Decreased left atrial function in morbid obese patients without known cardiac disease

Abstract

Abstract Background Obesity is an important risk factor for atrial fibrillation and heart failure. However, little is known about the underlying pathophysiology. Left atrial (LA) dysfunction due to diastolic dysfunction and chronic volume overload may play a significant role in morbid obesity. Purpose To compare LA function in morbid obese and non-obese individuals, and secondly, to determine whether LA function in morbid obese patients improves one year after bariatric surgery. Methods Data of morbid obese patients without known cardiac disease included in the CARdiac Dysfunction In Obesity (CARDIOBESE) study were used. Patients and age- and gender matched non-obese controls underwent transthoracic echocardiography. In the morbid obese patients echocardiography was repeated 1 year after bariatric surgery. LA reservoir strain (LASr), LA conduit strain (LAScd), and LA contractile strain (LASct) were analyzed with speckle tracking using dedicated software (TomTecArena, integrated in Sectra IDS7). Results 64 morbid obese patients were compared with 46 non-obese controls. Obese patients had significantly decreased LA function compared with non-obese individuals (LASr 39.6±10.8% vs 31.3±8.3%, p<0.001; LAScd −24.9±8.3% vs −19.5±7.2%, p<0.001; LASct −14.7±5.3% vs −11.8±3.5%, p=0.002). There was no significant difference in diastolic function between the non-obese and morbid obese group (normal function 38.2% vs 52.7%, intermediate function 3.6% vs 4.5%, dysfunction 0% vs 0.9%, p=0.689). In 47 obese patients LA strain did not improve significantly 1 year after bariatric surgery, although there was a trend of improvement in all phases of LA function (LASr 31.0±8.2% vs 33.1±8.2%, p=0.089; LAScd −19.4±7.1% vs −20.4±6.6%, p=0.349; LASct −11.6±3.3% vs −12.8±5.4%, p=0.151). Conclusions Morbid obese patients without known cardiac disease have impairment in all phases of LA function. This subclinical cardiac dysfunction would have remained largely unmasked with assessment of diastolic function according to current guidelines, as shown by the comparable proportion of obese and non-obese individuals with diastolic dysfunction. LA dysfunction in obesity may therefore be an early sign of cardiac disease and a predictor for developing atrial fibrillation and heart failure. LA function did not improve one year after bariatric surgery. Longer follow-up after bariatric surgery may be needed to investigate whether improvement of LA function will occur after a longer period following weight loss surgery. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): BeterKeten Outcomes of the study populationLeft atrial strain outcomes