Heart Failure With Preserved, Mid-Range, and Reduced Ejection Fraction

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The European Society of Cardiology (ESC) recently published new guidelines for the diagnosis and treatment of acute and chronic heart failure (HF).1 The new nomenclature includes separating patients with HF into 3 distinct groups depending on the left ventricular ejection fraction (LVEF): preserved LVEF (≥50%), mid-range LVEF (40–49%), and reduced LVEF (≤40%). Although there have been several studies that argue for and against stratifying HF patients by LVEF, the latest guidelines continue to focus mainly on the LVEF as the central determinant of prognosis in HF. However, further characterization of HF phenotype using etiology, comorbidities, and nonresponse to therapy among the 3 proposed groups are not incorporated into the definition. It is important to identify pathophysiological mechanisms and specific etiologies that underlie the clinical status, beyond the simplistic definition of preserved, mid-range, and reduced LVEF. Moreover, the term “preserved” could be misleading and confusing: quite comforting and mistakenly reassuring. As observed in the literature and in clinical practice, patients with preserved LVEF may have worse prognosis in terms of rehospitalization and mortality. Furthermore, it is necessary to highlight that the determination of LVEF from 2D echocardiographic images with Simpson’s biplane technique is relatively unreliable, with intra and interobserver variability of up to 13% and 15%, respectively, because of foreshortened views and geometric assumptions.2 Moreover, LVEF calculation is sensitive to changes in hemodynamic loading conditions. This is what occurs in patients with mitral regurgitation who have preserved LVEF despite severe ventricular dysfunction.3,4 The consequence of such variability in measurement and sensitivity to loading conditions may lead to a significant overlap among the 3 proposed categories that are separated by only a few percentage points. Moreover, calculating LVEF is considered a simple method to estimate ventricular function, but in fact it may be too simplistic. In the management of HF patients, it is more important to focus on ventricular function estimated by chamber volumes and pressures, as well as by Doppler flows and tissue Doppler imaging (TDI). In fact, in our opinion, the key means by which to determine the prognosis of HF patients involves establishing the presence or absence of ventricular dysfunction, that could be (1) systolic, ie, with increased ventricular volumes; (2) diastolic, ie, with abnormalities in transmitral and pulmonary veins flows, in TDI mitral annular velocities, and in left atrium volume; or (3) systo-diastolic, ie, including features of both systolic and diastolic dysfunction. The presence of systolic, diastolic, or systo-diastolic ventricular dysfunction determines low cardiac output, which is the crucial pathophysiological element of HF.