ICDs (108). Device programming parameters and intracardiac electrograms were studied. To carry out quantitative analysis of ICD therapy efficacy an application Discovery™ Link TachyMed was used. Statistical data are presented as Median (IQR 25%; 75%). Results: A dual zone ICD programming is frequently used (68%) in our center. A choice of single or triple ICD configuration is made rarely (in 22% and 10%, respectively). A zone of slow VT (sVT) corresponds to 179 (168; 182) bpm. A zone of fast VT (fVT) is programed in the range over 182 (176; 240) bpm and a zone of VF is detected in case of tachycardia equal or above 200 (188; 200) bpm. In most cases standard manufacturer discrimination algorithm is used. 690 episodes of VT were analyzed: 43 in VF zone (11 patients), 565 (12 patients) and 82 episodes (6 patients) in sVT and fVT zones respectively. ATP strategy was used in 78% cases (538 VT events). It was effective in 85% of initial VTs. These episodes were frequently referred to sVT and fVT. In 11% of analyzed VTs (76 events) a sinus rhythm was restored after ICD shock. It was usually due to VF events detection (75%). The vast majority of ICD shocks were delivered with submaximal values of energy (less than 35 Joules). Other episodes stopped spontaneously. Inappropriate shocks were delivered in 8 patients: in 5 of them due to atrial flutter with 1:1 conduction, in 2 patients because of atrial fibrillation with fast ventricular rate. In 1 case an electrical noise detected by a defibrillation lead was a reason for an appropriate shock. Conclusions: A low percent of inappropriate shocks was registered (7%). In most cases VT episodes were stopped by ATP, in cases of ICD shocks low values of energy were effective. Remote monitoring system provides facilities for early identification of the reasons of inappropriate ICD therapy. Discovery™ Link TachyMed application allows to carry out a quantitative analysis of ICD therapy efficacy which is especially necessary in centers with a high volume of ICD implantations.