(HealthDay News) – For patients receiving an implantable cardioverter-defibrillator (ICD), using 30 of 40 intervals to detect ventricular arrhythmias (long detection) during spontaneous fast ventricular arrhythmia episodes is associated with a reduced rate of antitachycardia pacing (ATP), shocks, and inappropriate shocks compared with the standard 18 of 24 intervals, according to a study published in the May 7 issue of the Journal of the American Medical Association.

Maurizio Gasparini, MD, from the Humanitas Clinical and Research Center in Rozzano, Italy, and colleagues examined whether using more intervals to detect ventricular tachyarrhythmias is associated with reducing unnecessary ICD therapies in a single-blind study involving 1,902 primary and secondary prevention patients undergoing first ICD implant. Patients were randomly allocated to long- or standard-detection intervals (948 and 954 patients, respectively).

During a median follow-up of 12 months, the researchers found that patients in the long-detection group had 346 delivered therapies vs. 557 in the standard-detection group (42 vs. 67 therapies per 100 person-years; incidence rate ratio [IRR], 0.63). The total number of ATPs was 23 per 100 person-years in the long-detection group compared with 37 ATPs in the standard-detection group (IRR, 0.58), and the number of shocks was 19 per 100 person-years in the long-detection group vs. 30 in the standard-detection group (IRR, 0.77; P=0.06). There was also a significant reduction in the incidence of inappropriate shocks in the long- vs. standard-detection group (5.1 vs. 11.6 per 100 person-years; IRR, 0.55).

“Among patients receiving an ICD, the use of a long- vs. standard-detection interval resulted in a lower rate of ATP and shocks, and inappropriate shocks,” the authors write. “This programming strategy may be an appropriate alternative.”

Several authors disclosed financial ties to medical device companies, including Medtronic, which funded the study.

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