title: Cardiac resynchronization in patients with congestive heart failure and chronic atrial fibrillation: effect of upgrading to biventricular pacing after chronic right ventricular pacing.
abstract: OBJECTIVE
  This study assessed the effects of biventricular pacing (BVP) on ventricular function, functional status, quality of life and hospitalization in patients with congestive heart failure (CHF), prior atrioventricular (AV) junction ablation and right ventricular (RV) pacing performed for chronic atrial fibrillation (AF).
  
  
  BACKGROUND
  Although the benefit of BVP in CHF should theoretically extend to the patient with chronic RV pacing and AF, to our knowledge, no study has determined the effects of BVP on symptoms and ventricular function in these patients. This patient population allows for the evaluation of ventricular resynchronization independent of any BVP-induced changes on the AV interval.
  
  
  METHODS
  Twenty consecutive patients with severe CHF (ejection fraction < or = 0.35, New York Heart Association [NYHA] functional class III or IV), prior AV junction ablation and RV pacing performed for permanent AF of at least six months' duration were studied. Electrocardiograms, echocardiograms, functional status evaluations and quality of life surveys were completed before and at three to six months after implant.
  
  
  RESULTS
  The NYHA functional classification improved 29% (p < 0.001). The left ventricular (LV) ejection fraction increased 44% (p < 0.001), the LV diastolic diameter decreased 6.5% (p <0.003) and the end-systolic diameter decreased 8.5% (p < 0.01). The number of hospitalizations decreased by 81% (p < 0.001). The scores on the Minnesota Living with Heart Failure survey improved by 33% (p < 0.01).
  
  
  CONCLUSIONS
  We conclude that BVP improves the LV function and the symptoms of CHF in patients with permanent AF and chronic RV pacing. These benefits are comparable to those described for patients in sinus rhythm suggesting that BVP acts through ventricular resynchronization rather than optimization of the AV delay.
authors.affiliation: Carlyle Fraser Heart Center, Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia 30365, USA. angel_leon@emory.edu
authors.forename: Angel R
authors.initials: AR
authors.lastname: Leon
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Greenberg
authors.forename: Narendra
authors.initials: N
authors.lastname: Kanuru
authors.forename: Cindy M
authors.initials: CM
authors.lastname: Baker
authors.forename: Fernando V
authors.initials: FV
authors.lastname: Mera
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Smith
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Langberg
authors.forename: David B
authors.initials: DB
authors.lastname: DeLurgio
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000150:complications* / Q000401:mortality / Q000628:therapy*; D002304:Cardiac Pacing, Artificial; D002908:Chronic Disease; D017147:Defibrillators, Implantable; D020878:Device Removal; D004452:Echocardiography; D017097:Electric Impedance; D004562:Electrocardiography; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D005845:Georgia; D006333:Heart Failure / Q000150:complications* / Q000401:mortality / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D013318:Stroke Volume / Q000502:physiology; D016019:Survival Analysis; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000502:physiology