Evaluation of defibrillation safety and shock reduction in implantable cardioverter-defibrillator patients with increased time to detection: A randomized SANKS study.
BACKGROUND
The need for ways to minimize the number of implantable cardioverter-defibrillator (ICD) shocks is increasing owing to the risk of its adverse effects on life expectancy. Studies have shown that a longer detection time for ventricular tachyarrhythmia reduces the safety of therapies, in terms of syncope and mortality, but not substantially in terms of the success rate. We aimed to evaluate the effects of increased number of intervals to detect (NID) VF on the safety of ICD shock therapy and on the reduction of inappropriate shocks.


METHODS
The present study was a prospective, multicenter, randomized, crossover study. Randomized VF induction testing with NID 18/24 or 30/40 was performed to compare the success rate of defibrillation with a 25-J shock and the time to detection. Inappropriate shock episodes were simulated retrospectively to evaluate a possibility of episodes avoidable at NID 24/32 and 30/40.


RESULTS
Thirty-one consecutive patients implanted with an ICD or cardiac resynchronization therapy-defibrillator (CRT-D) were enrolled in this study. The success rate of defibrillation was 100% in both NID groups at the first shock. The time from VF induction to detection showed a significant increase in the NID 30/40 group (6.16±1.29 s vs. 9.00±1.31 s, p<0.001). Among the 120 patients implanted with an ICD or CRT-D, 10 experienced 32 inappropriate shock episodes. The inappropriate shock reduction rate was 53.1% and 62.5% with NID 24/32 and 30/40, respectively.


CONCLUSIONS
The findings of this SANKS study suggest that VF NID 30/40 does not compromise the safety of ICD shock therapy, while decreasing the number of inappropriate shocks.
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Mahito
M
Noro
Biomedical Information Technology Laboratory, The University of Aizu, Japan.
Xin
X
Zhu
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Takahito
T
Takagi
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Naohiko
N
Sahara
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Yuriko
Y
Narabayashi
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Hikari
H
Hashimoto
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Naoshi
N
Ito
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Yoshinari
Y
Enomoto
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Shingo
S
Kujime
Division of Cardiovascular Medicine, Saiseikai Yokohamashi Tobu Hospital, Japan.
Tuyoshi
T
Sakai
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Takao
T
Sakata
Division of Cardiovascular Medicine, Tokyo Metropolitan Hospital, Japan.
Noriko
N
Matushita
Division of Cardiovascular Medicine, Tokyo Metropolitan Hospital, Japan.
Seiji
S
Fukamizu
Division of Cardiovascular Medicine, Toho University Oomori Medical Center, Japan.
Yoshifumi
Y
Okano
Medtronic Japan, Japan.
Yoshiaki
Y
Anami
Medtronic Japan, Japan.
Tomoyuki
T
Tejima
Medtronic Japan, Japan.
Kouji
K
Kuroiwa
Division of Cardiovascular Medicine, Toho University Oomori Medical Center, Japan.
Takanori
T
Ikeda
Division of Cardiovascular Medicine, Tokyo Metropolitan Hospital, Japan.
Harumizu
H
Sakurada
Division of Cardiovascular Medicine, Toho University Ohashi Medical Center, 2-17-6 Ohashi, Meguroku, Tokyo 153-8515, Japan.
Kaoru
K
Sugi
Detection duration; ICD; Shock therapy; Undersense; Ventricular fibrillation