Electrophysiologic manifestations of ventricular tachyarrhythmias provoking appropriate defibrillator interventions in high-risk patients with hypertrophic cardiomyopathy.
BACKGROUND
Our objective was to determine features of ventricular tachyarrhythmias triggering appropriate implantable cardioverter-defibrillator (ICD) interventions in hypertrophic cardiomyopathy (HCM).


RESULTS
The study cohort was 68 high-risk HCM patients who received ICDs for primary sudden cardiac death prevention from 1995 to 2003. All episodes of sustained ventricular tachyarrhythmias identified by stored intracardiac electrograms were analyzed. Nine patients had 51 episodes of sustained ventricular tachyarrhythmic events that required device therapy (mean follow-up, 3.4 +/- 2.2 years; cumulative event rate, 3.2% per year): five had 47 episodes of monomorphic ventricular tachycardia (VT); four each had one episode of ventricular fibrillation (VF). Sinus tachycardia or atrial fibrillation was the initiating rhythm in five of nine patients and in 43 of 51 episodes of events. Of the 17 episodes of monomorphic VT detected in the VT zone, 16 (94%) were terminated by antitachycardia pacing. Thirty episodes of monomorphic VT were detected in the VF zone and were terminated by defibrillation.


CONCLUSIONS
Sustained monomorphic VT is common in a high-risk cohort with HCM. Sinus tachycardia is often the initiating rhythm, suggesting that high sympathetic drive may be proarrhythmic when a susceptible substrate is present. Antitachycardia pacing is highly effective in terminating VT in this patient population.
Cha
Yong-Mei
YM
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA.
Gersh
Bernard J
BJ
Maron
Barry J
BJ
Boriani
Giuseppe
G
Spirito
Paolo
P
Hodge
David O
DO
Weivoda
Peggy L
PL
Trusty
Jane M
JM
Friedman
Paul A
PA
Hammill
Stephen C
SC
Rea
Robert F
RF
Shen
Win-Kuang
WK
D000293:Adolescent; D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000401:mortality* / Q000628:therapy*; D002648:Child; D015331:Cohort Studies; D015897:Comorbidity; D004554:Electric Countershock / Q000706:statistics & numerical data*; D004562:Electrocardiography / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000401:mortality* / Q000517:prevention & control*; D016896:Treatment Outcome