Clinical predictors of antitachycardia pacing response in implantable cardioverter defibrillator patients.
BACKGROUND
Antitachycardia pacing (ATP) provides safe and painless termination of reentrant ventricular arrhythmias in patients with implantable cardioverter defibrillator (ICDs), improving their quality of life. Established predictors of ATP responsiveness are not well known; only longer ventricular tachycardia (VT) cycle length and higher ejection fraction have been found to predict ATP success.


OBJECTIVE
To investigate clinical and ECG predictors of ATP response in ICD patients with monomorphic VT.


METHODS
The ICD clinic database was searched for monomorphic VT events requiring ICD therapy in patients with ischemic or non-ischemic cardiomyopathy. Each patient's first ICD encounter for VT was assessed. Patient demographics, clinical characteristics, VT rate, and ATP responsiveness (always, sometimes, and never successful) were recorded. An ECG was analyzed for QRS morphology and duration. Data was assessed for predictors of ATP responsiveness.


RESULTS
In 527 patients, characteristics associated with always successful ATP included ACE-I/ARB therapy and slower VT rate (never successful ATP 197 ± 28 bpm, sometimes successful ATP 190 ± 27 bpm, always successful ATP 183 ± 22 bpm, P < .0001). Secondary prevention indication, amiodarone therapy, and longer QRS duration were associated with ATP failure. After multivariate analysis, only faster VT rate and amiodarone therapy were predictive of ATP failure.


CONCLUSIONS
Neither QRS morphology nor duration was predictive of ATP success. Slower VT rate was predictive of repeated ATP responsiveness. Amiodarone therapy, which is known to increase VT cycle length, interestingly was associated with ATP failure for unclear reasons. More individualized and possibly more aggressive ATP programming may be warranted in patients on amiodarone.
['Harrison|Joshua W|JW|', 'Manola|Akrivi|A|', 'Kalluri|Lakshmi K|LK|', 'Duvall|W Lane|WL|', 'Giedrimiene|Dalia|D|', 'Kluger|Jeffrey W|JW|']
D000368:Aged D000369:Aged, 80 and over D017147:Defibrillators, Implantable D004562:Electrocardiography D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D011237:Predictive Value of Tests D012189:Retrospective Studies D017180:Tachycardia, Ventricular
antitachycardia pacing implantable cardioverter defibrillator ventricular tachycardia