Outcomes
Outcomes included VA and all-cause mortality. Follow up for outcomes was
initiated from the index hospitalization, when ICD/CRTD was implanted,
until mortality or last documented visit to HF or device clinic. VA was
defined as any VA episode for which an appropriate ATP or shock therapy
was delivered by the ICR/CRTD device, as detected during device clinic
follow-up. Device clinics were routinely scheduled 1,3 and every 6
months after device implant. During clinic visit, all VA episodes were
retrieved from the device and any treatment (ATP, shock or both) was
documented. When multiple VAs occurred, the first one was considered for
study outcome. Devices were programmed in a ’primary prevention’ mode
(similar in all device companies), in accordance with the updated expert
consensus on optimal ICD programming (25), consisting of the following
detection zones and therapies: VF therapy zone > 200-220
bpm for 24-30 beats, treated via ATP during charge and thereafter device
shocks; VT2 therapy zone > 185 bpm for 30
beats or 12 sec duration (BSC devices), treated via ≥1 ATP burst and
thereafter device shocks; and a VT1 monitor zone
>160 bpm used for monitoring only. Mortality was determined
from the Israeli Ministry of the Interior records. The study was
approved by the local institutional review board.