Comparison of echocardiogram and nuclear medicine gated cardiac blood pool scan for assessment of left ventricular ejection fraction in obese patients

Background: Obesity increases the risk of cardiovascular conditions including heart failure. This makes it important to have an accurate method to evaluate left ventricular ejection fraction (LVEF) for early diagnosis and treatment. While 2D echocardiogram is easily accessible, increased BMI affects image quality and subsequently the accuracy of LVEF. In this study, we compared the correlation between LVEF derived from a 2D echocardiogram and a gated cardiac blood pool scan (GCBPS) in obese patients who underwent both imaging modalities. Methods: We performed a retrospective single-centre cohort study of obese patients (BMI 30 kg/m 2 and above) who had both 2D echocardiogram and GCBPS within 6 months of either investigation at a large tertiary centre from January 2023 through May 2024. Baseline characteristics, including age, gender, comorbidities and indications for both investigations, were included. Results: A total of 30 patients (mean age 65.11 ± 16.79) were included. There is an overall strong positive Pearson correlation between LVEF derived from echocardiogram and GCBPS ( r = 0.69, P < 0.001). However, there is a nonsignificant, weak, positive Pearson correlation between LVEF derived from echocardiogram and GCBPS in the female sex ( r = 0.28, P = 0.370). The number of comorbidities, male sex, age, BMI, order, or days between scans does not affect the LVEF obtained. Conclusion: There is a good correlation between LVEF derived from either echocardiogram or GCBPS in the male sex with an insignificant weak correlation in the female sex. Assessment of LVEF in obese female patients would benefit from using a GCBPS instead of an echocardiogram.