Cardiac Asthma: Symptoms, Diagnosis, And Treatment

Cardiac asthma is a condition caused by congestive heart failure. While it doesn't have anything to do with typical bronchial asthma, the symptoms of these two conditions are similar. A person who develops cardiac asthma can experience asthma-like wheezing and coughing that may cause the doctor to misdiagnose the problem.

If left untreated, cardiac asthma could turn into a life-threatening condition. Timely diagnosis is the key to relieving the symptoms and treating the underlying cause of the problem, which is heart failure.

Let's take a closer look at diagnosing, treating, and preventing cardiac asthma.

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What is cardiac asthma? 

Cardiac asthma is a condition that is secondary to congestive heart failure. It's not related to traditional bronchial asthma. However, the symptoms of these two conditions are similar and include wheezing, coughing, difficulty breathing, and even coughing up blood.

The similarity of symptoms often causes doctors to misdiagnose cardiac asthma. However, since bronchial asthma and cardiac asthma are completely different, they require different treatments. Treating a person with cardiac asthma for bronchial asthma could worsen their condition.

Congestive heart failure occurs when the heart can't pump the blood out of the left ventricle (one of the four heart chambers) properly. When this happens, the excess fluid appears in the lungs and makes breathing problematic. This results in common asthma symptoms, such as coughing and wheezing.

However, the cause of typical bronchial asthma is airway constriction resulting from inflammation.

Treating cardiac asthma involves addressing the underlying problem and removing excess fluid from the lungs. When treated timely, this condition doesn't turn into a medical emergency.  

Symptoms of cardiac asthma 

One of the common symptoms occurs when an individual is sleeping and tends to be worse at night. They wake up suddenly and experience severe shortness of breath. Sitting up for about 30 minutes usually causes the symptoms to go away on their own.

That's one of the ways to distinguish cardiac asthma from a bronchial asthma attack. Symptoms of bronchial asthma don't usually subside without medication.  

Other symptoms of cardiac asthma are:

  • Dyspnea (difficulty breathing)

  • Wheezing

  • Coughing

  • Spitting up bloody or frothy mucus

  • Sweating

  • Cyanosis (bluish skin, lips, or fingernails)

  • Increased heart rate

Symptoms often worsen when an individual is lying down and subside when sitting or standing. If symptoms don't subside, you could be facing a medical emergency. This warrants a 911 call.

Even if symptoms go away on their own, it's important to contact a doctor. A medical professional can diagnose the condition and set up the right course of treatment.

Causes of cardiac asthma

The underlying cause of cardiac asthma is heart failure (also called congestive heart failure or left heart failure).

The common causes of heart failure are coronary artery disease, diabetes, and high blood pressure. In the United States, about 6.2 million people¹ live with heart failure.

Other causes of heart failure that lead to cardiac asthma include:

Past heart attacks

When a heart attack occurs, it damages the heart's muscle tissue. The weakened tissue doesn't allow the heart to pump blood properly.

Heart valve abnormalities

You could develop heart valve abnormalities after a disease, bacterial endocarditis (infection of the heart valve), or a congenital disorder. If the valve doesn't open or close properly when the heart beats, the heart muscle must pump harder. The excess workload can lead to heart failure.

Heart muscle problems

Anything that causes damage to the heart muscle (disease, infection, heavy alcohol use, or drug use) increases the risk of heart failure.

Congenital disorder

If the heart chambers don't form correctly while the fetus develops, other heart chambers, including the left ventricle, must work harder. Overworked chambers may cause heart failure.

Severe lung disease

If a person's lungs don't work properly, the heart must pump harder to bring oxygen to the body.

The main symptoms of heart failure are:

  • Shortness of breath during everyday activities

  • Breathing problems when lying down

  • Weight gain due to water retention in the legs, feet, ankles, and stomach

  • Fatigue

  • Weakness

While there is currently no cure for heart failure, it can be managed by medication and lifestyle changes. The key to alleviating the symptoms and preventing cardiac asthma is timely diagnosis.

Risk factors of cardiac asthma

Some people are more likely to develop cardiac asthma than others. Here are the risk factors to consider:


Generally, heart failure occurs in older people. Around 20% of Americans over 40² will develop heart failure in their lifetime. After the age of 65,³ the incidence of heart failure increases dramatically. For every 10-year increment, it doubles in men and triples in women.


Studies⁴ show that women tend to develop heart failure at an older age than men. Women have a 20%⁵ higher rate of heart failure within five years of a heart attack than men.


African Americans and Hispanics are more likely to develop heart failure than white Americans. African American women have the highest chance of developing the condition than any other combination of race and gender in the US.

Excess weight

According to studies,⁶ obesity-related factors cause 11% of heart failure cases in men and 14% in women.

Bad habits

Heavy alcohol and drug use can weaken the heart muscle and lead to heart failure, which in turn causes cardiac asthma. Smoking can also contribute to heart failure.

Overactive thyroid

If your thyroid gland is producing too many hormones, your entire body works at a faster pace. This means that the heart needs to pump blood harder to keep up. Such excessive workload could lead to heart failure.

Your doctor will review the risk factors while diagnosing the condition. Make sure to share your entire medical history, including past heart attacks and unhealthy lifestyle choices.

How to diagnose cardiac asthma 

If you live with heart failure, ask your doctor about the symptoms of cardiac asthma. It can help you identify the problem as soon as it occurs. However, cardiac asthma can be the first obvious symptom of heart failure. In this case, timely diagnosis is imperative.

Several ways exist for diagnosing cardiac asthma and differentiating it from bronchial asthma. Your doctor will likely do or administer the following:

1. Review medical and family history

Your history of heart problems and congenital heart defects can help your doctor identify the condition. Make sure to share your entire medical history and answer questions in detail.

2. Physical examination 

Your doctor will perform a physical exam to check for breathing problems, rapid heartbeat, and abnormal sounds in your lungs.

3. Lab tests

Your doctor may order blood and urine tests to confirm the diagnosis. These tests can show if other conditions are contributing to your symptoms. These will also help your doctor see if there is an underlying infection or anemia.

4. Breathing test

A breathing test, such as a spirometry test, can demonstrate how your lungs work. If there is excess fluid in the lungs, the test is likely to show a problem. This test isn't painful. It involves breathing into a spirometry machine through a mouthpiece.

A spirometry test can show whether your breathing problems are related to cardiac asthma or bronchial asthma.

5. ECG

ECG (electrocardiogram) reads electrical signals from your heart to help your doctor diagnose heart failure.

People who have heart failure usually have an abnormal ECG. However, 10%⁷ of people who live with this condition have a normal ECG. That's why diagnosing cardiac asthma with ECG alone is impossible.

6. Echocardiogram

An echocardiogram (often called echo) involves using an ultrasound to check how well your heart's chambers and valves are pumping blood. It shows your doctor if your heart has a pumping problem, which could be a sign of heart failure.

7. Chest x-ray 

A chest x-ray can help your doctor confirm the presence of congestion in your lungs. It can also help identify cardiomegaly (enlarged heart), which is a heart disorder symptom. Cardiomegaly often occurs in people with heart failure and cardiac asthma.

8. Stress test

A heart stress test can show your doctor how well your heart can pump blood. It usually involves a certain activity (e.g., walking on a treadmill) to make your heart pump harder. Throughout the exercise, your doctor measures your heart rate, electrical activity in your heart, oxygen levels, and more.

9. Cardiac CT and MRI

Computer tomography (CT) and magnetic resonance imaging (MRI) can help your doctor check the condition of your heart chambers, muscles, and valves. It can also help discover a congenital heart problem that could be contributing to your cardiac asthma.

Managing and treating cardiac asthma 

Managing and treating cardiac asthma involves addressing the underlying problem and reducing the amount of fluid in your lungs.

Lifestyle changes

Switching to a healthier lifestyle can help reduce cardiac asthma's symptoms and severity. These changes include:

  • Kicking bad habits, such as heavy drinking, drug use, and smoking

  • Maintaining a healthy weight

  • Eating a heart-healthy diet

  • Exercising regularly

  • Getting sufficient rest

  • Monitoring fluid intake

  • Getting sufficient sleep with your head propped up

If you have heart failure, you need to monitor your condition closely. Your doctor will recommend the frequency of check-ups.


The medication your doctor may prescribe includes:

  • Diuretics. A strong diuretic, such as Furosemide, can remove fluid from your lungs. This medication must be taken under medical supervision since it can have serious side effects.

  • ACE inhibitors. Angiotensin-converting enzyme inhibitors can lower your blood pressure and treat heart failure.

  • Beta-blockers. This medication can reduce the mortality rate of people with cardiac asthma and heart failure.

If you are having an acute cardiac asthma attack, your doctor may prescribe nitroglycerin and morphine to reduce the stress on your heart. In an advanced case, fluid aspiration (removing excess fluid through a needle) may be necessary.


Sometimes, a doctor may recommend surgery to treat an underlying heart problem. Surgeries that can improve heart failure are:

  • Coronary artery bypass graft

  • Valve replacement surgery

  • Angioplasty (expanding blocked or narrowed coronary arteries)

In advanced cases, a doctor may recommend heart transplantation.

Implantable cardioverter defibrillator (ICD)

If arrhythmia (abnormal heart rhythm) is one of the symptoms you regularly experience due to heart failure, your doctor may suggest using an ICD. This tiny device is implanted into your chest to control your heart rhythm.

If your heart rhythm is dangerously abnormal, the device administers an electrical shock to restore it. Today, an ICD is the only tool that can significantly reduce sudden death from arrhythmia. 

Cardiac rehabilitation program

People who live with heart failure can benefit from a cardiac rehabilitation program. This comprehensive therapy combines exercises, risk factor modification, diet, counseling, and psychological support. Ask your doctor about cardiac rehab options in your area.

How to prevent cardiac asthma

To reduce the risk of cardiac asthma, you can:

  • Keep your heart failure under control

  • Monitor your health to discover heart conditions

  • Maintain a healthy weight

  • Manage your stress

  • Exercise regularly

  • Take prescribed medication

Not all people who live with heart failure will have cardiac asthma. Speak to your doctor about effective preventive methods.

When to call your doctor 

If you start experiencing new symptoms or your existing symptoms worsen, you need to contact your healthcare provider. For example, if your ankles are constantly swollen, or you suddenly gain weight, you should let your doctor know.

You need to call 911 if you have serious breathing problems that don't go away after sitting or standing up.

The lowdown

Cardiac asthma is a condition that usually accompanies heart failure. Its symptoms are similar to what you may experience with bronchial asthma. However, these conditions have completely different causes and warrant different treatments.

With timely and proper diagnosis, both cardiac asthma and heart failure are manageable. Speak to your doctor about treatment options.

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