PURPOSE: Previous studies demonstrated that obesity is one of the risk factors for congestive heart failure (CHF). However, the cause of CHF in obese patients is not known. By analyzing a large scale echocardiogram database, we investigated the relationship between the increasing body mass index (BMI) and left ventricular systolic or suspected diastolic dysfunction.
METHODS: We retrospectively analyzed 24,265 echocardiograms performed at our institution between 1984 and 1998. Fractional shortening (FS) and (BMI) were available for 13,382 subjects in this cohort. FS was stratified into 4 groups: 1) FS>25% (normal), 2) FS 17.5-25% (mild systolic dysfunction), 3) FS 10-17.5% (moderate systolic dysfunction) and 4) FS<10% (severe systolic dysfunction). BMI was also divided into 4 groups: BMI <18.5 kg/m2 (underweight), 18.5-24.9 kg/m2 (normal), 25-30 kg/m2 (overweight) and >30 kg/m2 (obese).
RESULTS: There were no significant differences between the groups with regards to ventricular function either using FS or the subjective diagnosis of left ventricular systolic dysfunction by reading cardiologists. However, parameters suggestive of abnormal diastolic dysfunction remained directly associated with increasing in BMI after adjustment for age and gender (BMI>30 odds ratio (OR) 2.53, confidence interval (CI) 2.3-2.75 for left atrial size > 40 mm, p<0.0001, OR 1.61 CI 1.45-1.80 for left ventricular hypertrophy, p<0.0001 and OR 1.14 CI 1.02-1.25 for early vs. late diastolic mitral flow reversal, p<0.0001).
CONCLUSION: This study suggests that obesity is not associated with systolic dysfunction but may be with diastolic dysfunction.
CLINICAL IMPLICATIONS: Our study could, in part, explain the cause of reverse epidemiology in obese patients with heart failure. Based on our results, we suspect that obese patients presenting with heart failure most likely have a higher prevalence of diastolic dysfunction explaining better long-term prognosis in comparison to patients with congestive heart failure and a decrease in systolic left ventricular function.
DISCLOSURE: Mohammad-Reza Movahed, None.