title: Induction and maintenance of an experimental model of severe cardiomyopathy with a novel protocol of rapid ventricular pacing.
abstract: OBJECTIVE
  An animal model of chronic severe heart failure is needed to evaluate new mechanical devices, surgical procedures, and medical therapies. The purpose of this study was to evaluate a unique new model of severe heart failure developed by means of a novel protocol of rapid ventricular pacing.
  
  
  METHODS
  Heart failure was induced in 8 mongrel dogs by means of rapid ventricular pacing (230 beats/min) for 4 weeks. After a sham operation, maintenance pacing at a reduced rate (190 beats/min) was continued for another 4 weeks.
  
  
  RESULTS
  Left ventricular systolic function was significantly reduced at week 4 and remained low at week 8, including the slope of the end-systolic pressure-volume relationship (2.4 +/- 1.0 vs 0.7 +/- 0.2 vs 0.8 +/- 0.3 mm Hg/mL [baseline vs week 4 vs week 8, respectively]), ejection fraction (63% +/- 5% vs 28% +/- 7% vs 33% +/- 5%), and cardiac output (3.1 +/- 0.7 vs 2.0 +/- 0.3 vs 2.2 +/- 0.7 L/min). Significant ventricular remodeling changes took place with increased ventricular volumes and circumferential wall stress, which were stable between weeks 4 and 8. Serum catecholamine and atrial natriuretic polypeptide levels also increased from baseline but stabilized between weeks 4 and 8. The end-diastolic pressure-volume relationship also showed stable diastolic function between weeks 4 and 8.
  
  
  CONCLUSIONS
  Induction pacing at 230 beats/min readily created severe heart failure in all animals, and a new technique of maintenance pacing provided a consistent model of severe heart failure. This model can be used to study a variety of new interventions for heart failure.
authors.affiliation: Department of Biomedical Engineering, Lerner Research Institute, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
authors.forename: Masami
authors.initials: M
authors.lastname: Takagaki
authors.forename: Patrick M
authors.initials: PM
authors.lastname: McCarthy
authors.forename: Tomotsugu
authors.initials: T
authors.lastname: Tabata
authors.forename: Ray
authors.initials: R
authors.lastname: Dessoffy
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Cardon
authors.forename: Jason
authors.initials: J
authors.lastname: Connor
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Ochiai
authors.forename: James D
authors.initials: JD
authors.lastname: Thomas
authors.forename: Gary S
authors.initials: GS
authors.lastname: Francis
authors.forename: James B
authors.initials: JB
authors.lastname: Young
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Fukamachi
mesh_terms: D000818:Animals; D002304:Cardiac Pacing, Artificial; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging / Q000503:physiopathology; D004195:Disease Models, Animal; D004285:Dogs; D019560:Echocardiography, Three-Dimensional; D006439:Hemodynamics; D016277:Ventricular Function, Left