Atrial fibrillation (Afib) is a common heart rhythm disorder characterized by a fast and irregular heartbeat originating in the upper chambers of the heart. While Afib does not typically cause a direct cough reflex, the condition often initiates events that result in persistent coughing. This coughing is usually a sign of an underlying complication or a side effect of necessary medical treatment. Understanding the distinction between these causes is important for patients and providers.
Understanding the Primary Cause: Pulmonary Congestion
The primary way Afib leads to a cough is by impairing the heart’s pumping efficiency, which can cause or worsen congestive heart failure. When the upper chambers quiver chaotically instead of contracting effectively, the heart’s ability to move blood forward is significantly reduced. This inefficient pumping causes blood to back up into the pulmonary veins, which return oxygenated blood from the lungs to the heart.
This backward pressure forces fluid components of the blood to leak out of the capillaries and into the lung tissue and air sacs, a condition known as pulmonary edema or congestion. The excess fluid irritates the airways, triggering a persistent, reflexive cough as the body attempts to clear the moisture.
The severity of the Afib episode, particularly if the heart rate is very fast or the rhythm is sustained, determines the extent of this fluid backup. When the heart beats too rapidly or irregularly, the main pumping chambers do not have enough time to fully fill. This further compromises the forward flow and exacerbates the congestion, establishing the physiological link between the heart rhythm disorder and the respiratory symptom.
Coughing Triggered by Afib Medications
The second major cause of coughing in individuals with Afib is a side effect from medications used to manage the heart condition or related high blood pressure. Angiotensin-converting enzyme (ACE) inhibitors are a class of drug commonly prescribed for Afib patients, particularly those with co-existing hypertension or heart failure. These medications are well-known for causing a specific type of cough.
ACE inhibitors work by blocking the enzyme that narrows blood vessels, but this same enzyme also breaks down bradykinin. When the enzyme is inhibited, bradykinin and other inflammatory substances accumulate in the airways. This buildup increases the sensitivity of the cough receptors, leading to a persistent, irritating cough.
This medication-induced cough is typically dry, hacking, and non-productive, meaning it does not bring up phlegm. The cough can begin anywhere from a few hours to several months after starting the medication. If this reaction occurs, a healthcare provider will often switch the patient to an alternative drug, such as an Angiotensin Receptor Blocker (ARB), which works differently and avoids the bradykinin buildup.
How to Identify a Heart-Related Cough
A cough arising from heart issues, often called a “cardiac cough,” possesses specific characteristics that distinguish it from a cough caused by a respiratory infection or medication side effect. The cough resulting from pulmonary congestion is frequently wet or productive, and the sputum may appear white, pink, or frothy. This pink-tinged appearance results from fluid and red blood cells leaking into the air sacs.
A distinguishing feature is that the cough, along with associated shortness of breath, often worsens when the person lies flat, a symptom known as orthopnea. This happens because when a person reclines, gravity allows more fluid to distribute across the lungs, increasing the irritation. Patients may find they need to use extra pillows or sleep sitting up to find relief.
In contrast, the cough caused by an ACE inhibitor is consistently dry and does not change much with body position. The cardiac cough is commonly accompanied by other symptoms of reduced heart function, such as fatigue, swelling in the legs and ankles, and shortness of breath with minimal exertion. Recognizing these accompanying signs helps determine the source of the persistent cough.
When to Consult a Healthcare Provider
Any new or persistent cough in a person with Afib warrants a professional evaluation because it can signal a change in health status. If a cough develops shortly after starting a new medication, particularly an ACE inhibitor, it should be reported to the prescribing provider. They can determine if the drug needs to be adjusted or replaced to resolve the side effect.
Immediate medical attention is needed if the cough is sudden and severe, or if it is accompanied by concerning symptoms suggesting acute fluid buildup. Signs like coughing up pink, foamy, or bloody phlegm are indicators of advanced pulmonary congestion. Severe difficulty breathing, chest pain, or a feeling of being suffocated while lying down are red flags that require emergency care. These symptoms could indicate a rapid worsening of heart function.