Heart failure with normal ejection fraction: the complementary roles of echocardiography and CMR imaging

Heart failure with normal ejection fraction (HFNEF), previously referred to as diastolic heart failure, has increased in prevalence as a cause of heart failure, now accounting for up to 50% of all cases. Contrary to initial evidence, the prognostic outlook in HFNEF may be similar to that of heart failure with reduced ejection fraction. According to current consensus statements, the diagnosis of HFNEF requires the demonstration of relatively preserved systolic left ventricular function and evidence of diastolic dysfunction. Noninvasive imaging techniques now permit evaluation of these parameters without need for cardiac catheterization in the large majority of patients. Echocardiography is the modality of choice in the evaluation of diastolic function but suffers from limitations in its assessment of systolic function. Cardiac magnetic resonance (CMR) imaging is the gold standard in the volumetric quantification of systolic function; however, it has limitations in its ability to characterize diastolic function. This report aims to review the strengths and weaknesses of both imaging modalities in the diagnosis of HFNEF. With regards to echocardiography, it will specifically describe limitations in measuring left ventricular ejection fraction, describe novel techniques to assess systolic function such as tissue velocity and strain analysis, and will review the measurements used in the evaluation of diastolic function. With respect to CMR, this review will highlight its value in the assessment of systolic left ventricular function, will review ancillary CMR findings that may support the diagnosis of HFNEF such as tissue characterization, and will provide a brief overview of CMR techniques to assess diastolic function. We propose that these 2 modalities may play a complementary role in the diagnosis of HFNEF. The importance of imaging in the diagnosis of HFNEF extends to both the individual patient and to clinical trials of therapies for this condition.