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Heart Failure (cont.)

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What causes heart failure?

The cause of heart failure is a weakened or thickened cardiac muscle. For example, in chronic high blood pressure (hypertension), the heart must pump extra forcefully against the additional blood pressure. First it becomes enlarged and thickened. But over time, the heart weakens, scarring (fibrosis) develops, and it becomes less efficient at pumping. It can become larger (dilated) and weak or thickened and stiff. When the risk factors for heart failure are present, there usually is inflammatory stress, which further damages the cardiac muscle depleting cells of energy and antioxidants.

What are heart failure stages or classifications?

While doctors define heart failure in stages or classifications, it represents a progression of heart muscle weakness. Sometimes people refer to this process as chronic heart failure but technically that term isn't correct.

The New York Heart Association (NYHA) puts the stages of heart failure into four classifications:

  • Class I: no limitations in activity. Normal activities can be performed.
  • Class II: mild limitations and mild symptoms with activity; no symptoms at rest
  • Class III: noticeable limitations in activity; only comfortable at rest
  • Class IV: symptoms occur at any level of activity and uncomfortable even resting

The American Heart Association along with the American College of Cardiology grades heart failure in four stages, and takes into account that heart failure can be present even before symptoms appear:

  • Stage A: No heart failure, but at high risk due to another medical condition that can lead to heart failure, such as high blood pressure, diabetes, obesity, or coronary artery disease.
  • Stage B: The heart has been damaged by the patient's other medical condition(s) or other factors, but no symptoms are present yet.
  • Stage C: The heart is damaged and the patient is experiencing heart failure symptoms.
  • Stage D: The patient has severe heart failure that requires specialized care, despite receiving treatment (end-stage).

How is heart failure diagnosed?

  • Heart failure can be diagnosed by physical exam, reported symptoms, or chest X-ray.
  • An echocardiogram test can identify a low ejection fraction or a thickened, stiff heart muscle.
  • Echocardiograms may be used to distinguish between systolic and diastolic types of heart failure.
  • Blood tests such as BNP (beta naturetic peptide) suggest heart failure.
  • Algorithms and guidelines exist to score and weigh signs and symptoms to help make the diagnosis.
Medically Reviewed by a Doctor on 9/22/2016


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