Experience of ICD management at a UK center: cardiovascularly stable VT presentation predicts higher risk for appropriate ICD therapy.
BACKGROUND
It would be useful to identify patients at high risk of implantable cardioverter defibrillator (ICD) therapy via additional antiarrhythmic measures to minimize the morbidity of ICD therapies.


OBJECTIVE
We assessed baseline characteristics for predictors of device therapy in a general ICD population. We also compared the likelihood of therapy delivery by replacement ICDs implanted for battery depletion with the original implants.


METHODS
Clinical and ICD interrogation data from patients followed up at a UK center were analyzed looking for predictors of appropriate ICD therapy. Univariate and multivariate analysis was performed using Cox regression. We compared time to first appropriate therapy between first and second ICDs in patients who had undergone ICD replacement for battery depletion by log-rank testing.


RESULTS
One hundred and sixty-one patients were studied (129 men, age 65.7 +/- 12.9 years, follow-up 908 +/- 676 days). Appropriate therapy was delivered in 68 patients (42%). Univariate risk factors for appropriate ICD therapy were presentation with stable ventricular tachycardia (VT) (P = 0.0002), ischemic etiology (P = 0.03), tiered therapy programmed ICDs (P = 0.01), and beta-blocker use (P = 0.001). Stable VT and beta blocker use were independent predictors of ICD therapy on multivariate analysis. Thirty-three patients (20%) had at least one ICD replacement. Time to first appropriate therapy was no different between first and second ICD implants (P = 0.8).


CONCLUSIONS
Patients who present with cardiovascularly stable VT have a higher probability of receiving appropriate ICD therapy than those who do not. Following battery depletion of an original ICD, the replacement device is no less likely to administer therapy than the first.
Koa-Wing
Michael
M
Waller Cardiology Department, Imperial College and St. Mary's Hospital, Praed Street, London, United Kingdom. m.koawing@imperial.ac.uk
Wright
Ian
I
Peters
Nicholas S
NS
Davies
D Wyn
DW
Francis
Darrel P
DP
Kanagaratnam
Prapa
P
D000368:Aged; D002303:Cardiac Output, Low / Q000401:mortality* / Q000517:prevention & control*; D002304:Cardiac Pacing, Artificial / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D016019:Survival Analysis; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000401:mortality* / Q000517:prevention & control*; D006113:United Kingdom / Q000453:epidemiology