Heart failure is a condition in which the heart is unable to generate a cardiac output sufficient to meet the demands of the body without increasing diastolic pressure. It can result from any cardiac disease that compromises ventricular systolic or diastolic function or both. The term "congestive heart failure" is reserved for patients with breathlessness and abnormal sodium and water retention, resulting in edema.
This staged classification underscores the fact that established risk factors and structural abnormalities are necessary for the development of heart failure, recognizes its progressive nature, and superimposes treatment strategies on the fundamentals of preventive efforts. Heart failure may progress from stage A to stage D in a given patient, but generally does not follow the path in reverse.
Stage A: patients at high risk of developing heart failure because of the presence of conditions that are strongly associated with the development of heart failure (for example, hypertension, diabetes, or coronary disease); however, such patients have no identified structural or functional abnormalities of the pericardium, myocardium, or cardiac valves and have never shown signs or symptoms of heart failure.
Stage B: patients who have developed structural heart disease that is strongly associated with the development of heart failure but who have never shown signs or symptoms of heart failure (for example, asymptomatic post-infarction left ventricular dysfunction).
Stage C: patients who have current or prior symptoms of heart failure associated with underlying structural heart disease.
Stage D: patients with advanced structural heart disease and marked symptoms of heart failure at rest despite maximal medical therapy and who require specialized interventions (for example, heart transplant or left ventricular assist devices).
Heart failure is essentially a clinical diagnosis. Clinical criteria for diagnosing heart failure, the Framingham Criteria for the diagnosis of CHF, were established before the widespread use of echocardiographic assessment of systolic and diastolic dysfunction. The Framingham clinical criteria, listed below, have been extremely useful for identifying heart failure patients, both in clinical practice and in epidemiologic studies, for more than 40 years. However, because their specificity is greater than their sensitivity, it is recognized that they probably miss mild cases of heart failure. In order to come up with a definite diagnosis of CHF, one needs to have either 2 major criteria or the combination of 1 major and 2 minor criteria.
Neck vein distention
Acute pulmonary edema
Increased venous pressure greater than 16 cm of water
Circulation time greater than 25 seconds
Paroxysmal nocturnal dyspnea or orthopnea.
Dyspnea on exertion
Less than one third maximum vital capacity
Tachycardia (HR >120 bpm).
Major or minor criteria:
Weight loss greater than 4.5 kg in 5 days in response to treatment