Cardiovascular magnetic resonance for the assessment of left
Cardiovascular magnetic resonance (CMR) is increasingly used in the diagnostic workflow of patients with HF, providing reference standard assessment of ventricular volumes and function, as well as myocardial tissue characterization. Several CMR methods have also been developed to assess diastolic function (and by extension LVFP), although none of them is routinely used in the clinical environment. These include left atrial size and function (i.e. atrial ejection fraction), myocardial strain (using either tagging or feature-tracking), and phase-contrast CMR-derived transmitral and pulmonary venous flow. The advantage of CMR metrics is their accuracy and robustness, which opens up the possibility of directly predicting LVFP in patients with HF.

In this study, right heart catheterization (RHC) and CMR were performed within 24 h, and increased LVFP was defined as a PCWP of >15 mmHg. Importantly, a significant proportion of the study population (38%) had raised PCWP and the derivation and validation cohorts were large (706 and 127 patients, respectively), both of which increase confidence in the validity of the derived model. demonstrated that several CMR-based metrics correlated with invasively assessed PCWP on univariate analysis. However, only LV mass and left atrial volume (LAV) were independent predictors of PCWP. The importance of these metrics is not particularly surprising, as the association between left atrial size and LVFP is well recognized, and myocardial hypertrophy is a common cause of diastolic dysfunction. The novelty of this study is the subsequent use of these metrics to create a model that estimates PCWP.