Nocturnal atrial fibrillation in a patient with obstructive sleep apnoea

Atrial fibrillation in the elderly population: Challenges and management considerations

IMPORTANCE

Atrial fibrillation is the most clinically significant arrhythmia in humans when viewed both from a global and also a national perspective. In the United States, approximately 2.7-6.1 million people are estimated to have atrial fibrillation. With the aging of the population, this prevalence is on an increasing trend and remains an obstacle to cardiovascular health despite significant advancements specific to cardiovascular disease management.

OBSERVATION

In this specific group of patients, healthcare utilization is a concern from the public health perspective. Unfortunately, misconceptions dominate clinical decision making; for instance, the avoidance of safe and effective anticoagulation strategies in patients at the highest risk for embolic strokes continues to be widespread in clinical practice and is often based on a skewed assessment of risk versus benefit. Also, when there are contraindications to standard interventions for atrial fibrillation, a clear and nuanced understanding of second- and third-line interventions with proven benefit is often lacking.

CONCLUSIONS AND RELEVANCE

An individualized approach should be followed by physicians when managing atrial fibrillation in the elderly patient, taking into consideration the risk of complications, particularly the embolic stroke and the availability of treatment options for stroke prevention whether through pharmacological anticoagulation or left atrial appendage occluding devices. The following review sets out to clarify these issues.

Pathophysiological Mechanisms to Review Association of Atrial Fibrillation in Heart Failure With Obstructive Sleep Apnea

Sleep-disordered breathing (SDB) comprising obstructive sleep apnea (OSA) is found in more than half of patients with heart failure (HF) and may have negative impacts on cardiovascular function. Increased atherosclerotic cardiovascular disease and the development of coronary events and congestive heart failure are associated with OSA. It is associated with a substandard quality of life, increased hospitalizations, and a poor prognosis. Despite its association with severe cardiovascular morbidity and mortality, the condition is frequently underdiagnosed. The substantial clinical evidence has established OSA as an independent risk factor for bradyarrhythmias and tachyarrhythmias in the last decade. The mechanisms which lead to such arrhythmias are uncertain. In short, OSA patients have a significantly elevated risk of HF and atrial fibrillation (AF). The direct correlation between HF, SDB, and cardiac arrhythmias has been poorly understood. The purpose of this study is to get a better understanding of the relation between AF, OSA, and HF by focusing on the pathophysiological mechanisms underlying these conditions. Therefore, we searched for articles to support our association in PubMed and Google Scholar databases.

Sleep Apnea-Predictor of Functional Outcome in Acute Ischemic Stroke

BACKGROUND

Sleep apnea is increasingly being recognized as 1 of the important, modifiable risk factors of stroke and cardiovascular diseases. Sleep apnea is thought to impair the functional recovery following stroke. Hence, we evaluated the patients with acute ischemic stroke for prevalence of sleep apnea and compared the functional outcomes of patients with and without sleep apnea, at 3rd month of acute ischemic stroke.

METHOD

This study was conducted in Kasturba Medical College (KMC) hospital, Manipal, India, between May 2015 and August 2016. We included 102 consecutive patients of acute ischemic stroke with hemiplegic upper limb power of Medical Research Council (MRC) 3 or less. Sleep apnea was diagnosed in these patients using the sleep disordered Questionnaire, Berlin Questionnaire, and Epworth sleepiness scale. Functional outcome was measured using Barthel score on day 7 and at 3rd month following the onset of stroke.

RESULT

Out of 102 patients, sleep apnea was present in 31 (30.6%) patients, more in males (67.7%) and elderly. Hypertension was present in 66.6% of patients with sleep apnea. NIHSS score at admission did not differ between the 2 groups. At 3rd month, the Barthel score calculated was better among patient with no apnea, but this was not statistically significant (P = .119). When mean Barthel score at baseline and 3rd month was calculated using repeated measure Analysis of Variance (ANOVA) between the 2 groups, gain in functional independence in no apnea group was statistically significant (P < .001).

CONCLUSION

Sleep-disordered breathing is an independent risk factor for stroke, and sleep apnea is also associated with other known stroke risk factors like hypertension. In acute ischemic stroke, sleep apnea has a negative impact on functional recovery. Sleep apnea is amenable to treatment and should be considered in patients with acute ischemic stroke to improve the chance of recovery, and to reduce the risk of recurrence.

Obstructive Sleep Apnoea and Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia and is associated with significant morbidity and mortality. Obstructive sleep apnoea (OSA) is common among patients with AF. Growing evidence suggests that OSA is associated with the initiation and maintenance of AF. This association is independent of obesity, body mass index and hypertension. OSA not only promotes initiation of AF but also has a significant negative impact on the treatment of AF. Patients with untreated OSA have a higher AF recurrence rate with drug therapy, electrical cardioversion and catheter ablation. Treatment with continuous positive airway pressure (CPAP) has been shown to improve AF control in patients with OSA. In this article, we will review and discuss the pathophysiological mechanisms of OSA that may predispose OSA patients to AF as well as the standard and emerging therapies for patients with both OSA and AF.

Atrial arrhythmias in obstructive sleep apnea: underlying mechanisms and implications in the clinical setting

Obstructive sleep apnea (OSA) is a common disorder characterized by repetitive interruption of ventilation during sleep caused by recurrent upper airway collapse, which leads to intermittent hypoxia. The disorder is commonly undiagnosed despite its relationship with substantial cardiovascular morbidity and mortality. Moreover, the effects of the disorder appear to be particularly dangerous in young subjects. In the last decade, substantial clinical evidence has identified OSA as independent risk factor for both bradyarrhythmias and tachyarrhythmias. To date the mechanisms leading to such arrhythmias have not been completely understood. However, recent data from animal models and new molecular analyses have increased our knowledge of the field, which might lead to future improvement in current therapeutic strategies mainly based on continuous positive airway pressure. This paper aims at providing readers a brief and specific revision of current knowledge about the mechanisms underlying atrial arrhythmias in OSA and their clinical and therapeutic implications.

High prevalence of cyclical variation in heart rate before nocturnal episodes of paroxysmal atrial fibrillation

OBJECTIVE

Nighttime onset of atrial fibrillation (AF) is sometimes associated with obstructive sleep apnea accompanied by a characteristic heart rate (HR) pattern known as cyclical variation of HR. The aim of this study was to evaluate whether cyclical variation of HR is prevalent in patients with nocturnal AF.

METHODS

The subjects consisted of 34 patients (68±12 years) with paroxysmal AF, including 14 patients with daytime AF and 20 patients with nighttime AF. Holter electrocardiogram (ECGs) were examined for the presence of cyclical variation in HR and to quantify the HR variability within the 40-minute period preceding each AF episode using a fast Fourier transform (FFT) methods.

RESULTS

Cyclical variation in HR was observed in 12 of 20 (60%) nighttime episodes and in only two of 14 (14%) daytime episodes. The prevalence of cyclical variation in HR was significantly greater in the nighttime AF episodes than in the daytime AF episodes (Chi=5.34, p<0.05). The mean frequency of cyclical variation in HR was 0.015±0.003 Hz. The mean power of the VLF (very low frequency) component (0.008-0.04 Hz) before the onset of AF was significantly greater in the nighttime AF episodes than in the daytime AF episodes. Among the nighttime AF episodes, the power of the HF (high frequency), LF (low frequency) and very low frequency (VLF) components increased significantly just before the onset of AF compared with that observed 40 minutes before onset.

CONCLUSION

The high prevalence of cyclical variation in HR observed before nocturnal AF episodes suggests that sleep apnea may play a role in the onset of nighttime AF.

[Cardiac effects of obstructive sleep apnea]

Sleep disordered breathing, especially obstructive sleep apnea, are common in cardiovascular disease. Negative hemodynamic effects are mediated by nocturnal ischemia and intrathoracal pressure swings. Therefore "therapy resistant" arterial hypertension and congestive heart failure, as well as atrial fibrillation or sleep associated bradycardia are suggestive of sleep disordered breathing. Further on, clinical course of coronary artery disease seems to be influenced by nocturnal breathing disorders. Application of continuous positive airway pressure (CPAP) is effective in most of the patients and attenuates cardiodepressive hemodynamic effects of obstructive sleep apnea.