Electrical storm is an independent predictor of adverse long-term outcome in the era of implantable defibrillator therapy.
OBJECTIVE
Electrical storm (ES) is a life-threatening arrhythmia complication affecting patients treated with an implantable cardioverter defibrillator (ICD). Despite its increasing importance, existing data on prognosis and management of ICD patients affected by ES are limited and conflicting.


METHODS
We prospectively studied 169 consecutive patients receiving an ICD. Thirty-two patients presented with at least one episode of ES during the period of observation (33+/-26 months). ES patients were older (64+/-9 vs. 59+/-13 years, P=0.013) with more advanced congestive heart failure (CHF) but a similar incidence of an underlying organic heart disease.


RESULTS
Long-term total and cardiac mortality were both increased among ES patients. Seventeen of the 32 ES patients died as opposed to 19 of the 137 ICD patients without ES (53 vs. 14%, P<0.001). In multivariate Cox regression analysis adjusted for the main confounders, history of ES was significantly and independently associated with total and cardiac mortality (risk ratio (RR)=2.13, P=0.031 and RR=2.59, P=0.019, respectively).


CONCLUSIONS
ES is a relatively frequent complication affecting ICD patients treated for secondary prevention of sudden cardiac death (SCD). Although the acute management of this serious arrhythmia complication is usually successful, occurrence of ES is a strong independent predictor of poor outcome in ICD patients.
Gatzoulis
Konstantinos A
KA
First Cardiac Department, Hippokration General Hospital, University of Athens, Athens, Greece.
Andrikopoulos
George K
GK
Apostolopoulos
Theodoros
T
Sotiropoulos
Elias
E
Zervopoulos
George
G
Antoniou
John
J
Brili
Stella
S
Stefanadis
Christodoulos I
CI
D000368:Aged; D016009:Chi-Square Distribution; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004554:Electric Countershock; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D017180:Tachycardia, Ventricular / Q000503:physiopathology* / Q000628:therapy*