Atrial fibrillation (AFib) is one of the most common examples of cardiac arrhythmia with significant clinical importance. This supraventricular arrhythmia is characterized by a complete disorganization of atrial electric activity, causing irregular atrial beats at a frequency of 350 beats per minute, which leads to a loss of coordinated atrial contraction.
Before exploring the relationship between atrial fibrillation and obstructive sleep apnea (OSA), it is essential to understand how the heart functions and regulates its beat frequency.
The heart consists of four chambers: the upper chambers (the atria) and the lower chambers (the ventricles). Usually, the heart beats rhythmically and in synchronization, following a sequence of electrical impulses that begin in the atria and travel to the ventricles.
A normal heart rate ranges from 50 to 100 beats per minute. Provided that the rate remains constant, any variations within this range may not indicate a disease.
Therefore, cardiac arrhythmia is characterized by an irregular heart rate, indicating a problem with the heart's electrical activity.
Atrial Fibrillation: A Multifactorial Disease With Or Without Symptoms
In essence, atrial fibrillation is a common subtype of cardiac arrhythmia, characterized by the heart beating too quickly or irregularly due to disorganization of electric activity in the upper chambers (atria).
As a multifactorial disease, atrial fibrillation can arise from various factors, including modifiable factorslike lifestyle and non-modifiable factorssuch as age, cardiovascular diseases , and genetic predisposition.
Atrial fibrillation affects the heart’s ability to pump blood efficiently throughout the body, and patients may experience symptoms such as palpitations. However, it is estimated that 15% to 30% of the patients remain asymptomatic, with older patients being the most affected due to the absence of obvious signs.
Atrial fibrillation typically presents in two ways:
- Without symptoms: No noticeable symptoms. This type of atrial fibrillation can be detected through routine cardiac checks, emphasizing the importance of regular examinations to prevent the first clinical signs from being severe cardiovascular events like stroke.
- With symptoms: In this case, atrial fibrillation appears in several forms. Symptoms include palpitations, shortness of breath, fatigue, chest pain, difficulty with daily activities, and sometimes dizziness and fainting.
Possible Treatments for Atrial Fibrillation
It is estimated that over 60 million people suffer from atrial fibrillation, excluding a significant number of undiagnosed cases.
Therefore, early diagnosis, as well as proper and continuous treatment, are crucial in preventing severe complications such as stroke, heart failure and other cardiovascular issues.
Key treatments include:
- Medical treatment: Including antiarrhythmic drugs and/or anticoagulants..
- Cardioversion: An electric shock to attempt to reverse atrial fibrillation.
- Ablation: A minimally invasive procedure via catheterization.
Unlike other arrhythmias, atrial fibrillation is progressive. Even after it is controlled or reversed, underlying conditions like sleep apneamust be treated to prevent the arrhythmia from recurring.
The Relationship Between Atrial Fibrillation and Obstructive Sleep Apnea
According to the aforementioned, atrial fibrillation is the most common subtype of cardiac arrhythmia, a heart rhythm disorder.
Obstructive sleep apnea is one of the most common respiratory sleep disorders. It is characterized by breathing pauses during sleep, resulting in intermittent hypoxia, sleep fragmentation, and increased negative intrathoracic pressure.
However, is there a relationship between these two conditions?
Studies show that atrial fibrillation and sleep apnea have a complex two-way relationship. That is, atrial fibrillation can contribute to developing atrial fibrillation and vice versa.
This relationship stems from intermittent hypoxia and increased negative intrathoracic pressure.
Intermittent hypoxia and its consequent hypercapnia can result in dysautonomia, with prevailing sympathetic activity, inflammation, and oxidative stress. These factors are related to increased susceptibility to arrhythmia, such as atrial fibrillation.
Moreover, increased negative intrathoracic pressure caused by forced inhalation to unblock the airways can increase cardiovascular pressure and atria size. It can also stress the atrial wall, leading to atrial remodeling and arrhythmia, such as atrial fibrillation.
Although atrial fibrillation is common among sleep apnea patients, those undergoing tests for OSA are not routinely screened for atrial fibrillation.
To address this pressing problem, Biologix developed a neural networkalgorithm capable of detecting atrial fibrillation in patients suspected of having obstructive sleep apnea. This feature is most interesting because it can be used in diagnosis and continuous monitoring.
A New Parameter of The Biologix Sleep Test®: Atrial Fibrillation Risk
Did you know that patients with atrial fibrillation are twice as likely chances to have obstructive sleep apnea and that those patients with severe sleep-disordered breathing are four times more likely chances to develop atrial fibrillation?
After identifying that patients undergoing diagnostic exams for obstructive sleep apnea are not systematically evaluated to rule out the possibility of atrial fibrillation, Biologix introduced a new feature in its sleep test. This feature detects atrial fibrillation in patients suspected of having obstructive sleep apnea.
This new algorithm, designed into two stages, has proven effective in detecting atrial fibrillation risk. By analyzing both the intervals between heartbeats in the electrocardiogram and the plethysmography data from the Oxistar Sensor®.
Key highlights of the new parameter include:
- Detection of atrial fibrillation risk as well as sleep apnea diagnosis in the same exam.
- Inovação ao empregar a técnica de fotopletismografia (PPG) para a avaliação do risco de fibrilação atrial, oferecendo uma ferramenta não invasiva e simplificada que facilita o monitoramento dos pacientes durante o sono.
- Performance excelente do algoritmo, com sensibilidade de 92%, especificidade de 98% and acurácia de 93%.
By combining the detection of atrial fibrillation risk with sleep apnea diagnosis, the Biologix Sleep Test® offers an integrated approach to healthcare practitioners towards the cardiovascular care of their patients. Consequently, the results lead to precise diagnoses and personalized treatments.
REFERENCES:
- Rienstra M, Lubitz SA, Mahida S, Magnani JW, Fontes JD et al. (2012) Symptoms and functional status of patients with atrial fibrillation: state of the art and future research opportunities.
- Boriani G, Laroche C, Diemberger I, Fantecchi E, Popescu MI et al. (2015) Asymptomatic atrial fibrillation: clinical correlates, management, and outcomes in the EORP-AF Pilot General Registry. Am J Med 128 (5): 509-518 e502.
- Gami AS et al. Circulation. 2004;110(4):364-7
- Mehra R et al. Am J Respir Crit Care Med. 2006;173(8):910-6
