Implantable cardioverter-defibrillators (ICDs) are now the standard of care in primary and secondary prevention of malignant arrhythmias, however with their increasing use it has been noted that ICD therapies – both appropriate and inappropriate – are associated with an increased risk of death and worsening of heart failure. The recent Multicenter Automatic Defibrillator Implantation Trial to Reduce Inappropriate Therapy (MADIT-RIT) found that for primary prevention, prolonging the arrhythmia detection interval or setting a high cut-off rate reduced inappropriate therapies.

The purpose of the ADVANCE III (Avoid Delivering Therapies for Nonsustained Arrhythmias in ICD Patients III) trial was to assess whether increasing the number of detection intervals was beneficial in any type of ICD with the capability of delivering antitachycardia pacing (ATP) during capacitor charge, in this case among patients with both primary and secondary indications for an ICD implant. Specifically the trial looked at whether using 30 of 40 intervals to detect ventricular arrythmias, as opposed to standard detection with 18 of 24 intervals, could reduce ATP and shock delivery during spontaneous fast VT episodes.

1902 primary and secondary prevention patients with ischaemic and nonischaemic indications for first ICD implantation were enrolled, and randomised in a single-blind fashion to programming with long- (30 of 40) or standard-detection (18 of 24) intervals. The main outcome measure was the total number of ATPs and shocks delivered for all episodes; inappropriate shocks, mortality, and syncopal rates were secondary outcomes.

Over a median follow-up of 12 months, patients in the long-detection group had 346 delivered therapies compared to 557 in the standard-detection group (P<.001). The long- vs. standard-detection group also had fewer ATPs (23 per 100 person-years vs. 37 per 100 person-years; P<.001), fewer shocks (19 vs. 30; P=.06), and a reduction in the first occurrence of inappropriate shocks. However, mortality (P=.50) and arrhythmic syncope rates (P=.22) did not differ significantly between groups.

Conclusions:

Among patients undergoing first ICD implantation, the use of long- vs standard-detection intervals resulted in lower rates of ATP and shocks. This programming strategy may therefore be a useful alternative approach for ICD recipients.

• Gasparini M, Proclemer A, Klersy C et al. Effect of Long-Detection Interval vs Standard-Detection Interval for Implantable Cardioverter-Defibrillators on Antitachycardia Pacing and Shock Delivery. The ADVANCE III Randomized Clinical Trial. JAMA 2013;309:1903-1911.