An introduction to acute heart failure syndromes: definition and classification

Abstract

Acute Heart Failure (AHF) is defined as a change in heart failure signs and symptoms resulting in the need for urgent therapy. Although AHF is associated with a poor prognosis only recently guidelines from Europe and USA [1, 2] have begun to address management of AHF syndromes (AHFS), and the clinical trial data supporting the recommendations are limited. Moreover, most of these clinical trials failed to show a decrease in mortality. A potential explanation is the heterogeneity of AHFS and the lack of a classification which could help design appropriate treatment algorithms. The European Society of Cardiology (ESC) guidelines [1] were the first to classify patients with AHFS into distinct clinical conditions. These include: i) acute decompensated heart failure, de novo or decompensated chronic heart failure ii) hypertensive acute heart failure iii) pulmonary edema iv) cardiogenic shock v) high output failure and vi) right heart failure (Table 1). However, the ESC classification is complex and is based on pathophysiology, clinical phenotype and disease severity on presentation. Moreover, most of these conditions are not well defined and this is the reason for the differences in the epidemiology of AHF, in the recently published registries (Figs. 1 and 2). Therefore, in clinical practice it is difficult to differentiate the groups because there is significant overlap among these conditions (Fig. 2). It has been recently suggested that patients with AHFS can be classified into 3 main groups (Fig. 3) with different characteristics [3]. Although many different names have been proposed for these groups, the characteristic difference among the groups that can be used in clinical practice to guide management is the patient’s blood pressure at the time of presentation. These groups are (Fig. 3): 1) Hypertensive AHF (Acute de novo heart failure or vascular failure): The symptoms develop rapidly and it is usually the first episode of AHF or the patient was asymptomatic or oligosymptomatic for a long period. The blood pressure is elevated and there is an increased sympathetic tone and neurohormonal activation. It is related to increased pulmonary capillary wedge pressure and redistribution of fluids (from systemic to pulmonary circulation). Because symptoms develop abruptly, the patients could be euvolemic or only mildly hypervolemic. The left ventricular ejection fraction is relatively preserved, and the patients present with pulmonary rales and congestion in the chest X-ray with minimal weight gain and usually without signs of systemic congestion (e.g., peripheral edema). The response to therapy is rapid. This condition is more common in females. 2) Normotensive AHF (Acutely decompensated chronic heart failure or cardiac failure): Blood pressure is normal and there is usually a history of progressive worsening of chronic HF. In this group symptoms and signs develop gradually, over days, and not only pulmonary but also systemic congestion (jugular venous distension and G. Filippatos (&) Heart Failure Unit, Department of Cardiology, Athens University Hospital Attikon, 12461 Athens, Greece e-mail: geros@otenet.gr