Outcome in patients with an ICD incorporating cardiac resynchronisation therapy: differences between primary and secondary prophylaxis.
BACKGROUND
The incidence of ventricular tachyarrhythmias in ICD patients with cardiac resynchronisation therapy (CRT-D) is not well studied.


OBJECTIVE
To analyse event free survival in CRT-D patients with a primary or a secondary prophylactic ICD indication.


METHODS
Prospective, single centre. Eighty-six patients, 44% with a primary prophylactic indication. Actuarial event-free rates for mortality and arrhythmias were calculated.


RESULTS
Baseline clinical characteristics were not significantly different between primary and secondary prophylaxis. Primary prophylaxis patients were more likely to be in NYHA class III. Over 21 months, 724 ventricular events with therapy occurred in 36 patients (42%). The actuarial event-free rates, at 1 and 3 years, from appropriate ICD therapy were higher (P<0.001) for primary (79.0% and 67.8%) than for secondary prophylaxis (45.6% and 27.0%). Appropriate ICD therapy occurred more in NYHA class II compared to class III (P=0.016). Underlying disease (ischemic versus non-ischemic) and functional class did not play a role in multivariate analysis.


CONCLUSIONS
Important arrhythmic events in patients with heart failure, and CRT-D occur at a very high rate when the indication is secondary prophylaxis. Patients with primary prophylaxis have an annual event rate of 10%, even though they tend to have a worse heart failure class.
Theuns
Dominic A M J
DA
Department of Cardiology, Erasmus MC, Rotterdam, The Netherlands. d.theuns@erasmusmc.nl
Thornton
Andrew S
AS
Klootwijk
A Peter J
AP
Scholten
Marcoen F
MF
Vantrimpont
Pascal J M J
PJ
Balk
Aggie H M M
AH
Jordaens
Luc J
LJ
D000368:Aged; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D005260:Female; D006329:Heart Conduction System; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011322:Primary Prevention / Q000379:methods*; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D012008:Recurrence; D018570:Risk Assessment; D012720:Severity of Illness Index; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000401:mortality* / Q000517:prevention & control* / Q000628:therapy; D013997:Time Factors; D016896:Treatment Outcome