Heart attack and heart failure are two distinct but often confused cardiovascular conditions. A heart attack occurs suddenly when blood flow to part of the heart muscle is blocked, causing tissue damage due to a lack of oxygen. While heart failure can also come on suddenly, it usually develops gradually as the heart becomes too weak or stiff to pump blood effectively.Despite these very different causes, the two heart conditions share some overlapping symptoms, which can sometimes make it difficult to tell them apart. In fact, a heart attack can lead to heart failure, and some people may experience both in their lifetime. Recognizing how these conditions overlap and differ is key to seeking and receiving timely and appropriate medical care.

A heart attack, or myocardial infarction, occurs when blood flow to part of the heart muscle is reduced or blocked, starving it of oxygen-rich blood and eventually causing it to die. Most often, this blockage occurs after plaque — deposits of fat, cholesterol, and other substances — builds up in the coronary arteries, which supply the heart muscle with blood. When that plaque ruptures or breaks, a blood clot forms around it, blocking the already narrowed blood vessel.Chest pain or discomfort is the hallmark symptom of heart attack. It’s usually felt in the center or left side of the chest as a sharp crushing, squeezing, or pressing sensation or a kind of painful heaviness or fullness. It can also present as a stabbing or burning feeling like heartburn or indigestion. This chest discomfort may last a few minutes or more than 20 minutes, or come and go.Sudden upper-body pain or discomfort is another sign of heart attack. This feeling may initially appear to radiate from chest discomfort, but it may also occur separately and affect your:

• Arms (one or both)

• Back

• Jaw

• Neck

• Shoulders

• Upper stomach

Shortness of breath is often an early sign of heart attack, especially for older adults. It usually accompanies chest discomfort, but it can also occur beforehand when you’re resting or moving through light physical activity. It may even be the only symptom you experience.Other symptoms to be aware of include:

• Cold sweat

• Dizziness or lightheadedness

• Nausea and vomiting

• Rapid or irregular heartbeat

• Sleep disturbances

• Unusual fatigue or weakness

These symptoms may also be early warning signs of a heart attack, suddenly appearing weeks before any dramatic chest discomfort occurs.

Some heart attacks are even “silent,” occurring without symptoms or with mild symptoms that feel more like heartburn or the flu. These events may be more common in women and people with diabetes.Heart attacks in women tend to be more subtle and easy to miss. While chest pain is still the most common sign, women often experience it as pressure or tightness rather than a crushing pain. And they are more likely than men to experience other heart attack symptoms, such as fatigue, sleep disturbances, and digestive symptoms like nausea and indigestion. Some women also experience:

• A squeezing or pressure in the upper back that feels like a rope is being tied around them

• Cough

• Heart flutters

• Heartburn

• Loss of appetite

Heart failure simply means your heart is unable to pump blood effectively. It can develop rapidly as a result of damage to your heart, such as from coronary artery disease, but in most cases, it’s a condition in which symptoms develop gradually and worsen over time. Heart failure can affect one or both sides of your heart, which determines what symptoms you may experience.Left-sided heart failure is much more common and occurs when your left ventricle (heart chamber) is unable to pump enough oxygenated blood to the rest of your body. It reduces the ability of your organs, muscles, and other tissues to function properly, and it can cause blood to pool in your lungs.Shortness of breath from activities like climbing stairs is one of the hallmark symptoms of heart failure and usually one of the first symptoms people notice. It tends to worsen over time as the heart weakens, and you may even experience it simply from walking across a room or bending down (or even while lying down).

Other symptoms that develop from left-sided heart failure include:

• Abdominal swelling

• Blue discoloration of the fingers and lips

• Cough

• Fatigue and weakness, even after resting

• Inability to sleep while lying flat

• Sleepiness and trouble concentrating

• Swelling of the scrotum

• Weight gain

If you have right-sided heart failure, it means your heart is too weak to pump enough deoxygenated blood from your body back to your lungs, where the blood refills with oxygen. It results in blood building up and increasing pressure in your veins until the fluid eventually leaks out and collects in various tissues in your body. Symptoms that may develop with right-sided heart failure include:

• Abdominal pain

• Breathlessness

• Frequent urination

• Heart palpitations

• Nausea and loss of appetite

• Swelling in your lower extremities, abdomen, and neck veins

• Weight gain

While not a hallmark of the condition, chest pain or discomfort can be an early symptom of right-sided heart failure. It’s typically described as discomfort in the chest, like pressure or tightness, unlike the sudden, crushing pain of a heart attack. But because chest pain can also signal a heart attack, it should never be ignored.

Knowing when to call 911 versus your doctor can be lifesaving.

Always treat severe chest pain as an emergency, and call 911 immediately.Even if you’re not sure you’re having a heart attack, call 911 if you experience:

• Chest discomfort in the center of the chest that lasts a few minutes or comes and goes

• Sudden pain or discomfort in the upper body, including the arms, back, jaw, neck, and shoulders

• Any combination of other heart attack symptoms, especially for women, such as shortness of breath, unexplained fatigue, nausea and vomiting, and lightheadedness or dizziness

• Sudden loss of responsiveness or inability to breathe normally, which may indicate cardiac arrest

Also call 911 if you have heart failure and you experience:

• Constant, hacking cough

• Cough with pink, foamy mucus

• Inability to lie flat

• Increased swelling in the lower body

• Shortness of breath at rest

• Weight gain of more than 5 pounds in a week

Call your doctor right away if you notice:

• Heart palpitations

• New or worsening swelling in your abdomen, ankles, feet, or legs

• Shortness of breath during mild activities

• Unexplained weight gain of more than 2 to 3 pounds overnight or 5 pounds in a week

• Unusual fatigue or weakness

Both heart attack and heart failure can be treated effectively. Heart failure requires long-term management with medications to improve heart health, lifestyle changes like following a heart-healthy diet, and, if necessary, implanted devices like pacemakers. Heart attack, on the other hand, demands emergency treatment with medications to destroy and prevent blood clots and treat chest pain, oxygen therapy, and procedures to improve blood flow.

• A heart attack is a sudden, emergency event caused by a blockage in the blood flow to the heart, while heart failure is a chronic condition that develops over time as the heart becomes too weak to pump blood effectively.

• Heart attack symptoms commonly include sudden chest pain or discomfort, radiating pain in the upper body, and shortness of breath, with some symptoms presenting differently in women.

• Heart failure symptoms often include shortness of breath with activity, fatigue, swelling in the abdomen or lower extremities, and weight gain.

• Always call 911 for severe chest pain, symptoms like chest discomfort that last for more than a few minutes, or sudden upper-body pain, as they may be signs of a heart attack.