Does the rate of inappropriate therapy differ in implantable cardioverter–defibrillators from different manufacturers?

Objective We conducted this study to compare the rate of ≥1 inappropriate therapy between ICDs from two manufacturers which use different discriminatory protocols. Method One hundred sixty two patients (mean age 58 ± 13 years, 126 male) who received ICDs between January 2001 and 2005 were included in the study. Clinical, electrocardiographic, and ICD stored data and electrograms were collected and analyzed. Immediately after implantation all the detection and discrimination criteria were activated with the nominal values in order to compare the two discriminatory protocols under the default manufacturer’s settings. Results During the follow up period of 14.3 ± 10 months, 49 (30%) patients received ≥1 inappropriate ICD therapy. The rate of ≥1 inappropriate ICD therapy in manufacturer A and B ICDs was 26% (n = 29) and 41% (n = 20), respectively. Comparing the rate of ≥1 inappropriate ICD therapy between the two groups by Kaplan–Meier analysis and the log rank test resulted in P = 0.04. Conclusion Having all discriminatory variables activated with the nominal values, discriminatory performance differs between the two manufacturers. Further larger-scale studies are warranted to prospectively compare the performance of various available ICDs’ discriminatory protocols, and define the optimum combination of discriminators in each ICD to decrease the rate of inappropriate therapy.