Despite the traditional characterization of heart failure (HF) as primarily associated with systolic dysfunction of the left ventricle (LV) and reduced ejection fraction (EF), recent findings reveal that more than 50% of HF patients have preserved EF while exhibiting diastolic dysfunction (DD). [1]

When HF is predominantly or exclusively caused by abnormalities in diastolic function, it is classified as the clinical syndrome of diastolic HF. By definition, this requires the presence of signs and symptoms of HF, preserved EF, and evidence of abnormal diastolic function. Diastolic function is governed by two main factors: the passive compliance of the ventricular wall and the active relaxation of the myocardium. [1-2]

Diastolic dysfunction is characterized by elevated left ventricular filling pressure (LVFP) at rest or during exertion, resulting from stiffness or impaired relaxation. Imaging plays a critical role in diagnosing DD by fulfilling four main purposes: identifying DD, determining its severity, identifying underlying causes, and assessing prognosis and risk factors. [3]

Although left ventricular catheterization remains the gold standard for assessing LVFP and LV end-diastolic pressure, echocardiography is the most widely used non-invasive modality. Echocardiography evaluates the degree of DD by analyzing the E/A ratio (the velocity of the E-wave compared to the A-wave across the mitral valve), the E/e' ratio (e' being the Doppler velocity of the mitral annulus), tricuspid valve velocity, and indexed left atrial (LA) size. Grade II DD, or pseudonormalization, represents impaired relaxation with mildly elevated LV end-diastolic pressure. [4-5]

Cardiac magnetic resonance imaging (CMR) provides complementary information to echocardiography in assessing DD, particularly for identifying underlying causes and evaluating prognosis and risk in conditions such as infiltrative diseases or ischemic heart disease. Its role has been increasing in recent years. [3]

To evaluate the E and A wave velocities via transmitral flow using CMR, a through-plane velocity-encoded sequence is utilized. This is positioned at the mitral valve annulus, where the MR signal is proportional to velocity, with low encoding velocities (80–100 cm/s) being applied. The Phase Contrast (PC) sequence is a well-established technique for flow assessment, routinely applied to the aortic and pulmonary valves but less commonly to the mitral valve (MV). Impaired relaxation is identified when E < A, while an E/A ratio >2 indicates a restrictive filling pattern. [3,6]

CMR can also quantify LA size using high temporal resolution steady-state free precession (SSFP) cine sequences. Measurements are typically performed in the four-chamber view, focusing on the maximum LA volume at end-systole, just before mitral valve opening. [7,8]

Key parameters indicative of grade II DD or pseudonormalization include an E/A ratio >0.8, reduced e' velocity, and a dilated left atrial volume. [6]

The aim of our study was to evaluate whether the CMR-based assessment of type II diastolic dysfunction – pseudonormalization, utilizing only MV flow and left atrial size, is sufficiently accurate compared to the gold standard for non-invasive evaluation, echocardiography, which employs multiple parameters for grading and diagnosing grade II DD.