Diffuse myocardial fibrosis evaluated by post-contrast t1 mapping correlates with left ventricular stiffness

Area of Science:

• Cardiology
• Cardiovascular Imaging
• Transplant Medicine

Background:

• Left ventricular (LV) diastolic dysfunction is a common complication in cardiac transplant recipients.
• The role of diffuse myocardial fibrosis in diastolic dysfunction remains unclear.

Purpose of the Study:

• To investigate the association between diffuse myocardial fibrosis and diastolic function in heart transplant recipients.
• Utilize cardiac magnetic resonance (CMR) imaging and invasive pressure-volume (PV) measurements.

Main Methods:

• Performed CMR with T1 mapping and invasive LV PV measurements in 20 heart transplant recipients.
• Assessed diffuse myocardial fibrosis using post-contrast T1 time and extracellular volume fraction.
• Measured LV stiffness (β) and relaxation (τ) using PV loops.

Main Results:

• Post-contrast T1 time and extracellular volume fraction correlated with LV stiffness (β).
• Post-contrast T1 time was the sole independent predictor of LV stiffness (β) after multivariate analysis.
• No significant associations were found between T1 time and LV relaxation (τ) or load-dependent diastolic parameters.

Conclusions:

• Diffuse myocardial fibrosis, assessed by CMR T1 time, is correlated with invasively measured LV stiffness in heart transplant recipients.
• Increased passive ventricular stiffness due to fibrosis likely contributes significantly to diastolic dysfunction in these patients.