Originally published during Heart Failure Awareness Week 2023, this article explores symptoms, causes and underlying conditions that may lead to a diagnosis of heart failure.
Types of Heart Failure and Diagnosis
Heart failure is diagnosed by a constellation of symptoms and signs of fluid overload due to either a weak heart (heart failure with reduced ejection fraction, or HFrEF) or a strong heart with poor heart relaxation (heart failure with preserved ejection fraction or HFpEF). Ejection fraction (EF) measures the amount of blood the left ventricle pumps out with each contraction. People with a healthy heart have an EF of about 60%, while people with heart failure have a reduced ejection fraction with EF < 40% (HFrEF), a mildly reduced ejection fraction with EF at 40-49%, or a preserved ejection fraction with EF >50% (HFpEF). 
Medical providers often order an echocardiogram, or “echo” to determine the strength of the heart. An echocardiogram is an ultrasound of the heart that measures the ejection fraction (EF), wall thickness, and the flow of blood through valves in your heart. 
In order to determine the best course of therapy, physicians often assess the stage of heart failure (HF) as well as the patient’s functional status. These are done by two systems:
The American College of Cardiology/American Heart Association classification of heart failure has four stages.
STAGES OF HEART FAILURE (HF)
|A - At risk for HF||High risk for HF but without symptoms, structural heart disease, or cardiac biomarkers of stretch or injury|
|B - Pre-HF||
No symptoms or signs of HF and evidence of 1 of the following:
|C – HF||Structural heart disease with current or previous symptoms of HF|
|D – Advanced HF||Marked HF symptoms that interfere with daily life and with recurrent hospitalizations despite attempts to optimize guideline directed medical therapy |
Heart failure is also classified according to the severity of a patient’s self-reported symptoms using the New York Heart Association (NYHA) functional classification system.
|NYHA Class||Patient Symptoms|
|Class I (Mild)||No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, or dyspnea (shortness of breath).|
|Class II (Mild)||
Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in fatigue, palpitation, or dyspnea.
|Class III (Moderate)||Marked limitation of physical activity. Comfortable at rest, but less than ordinary activity causes fatigue, palpitation, or dyspnea.|
|Class IV (Severe)||Unable to carry out any physical activity without discomfort. Symptoms of cardiac insufficiency at rest. If any physical activity is undertaken, discomfort is increased.|
Underlying Conditions That May Cause Heart Failure
It may be determined that your heart failure is caused by an underlying condition, which may even be genetic. Underlying conditions may include coronary heart disease, heart inflammation, high blood pressure, cardiomyopathy, or an irregular heartbeat. 
Cardiomyopathy is a condition that causes problems with your heart muscle that can make it harder for your heart to pump blood. Depending on the type of cardiomyopathy that you have, your heart muscle may become thicker, stiffer, or larger than normal. This can weaken your heart and cause an irregular heartbeat, heart failure, or a life-threatening condition called cardiac arrest. 
Types of cardiomyopathies, some of which are genetic, can include:
- Arrhythmogenic cardiomyopathy 
- Dilated cardiomyopathy
- Hypertrophic cardiomyopathy
- Takotsubo cardiomyopathy
- Peripartum cardiomyopathy
You can explore these types of cardiomyopathies here.
Peripartum cardiomyopathy occurs during pregnancy, often happening at a late-stage or within a few months postpartum. The condition affects about 1 in 1,000 to 1 in 4,000 pregnant women in the United States. Doctors are not sure what causes cardiomyopathy during pregnancy, and while some women recover completely, others can have serious, long-term or life-threatening complications. It’s best to speak with your care team for specifics on your individual case. 
Explore the resources and references below for more information on these topics.
- HFSA Heart Failure Awareness 365 campaign September/October 2022 theme: Types of Heart Failure and Relate Conditions/Diseases
- The Basics of Heart Failure: Heart Failure Stages Video
- The Basics of Heart Failure: HFpEF vs HFrEF Video
- The Basics of Heart Failure: NYAH Classifications Video
- HFSA Patient Education Module: Managing Other Chronic Conditions