title: Association of subclinical right ventricular dysfunction with obesity.
abstract: OBJECTIVE
  The purpose of this research was to identify the determinants of right ventricular (RV) dysfunction in overweight and obese subjects.
  
  
  BACKGROUND
  Right ventricular dysfunction in obese subjects is usually ascribed to comorbid diseases, especially obstructive sleep apnea. We used tissue Doppler imaging to identify the determinants of RV dysfunction in overweight and obese subjects.
  
  
  METHODS
  Standard and tissue Doppler echocardiography was performed in 112 overweight (body mass index [BMI] 25 to 29.9 kg/m2) or obese (BMI >30 kg/m2) subjects and 36 referents (BMI <25 kg/m2), including 22 with obstructive sleep apnea but no obesity. Tissue Doppler was used to measure RV systolic (s(m)) and diastolic (e(m)) velocities and strain indexes.
  
  
  RESULTS
  Obese subjects with BMI >35 kg/m2 had reduced RV function compared with referent subjects, evidenced by reduced s(m) (6.5 +/- 2.4 cm/s vs. 10.2 +/- 1.5 cm/s, p < 0.001), peak strain (-21 +/- 4% vs. -28 +/- 4%, p < 0.001), peak strain rate (-1.4 +/- 0.4 s(-1) vs. -2.0 +/- 0.5 s(-1), p < 0.001), and e(m) (-6.8 +/- 2.4 cm/s vs. -10.3 +/- 2.5 cm/s, p < 0.001), irrespective of the presence of sleep apnea. Similar but lesser degrees of reduced systolic function (p < 0.05) were present in overweight (BMI 25 to 29.9 kg/m2) and mildly obese (BMI 30 to 35 kg/m2) groups. Differences in RV e(m), s(m), and strain indexes were demonstrated between the severely versus overweight and mildly obese groups (p < 0.05). Body mass index remained independently related to RV changes after adjusting for age, log insulin, and mean arterial pressures. In obese patients, these changes were associated with reduced exercise capacity but not the duration of obesity and presence of sleep apnea or its severity.
  
  
  CONCLUSIONS
  Increasing BMI is associated with increasing severity of RV dysfunction in overweight and obese subjects without overt heart disease, independent of sleep apnea.
authors.affiliation: University of Queensland, Brisbane, Australia.
authors.forename: Chiew Y
authors.initials: CY
authors.lastname: Wong
authors.forename: Trisha
authors.initials: T
authors.lastname: O'Moore-Sullivan
authors.forename: Rodel
authors.initials: R
authors.lastname: Leano
authors.forename: Craig
authors.initials: C
authors.lastname: Hukins
authors.forename: Carly
authors.initials: C
authors.lastname: Jenkins
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Marwick
mesh_terms: D000328:Adult; D001794:Blood Pressure; D015992:Body Mass Index; D004452:Echocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology; D050177:Overweight; D010101:Oxygen Consumption; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology; D013318:Stroke Volume; D018497:Ventricular Dysfunction, Right / Q000000981:diagnostic imaging / Q000209:etiology*