Cardiac asthma is the medical condition of intermittent

wheezing A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed (for example narrowing of the lower respiratory tract ...

, coughing, and

shortness of breath Shortness of breath (SOB), also medically known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing di ...

that is associated with underlying

congestive heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

(CHF). Symptoms of cardiac asthma are related to the heart's inability to effectively and efficiently pump blood in a CHF patient. This can lead to accumulation of fluid in and around the lungs (

pulmonary congestion Pulmonary edema, also known as pulmonary congestion, is excessive liquid accumulation in the tissue and air spaces (usually alveoli) of the lungs. It leads to impaired gas exchange and may cause hypoxemia and respiratory failure. It is due t ...

), disrupting the lung's ability to oxygenate blood. Cardiac asthma carries similar symptoms to bronchial asthma, but is differentiated by lacking inflammatory origin. Because of the similarity in symptoms, diagnosis of cardiac versus bronchial asthma relies on full cardiac workup and

pulmonary function testing Pulmonary function testing (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity ...

. Treatment is centered on improving cardiac function, maintaining blood oxygen saturation levels, and stabilizing

total body water In physiology, body water is the water content of an animal body that is contained in the tissues, the blood, the bones and elsewhere. The percentages of body water contained in various fluid compartments add up to total body water (TBW). This w ...

volume and distribution.

Signs and symptoms

The most common findings of cardiac asthma are the presence of wheeze, cough, or shortness of breath (predominantly occurring at night or when laying down) in a patient that possesses signs of congestive heart failure. Additional findings consist of production of frothy or watery sputum and presence of water in the lungs that can be heard via stethoscope. In severe cases, a patient can experience multiple night time episodes of breathlessness, changes in skin coloration, and episodes of bloody sputum.

Pathophysiology

The underlying causes for cardiac asthma stem from the eventual back up of fluid into the pulmonary vasculature as a result of the heart's, particularly left sided, inability to effectively and efficiently pump blood. The accumulation of fluid in the heart creates a higher than normal pressure system that places increasing pressure demands on the pulmonary venous system in order for appropriate oxygenation of blood to occur. This results in what is called pulmonary venous hypertension (PVH), and results in distention and recruitment of

pulmonary capillaries A capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter. Capillaries are composed of only the tunica intima, consisting of a thin wall of simple squamous endothelial cells. They are the smallest blood vessels in the body: ...

to help distribute the increased pressure gradient. At the capillary, there is a microvascular barrier that helps regulate fluid status via molecular pressure forces such as forces that push outward from vessels and pressures that pull or attract into vessels. With increasing PVH, pressure outward overcomes pressure inward, and fluid is distributed to th
lung interstitium
preserving oxygen exchange at the capillary. Fluid is transported to the hilum and

pleural space The pleural cavity, pleural space, or interpleural space is the potential space between the pleurae of the pleural sac that surrounds each lung. A small amount of serous pleural fluid is maintained in the pleural cavity to enable lubrication bet ...

, and removed via the lymphatic system. At first, the body is capable of handling excess water. Later, the capillary vasculature is overwhelmed by increased pressure and fluid backs up into the

alveolar sac A pulmonary alveolus (plural: alveoli, from Latin ''alveolus'', "little cavity"), also known as an air sac or air space, is one of millions of hollow, distensible cup-shaped cavities in the lungs where oxygen is exchanged for carbon dioxide. Al ...

, resulting in pulmonary edema and decreased oxygenation capability. Additionally, increased pressure demands on capillary vasculature result in increases in vascular tone to include remodeling of pre-capillary vessels such a
medial wall hypertrophic changes
Over time, the remodeling efforts of the vessels can progress to

hyperplastic Hyperplasia (from ancient Greek ὑπέρ ''huper'' 'over' + πλάσις ''plasis'' 'formation'), or hypergenesis, is an enlargement of an organ or tissue caused by an increase in the amount of organic tissue that results from cell proliferatio ...

changes of the vessels' wall construction, and results in increased pulmonary vascular resistance. There is ongoing interest into establishing connections of cardiac asthma to abnormalities in

bronchiole The bronchioles or bronchioli (pronounced ''bron-kee-oh-lee'') are the smaller branches of the bronchial airways in the lower respiratory tract. They include the terminal bronchioles, and finally the respiratory bronchioles that mark the start ...

anatomy. Current evaluation has proposed multiple mechanisms for increased airway resistance, and focus is on four alternate explanations: *

Bronchoconstriction Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath. Causes The condition has a number of causes, the most common be ...

as a result of pulmonary edema. *

Intrathoracic The thoracic cavity (or chest cavity) is the chamber of the body of vertebrates that is protected by the thoracic wall (rib cage and associated skin, muscle, and fascia). The central compartment of the thoracic cavity is the mediastinum. There a ...

space competition from heart enlargement and pulmonary edema (complications of CHF) that compress airway construction and bronchioles. * Bronchial obstruction secondary to intraluminal edema. * Bronchial mucosa edema.

Diagnosis

The diagnosis of cardiac asthma is accomplished through workup of congestive heart failure, complete with: * Evaluation of current symptoms with specific consideration of chronological progression or worsening. * Past Medical History screen with consideration for conditions that predispose to heart failure, such as prior

heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which ma ...

, history of coronary revascularization, high blood pressure, or diabetes (heart). * Physical Exam with emphasis on listening for abnormalities of heart sound, abnormalities of lung sound, or presence of increased fluid retention in neck or in extremities. * Laboratory Evaluation with specific interest in B-type natriuretic peptide levels. * Electrocardiography to evaluate for irregularities in heart rhythm. * Chest Radiograph to evaluate for presence of lung congestion or increased heart size. * Echocardiography to evaluate heart function. Echocardiography is the preferred choice for diagnosis of heart failure in patients. As well as evaluation of lung function via: *

Pulmonary function testing Pulmonary function testing (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity ...

(PFT) complete with bronchoprovocation testing. PFTs represent the preferred method for evaluating for bronchial asthma.

Management

Treatment of asthma symptoms in CHF patients is directed towards optimizing the patient's cardiovascular status and correcting potential oxygen deficit. Current recommendations in acute asthma symptoms are utilization of diuretics such as

furosemide Furosemide is a loop diuretic medication used to treat fluid build-up due to heart failure, liver scarring, or kidney disease. It may also be used for the treatment of high blood pressure. It can be taken by injection into a vein or by m ...

, venodilators such as nitroglycerin, and

morphine Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a pain medication, and is also commonly used recreationally, or to make other illicit opioids. T ...

. The initial strategy should focus on decreasing patient fluid retention with diuretic therapy, thereby decreasing cardiac preload and overall fluid load in pulmonary circuit (

). Next, if aggressive diuresis is not adequately correcting symptoms, venodilators can be used to distribute blood and fluid to the venous system, thereby decreasing cardiac preload and left heart pressures contributing to pulmonary congestion. Lastly, morphine can be utilized for assistance in improving ease of breathing through a presumed mechanism similar to venodilation, as well as reducing patient anxiety. Additionally, applications of supplemental oxygen and repositioning to upright or standing positions in events of low blood oxygen saturation and difficulty breathing can be utilized as needed. Chronic management of cardiac asthma is directed at optimizing therapy of heart failure. Current recommendations can be found at its respective page (

). There is importance of distinguishing whether asthma is of bronchial or cardiac origin because management of bronchial asthma is primarily centered on utilization of inhalers, such as

bronchodilators A bronchodilator or broncholytic (although the latter occasionally includes secretory inhibition as well) is a substance that dilates the bronchi and bronchioles, decreasing resistance in the respiratory airway and increasing airflow to the lungs ...

and corticosteroids. At this point in time, there has been limited evidence of improvement of cardiac asthma symptoms with utilization of inhalers.

References

External links