title: Importance of preserving the apex and plication of the base in left ventricular volume reduction surgery.
abstract: OBJECTIVE
  Volume reduction surgery for dilated cardiomyopathy has not yielded predictable outcomes. The purpose of this study was to clarify the efficacy of modified volume reduction surgery in preserving the left ventricular apex and reducing the left ventricular diameter at the base to maintain fiber continuity.
  
  
  METHODS
  Heart failure was induced with propranolol in 12 dogs, and the animals were randomized into 2 groups. In one group the left ventricular wall was plicated between the 2 papillary muscles from the middle to the apex (apex-sacrificing volume reduction surgery, group A, n = 6), and in the other group plication was done from the base to the middle (apex-sparing volume reduction surgery, group B, n = 6). Left ventricular function was then compared between the groups by using echocardiography and sonomicrometry crystals.
  
  
  RESULTS
  After volume reduction surgery, the fractional area change at the base in group B was greater than that in group A (40% +/- 3% vs 27% +/- 4%, P =.003). Cardiac output in group B was better than that in group A (2.5 +/- 0.2 vs 1.8 +/- 0.2 L/min, P =.023). Left ventricular end-diastolic pressure in group A was higher than that in group B (16 +/- 2 vs 8 +/- 1 mm Hg, P =.001). Fractional shortening in the long axis, as assessed by means of sonomicrometry, was better in group B than in group A.
  
  
  CONCLUSIONS
  Apex-sparing volume reduction surgery capable of maintaining left ventricular fiber continuity provided better left ventricular function in both the systolic and diastolic phases than apex-sacrificing volume reduction surgery in the acute heart failure model. This modification might improve the results of left ventricular volume reduction surgery.
authors.affiliation: Department of Cardiovascular Surgery, Graduate School of Medicine, Kyoto University, Japan.
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Koyama
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Nishimura
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Soga
authors.forename: Oriyanhan
authors.initials: O
authors.lastname: Unimonh
authors.forename: Koji
authors.initials: K
authors.lastname: Ueyama
authors.forename: Masashi
authors.initials: M
authors.lastname: Komeda
mesh_terms: D000208:Acute Disease; D000818:Animals; D002302:Cardiac Output; D002306:Cardiac Volume; D002311:Cardiomyopathy, Dilated / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D003971:Diastole; D004285:Dogs; D004452:Echocardiography; D006352:Heart Ventricles / Q000503:physiopathology / Q000601:surgery*; D006439:Hemodynamics; D017379:Hypertrophy, Left Ventricular / Q000139:chemically induced / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D011433:Propranolol; D011897:Random Allocation; D013318:Stroke Volume; D013599:Systole; D016896:Treatment Outcome; D016277:Ventricular Function, Left
chemical_list: D011433:Propranolol