title: Right ventricular systolic function is not depressed in morbid obesity.
abstract: BACKGROUND
  The increased pulmonary blood volume associated with the increased total blood volume in morbidly obese patients increases pulmonary artery pressure and pulmonary vascular resistance, resulting in increased right ventricular (RV) afterload. Thus, the morbidly obese may develop RV dysfunction owing to the increased RV afterload. We examined this possibility by assessing RV contractile function in morbidly obese patients, using RV end-systolic pressure-volume relationship and RV systolic time intervals.
  
  
  METHODS
  Included were 25 morbidly obese patients undergoing gastric bypass surgery under general anesthesia. Pulmonary artery pressure and RV end-systolic volume were measured with a thermodilution pulmonary artery catheter. Pulmonary arterial dicrotic notch pressure was used as an estimate of RV end-systolic pressure. Two data points were used to define RV end-systolic pressure-volume relationship. RV systolic time intervals were determined by simultaneous graphic display of the electrocardiograph, phonocardiograph, and pulmonary artery pressure curve, and were expressed as a pre-ejection period/RV ejection time ratio.
  
  
  RESULTS
  The mean slope of right ventricular end-systolic pressure-volume relationship line was 0.54 +/- 0.13 and mean pulmonary vascular resistance 274 +/- 80 dyne.sec.cm(-5).m(-2). The mean pre-ejection period/RV ejection time ratio was 0.4 +/- 0.11. There was an inverse correlation between the pre-ejection/RV ejection time ratio and the slope of RV end-systolic pressure-volume relationship line (R(2)=0.658, P<0.0001).
  
  
  CONCLUSIONS
  Our data indicate that RV function is not depressed in morbid obesity despite increased RV afterload.
authors.affiliation: Department of Anesthesiology, New York Medical College, Valhalla, NY 10595, USA. Charles6133@msn.com
authors.forename: Charles
authors.initials: C
authors.lastname: Her
authors.forename: Thomas
authors.initials: T
authors.lastname: Cerabona
authors.forename: Mosses
authors.initials: M
authors.lastname: Bairamian
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: McGoldrick
mesh_terms: D000328:Adult; D015897:Comorbidity; D004562:Electrocardiography; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000503:physiopathology*; D011651:Pulmonary Artery / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology / Q000503:physiopathology; D013318:Stroke Volume; D013599:Systole / Q000502:physiology*; D014655:Vascular Resistance; D016278:Ventricular Function, Right