Types of Heart Failure: Stages and Classes
Nature of Heart Failure
The normal human heart is the most advanced and reliable machine on earth. Nothing comes close. The heart beats 100-150,000 times every day. Multiply that by 365 days a year times the 75-80 years of an average human life span and you begin to see what an incredibly amazing and reliable machine the heart is.
Heart failure is the slow progressive destruction of the heart. Heart failure is not so much a disease as it is a constellation of signs and symptoms caused by the heart’s inability to pump enough blood to meet the body’s needs.
There are many different types of heart failure depending on the cause but the fundamental problem is the same: the heart’s function is not adequate which causes every organs to deal with limited oxygen and nutrients. The severity of heart failure depends on the degree to which the body’s needs are not being met.
The Ejection Fraction
One common measure of heart function is called the ejection fraction or EF. After oxygenation in the lungs, blood returns to the heart and then a fraction of it is pumped out to the rest of the body. The fraction pumped out is called the ejection fraction or EF and is normally about 50-60% of the blood contained in the heart. This ejected fraction is normally more than enough to meet the body’s needs. EF is measured by a number of different tests. Most commonly an echocardiogram is obtained using an ultrasound machine. The EF by echo is very easy to obtain and a very reliable way to measure the EF over time.
Classification of Symptoms Remote
In addition to the ejection fraction or EF, another way to classified heart failure severity is by symptoms and by looking at how much activity it takes for the heart to start failing. One classification system used by everyone is the New York Heart Association (NYHA) classification system:
- Class I – Symptoms of CHF only happen at serious activity levels and exercise that would limit anybody except an athlete
- Class II – Symptoms of CHF happen with ordinary exertion such as walking, carrying groceries, climbing stairs, etc
- Class III – Symptoms of CHF happen with less than ordinary exertion
- Class IV – Symptoms of CHF happen at rest with no physical activity except just sitting or lying down.
Stages of Heart Failure
Because heart failure is progressive condition, it is important to gage where along the course a person is. In 2001, the American Heart Association and American College of Cardiology developed a rating system to evaluate the progression of heart failure symptoms (called AHA Stages). This system allows doctors all over the world to speak a common language when it comes to how advanced a patient’s heart failure has become.
Staging heart failure, similar to staging cancer, allows the appropriate medications and devices to be deployed at the right time and for the right patient.