Heart failure module 1: background, epidemiology and pathophysiology

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Background

Heart failure (HF) is defined clinically as a syndrome in which patients have typical symptoms (e.g. breathlessness, ankle-swelling and fatigue), and signs (e.g. elevated jugular venous pressure), resulting from an abnormality of cardiac structure or function.1 Its prevalence is high and increasing due to the increasing age of the population, improved survival rates post-infarction and better medical care. Patients with HF have a poor quality of life, and reduced life expectancy. There are wide variations in the management of HF across the UK.2

Clinical definition

Patients can present with acute heart failure, when the pathophysiology of the condition can usually be understood in terms of abnormal haemodynamics, but the pathophysiology of chronic heart failure, especially when treated, is more complex.

HeFREF/HeFNEF

HF is often described in relation to left ventricular ejection fraction (EF).

Systolic HF is HF with a reduced ejection fraction (EF) or HeFREF. Some patients appear to have HF but have a normal EF (see figure 1). Such patients are variously labelled as having HeFNEF, HeFPEF (where the P stands for “preserved”) or “diastolic HF” (see figure 2).

Figure 1. Apical four chamber diastolic view of two-dimensional echocardiograms and M-mode echocardiograms of the left ventricle recorded in a normal subject (A, C) and a patient with dilated cardiomyopathy (B,D). The left ventricular size is greatly enlarged and its function reduced in the latter (click to enlarge)
Figure 1 redraw
Figure 2. Distribution of left ventricular ejection fraction measured within 12 months of the EuroHeart Failure survey among women (n = 2,048; 41% of total enrolled) and men (n = 3,249; 57% of total enrolled) enrolled in the EuroHeart Failure survey. Where more than one ejection fraction measurement was available, the most recent one was used. 51% of men but only 28% of women had a left ventricular ejection fraction <40% (click to enlarge)
Figure 2. Distribution of left ventricular ejection fraction measured within 12 months of the EuroHeart Failure survey among women (n = 2,048; 41% of total enrolled) and men (n = 3,249; 57% of total enrolled) enrolled in the EuroHeart Failure survey. Where more than one ejection fraction measurement was available, the most recent one was used. 51% of men but only 28% of women had a left ventricular ejection fraction <40%