MEASURING PCR/ATP AS A MARKER OF MYOCARDIAL ENERGETICS ACROSS THE SPECTRUM OF METABOLIC CARDIAC DISEASE

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