Impact of obstructive sleep apnea on the atrial electromechanical activation time

Evaluation of obstructive sleep apnea among consecutive patients with all patterns of atrial fibrillation using WatchPAT home sleep testing

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice and is associated with significant morbidity, mortality, and financial burden. Obstructive sleep apnea (OSA) is more common in individuals with AF and may impair the efficacy of rhythm control strategies including catheter ablation. However, the prevalence of undiagnosed OSA in all-comers with AF is unknown.

DESIGN

This pragmatic, phase IV prospective cohort study will test 250-300 consecutive ambulatory AF patients with all patterns of atrial fibrillation (paroxysmal, persistent, and long-term persistent) and no prior sleep testing for OSA using the WatchPAT system, a disposable home sleep test (HST). The primary outcome of the study is the prevalence of undiagnosed OSA in all-comers with atrial fibrillation.

RESULTS

Preliminary results from the initial pilot enrollment of approximately 15% (N = 38) of the planned sample size demonstrate a 79.0% prevalence of at least mild (AHI≥5) OSA or greater in consecutively enrolled patient with all patterns of AF.

CONCLUSIONS

We report the design, methodology, and preliminary results of our study to define the prevalence of OSA in AF patients. This study will help inform approaches to OSA screening in patients with AF for which there is currently little practical guidance.

CLINICAL TRIAL REGISTRATION

NCT05155813.

Atrial electrophysiological and molecular remodelling induced by obstructive sleep apnoea

Obstructive sleep apnoea (OSA) affects 9-24% of the adult population. OSA is associated with atrial disease, including atrial enlargement, fibrosis and arrhythmias. Despite the link between OSA and cardiac disease, the molecular changes in the heart which occur with OSA remain elusive. To study OSA-induced cardiac changes, we utilized a recently developed rat model which closely recapitulates the characteristics of OSA. Male Sprague Dawley rats, aged 50-70 days, received surgically implanted tracheal balloons which were inflated to cause transient airway obstructions. Rats were given 60 apnoeas per hour of either 13 sec. (moderate apnoea) or 23 sec. (severe apnoea), 8 hrs per day for 2 weeks. Controls received implants, but no inflations were made. Pulse oximetry measurements were taken at regular intervals, and post-apnoea ECGs were recorded. Rats had longer P wave durations and increased T wave amplitudes following chronic OSA. Proteomic analysis of the atrial tissue homogenates revealed that three of the nine enzymes in glycolysis, and two proteins related to oxidative phosphorylation, were down regulated in the severe apnoea group. Several sarcomeric and pro-hypertrophic proteins were also up regulated with OSA. Chronic OSA causes proteins changes in the atria which suggest impairment of energy metabolism and enhancement of hypertrophy.

Comparison of Prolonged Atrial Electromechanical Delays with Different Definitions in the Discrimination of Patients with Non-Valvular Paroxysmal Atrial Fibrillation

Background and Objectives

Previous studies have evaluated atrial electromechanical delays (AEMDs) with a number of different definitions to discriminate patients with paroxysmal atrial fibrillation (PAF) from controls without PAF. However, their discriminative values for PAF have not previously been directly compared.

Subjects and Methods

A total of 65 PAF patients and 130 control subjects matched for age, sex, history of hypertension, and diabetes mellitus were selected. The AEMDi and AEMDp were defined as the time intervals from the initiation of the P wave on the surface electrocardiogram to the initiation and peak of the late diastolic transmitral inflow on pulsed wave Doppler images, respectively. The AEMDim and AEMDpm were defined as the time intervals from the initiation of the P wave on the surface electrocardiogram to the initiation and peak of the late diastolic lateral mitral annular motion on tissue Doppler images, respectively.

Results

There were no significant differences in the clinical characteristics between the two groups. All 4 AEMDs were consistently longer in the PAF group, and proven effective to differentiate the PAF patients from the controls. The AEMDi measurement had a larger area under the curve (AUC) than the other AEMDs, left atrial volume index, and P wave amplitude. However, the AEMDp, AEMDim, and AEMDpm measurements had AUCs similar to those of the left atrial volume index and P wave amplitude.

Conclusion

The findings suggest that the AEMDi is better than the other AEMDs for the discrimination of PAF patients from the controls.

Structural and Functional Remodeling of the Left Atrium: Clinical and Therapeutic Implications for Atrial Fibrillation

Atrial fibrillation (AF) is the most commonly encountered arrhythmia in clinical practice. Despite advances in our understanding of the pathophysiology of this complex arrhythmia, current therapeutic options remain suboptimal. This review aimed to delineate the atrial structural and functional remodeling leading to the perpetuation of AF. We explored the complex changes seen in the atria in various substrates for AF and the therapeutic options available to prevent these changes or for reverse remodeling. Here we also highlighted the emerging role of aggressive risk factor management aimed at the arrhythmogenic atrial substrate to prevent or retard AF progression.

The Relationship between Obstructive Sleep Apnea and Atrial Fibrillation: A Complex Interplay

In recent years, growing evidence suggests an association between obstructive sleep apnea (OSA), a common sleep breathing disorder which is increasing in prevalence as the obesity epidemic surges, and atrial fibrillation (AF), the most common cardiac arrhythmia. AF is a costly public health problem increasing a patient's risk of stroke, heart failure, and all-cause mortality. It remains unclear whether the association is based on mutual risk factors, such as obesity and hypertension, or whether OSA is an independent risk factor and causative in nature. This paper explores the pathophysiology of OSA which may predispose to AF, clinical implications of stroke risk in this cohort who display overlapping disease processes, and targeted treatment strategies such as continuous positive airway pressure and AF ablation.

Tissue Doppler atrial conduction times and electrocardiogram interlead P-wave durations with varying severity of obstructive sleep apnea

OBJECTIVES

Obstructive sleep apnea (OSA) has been reported to be associated with an increased risk of atrial fibrillation. The aim of this study was to investigate atrial electromechanical couplings in patients with OSA and the relationship between these parameters and P-wave dispersion (Pd).

METHODS

One hundred twenty-six patients were enrolled in this study. All patients underwent polysomnographic examination. The apnea-hypopnea index (AHI) was defined as the number of apneas and hypopneas per hour of sleep. An AHI score of 5 or more was diagnosed as OSA, and an AHI score of less than 5 was diagnosed as OSA (-). Thirty-nine of the patients had an AHI score of less than 5 (group 1), 42 of the patients had AHI score between 5 and 30 (mild and moderate, group 2), 45 of the patients had an AHI score more than 30 (severe, group 3). Atrial electromechanical coupling (PA), intra-atrial, and interatrial electromechanical delay were measured with tissue Doppler imaging. P-wave dispersion was calculated from 12-lead electrocardiogram.

RESULTS

Maximum P-wave duration was higher in group 3 compared with groups 2 and 1 (126.0 ± 16.7 vs 111.0 ± 12.5 [P < .001] and 126.0 ± 16.7 vs 99.9 ± 10.0 [P < .001], respectively). Maximum P-wave duration was higher in group 2 than in group 1 (111.0 ± 12.5 vs 99.9 ± 10.0, P < .001). P-wave dispersion was higher in group 3 compared with groups 2 and 1 (50.9 ± 11.5 vs 37.0 ± 8.6 [P < .001] and 50.9 ± 11.5 vs 27.9 ± 6.8 [P < .001], respectively). P-wave dispersion was higher in group 2 than in group 1 (37.0 ± 8.6 vs 27.9 ± 6.8, P < .001). Minimum P-wave duration did not differ between the groups. Atrial PA at the left lateral mitral annulus (lateral PA), septal mitral annulus (septal PA), and right ventricular tricuspid annulus (RV PA) were significantly higher in group 3 than in group 2 (P < .001, P = .001, and P = .009, respectively). Lateral PA, septal PA, and RV PA were higher in group 2 compared with group 1 (P < .001, P = .003, and P = .009, respectively). Interatrial electromechanical delay (lateral PA - RV PA) was significantly longer in group 3 compared with groups 2 and 1 (33.6 ± 12.1 vs 22.4 ± 9.4 [P < .001] and 33.6 ± 12.1 vs 14.9 ± 9.2 [P < .001], respectively). Interatrial electromechanical delay was longer in group 2 than in group 1 (22.4 ± 9.4 vs 14.9 ± 9.2, P = .001). There was a positive correlation between AHI and Pd, lateral PA, septal PA, RV PA, interatrial electromechanical delay, and left-sided intra-atrial electromechanical delay.

CONCLUSION

Prolongation of electromechanical delay and increased Pd are associated with apnea-hypopnea index (AHI) and hence the severity of disease.

Documentation of impaired coronary blood flow in chronic obstructive pulmonary disease patients

BACKGROUND

In the current study, the effects of moderate to severe chronic obstructive pulmonary disease (COPD) on coronary blood flow in patients with angiographically proven normal coronary arteries was evaluated.

METHODS AND RESULTS

A total of 85 patients with moderate to severe COPD and 39 age- and sex-matched control partcipants, who underwent diagnostic coronary angiography and found to have normal epicardial coronary angiogram constituted the COPD and control groups, respectively. The 2 groups were compared for Thrombolysis In Myocardial Infarction (TIMI) frame counts in each major coronary artery. The TIMI frame count of the COPD group was significantly higher than that of control group for all 3 major individual coronary arteries: left anterior descending (corrected), 37+/-13 vs 20+/-4; right coronary artery, 32+/-14 vs 21+/-4; and left circumflex artery, 34+/-12 vs 20+/-5, (P<0.001 for all). In addition, TIMI frame counts in individual coronary arteries were found to be positively correlated with forced expiratory volume 1 s percent, serum high sensitive C-reactive protein and fibrinogen concentrations, in the COPD group.

CONCLUSIONS

Our findings suggest that an increased slow coronary flow might be a manifestation of harmful effects of COPD on the coronary circulation, regardless of the underlying mechanism.