Myocardial steatosis as a possible mechanistic link between diastolic dysfunction and coronary microvascular...

Area of Science:

• Cardiology
• Cardiovascular Imaging
• Metabolic Heart Disease

Background:

• Coronary microvascular dysfunction (CMD) without obstructive coronary artery disease (CAD) is linked to increased heart failure with preserved ejection fraction (HFpEF) in women.
• The underlying mechanisms of HFpEF in this population remain unclear.
• Myocardial steatosis (ectopic fat in the heart muscle) is associated with diastolic dysfunction in other metabolic conditions.

Purpose of the Study:

• To investigate the prevalence of myocardial steatosis and diastolic dysfunction in women with CMD and subclinical HFpEF.
• To explore the relationship between myocardial fat content and diastolic function in this specific patient group.

Main Methods:

• Study included 13 women: 8 controls and 5 with CMD and subclinical HFpEF (elevated left ventricular end-diastolic pressure).
• Myocardial triglyceride content was measured using proton magnetic resonance spectroscopy.
• Diastolic function was assessed via magnetic resonance tissue tagging.

Main Results:

• Women with CMD exhibited significantly higher myocardial triglyceride content compared to controls (0.83% ± 0.12% vs. 0.43% ± 0.06%, P = 0.025).
• Diastolic circumferential strain rate was lower in women with CMD (168 ± 12%/s vs. 217 ± 15%/s, P = 0.012).
• Myocardial triglyceride content showed a significant inverse correlation with diastolic circumferential strain rate (r = -0.779, P = 0.002).

Conclusions:

• This proof-of-concept study suggests myocardial steatosis may be a key factor in diastolic dysfunction among women with CMD and no obstructive CAD.
• Further longitudinal research is needed to confirm these findings and evaluate targeted treatments for myocardial steatosis.
• Understanding the role of myocardial fat could lead to novel therapeutic strategies for HFpEF in women with CMD.