Your Subtype, Stage, and Ejection Fraction

When you are diagnosed with heart failure, your doctors will use several classification systems to describe exactly how your heart is working. These labels are not just “medical jargon”—they help your care team determine the most effective treatment for your specific situation.

Understanding Ejection Fraction (EF)

As mentioned in the diagnosis page, your medical team uses imaging like an echocardiogram to measure how well your heart pumps blood ^[1]. One important measure from this test is your Ejection Fraction (EF).

Think of your heart’s left ventricle as a glass of water. When the heart beats, it doesn’t empty completely. The EF is the percentage of blood that is pumped out of the ventricle with each contraction ^[2]. A normal EF typically ranges from roughly 55% to 70%. In heart failure, this number helps doctors categorize your condition into different subtypes ^[2][3]:

• HFrEF (Heart Failure with Reduced EF): Your EF is 40% or less. This means the heart muscle has weakened and cannot pump with enough force ^[2].
• HFmrEF (Heart Failure with Mildly Reduced EF): Your EF is between 41% and 49%. This is considered a middle ground where the heart’s pumping ability is slightly impaired ^[3].
• HFpEF (Heart Failure with Preserved EF): Your EF is 50% or higher. An EF in this range does not automatically mean you have HFpEF; the diagnosis requires matching symptoms alongside evidence of high filling pressures or congestion, indicating the heart is too stiff to fill properly ^[4][2].
• HFimpEF (Heart Failure with Improved EF): This describes a trajectory where a person previously had an EF of 40% or less, but after treatment, their EF improved to above 40% ^[2][5].

The “Remission” Concept: Why HFimpEF is Not a Permanent Cure

If your EF improves significantly, it is a major victory and a sign that your treatment is working. However, medical guidelines are very clear: improved EF reflects a state of remission or recovery, not a permanent cure ^[2][6].

The underlying vulnerabilities of the heart remain. Research shows that stopping medications can lead to a severe relapse. In one small study of patients who recovered from a specific type of dilated cardiomyopathy (the TRED-HF trial), roughly 40% relapsed within six months of stopping their medications ^[7]. Because of this risk, doctors generally recommend staying on your guideline-directed heart failure therapies indefinitely ^[8][9]. Always consult your doctor before making any medication changes.

Two Ways of Measuring Your Progress

Doctors use two different “staging” systems to track your heart failure. One looks at the physical progression of the disease, while the other looks at how you feel and function in daily life.

1. ACC/AHA Stages (The Structural Path)

This system (Stages A through D) tracks the progression of the disease itself. It helps doctors understand your medical history and the structural changes in your heart ^[10].

• Stage A: You are at high risk for heart failure (e.g., you have high blood pressure or diabetes) but have no structural heart issues and no symptoms ^[10].
• Stage B: You have structural heart disease (like a low EF or a thickened heart wall) but have never felt symptoms of heart failure ^[10].
• Stage C: You have structural heart disease and either currently have symptoms or have had them in the past ^[10]. Most people diagnosed with heart failure are in Stage C.
• Stage D: You have advanced heart failure that causes severe symptoms despite optimal treatments, and may require specialized interventions ^[10].

2. NYHA Functional Class (The Symptom Scale)

Unlike the stages above, your New York Heart Association (NYHA) Class can improve as treatment takes effect. This scale measures how much your symptoms limit your physical activity ^[11]. Your clinician will assign this class based on your usual routines and other health conditions.

By understanding both your stage and your class, you can better monitor your health. Your Stage tells you where you are in the overall journey of the disease, while your Class reflects how well your current treatment is helping you live your life ^[9][11].