143 Measuring pcr/atp as a marker of myocardial energetics across the spectrum of metabolic cardiac disease. (6th June 2022) - Henry, John Aaron
Abstract : Introduction: Derangements in myocardial energetics are thought to play an important role in the pathophysiology of several cardiac diseases. Myocardial energetics can non-invasively be assessed by measuring the phosphocreatine-to-adenosine triphosphate ratio (PCr/ATP) using 31Phosphorus magnetic resonance spectroscopy (31P-MRS). Here we compare cardiac PCr/ATP across a spectrum of metabolic cardiac pathologies. MethodsUsing a 3D chemical shift imaging sequence and surface coil we recorded PCr/ATP in 433 participants: athletes (n=17), healthy controls with normal weight (n=148), overweight (n=67) and with obesity (n=73), diabetes (n=23), heart failure with preserved ejection fraction (HFpEF) (n=33), heart failure with reduced ejection fraction (HFrEF) (n=63) and amyloid (n=9). Results: A spectrum of myocardial PCr/ATP exists ranging from normal in athletes (2.23 ± 0.28) and those with normal weight (2.05 ± 0.38) to severely impaired in those with cardiac amyloid (1.34 ± 0.19, Figure 1). Despite normal systolic function (all LVEF >57%) those living with obesity and diabetes have lower PCr/ATP than normal (all p<0.001). In all groups with HF, regardless of aetiology, myocardial energetics were impaired (all p<0.001). Across the whole cohort PCr/ATP was negatively correlated with body mass index (r -0.28, p <0.001), age (r -0.34, p<0.001) and LV mass (r -0.1, p<0.001). PCr/ATP was not related to systolic or diastolic blood pressure in these cohorts. Conclusions: Despite normal systolic function, overweight, obesity and diabetes are associated with lower PCr/ATP ratios than normal weight controls. These changes in myocardial energetics appear to exist on a spectrum with further derangement present in overt cardiac pathology. Derangements in myocardial energetics are present in myocardial pathologies independent of underlying aetiology and thus may represent a viable therapeutic target in several conditions. Conflict of Interest: None