Slow ventricular tachycardia in patients with implantable cardioverter defibrillator

Abstract

Objective This study aims to assess the incidence of slow ventricular tachycardia(VT)and its treatment strategies in implantable cardioverter defibrillator(ICD)patients. Methods All 353 patients with including single and dual-chamber ICD or cardiac resyncronization therapy defibrillator(CRT-D)were enrolled in this study in Zhejiang Greentown Cardiovascular Hospital from January 2008 to December 2014.Patients had a 3-zone detection configuration: monitoring non treatment(ventricular rate 120 to 180 bpm), anti-tachyarrhythmia pacing(ATP)-low energy shock zone(ventricular rate 180 to 200 bpm), and a ventricular fibrillation zone.When VT burden was more than 10% and the ventricular rate was less than 160 bpm it needed to optimize the parameters to treat the slow VT.Patients were divided into group A ATP-low energy cardioverter groups(ATP1time-5 J-10 J-maximum energy shock); group B ATP-high energy(ATP 3 times-20 J-the largest energy). Results VT occurred in 102(29%)patients, slow VT occurred in 46(13.1%)patients.Parameters optimization was carried for slow VTs in 27(7.6%)patients.One time ATP therapy success rate was 67% in group A, ATP+ 5 J success rate was 79%, ATP+ 5 J+ 10 J was 92%.Group B 3 times ATP success rate was 71%, ATP 3 times+ 20 J was 89%. Conclusion The slow VT had a high incidence in patients with ICD, especially in patients who took up large doses of amiodarone and β receptor blockers.For patients with heavier burden of slow VTs, ATP and small energy electric shock therapy may have greater benefit. Key words: Implantable cardioverter defibrillator; Ventricular tachycardia