Causes | Symptoms | Diagnosis | Treatment | Get Support

Pulmonary hypertension (PH) is a lung disease that occurs when the blood pressure in the pulmonary arteries (the arteries of the lungs) is too high. Although PH is a lung disease, it can also lead to complications in the heart and increase the risk of arrhythmia, especially one form of arrhythmia called atrial fibrillation (AFib). AFib affects about 1 percent to 2 percent of the general population but up to one-third of people with PH.

Here’s what to know about AFib in PH, including its causes and symptoms, as well as what you can expect from diagnosis and treatment.

What Causes Atrial Fibrillation?

To understand AFib in PH, it helps to first understand how the healthy heart functions.

The heart is a highly specialized muscle that pumps blood throughout the body. The heart pumps blood using four different chambers. The two upper chambers are called the atria and include the right atrium and the left atrium. The atria pump blood through valves into the lower chambers of the heart, called the left ventricle and right ventricle. The ventricles then pump blood to different parts of the body — the right ventricle pumps oxygen-poor blood to the lungs to pick up more oxygen, while the left ventricle pumps oxygen-rich blood to the rest of the body.

Pumping blood throughout the body requires the heart to follow a very specific rhythm. Special cells in the heart make up the sinus node. The sinus node makes sure that the heart is pumping at a normal rhythm, called a sinus rhythm. The cells of the sinus node send electrical signals through the heart that tell the atria and ventricles when to pump or contract.

If the electrical signals that tell the heart chambers when to pump get disrupted or distorted, the rhythm of the heart is thrown off, resulting in arrhythmia. When this incorrect signaling affects the atria of the heart, the arrhythmia is called atrial flutter or atrial fibrillation. During AFib, the atria beat chaotically and out of sync with the ventricles.

How Does Pulmonary Hypertension Affect the Heart?

Research suggests that AFib in people with PH is caused by structural changes in the heart and arteries that disrupt the electrical signals directing the normal heart rhythm.

PH can lead to heart disease due to increased stress on the heart. In pulmonary arterial hypertension (PAH), narrowing of the pulmonary arteries (arteries in the lung) increases the pulmonary artery pressure to unhealthy levels. The narrowed vessels make it more difficult for the right ventricle to pump blood through the lungs. In response, the right ventricle works harder to push blood through the constricted vessels and becomes enlarged, a condition called right ventricle hypertrophy. Over time, the right ventricle gets too weak to pump enough blood to the lungs, resulting in right heart failure.

Risk Factors for Atrial Fibrillation in Pulmonary Hypertension

Scientists are not sure if the increased incidence of arrhythmias in people with PH suggests that AFib is a cause of PH or a result of the heart changes that can happen in PH. Although an increased risk of AFib is seen in people with all types of PH, the few studies that exist on PH and AFib tend to focus on idiopathic PAH and chronic thromboembolic PH.

Predictors that someone with PAH will develop AFib include:

• Enlarged right atria and right ventricle
• Increased right atrial pressure
• Lower cardiac output
• Raised pulmonary vascular resistance (blood flow difficulties through the pulmonary arteries)

Increased pulmonary artery pressure on the right ventricle may also affect the right atrium, which could change normal signaling to the atrium and result in AFib.

Symptoms of Atrial Fibrillation

Episodes of AFib may come and go, or AFib may not go away on its own. Some of the symptoms of AFib are similar to the symptoms of PH, including chest pain, lightheadedness or dizziness, shortness of breath, and fatigue. AFib also causes an irregular heartbeat and sometimes a fast heart rate.

AFib is a dangerous condition that requires medical attention. AFib increases the chance of developing blood clots in the heart, which can block blood flow or cause a stroke.

Diagnosing Atrial Fibrillation in Pulmonary Hypertension

A doctor can use different diagnostic tests to determine if you have PH and AFib.

PH can be diagnosed using a right heart catheterization to measure your pulmonary artery pressure. High blood pressure is a sign of PH. A doctor can also use an imaging test called echocardiography to look at the blood flow and structure of your heart and check for signs of PH.

An electrocardiogram is a reading of your heart’s electrical signals that can help a doctor determine if you have AFib.

Treatment of Pulmonary Hypertension and Atrial Fibrillation

There are many treatments to manage both PH and AFib. If you are living with both conditions, talk with your doctor about which medications are compatible for you.

The main goal for treating AFib is cardioversion (returning the heart rhythm back to normal), which can be done using medications or electrical signals. Surgical procedures can help prevent future AFib.

Antiarrhythmic Drugs

Antiarrhythmic drugs such as beta-blockers and calcium channel blockers are often used to control the heart rate during AFib.

Amiodarone is another kind of antiarrhythmic drug that works by calming overactive heart muscles. Amiodarone can change how a PH medication called bosentan (sold as Tracleer) is metabolized, or processed, in the body. Talk to your doctor if you are taking both of these medications to make sure you are taking them safely.

Dronedarone is an antiarrhythmic drug similar to amiodarone that helps the heart beat normally. This drug can be very dangerous to people with advanced heart failure, which can occur with severe PH.

Catheter Ablation

A surgical procedure called catheter ablation can remove parts of the heart that are disrupting electrical signals. This procedure allows electrical signals to travel normally through the heart so that a normal rhythm is maintained. Catheter ablation is slightly more challenging in people with PH due to changes in the heart and blood vessels.

Anticoagulation Medications

AFib increases the risk of blood clots forming in the atria of the heart. Blood clots can travel to other parts of the body and block blood flow, which can cause serious health issues such as stroke.

Anticoagulant medications (blood thinners) help prevent blood clots from forming. The effect of blood thinners on people with PH who are taking other PH medications is not well studied. Talk to your doctor if you are taking blood thinners and medications to treat PH.

Talk to People Who Understand

On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 46,000 members come together to ask questions, give advice, and share their stories with others who understand life with pulmonary hypertension.

Are you managing atrial fibrillation and pulmonary hypertension? Share your experience in the comments below, or start a conversation on myPHteam.