Abstract 9949: Characterising the Impact of Type Two Diabetes on the Phenotypic Expression of Hypertrophic Cardiomyopathy

Background: Hypertrophic cardiomyopathy (HCM) and type 2 diabetes mellitus (DM) are increasingly frequent comorbidities. DM is associated with worsened survival outcomes in HCM patients. HCM and DM, though differing in their etiologies, share features of alterations in myocardial energetics and perfusion. The mechanisms for this adverse prognostic association are incompletely understood but are likely to include the collective impact of DM and HCM on myocardial metabolism and perfusion. Objectives: We aimed to determine if cardiac energetics, measured as the phosphocreatine (PCr)/ATP ratio, and rest and adenosine stress myocardial blood flows (MBF) showed greater reductions in patients with concomitant HCM and DM (HCMDM) compared to isolated HCM or isolated DM using 31 Phosphorus magnetic resonance spectroscopy ( 31 P-MRS) and cardiovascular magnetic resonance (CMR). Methods: A total of 75 age and sex matched participants were recruited (20 HCMDM, 20 HCM, 20 DM and 15 controls). HCM groups were matched for HCM phenotype (8 with apical and 12 with asymmetric septal hypertrophy in both groups). DM groups were matched for diabetes treatment and HBA1c. Patients with a history of ischemic heart disease were excluded. Results: Table-1 shows clinical and CMR/ 31 P-MRS data.Left ventricular ejection fraction and mass index were similar in both HCM groups. Global longitudinal strain and left atrial function were significantly reduced in HCMDM compared to HCM. PCr/ATP was similarly reduced in HCMDM and DM groups compared to HCM and controls. Stress MBF was significantly reduced only in HCMDM group. Conclusions: The presence of diabetes as a comorbidity confers a more malignant phenotypic expression in HCM patients with greater reductions in myocardial energetics, contractile function, and perfusion. These phenotypic differences may account for the worsened clinical outcomes in HCM patients with concomitant DM. Table 1: Clinical Characteristics and CMR findings