Heart failure (HF) may be classified in several ways. When defined according to ventricular function, there may be impaired contraction (heart failure with reduced ejection fraction) or filling (preserved ejection fraction) or a combination of both. The New York Heart Association (NYHA) classification summarised in the table below classifies heart failure according to the individual’s symptoms and physical function. See also New York Heart Association (NYHA) classification.
Heart failure with reduced ejection fraction
Heart failure with reduced ejection fraction (HFREF), which was previously referred to as systolic heart failure, occurs when the ventricle, in particular the left ventricle, cannot contract properly and fails to effectively eject blood resulting in reduced cardiac output, i.e,. left ventricular ejection fraction of less than 45%. This type of HF is the most responsive to pharmacological management.
HFREF is most commonly caused by ischaemic or coronary heart disease resulting in inadequate oxygen supply or necrosis of heart muscle tissue secondary to infarction. Presence of hypertension is very common and can exacerbate the progress of HF. About 5-10% of HF is from non-ischaemic dilated cardiomyopathies. Other causes include cardiac valvular incompetence, uncontrolled chronic arrhythmias, viral cardiomyopathy, inflammatory cardiomyopathy, peripartum cardiomyopathy, alcohol related, medication related and thyroid dysfunction. See Causes of heart failure for further information.
Heart failure with preserved ejection fraction (HFPEF)
HF with preserved ejection fraction (HFPEF) results from impairment of the left ventricle to relax and therefore fill with blood. This type of HF is also referred to as diastolic HF or HF with preserved systolic function. HFPEF is commonly seen in elderly women and is associated with hypertension, coronary heart disease and diabetes. Other causes may include valvular disease, hypertrophic cardiomyopathy and restrictive cardiomyopathies such as amyloidosis. See Causes of heart failure for further information.
Although HFREF and HFPEF may coexist, it is important to establish which is affecting cardiac performance as pharmacological treatment is different . See Medications for heart failure.
Table 1: New York Heart Association Classification (NYHA) [#american-heart-association.-classes-of-heart-failure]
The NYHA classification grades heart failure symptoms on a four point scale:
No limitation of physical activity.
Ordinary physical activity does not cause undue fatigue, palpitation, dyspnoea (shortness of breath).
Slight limitation of physical activity.
Comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnoea (shortness of breath).
Marked limitation of physical activity.
Comfortable at rest. Less than ordinary activity causes fatigue, palpitation, or dyspnoea.
Unable to carry on any physical activity without discomfort.
Symptoms of heart failure at rest. If any physical activity is undertaken, discomfort increases.