Sleep Apnea and Afib

April 22, 2024

Atrial fibrillation, also called Afib, affects over 33 million people worldwide. It is the most common irregular heartbeat (arrhythmia). Almost 40 million US adults have obstructive sleep apnea in the US alone. Both conditions increase the risk of stroke and death. Research has shown a connection between Afib and sleep apnea.

Sleep apnea disrupts breathing during sleep. Alternately, sleep apnea can lead to shallow breaths. Either disrupts the natural rhythm of sleep. There are two primary types of sleep apnea: obstructive sleep apnea (OSA), which is from a physical airway obstruction, and central sleep apnea (CSA), which disrupts the brain’s respiratory control.

Sleep apnea is more common in men over 40. Risk increases with obesity, age, and chronic conditions like hypertension (high blood pressure) and diabetes.

Mechanics of Sleep Apnea

During periods of apnea (pauses in breathing), the body experiences hypoxia (a decrease in oxygen getting to the body). As the body struggles with low oxygen, its natural fight-or-flight response kicks in, which increases the heart rate and blood pressure to compensate. This puts strain on the heart.

Mechanisms of Afib

The heart comprises four chambers: the left and right atria at the top and the left and right ventricles at the bottom. Together, they cycle blood from the body to the lungs and back out to the body. The body’s natural pacemaker is an electrical pulse in the atria that sets the heart’s rhythm. Any disruption in this rhythm can affect the heart’s ability to pump blood, which increases the risk of clot formation and subsequent possibility of stroke.

The Correlation Between Sleep Apnea and Afib

Recent studies have shed light on the connection between sleep apnea and Afib. A Sleep Medicine Reviews journal study notes that patients with sleep apnea have higher incidences of Afib, which significantly impacts broader cardiovascular health. Disrupting oxygen and subsequent sympathetic response (fight-or-flight) stresses the heart and leaves it vulnerable to arrhythmias.

Another study published in the Journal of the American College of Cardiology explores this connection and promising treatments and preventative measures to lower the risk of Afib occurrence. When the body receives adequate oxygenation during sleep with assistive therapies such as continuous positive airway pressure (CPAP), the development and recurrence of Afib is reduced.

Understanding What Processes Connect Them

You might wonder how a condition that affects the heart and another that affects the lungs are connected. Is it as simple as sleep apnea causing poor sleep to make the whole body feel worse? Let’s break down the processes in the body that connect these two conditions.

Autonomic Nervous System

The autonomic nervous system (ANS) is the body’s autopilot; it handles all the involuntary functions that do not require conscious effort: heart rate, digestion, breathing, and blood pressure. Its purpose is to support or stabilize the body’s internal systems. The ANS is comprised of two branches: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). When the body lacks restful sleep due to sleep apnea, the ANS does not work correctly, which can lead to Afib.

Inflammation and Oxidative Stress

Your body is a machine. When that machine is well-oiled, everything works smoothly. However, the machine struggles to work correctly when you have a condition like sleep apnea, which can cause inflammation (swelling) and oxidative stress.

Oxidative stress happens when there are too many unstable molecules, called free radicals, in the body. Antioxidants usually keep these free radicals in check, but when the body is stressed from sleep apnea, it cannot keep processes working correctly. Oxidative stress can cause problems like inflammation, heart disease, and, you guessed it, Afib.

Endothelium

The endothelium is the inner lining of the blood vessels. It regulates various functions within the cardiovascular system, including controlling blood flow, maintaining blood pressure, and preventing blood clot formation. When it is not functioning correctly, the heart has to work harder, which increases the likelihood of Afib.

Structure of the Heart

The structure of your heart plays a vital role in the body’s functions. It comprises four chambers and has an electrical system to keep it pumping correctly. The stress from sleep apnea can cause changes to the shape of the heart, which can affect how it works and ultimately may lead to Afib.

Why Diagnosis and Treatment are Crucial

Understanding the relationship between sleep apnea and Afib helps healthcare providers implement care plans for patients with underlying factors through early diagnosis, prevention, and comprehensive treatment plans. Screening for Afib in patients with sleep apnea and vice versa, as well as adherence to treatment plans and lifestyle modifications, can improve patient outcomes and reduce the risk of complications.

By understanding the connections between sleep apnea and Afib, we can see how important it is to care for our sleep and heart. Treatment plans are individualized based on patient-specific factors, including the patient’s general health and treatment preferences. Simple things like using a special mask at night (CPAP) can help keep both problems under control and improve quality of life. Longer-term, cardiac catheter ablation or pulsed field ablation are procedural options that can address Afib more permanently.

RESOURCES:

• Marulanda-Londoño E, Chaturvedi S. The Interplay between Obstructive Sleep Apnea and Atrial Fibrillation. Front Neurol. 2017;8:668. Published 2017 Dec 11. doi:10.3389/fneur.2017.00668
• Tavares L, Lador A, Valderrábano M. Sleep Apnea and Atrial Fibrillation: Role of the Cardiac Autonomic Nervous System. Methodist Debakey Cardiovasc J. 2021;17(1):49-52. doi:10.14797/ZYUT2951