title: Clinical efficacy of ivabradine in patients with inappropriate sinus tachycardia: a prospective, randomized, placebo-controlled, double-blind, crossover evaluation.
abstract: OBJECTIVE
  The purpose of this study was to investigate the role of ivabradine in the treatment of symptomatic inappropriate sinus tachycardia using a double-blind, placebo-controlled, crossover design.
  
  
  BACKGROUND
  Due to its I(f) blocking properties, ivabradine can selectively attenuate the high discharge rate from sinus node cells, causing inappropriate sinus tachycardia.
  
  
  METHODS
  Twenty-one patients were randomized to receive placebo (n=10) or ivabradine 5 mg twice daily (n=11) for 6 weeks. After a washout period, patients crossed over for an additional 6 weeks. Each patient underwent symptom evaluation and heart rate assessment at the start and finish of each phase.
  
  
  RESULTS
  After taking ivabradine, patients reported elimination of >70% of symptoms (relative risk: 0.25; 95% CI: 0.18 to 0.34; p<0.001), with 47% of them experiencing complete elimination. These effects were associated with a significant reduction of heart rate at rest (from 88±11 beats/min to 76±11 beats/min, p=0.011), on standing (from 108±12 beats/min to 92±11 beats/min, p<0.0001), during 24 h (from 88±5 beats/min to 77±9 beats/min, p=0.001), and during effort (from 176±17 beats/min to 158±16 beats/min, p=0.001). Ivabradine administration was also associated with a significant increase in exercise performance. No cardiovascular side effects were observed in any patients while taking ivabradine.
  
  
  CONCLUSIONS
  In this cohort, ivabradine significantly improved symptoms associated with inappropriate sinus tachycardia and completely eliminated them in approximately half of the patients. These findings suggest that ivabradine may be an important agent for improving symptoms in patients with inappropriate sinus tachycardia.
authors.affiliation: Arrhythmias and Electrophysiology Center, I.R.C.C.S. Policlinico San Donato, Milan, Italy. rcappato@libero.it
authors.forename: Riccardo
authors.initials: R
authors.lastname: Cappato
authors.forename: Serenella
authors.initials: S
authors.lastname: Castelvecchio
authors.forename: Cristian
authors.initials: C
authors.lastname: Ricci
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Bianco
authors.forename: Laura
authors.initials: L
authors.lastname: Vitali-Serdoz
authors.forename: Tomaso
authors.initials: T
authors.lastname: Gnecchi-Ruscone
authors.forename: Mario
authors.initials: M
authors.lastname: Pittalis
authors.forename: Luigi
authors.initials: L
authors.lastname: De Ambroggi
authors.forename: Mirko
authors.initials: M
authors.lastname: Baruscotti
authors.forename: Maddalena
authors.initials: M
authors.lastname: Gaeta
authors.forename: Francesco
authors.initials: F
authors.lastname: Furlanello
authors.forename: Dario
authors.initials: D
authors.lastname: Di Francesco
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Lupo
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001552:Benzazepines / Q000008:administration & dosage*; D018592:Cross-Over Studies; D054815:Cyclic Nucleotide-Gated Cation Channels; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D000077550:Ivabradine; D008297:Male; D011446:Prospective Studies; D012849:Sinoatrial Node / Q000187:drug effects / Q000503:physiopathology*; D013616:Tachycardia, Sinus / Q000188:drug therapy* / Q000503:physiopathology; D016896:Treatment Outcome
chemical_list: D001552:Benzazepines; D054815:Cyclic Nucleotide-Gated Cation Channels; D000077550:Ivabradine