Implantable cardioverter defibrillator utilization among device recipients presenting exclusively with syncope or near-syncope.
BACKGROUND
Implantable cardioverter defibrillators (ICDs) are occasionally used in presumed high-risk patients with electrocardiographically undocumented syncope, although the incidence of ventricular tachyarrhythmias in this population is not well defined.


RESULTS
We studied 33 consecutive patients receiving an ICD (67% nonthoracotomy and 70% tiered therapy) after electrophysiologic testing for unmonitored "syncope" (n = 29) or "near-syncope" (n = 4). Atherosclerotic heart disease was present in 24 (73%); mean left ventricular ejection fraction (LVEF) was 0.39 +/- 0.15; and sustained monomorphic ventricular tachycardia (SMVT) was inducible in 18 (55%). Over a median follow-up of 17 months (range 4 to 61), 12 patients (36%) received > or = 1 appropriate ICD discharge triggered by SMVT (cycle length 230 to 375 msec) in 10 and ventricular flutter or fibrillation in 2--without concomitant antiarrhythmic medication in 8 of 12 cases. Inducible SMVT and LVEF < or = 0.35 were statistically significant, independent predictors of an appropriate ICD discharge (P < 0.02 and P < 0.03, respectively). Estimated 1-year cumulative survival free of appropriate discharge was 34% versus 87%, respectively, in patients with versus without inducible SMVT (P < 0.02), and 18% versus 56%, respectively, in patients with LVEF < or = 0.35 versus LVEF > 0.35 (P < 0.03).


CONCLUSIONS
In this highly select, multicenter population of ICD recipients with electrocardiographically undocumented syncope, a substantial incidence of appropriate device discharges was observed, particularly in patients with inducible SMVT and LVEF < or = 0.35. These findings support the notion that, in patients with LV dysfunction and inducible SMVT, ventricular tachyarrhythmias are likely to account for episodes of syncope or near-syncope.
Militianu
A
A
The Arrhythmia Center/Sinai Hospital and St. John Hospital, Detroit, Michigan 48235, USA.
Salacata
A
A
Seibert
K
K
Kehoe
R
R
Baga
J J
JJ
Meissner
M D
MD
Pires
L A
LA
Schuger
C D
CD
Steinman
R T
RT
Mosteller
R D
RD
Palti
A J
AJ
David
J B
JB
Lessmeier
T J
TJ
Lehmann
M H
MH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003625:Data Collection; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation*; D004599:Electric Stimulation Therapy; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006334:Heart Function Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D016019:Survival Analysis; D013575:Syncope / Q000628:therapy*