What Is Heart Failure?
Heart failure is a condition in which the structure or function of the heart does not allow for sufficient cardiac output, or blood flow, to satisfy the body’s needs. It is different from cardiac arrest, a situation in which there is no cardiac output at all. When activity levels are normal and the blood flow is low, it is often referred to as congestive heart failure.
Classification of Heart Failure
There are many different ways to categorize heart failure, including:
- The side of the heart involved (left heart failure vs. right heart failure).
- Whether the abnormality is due to contraction or relaxation of the heart (systolic dysfunction vs. diastolic dysfunction).
- Whether the problem is primarily increased venous back pressure (behind) the heart or failure to supply adequate arterial perfusion (in front of) the heart (backward vs. forward failure).
- Whether the abnormality is due to low cardiac output with high systemic vascular resistance or high cardiac output with low vascular resistance (low-output heart failure vs. high-output heart failure).
- The degree of functional impairment conferred by the abnormality (as in the NYHA functional classification).
New York Heart Association (NYHA) Functional Classification
The NYHA Functional Classification provides a simple way of classifying the extent of heart failure. It places patients in one of four categories based on how much they are limited during physical activity; the limitations/symptoms are in regards to normal breathing and varying degrees in shortness of breath and or angina pain.
The classes (I-IV) are:
- Class I: No limitation is experienced in any activities; there are no symptoms from ordinary activities.
- Class II: Slight, mild limitation of activity; the patient is comfortable at rest or with mild exertion.
- Class III: Marked limitation of any activity; the patient is comfortable only at rest.
- Class IV: Any physical activity brings on discomfort and symptoms occur at rest.
This score documents the severity of symptoms, and can be used to assess response to treatment. While its use is widespread, the NYHA score is not very reproducible and doesn’t reliably predict the walking distance or exercise tolerance in formal testing.
American College of Cardiology (ACC) Classification System
In its 2001 guidelines, the American College of Cardiology (ACC) / American Heart Association (AHA) working group introduced four stages of heart failure:
- Stage A: Patients at high risk for developing heart failure in the future, but no functional or structural heart disorder.
- Stage B: Structural heart disorder, but no symptoms at any stage.
- Stage C: Previous or current symptoms of heart failure in the context of an underlying structural heart problem, but managed with medical treatment.
- Stage D: Advanced disease requiring hospital-based support, a heart transplant, or palliative care.
The ACC staging system is useful in that Stage A encompasses “pre-heart failure” – a stage where intervention with treatment can presumably prevent progression to overt symptoms. ACC Stage A does not have a corresponding NYHA class. ACC Stage B would correspond to NYHA Class I. ACC Stage C corresponds to NYHA Class II and III, while ACC Stage D overlaps with NYHA Class IV.
How Do Left Ventricular Assist Devices Help?
Patients with NYHA Class III or IV heart failure may benefit from a current treatment that involves the use of the Heartmate II, which is a left ventricular assist device (LVAD). LVADs are battery-operated mechanical pump-type devices that are surgically implanted on the upper part of the abdomen. They take blood from the left ventricle and pump it through the aorta. LVADs are becoming more common and are often used by patients who have to wait for heart transplants.
Related Articles:
You must log in to post a comment.