Right ventricular systolic function is not depressed in morbid obesity

Area of Science:

• Cardiology
• Pulmonary Medicine
• Obesity Research

Background:

• Morbid obesity is linked to increased total blood volume, elevating pulmonary artery pressure and vascular resistance.
• This increased afterload may potentially impair right ventricular (RV) function.
• The study investigates RV contractile function in morbidly obese individuals.

Purpose of the Study:

• To assess right ventricular (RV) contractile function in morbidly obese patients.
• To determine if increased RV afterload in morbid obesity leads to RV dysfunction.

Main Methods:

• Evaluated 25 morbidly obese patients undergoing gastric bypass surgery.
• Measured pulmonary artery pressure and RV end-systolic volume using a thermodilution catheter.
• Assessed RV function via end-systolic pressure-volume relationship and RV systolic time intervals (pre-ejection period/RV ejection time ratio).

Main Results:

• The mean slope of the RV end-systolic pressure-volume relationship was 0.54 +/- 0.13.
• Mean pulmonary vascular resistance was 274 +/- 80 dyne.sec.cm(-5).m(-2).
• An inverse correlation was observed between the pre-ejection/RV ejection time ratio and the RV end-systolic pressure-volume relationship slope (R(2)=0.658, P<0.0001).

Conclusions:

• Despite increased right ventricular (RV) afterload in morbid obesity, RV function is not depressed.
• RV contractile function appears preserved in this patient population.