title: Complete reversibility of cat right ventricular chronic progressive pressure overload.
abstract: Chronic, progressive pressure overload of the cat right ventricle produces persistent, ongoing abnormalities of contractile, energetic, and biochemical function in vitro at a time when in vivo pump function is still normal. The present study tested the reversibility of the in vitro changes in this clinically relevant hypertrophy model. Fourteen sham-operated and 14 reversal cats were studied. After banding the animals as 1-kg kittens, right ventricular pressures were normal. Before band removal (25.2 +/- 0.5 weeks later for the control group and 25.5 +/- 0.3 weeks later for the hypertrophy reversal group), systolic right ventricular pressures were 24 +/- 1 mm Hg for controls and 71 +/- 5 mm Hg for the hypertrophy reversal group (P less than 0.05). At study, 19.5 +/- 1.1 weeks after a second sham operation for controls or 18.7 +/- 0.7 weeks after band removal for the hypertrophy reversal group, these pressures were 24 +/- 1 mm Hg for controls and 23 +/- 1 mm Hg for the hypertrophy reversal group (P = NS); cardiac output was 0.18 +/- 0.01 liters/kg per min for controls and 0.19 +/- 0.01 liters/kg per min for the hypertrophy reversal group (P = NS). The ratio of right ventricle to body weight was normal in both groups, as was the right ventricular papillary muscle myocyte cross-sectional area and the myocardial collagen concentration. A right ventricular papillary muscle from each cat was studied at 29 degrees C in a polarographic myograph. Preloaded shortening velocity was 0.79 +/- 0.04 muscle lengths/sec for controls and 0.86 +/- 0.03 muscle lengths/sec for the hypertrophy reversal group (P = NS); extent of shortening was 0.15 +/- 0.01 muscle lengths for controls and 0.16 +/- 0.01 muscle lengths for the hypertrophy reversal group (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001794:Blood Pressure; D001835:Body Weight; D006332:Cardiomegaly / Q000378:metabolism / Q000503:physiopathology*; D002415:Cats; D002908:Chronic Disease; D006909:Hydroxyproline / Q000378:metabolism; D008099:Liver / Q000033:anatomy & histology; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D009929:Organ Size; D010101:Oxygen Consumption
chemical_list: D006909:Hydroxyproline