Abstracts

Background and Objectives: Dyssynchrony refers to abnormal myocardial activation leading to inhomogenous contraction of the left ventricular (LV) muscle fibers and reduced LV ejection fraction. The role of LV mechanical dyssynchrony assessment with gated single-photon emission computed tomography in selection and response assessment of patients, who undergo cardiac resynchronization therapy, is widely discussed. Recently, there is emerging evidence to assess the role of dyssynchrony in identifying asymptomatic diabetic patients who may develop diabetic cardiomyopathy. This study aims to evaluate LV mechanical dyssynchrony with N-13 labeled NH3 positron emission tomography (PET) in asymptomatic diabetic patients (>3 years) compared to age-matched healthy controls. Materials and Methods: We retrospectively analyzed 124 patients aged 30–78 years who underwent 1 day stress/rest N-13 labeled NH3 cardiac PET from December 2015 to July 2018. Among them, 33 patients aged 40–70 years (21 males, 12 females) with asymptomatic type II diabetes, absence of obesity, and other comorbidities underwent N-13-labeled NH3 cardiac PET. Twenty-eight patients (12 males, 16 females) aged 39–72 years with the absence of diabetes, obesity, and low risk for coronary artery disease who underwent N-13 labeled NH3 cardiac PET were taken as controls. LV dyssynchrony assessment was done using phase analysis with Corridor 4DM software. Phase standard deviation (PSD) and histogram bandwidth (HBW) were recorded from phase histogram in both rest and stress PET images in all the patients included in our study. The statistical significance of the dyssynchrony parameters (PSD and HBW) in asymptomatic diabetics versus normal healthy controls was assessed using the Mann–Whitney test. Results: The mean PSD and HBW of resting study were significantly higher in diabetic patients compared to nondiabetic healthy controls (PSD = 28 vs. 15.4, P = 0.01) (HBW = 100 vs. 62.2, P = 0.01). Mean PSD and mean HBW of stress study were also significantly higher in patients with asymptomatic diabetes compared to normal nondiabetic controls (PSD = 25.2 vs. 14.7, P = 0.01) (HBW = 98.6 vs. 58.6, P = 0.009). Conclusion: Our findings indicate that asymptomatic diabetic patients have significant dyssynchrony compared to normal healthy nondiabetic controls and dyssynchrony on phase analysis with cardiac PET can be used to predict diabetic cardiomyopathy.