Clinical predictors of appropriate implantable-cardioverter defibrillator discharge.

BACKGROUND: The implantable cardioverter-defibrillator (ICD) is the mainstay of treatment for ventricular tachyarrhythmias due to its impact on mortality. ICD discharges may be appropriate or inappropriate, and identification of patients at risk for ICD discharge is essential. We sought to determine the predictors of appropriate ICD discharge.
METHODS: We analyzed data from 591 ICD recipients (mean age 67.9 +/- 13.0 years; 474 men; mean follow-up 10.9 +/- 13.8 months). The association between ICD discharges and multiple clinical variables, including age, gender, hypertension, diabetes, coronary artery bypass graft (CABG) surgery, syncope, atrial fibrillation (AF), prior coronary intervention, left ventricular ejection fraction (LVEF), left ventricular end diastolic dimension, left ventricular end systolic dimension (LVESD), and ambient drug therapy was examined.
RESULTS: The rates of appropriate or inappropriate discharges, delivered to 155 patients, were 0.49 per follow-up year (F/Y). The median time-to-first appropriate discharge was 3.4 years. Among the discharges delivered, 97(63%) were appropriate and 58(37%) were inappropriate. Risk factors associated with a trend toward earlier appropriate discharges included age </= 65 years, and diuretic and digitalis use. By multiple variable analysis, no history of CABG and an enlarged LVESD were independent predictors of earlier appropriate ICD discharge.
CONCLUSIONS: Patients who did not have CABG revascularization were 2.8-fold more likely than those who underwent CABG, and patients with enlarged LVESD were 2.5-fold more likely than those with normal LVESD to receive appropriate ICD discharges. These patients deserve special vigilance and management in order to prevent the occurrence of ventricular tachyarrhythmias triggering ICD discharges.