title: Relation of ventricular tachycardia/fibrillation to beta-blocker dose maximization guided by pacing mode analysis in nonpacemaker-dependent patients with implantable cardioverter-defibrillator.
abstract: We hypothesized that uptitration of β blockade and adjustment of pacing parameters to achieve a prevalence of single chamber atrial inhibited rate-responsive (AAIR) pacing in patients with dual-chamber implantable cardioverter--defibrillators (ICDs) would result in maximization of β-blocker dosage and thus decrease appropriate ICD therapies. We included patients with ischemic or dilated cardiomyopathy and implanted ICDs without contraindications to β blockers and atrioventricular conduction disturbances. Two 6-month periods were compared: clinically guided phase (pacing function set at back-up dual-chamber rate-responsive pacing mode at a lower rate of about 40 beats/min) and pacing-guided phase, during which β-blocker dosage was titrated with a target of achieving >90% AAIR pacing (lower rate 60 beats/min). Sixty-one patients (64.2 ± 8.3 years old) were included. During the pacing-guided phase the target of ≥90% AAIR pacing was achieved in 80.3% of patients. Mean metoprolol dose during the clinically guided phase was 96.7 ± 29.4 versus 127.0 ± 39.6 mg/day in the pacing-guided phase (p <0.001). Appropriate ICD therapies were recorded in 35 patients (57.4%) during the clinically guided phase versus 20 (32.8%) during the pacing-guided phase (p <0.001; 1.15 and 0.48 appropriate ICD therapies per patient, respectively, p <0.001). In multivariate analysis, AAIR pacing and β-blocker dose were inversely related to appropriate ICD therapies. In conclusion, a pacing-guided approach for maximizing β-blocker doses guided by maximizing AAIR pacing in patients with ICDs may be beneficial compared to the conventional strategy. This pacing-guided approach led to higher daily β-blocker doses, which were correlated to fewer appropriate ICD therapies.
authors.affiliation: Department of Cardiology, Athens General Hospital G. Gennimatas, Athens, Greece.
authors.forename: Spyridon
authors.initials: S
authors.lastname: Deftereos
authors.forename: Georgios
authors.initials: G
authors.lastname: Giannopoulos
authors.forename: Charalampos
authors.initials: C
authors.lastname: Kossyvakis
authors.forename: Andreas
authors.initials: A
authors.lastname: Kaoukis
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Raisakis
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Panagopoulou
authors.forename: Olga
authors.initials: O
authors.lastname: Ntzouvara
authors.forename: Anastasia
authors.initials: A
authors.lastname: Perpinia
authors.forename: Ilias
authors.initials: I
authors.lastname: Rentoukas
authors.forename: Vlasios
authors.initials: V
authors.lastname: Pyrgakis
authors.forename: Antonios S
authors.initials: AS
authors.lastname: Manolis
authors.forename: Christodoulos
authors.initials: C
authors.lastname: Stefanadis
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage*; D000368:Aged; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000008:administration & dosage; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000188:drug therapy / Q000503:physiopathology* / Q000601:surgery
chemical_list: D000319:Adrenergic beta-Antagonists; D008790:Metoprolol