What Is Cardiac Asthma?

In This Article
Table of Contents

Cardiac asthma is not a medical condition itself. Rather, it's a term used to describe asthma-like symptoms that occur with left-sided heart failure, a condition in which a lower chamber of the heart (called the left ventricle) is unable to pump blood efficiently. When this occurs, it can cause respiratory symptoms (like shortness of breath and wheezing) that are easily mistaken for asthma.

Because the causes of asthma and heart failure are different, a correct diagnosis is needed to ensure appropriate treatment. If heart failure is treated as asthma, the overuse of certain medications can actually make the condition worse.

Cardiac Asthma Symptoms

The respiratory symptoms of left ventricular failure can mimic those of asthma, particularly in the earlier stages of the disease. They may include:

For some people, the respiratory symptoms of heart failure may be the first or most prominent symptoms. But, more often than not, they will occur alongside other symptoms, some of which may be missed or attributed to other causes. These include:

  • Chronic fatigue
  • Persistent weakness
  • Shortness of breath when lying flat or exercising
  • Unexpected weight gain with fluid retention
  • Lack of appetite or nausea
  • Edema (tissue swelling, mainly of the lower extremities)
  • Difficulty concentrating
  • Rapid or irregular heartbeat
  • Increased need to urinate at night (nocturia)

Symptoms like these, particularly ones that are persistent or worsening, can indicate that something other than asthma is involved. Cardiac asthma is especially common in the elderly, of whom nearly a third will present with wheezing when first diagnosed. 

Asthma attacks tend to develop abruptly and end in kind, and the majority of people fully recover with no lasting effects. The chronic, progressive nature of heart failure is such that symptoms like shortness of breath, cough, and fatigue may transiently improve, but will almost invariably persist until the appropriate treatment is received.

Causes

Left-sided heart failure occurs when decreased cardiac output causes fluid to accumulate in the body. The backup of fluid into the lungs (called pulmonary edema) can manifest with breathing problems as the airways and tiny air sacs of the lungs begin to fill with fluid.

While these effects may seem similar to those that occur with asthma, they are instead owed to inflammation and narrowing of the airways.

Certain risk factors also differentiate the two diseases. Broadly speaking, heart failure will usually occur with other chronic health conditions, such as:

  • High blood pressure
  • Diabetes
  • Obesity
  • Smoking
  • Coronary artery disease
  • A previous heart attack or heart injury
  • Heart rhythm disorders
  • Heart valve problems

Asthma, on the other hand, can affect even the most healthy of individuals.

Diagnosis

Because the symptoms of cardiac asthma mimic those of true asthma, misdiagnosis is possible. Aside from the fact that the diagnosis of asthma is complicated, some practitioners jump to asthma as the cause based on symptoms alone. A review of risk factors, medical history, and non-respiratory symptoms can suggest other possibilities.

Even if the initial symptoms point to asthma as the cause, an evaluation of lung sounds using a stethoscope can often differentiate asthma from other conditions like heart failure.

With left-sided heart failure, popping sounds (called rales or crackles) can often be heard when air tries to pass through fluid-filled airways. There may also be a so-called "third-heart sound" in which the two normal heartbeats are accompanied by a vibrating noise as the ventricle fills with blood.

These sounds are not characteristic of asthma. Even during an attack, asthma chest sounds are usually limited to wheezing (a high-pitched whistling noise) during exhalation.

Lab Tests and Procedures

Based on initial findings, your doctor will order tests to investigate further. If asthma is suspected, you would generally be referred to a pulmonologist or pulmonology lab for evaluation with in-office spirometry and other pulmonary function tests (PFTs).

If heart failure is suspected, a number of common lab tests, imaging studies, and procedures can be performed to confirm the diagnosis. You may get these initially or only after pulmonary tests have been conducted and reviewed:

  • B-type natriuretic peptide (BNP), a blood test that detects a hormone released with increased ventricular pressure
  • Echocardiogram, a non-invasive ultrasound test that can visualize how well your heart is pumping
  • Electrocardiogram (ECG), used to measure the electrical impulses during heartbeats to detect irregularities
  • Stress testing, in which your ECG and respiratory function are evaluated while exercising on a treadmill or stationary bike
  • Cardiac magnetic resonance imaging (MRI), a detailed imaging study of the heart using powerful magnetic and radio waves
  • Computed tomography (CT) angiography, a 3-D imaging study using a series of X-rays to map the structure of the heart
  • Chest X-ray, generally less useful in diagnosis but that may help exclude other causes of heart dysfunction

It is important to seek a full and proper diagnosis of your condition whether heart failure or asthma is suspected.

A 2017 study in the journal JAMA reported that no less 33% of adults previously diagnosed with asthma were, in fact, misdiagnosed. Of the 213 participants in the study, 12 were found to have a serious cardiorespiratory illness.

Because some doctors will presumptively treat mild asthma based on symptoms and non-specific PFTs (like pulse oximetry), you need to intervene if a diagnosis is rushed or doesn't seem right to you.

Treatment

The treatment of left-sided heart failure depends largely on the severity of the disease and the degree of cardiovascular impairment. Cardiac asthma symptoms may also be treated, but never in isolation.

The treatment of heart failure typically involves medications to improve cardiac output, reduce blood pressure, and alleviate structural stress in the affected ventricle. This alone can help relieve cardiac asthma symptoms in many people, particularly those with less severe disease.

Drugs commonly used to treat heart failure include:

Cardiac asthma symptoms may be directly treated but generally in those with advanced heart failure. Although some doctors have been known to prescribe short-acting beta-agonists (a.k.a. "rescue inhalers") to relieve acute symptoms, there is no evidence that they are useful in people with cardiac asthma.

People with cardiac asthma who are inappropriately treated with asthma medications run the risk of "masking" the symptoms of heart failure. Moreover, the use of long-acting bronchodilators, often prescribed to people with persistent asthma, may increase the cardiovascular risk in older people.

In more advanced cases, fluid aspiration (extraction with a needle) may be needed to relieve pressure on the heart. Intravenous nitrates (delivered via injection into a vein) may also be recommended along with oxygen therapy.

Morphine may be needed in people approaching end-stage heart failure. The drug works by relaxing airways and blood vessels and can significantly relieve breathing impairment.

A Word From Verywell

Cardiac asthma is a misleading term and one that highlights the confusion that can arise when diagnosing asthma-like symptoms. As a symptom of heart disease, cardiac asthma is not treated on its own. It requires the care of a cardiologist able to diagnose, treat, and manage left-sided heart failure. With appropriate care, the respiratory symptoms of heart failure can ease along with the other symptoms.

Was this page helpful?
Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Tanabe T, Rozycki HJ, Kanoh S, Rubin BK. Cardiac asthma: New insights into an old disease. Expert Rev Respir Med. 2012;6(6):705-14. doi:10.1586/ers.12.67

  2. Tanabe T, Kanoh S, Moskowitz WB, Rubin BK. Cardiac asthma: transforming growth factor-β from the failing heart leads to squamous metaplasia in human airway cells and in the murine lung. Chest. 2012;142(5):1274-83. doi:10.1378/chest.11-1710

  3. Jorge S, Becquemin MH, Delerme S, et al. Cardiac asthma in elderly patients: Incidence, clinical presentation and outcomeBMC Cardiovasc Disord. 2007;7:16. doi:10.1186/1471-2261-7-16

  4. Chahine J, Alvey H. Left ventricular failure. In: StatPearls. Updated June 14, 2019.

  5. Hashmi MF, Tariq M, Cataletto ME. Asthma. In: StatPearls. Updated March 25, 2020.

  6. Wang Z, Xiong YX. Lung sound patterns help to distinguish congestive heart failure, chronic obstructive pulmonary disease, and asthma exacerbations. Acad Emerg Med. 2012;19(1):79-84. doi:10.1111/j.1553-2712.2011.01255.x

  7. Nagasaka Y. Lung sounds in bronchial asthma. Allergol Int. 2012;61(3):353-63. doi:10.2332/allergolint.12-RAI-0449

  8. Inamdar AA, Inamdar AC. Heart failure: Diagnosis, management and utilization. J Clin Med. 2016;5(7):62. doi:10.3390/jcm5070062

  9. Aaron SD, Vandemheen KL, Fitzgerald JM, et al. Reevaluation of diagnosis in adults with physician-diagnosed asthma. JAMA. 2017;317(3):269-79. doi:10.1001/jama.2016.19627

  10. Litzinger MHJ, Aluyen JKN, et al. Cardiac asthma: Not your typical asthma. US Pharm. 2013;38(2):HS12-8.

  11. Gershon A, Croxford R, Calzavara A, et al. Cardiovascular safety of inhaled long-acting bronchodilators in individuals with chronic obstructive pulmonary disease. JAMA Intern Med. 2013;173(13):1175-85. doi:10.1001/jamainternmed.2013.1016

  12. Miró Ò, Gil V, Peacock WF. Morphine in acute heart failure: good in relieving symptoms, bad in improving outcomes. J Thorac Dis. 2017;9(9):E871-4. doi:10.21037/jtd.2017.08.22

Additional Reading