Distinguishing between the respiratory and cardiac causes of breathlessness

Breathlessness, or shortness of breath, is a common symptom experienced by many people and can be caused by various underlying conditions. It is often linked to either respiratory or cardiac issues, both of which impact the body's ability to effectively transport oxygen.

Understanding the differences between respiratory and cardiac causes of breathlessness is essential for accurate diagnosis and treatment. Here to provide a detailed insight is leading consultant physician in respiratory and general (internal) medicine Dr Bhashkar Mukherjee.

What are the respiratory causes of breathlessness?

Breathlessness related to the respiratory system typically arises when the lungs are unable to efficiently exchange oxygen and carbon dioxide. Common respiratory conditions that lead to breathlessness include:

• Chronic obstructive pulmonary disease (COPD): COPD is an umbrella term for lung diseases like emphysema and chronic bronchitis. It restricts airflow in the lungs, making it difficult to breathe.
• Asthma: Asthma is a chronic inflammatory disease that causes narrowing of the airways, resulting in episodes of breathlessness, wheezing and coughing.
• Pneumonia: An infection of the lungs, pneumonia causes inflammation and fluid build-up in the alveoli, the tiny air sacs, which leads to difficulty in breathing.
• Pulmonary embolism: This occurs when a blood clot lodges in the lungs, blocking blood flow and causing sudden shortness of breath, often accompanied by chest pain.
• Interstitial lung disease: A group of lung disorders that result in scarring of lung tissue, interstitial lung disease makes the lungs stiff, limiting the amount of oxygen that can be absorbed.
• Lung cancer: Tumours in the lungs can obstruct airways or reduce lung capacity, leading to shortness of breath, especially during physical activity.

What are the cardiac causes of breathlessness?

Breathlessness related to the heart generally occurs when the heart is unable to pump enough blood to meet the body's oxygen demands. Some of the primary cardiac causes include:

• Heart failure: When the heart cannot pump efficiently, blood backs up in the lungs, causing fluid to accumulate and leading to shortness of breath, particularly during exertion or when lying down.
• Coronary artery disease (CAD): CAD is caused by the narrowing or blockage of the coronary arteries, which supply blood to the heart muscle. A lack of oxygen to the heart can cause breathlessness, often accompanied by chest pain.
• Arrhythmias: Irregular heart rhythms can disrupt the flow of blood and oxygen to the body, causing fatigue and shortness of breath.
• Cardiomyopathy: This condition involves the weakening of the heart muscle, making it difficult for the heart to pump blood efficiently, resulting in breathlessness during exertion or rest.
• Valvular heart disease: Malfunctioning heart valves, such as in aortic stenosis or mitral regurgitation, can reduce blood flow through the heart, causing fluid to accumulate in the lungs and leading to breathlessness.

Why is it important to speak to a medical professional about breathlessness?

Breathlessness can have a variety of causes related to both the respiratory and cardiac systems. It is crucial to consult a healthcare professional for a proper diagnosis if you experience persistent or sudden shortness of breath. Early detection of the underlying cause is key to effective treatment and improving quality of life.

If you're looking for expert treatment for breathlessness, arrange a consultation with Dr Mukherjee via his Top Doctors profile.