Obesity linked to cardiac dysfunction
MedWire News: Results from a Swedish study indicate that obesity is significantly associated with cardiac dysfunction.
"We confirm that obesity is associated with discrete but distinct disturbances in the left ventricular systolic and diastolic performances," explain Dimitris Kardassis (Sahlgrenska University Hospital, Gothenburg, Sweden) and team in the International Journal of Cardiology.
In addition, persistent weight loss was significantly associated with improved cardiac function, as indicated by increased myocardial contractility and enhanced left ventricular relaxation, they say.
Using data from the Swedish Obese Subjects study cohort, the researchers identified 44 bariatric surgery patients who, after 10 years, displayed a weight loss of more than 15% (surgery group), and 44 obese (body mass index [BMI] of ≥34 kg/m2 for men and ≥38 kg/m2 for women) controls, whose weight had not changed by more than 5% in the same time period (obese group). The team also included 44 normal-weight individuals (lean group) from a random population sample.
All participants underwent a cross-sectional examination to obtain measures of body composition, fat distribution, and cardiac function using dual-energy X-ray absorptiometry, computed tomography, and echocardiography, respectively.
Kardassis et al report that the respective mean BMIs for the obese, surgery, and lean groups were 42.5, 31.5, and 24.4 kg/m2.
Left ventricular mass and left ventricular diastolic and systolic volume decreased across the three groups, from obese (201.4 g, 113.8 ml, and 42.5 ml, respectively), to surgery (157.7 g, 87.0 ml, and 31.0 ml) and lean (133.9 g, 85.3 ml, and 29.8 ml).
Furthermore, cardiac output and pulmonary pressure decreased with decreasing degrees of obesity; the respective measures were 6.4 l/min and 24.3 mmHg in the obese group, compared with 5.3 l/min and 20.9 mmHg in the surgery group, and 5.2 l/min and 20.7 mmHg in the lean group. Heart rate was also significantly lower in the surgery group compared with the obese group, at 64.5 versus 72.8 bpm, respectively.
The researchers found independent positive associations between lean body mass and left ventricular volume, stroke volume, and cardiac output, whereas blood pressure, heart rate, and variables reflecting cardiac dysfunction were more closely related to total body fat and visceral adiposity.
Commenting on their findings, Kardassis and team say: "Cardiac dysfunction appears to be related to both the total amount of body fat and the degree of visceral adiposity.
"Persistent weight loss, on the other hand, was associated with increased myocardial contractility and enhanced left ventricular relaxation."
The researchers conclude: "Surgical obesity intervention appears to have long-term favorable effects on the left ventricular systolic and diastolic function and could be considered as a treatment option in chronic heart failure."
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By Nikki Withers