Inappropriate implantable cardioverter-defibrillator (ICD) therapies are associated with adverse outcomes. The aim of this study is to determine the frequency and cause of inappropriate therapies in patients under the care of Royal Papworth Hospital NHS Foundation Trust, UK.
All patients with ICDs on remote follow-up between January and December 2021 who experienced therapy were included in this study. Device therapies and arrhythmias were compared by device type and manufacturer. Device settings were compared to the 2019 Heart Rhythm Society consensus on ICD programming.
Single-chamber ICDs and CRT-Ds administered more inappropriate ATP (p <0.001), but not inappropriate shock (p=0.155) therapy, compared with dual-chamber ICDs. Atrial fibrillation and atrial flutter caused more inappropriate therapy (p<0.001) in single-chamber ICDs, and supraventricular tachycardias (SVT) in dual-chamber ICDs and CRT-Ds. Boston Scientific administered less inappropriate ATP (p<0.001) and shock (p<0.001) therapy, compared with other manufacturers. A significant (p<0.001) cause for inappropriate therapy from Boston Scientist was SVT and atrial flutter from Medtronic. These differences were caused by a small group of patients that experienced numerous therapies; 85.4% of episodes in which patients experienced inappropriate therapy did not follow guidelines for ICD programming.
Dual-chamber ICDs and Boston Scientific had a lower rate of inappropriate therapies, likely a result of the presence of an atrial lead and SVT discriminator limitations. Recommended programming and more robust SVT discrimination, particularly in the VF zone (which is only currently available in Medtronic), could reduce the number of inappropriate therapies. ❑
