Device complications and inappropriate implantable cardioverter defibrillator shocks in patients with hypertrophic cardiomyopathy.
BACKGROUND
Although the benefit of implantable cardioverter defibrillator (ICD) therapy in patients with hypertrophic cardiomyopathy (HCM) at risk for sudden cardiac arrest is well established, there may be a higher risk for device complications and inappropriate shocks.


OBJECTIVE
To determine the incidence of inappropriate ICD shocks and device complications in HCM patients and the impact of young age at ICD implant and atrial fibrillation.


METHODS
HCM patients who underwent ICD implantation between January 1988 and December 2005 were included. The frequency of device complications, including pneumothorax, pericardial effusion, haematoma, lead revisions, infection and rate of inappropriate shocks, was determined. ICD shocks were characterised as inappropriate if triggered by sinus tachycardia, atrial fibrillation or device malfunction.


RESULTS
A total of 181 patients were included (mean age 44 (SD 17) years; 62% males). During a mean follow-up of 59 (42) months (4.92 years; 830.75 patient-years), 65 patients (36%) had a total of 88 device complications, including 42 (23%) patients with inappropriate shocks. The rate of inappropriate shocks was 5.3% per year (vs 4% risk of appropriate shocks), and the likelihood of inappropriate ICD shocks per 100 patient-years was 5.1. Younger age and atrial fibrillation were associated with an increased risk of inappropriate ICD discharges.


CONCLUSIONS
The rate of inappropriate ICD shocks and frequency of device complications in HCM patients are not insignificant and are most common in younger patients and those with atrial fibrillation. Inappropriate ICD shocks are the most common device complication and should be accounted for when counselling high-risk HCM patients for ICD implantation.
Lin
G
G
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota 55905, USA.
Nishimura
R A
RA
Gersh
B J
BJ
Phil
D
D
Ommen
S R
SR
Ackerman
M J
MJ
Brady
P A
PA
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000628:therapy*; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications* / Q000401:mortality; D002648:Child; D002675:Child, Preschool; D002983:Clinical Competence; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D012189:Retrospective Studies; D018570:Risk Assessment; D055815:Young Adult