title: Effects of sinus rhythm maintenance on left heart function after electrical cardioversion of atrial fibrillation: implications for tachycardia-induced cardiomyopathy.
abstract: BACKGROUND
  The role of tachycardia-induced cardiomyopathy vs tachycardia-related short diastolic filling period and reduced atrial contraction in decline of left ventricular ejection fraction (LVEF) in atrial fibrillation (AF) is uncertain. We aimed to characterize left heart changes over time in patients with AF who undergo electrical cardioversion (ECV).
  
  
  METHODS
  Consecutive AF patients who were to undergo ECV were enrolled. Patients with unstable or acute heart failure, severe valvular diseases, recent open-heart surgery, major disorders, or an unsuccessful ECV were excluded. Transthoracic echocardiography, including 3-dimensional left atrial and ventricular volume acquisitions, was performed 1-2 hours before and after ECV, and 4-6 weeks later.
  
  
  RESULTS
  In 73 patients (77% male, 66 ± 11 years), ECV resulted in an immediate increase in LVEF (from 43 [interquartile range (IQR), 33-50%] to 48 [IQR, 40-53%]; P < 0.0001). Four to 6 weeks after ECV, ejection fraction increased further in patients who remained in sinus rhythm (SR) (n = 55) to 55 (IQR, 44-62)%; P < 0.001. In patients with AF relapse, LVEF returned to values comparable to pre-ECV (n = 18) (44 [IQR, 32-51]%; P = 0.03). The atrial emptying fraction did not significantly change immediately after ECV (n = 69; from 20 [IQR, 13-25]% to 20 [IQR, 15-28]%; P = 0.14). Only patients who remained in SR showed an increase in atrial emptying fraction after 4-6 weeks (n = 51; to 37 [IQR, 26-48]%; P < 0.0001 vs post-ECV).
  
  
  CONCLUSIONS
  Immediate improvement in LVEF after ECV explains approximately 50% of total LVEF increase over time. However, in SR, LVEF, and atrial function continuously increase over 4-6 weeks after ECV. This might be attributable to recovery of tachycardia-induced cardiomyopathy.
authors.affiliation: Department of Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Zimmermann
authors.affiliation: Department of Medicine, University Hospital Basel, Basel, Switzerland; Cardiology Division, University Hospital Basel, Basel, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Bossard
authors.affiliation: Department of Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Aeschbacher
authors.affiliation: Department of Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Tobias
authors.initials: T
authors.lastname: Schoen
authors.affiliation: Department of Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Gian
authors.initials: G
authors.lastname: Voellmin
authors.affiliation: Cardiology Division, University Hospital Basel, Basel, Switzerland.
authors.forename: Yves
authors.initials: Y
authors.lastname: Suter
authors.affiliation: Department of Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Anouk
authors.initials: A
authors.lastname: Lehmann
authors.affiliation: Department of Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hochgruber
authors.affiliation: Department of Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Katrin
authors.initials: K
authors.lastname: Pumpol
authors.affiliation: Cardiology Division, University Hospital Basel, Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Sticherling
authors.affiliation: Cardiology Division, University Hospital Basel, Basel, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Kühne
authors.affiliation: Department of Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Conen
authors.affiliation: Cardiology Division, University Hospital Basel, Basel, Switzerland. Electronic address: beat.kaufmann@usb.ch.
authors.forename: Beat A
authors.initials: BA
authors.lastname: Kaufmann
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D009202:Cardiomyopathies / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D019560:Echocardiography, Three-Dimensional; D004554:Electric Countershock; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008297:Male; D020127:Recovery of Function; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology*