Congestive heart failure classification

Overview
There are several classification schemes used to characterize
 * The pathophysiology of heart failure (systolic vs diastolic; left vs right; low output vs high output)
 * To assess the chronicity of heart failure (acute or chronic)
 * To assess the severity of heart failure (the NY Heart Association Class)
 * To assess the stage congestive heart failure (AHA Class A,B,C,D)

Types of Heart Failure
There are several classification schemes used to characterize the pathophysiology of heart failure as either systolic vs diastolic; left vs right; or low output vs high output

Systolic versus Diastolic Heart Failure
Patients may be broadly classified as having heart failure with depressed contractility or depressed relaxation

Systolic Dysfunction
The left ventricular ejection fraction is reduced in systolic dysfunction and there is depressed contractility of the heart.

Disastolic Dysfunciton
The left ventricular ejection fraction is preserved in diastolic dysfunction and there is an abnormality in myocardial relaxation or excessive myocardial stiffness. Systolic and diastolic dysfunction commonly occur in conjunction with each other.

Left, Right and Biventricular Failure
Another common method of classifying heart failure is based upon the ventricle involved (left sided versus right sided).

Left Heart Failure

 * There is impaired left ventricular function with reduced flow into the aorta.

Right Heart Failure

 * There is impaired right ventricular function with reduced flow into the pulmonary artery and lungs.

Biventricular Failure

 * The most common cause of right heart failure is left heart failure, and mixed presentations are common, especially when the cardiac septum is involved.

Low Output Failure

 * The cardiac output is reduced, and the systemic vascular resistance (SVR) is high. In low output failure, there is an inadequate supply of blood flow to meet normal metabolic demands.

High Output Failure

 * The cardiac output is increased, and the systemic vascular resistance (SVR) is low. Rather than an inadequate supply of blood flow to meet normal metabolic demands as occurs in low output failure, in high output failure there is an excess requirement for oxygen and nutrients and the demand outstrips what the heart can provide. Causes of high output heart failure include severe anemia, Gram negative septicaemia, beriberi (vitamin B1/thiamine deficiency), thyrotoxicosis, Paget's disease, arteriovenous fistulae, or arteriovenous malformations.

Acute or Decompensated
Acute or decompensated heart failure is a term used to describe exacerbated or decompensated heart failure, and refers to an episode in which a patient sustains a change in heart failure signs and symptoms that necessitates urgent therapy or hospitalization.

Chronic
There is stable symptomatology in chronic heart failure.

Assessing the Severity of Heart Failure: The New York Heart Association Criteria (NYHA)

 * NYHA I: No symptoms with ordinary activity.


 * NYHA II: Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in fatigue, palpitation, dyspnea, or angina.


 * NYHA III: Marked limitation of physical activity. Comfortable at rest, but less than ordinary physical activity results in fatigue, palpitation, dyspnea, or anginal pain.


 * NYHA IV: Unable to carry out any physical activity without discomfort. Symptoms of cardiac insufficiency present at rest.

ACC/AHA Classification of Chronic Heart Failure Based on the Structural and Symptomatic Stages of the Syndrome
The ACC/AHA classification system was introduced to emphasize the natural history of the heart failure syndrome and to identify opportunities to intervene earlier and prevent disease progression.

Stage A
Patients “at Risk”
 * Hypertension
 * Diabetes mellitus
 * Coronary artery disease
 * Exposure history to cardiac toxins:
 * History of cardiotoxic drug therapy.
 * History of alcohol abuse.
 * Familial history of cardiomyopathy

Stage B
Patients with structural heart disease, but no history of signs or symptoms of heart failure.
 * Left ventricular hypertrophy (LVH)
 * Myocardial fibrosis
 * Left ventricular dilatation or dysfunction
 * Asymptomatic valvular heart disease
 * Previous myocardial infarction

Stage C
Underlying structural heart disease and symptoms of heart failure.
 * Dyspnea or fatigue due to left ventricular systolic dysfunction.
 * Asymptomatic patients receiving treatment for prior symptoms of heart failure.

Stage D
Despite of maximal medical therapy, symptoms of heart failure at rest and advanced structural heart disease.
 * Being considered for advance options including LVAD and heart transplantation
 * Requiring continuous inotropic or mechanical support
 * Receiving or being considered for palliative care/end of life care.

Guidelines Resources

 * The ACC/AHA 2005 Guideline Update for the Diagnosis and Management of Chronic Heart Failure in the Adult


 * 2009 focused update: ACCF/AHA Guidelines for the Diagnosis and Management of Heart Failure in Adults: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines: developed in collaboration with the International Society for Heart and Lung Transplantation