Cardiac arrhythmias in obstructive sleep apnea (from the Akershus Sleep Apnea Project)

Premature Ventricular Contractions (PVCs): A Narrative Review

Premature ventricular complexes/contractions (PVCs) are relatively common, occurring in 3%-20% of the general population, and are often found during work-up of palpitations or incidentally on routine electrocardiographic testing. They are usually considered benign but can be a sign of underlying cardiac disease and cause significantly impairing symptoms. While often thought of as a problem for the cardiologist, it is not uncommon for PVCs to be identified initially in a primary care or inpatient general medicine setting. This paper will review etiologies, epidemiology, evaluation, and management of PVCs for the internist.

A case report of an improvement in premature ventricular complex–induced cardiomyopathy following continuous positive airway pressure therapy in a patient with severe obstructive sleep apnoea

Background

Premature ventricular complexes (PVCs) are the most common arrhythmias observed in patients without structural heart disease (SHD). Frequent PVCs cause left ventricular dilation and dysfunction without SHD, the so-called PVC-induced cardiomyopathy (PIC). Obstructive sleep apnoea (OSA) is a highly prevalent disease worldwide and is strongly associated with arrhythmias including PVCs. PVCs have been reported in up to two-thirds of patients with OSA. Continuous positive airway pressure (CPAP) is a well-established primary treatment modality in patients with moderate-to-severe OSA.

Case summary

We present a 69-year-old male case with severe OSA and an improvement in his PIC following CPAP therapy. He has remained well without any symptoms or arrhythmias for 2 years after the introduction of the CPAP therapy for his OSA.

Discussion

Using CPAP therapy for the treatment of his OSA, we could improve his PIC in accordance with a reduction in frequent PVCs without ablation of the PVCs. Only ablation without CPAP therapy may not be able to completely treat PIC associated with OSA, as in the present case. Thus, physicians should be aware of the possibility of PVCs associated with OSA when examining patients with PVCs. To the best of our knowledge, this is the first report of a case of improvement in PIC following CPAP therapy in a patient with severe OSA. Future investigations should focus on whether CPAP therapy can improve PIC associated with OSA and prevent a progression to heart failure and also result in an improvement in the prognosis.

Methodology for the nocturnal cardiac arrhythmia ancillary study of the ADVENT-HF trial in patients with heart failure with reduced ejection fraction and sleep-disordered breathing

Background

Sleep disordered breathing (SDB) may trigger nocturnal cardiac arrhythmias (NCA) in patients with heart failure with reduced ejection fraction (HFrEF). The NCA ancillary study of the ADVENT-HF trial will test whether, in HFrEF-patients with SDB, peak-flow-triggered adaptive servo-ventilation (ASVpf) reduces NCA. To this end, accurate scoring of NCA from polysomnography (PSG) is required.

Objective

To develop a method to detect NCA accurately from a single-lead electrocardiogram (ECG) recorded during PSG and assess inter-observer agreement for NCA detection.

Methods

Quality assurance of ECG analysis included training of the investigators, development of standardized technical quality, guideline-conforming semi-automated NCA-scoring via Holter-ECG software and implementation of an arrhythmia adjudication committee. To assess inter-observer agreement, the ECG was analysed by two independent investigators and compared for agreement on premature ventricular complexes (PVC) /h, premature atrial complexes/h (PAC) as well as for other NCA in 62 patients from two centers of the ADVENT-HF trial.

Results

The intraclass correlation coefficients for PVC/h and PAC/h were excellent: 0.99 (95%- confidence interval [CI]: 0.99-0.99) and 0.99 (95%-CI: 0.97-0.99), respectively. No clinically relevant difference in inter-observer classification of other NCA was found. The detection of non-sustained ventricular tachycardia (18% versus 19%) and atrial fibrillation (10% versus 11%) was similar between the two investigators. No sustained ventricular tachycardia was detected.

Conclusion

These findings indicate that our methods are very reliable for scoring NCAs and are adequate to apply for the entire PSG data set of the ADVENT-HF trial.

Sleep-Disordered Breathing in Hospitalized Patients: A Game Changer?

Sleep disorders, including sleep apnea, have become a significant health issue in the United States. It is estimated that 22 million Americans have sleep apnea, with 80% of cases of moderate and severe OSA going undiagnosed. This number continues to increase with the obesity epidemic. Sleep-disordered breathing (SDB) is associated with multiple cardiopulmonary diseases and has been shown to affect disease outcomes adversely. Hospitalized patients have a disproportionately high prevalence of cardiovascular and respiratory diseases. Screening for SDB in hospitalized patients provides an opportunity to identify the disease in individuals whose disease otherwise may go unrecognized. Data suggest that identification of SDB in hospitalized individuals may have a positive impact on a patient's course after hospitalization. Unfortunately, sleep medicine currently remains an ambulatory practice. Hospital sleep medicine addresses this separation. Herein, we discuss our experience and the future potential of hospital sleep medicine programs.

Ventrikuläre Arrhythmien bei obstruktiver und zentraler Schlafapnoe

Hintergrund

Ventrikuläre Arrhythmien treten mit einer hohen Prävalenz auf und sind mit einer hohen Morbidität und Mortalität assoziiert. Sowohl die obstruktive (OSA) als auch die zentrale (ZSA) Schlafapnoe können auf Grund ihrer Pathophysiologie zu vermehrten ventrikulären Arrhythmien beitragen.

Ziel

Dieser Artikel soll die komplexen Zusammenhänge und Erkenntnisse jüngster Forschungen bezüglich schlafbezogenen Atmungsstörungen (SBAS) und ventrikulärer Arrhythmien und deren Therapiemöglichkeiten beleuchten.

Material und Methoden

Es erfolgte eine Literaturrecherche basierend auf prospektiven, retrospektiven, klinischen und experimentellen Studien sowie Reviews, Metaanalysen und aktuellen Leitlinien, die seit 2014 in der Medline-Datenbank gelistet wurden.

Ergebnisse

Es besteht ein bidirektionaler Zusammenhang zwischen der SBAS und ventrikulären Arrhythmien. Intermittierende Hypoxie, oxidativer Stress, wiederkehrende Arousals, intrathorakale Druckschwankungen und kardiales Remodeling tragen im Rahmen der SBAS zu einer erhöhten ventrikulären Arrhythmieneigung bei. Der Schweregrad der OSA, gemessen mittels Apnoe-Hypopnoe-Index, ist mit der Prävalenz ventrikulärer Arrhythmien assoziiert. Ähnliche Ergebnisse liegen für Patienten mit ZSA und Herzinsuffizienz vor. Studien zu ventrikulären Arrhythmien bei ZSA-Patienten ohne Herzinsuffizienz fehlen. Eine Positivdrucktherapie (PAP) bei OSA- oder ZSA-Patienten führte in verschiedenen Studien zu einer reduzierten Anzahl an ventrikulären Arrhythmien. Dieser Zusammenhang konnte jedoch nicht in allen Studien bestätigt werden. Ventrikuläre Arrhythmien treten bei der OSA gehäuft nachts auf, bei der ZSA gleichmäßig über den Tag verteilt.

Diskussion

Bisherige Studien weisen einen Zusammenhang zwischen der OSA bzw. der ZSA und ventrikulären Arrhythmien trotz unterschiedlicher Pathophysiologie nach. Hinsichtlich des Effektes der PAP auf ventrikuläre Arrhythmien bei Patienten mit OSA und ZSA sind weitere Studien erforderlich.

Increased heart rate with sleep disordered breathing in hypertrophic cardiomyopathy

BACKGROUND

Current guidelines recommend medications with rate control properties for symptomatic patients with hypertrophic cardiomyopathy (HCM) based on the rationale that lowering heart rate (HR) improves their symptoms. Whether sleep disordered breathing (SDB) is associated with increased HR in HCM patients is not known.

METHOD

We diagnosed uncontrolled SDB (oxygen desaturation index ≥5) in consecutive echocardiographically confirmed HCM patients seen at Mayo Clinic, Rochester, and analyzed their HR as recorded by a 24-h Holter monitor. We compared mean, minimum, maximum HR between those with vs without SDB. In a pilot subanalysis of HCM patients with SDB who also underwent subsequent diagnostic polysomnography (PSG), we analyzed RR interval changes coinciding with obstructive sleep apnea and hypopnea episodes.

RESULTS

Of the 230 HCM patients included in this study (age 54 ± 16 years; 138 male; LVOT pressure gradient at rest 45 ± 39 mmHg), 115 (50%) patients had SDB. HCM patients with SDB were recorded to have higher mean HR (71 vs. 67 bpm; p = .002, adjusted p = .001), and this difference was most pronounced during night hours of 10 PM to 5 AM (61 vs. 67 bpm; p < .001). In the pilot analysis of the available PSG data, the release of obstructive sleep apneas and hypopneas coincided with fluctuation of HR.

CONCLUSIONS

SDB is independently associated with higher mean HR in patients with HCM, and this difference is most significant during sleep. Treatment of SDB, which is readily available, should be tested as a complementary modality to the currently recommended pharmacotherapy aimed at lowering HR in patients with symptomatic HCM.

[Adherence and efficacy of long-term PAP therapy in patients with sleep-related breathing disorders associated with cardiac conduction disorders]

AIM

To study the effectiveness of prolonged use of PAP therapy (positive airway pressure therapy) in eliminating sleep respiratory disorders and associated cardiac conduction disturbances.

MATERIALS AND METHODS

We included 21 patients who were examined at the Myasnikov Institute of Clinical Cardiology, National Medical Research Center of Cardiology, regarding cardiac rhythm and conduction disturbances, as well as obstructive sleep apnea and who have been on PAP therapy for more than 12 months. The average age was 66.5 [63.5; 73.2] years, body mass index 33.0 [30.2; 38.5] kg/m2, apnea-hypopnea index 65.0 [59.0; 86.3]/h. At the time of analysis, 15 patients continued to use PAP therapy (mean time of use: 6.0 years [4.7; 9.2]) and 6 patients refused long-term use of PAP therapy, mean time to use PAP therapy until failure amounted to 2.82.1 years.

RESULTS

PAP therapy lead to a persistent decrease in apnea-hypopnea index of 63.6/h to 3.7/h was (p=0.0002). 86% of patients met the criteria for adherence to PAP therapy (use 4 hours/night, more than 70% of nights). Initially, before the use of PAP therapy, all cardiac conduction disorders were during sleep and exceeded 3 seconds, with fluctuations from 3.1 to 10.6 seconds. PAP therapy appeared to be effective in all patients: no asystoles, duration of more than 3 seconds, were detected.

CONCLUSION

In obstructive sleep apnea patients with concomitant nighttime cardiac conduction disturbances, the long-term use of PAP therapy is effective and with good adherence.

Elimination of Benign Ventricular Premature Beats or Ventricular Tachycardia with Catheter Ablation versus Two Different Optimal Antiarrhythmic Drug Treatment Regimens (Sotalol or Verapamil/Flecainide)

BACKGROUND

Symptomatic idiopathic ventricular arrhythmias (VA), including premature beats (VPB) and nonsustained ventricular tachycardia (VT) are commonly encountered arrhythmias. Although these VA are usually benign, their treatment can be a challenge to primary and secondary health care providers. Mainstay treatment is comprised of antiarrhythmic drugs (AAD) and, in case of drug intolerance or failure, patients are referred for catheter ablation to tertiary health care centers. These patients require extensive medical attention and drug regimens usually have disappointing results. A direct comparison between the efficacy of the most potent AAD and primary catheter ablation in these patients is lacking. The ECTOPIA trial will evaluate the efficacy of 2 pharmacological strategies and 1 interventional approach to: suppress the VA burden, improve the quality of life (QoL), and safety.

HYPOTHESIS

We hypothesize that flecainide/verapamil combination and catheter ablation are both superior to sotalol in suppressing VA in patients with symptomatic idiopathic VA.

STUDY DESIGN

The Elimination of Ventricular Premature Beats with Catheter Ablation versus Optimal Antiarrhythmic Drug Treatment (ECTOPIA) trial is a randomized, multicenter, prospective clinical trial to compare the efficacy of catheter ablation versus optimal AAD treatment with sotalol or flecainide/verapamil. One hundred eighty patients with frequent symptomatic VA in the absence of structural heart disease or underlying cardiac ischemia who are eligible for catheter ablation with an identifiable monomorphic VA origin with a burden ≥5% on 24-h ambulatory rhythm monitoring will be included. Patients will be randomized in a 1:1:1 fashion. The primary endpoint is defined as >80% reduction of the VA burden on 24-h ambulatory Holter monitoring. After reaching the primary endpoint, patients randomized to one of the 2 AAD arms will undergo a cross-over to the other AAD treatment arm to explore differences in drug efficacy and QoL in individual patients. Due to the use of different AAD (with and without β-blocking characteristics) we will be able to explore the influence of alterations in sympathetic tone on VA burden reduction in different subgroups. Finally, this study will assess the safety of treatment with 2 different AAD and ablation of VA.

Cardiovascular Consequences of Obstructive Sleep Apnea

PURPOSE OF REVIEW

To review the clinical evidence for a relationship between obstructive sleep apnea and hypertension, arrhythmias, coronary artery disease, and congestive heart failure.

RECENT FINDINGS

Current data show that obstructive sleep apnea is a risk for cardiovascular disease. Studies have linked untreated moderate to severe obstructive sleep apnea to hypertension, cardiac arrhythmias, coronary artery disease, and congestive heart failure. However, uncertainty regarding benefits of treatment of obstructive sleep apnea to reduce the risk of cardiovascular disease still exists. The issue of poor compliance has been an on-going limitation of CPAP trials. Evidence shows obstructive sleep apnea is a risk factor for cardiovascular disease but trials have yet to clarify if cardiovascular disease morbidity and mortality decreases with treatment of the apnea. Future treatment trials are needed to address the question of whether treatment decreases cardiovascular risk in patients with obstructive sleep apnea.

Ventricular Arrhythmias in Patients with Obstructive Sleep Apnea

Obstructive Sleep Apnea (OSA) is a prevalent condition thought to increase in the future. Being mostly undiagnosed, the most serious complications are cardiovascular diseases, among which are arrhythmias. Controversy remains as to whether OSA is a primary etiologic factor for ventricular arrhythmias, because of the high incidence of cardiovascular comorbidities in OSA patients. Howev-er, there is mostly a strong evidence of a relation between OSA and ventricular arrhythmias. A few mechanisms have been proposed to be responsible for this association and some electrocardiographic changes have also been demonstrated to be more frequent in OSA patients. Treatment of OSA with Continuous Positive Airway Pressure (CPAP) has the potential to reduce arrhythmias and confer a mortality benefit.

Cardiac effects of CPAP treatment in patients with obstructive sleep apnea and atrial fibrillation

PURPOSE

Obstructive sleep apnea (OSA) has been recognized as an independent risk factor for the development and progression of atrial fibrillation (AF). We aimed to investigate the changes in heart rate and atrial and ventricular ectopy after continuous positive airway pressure (CPAP) treatment in patients with OSA and AF.

METHODS

Consecutive patients with AF underwent ambulatory sleep monitoring, and OSA was defined as an Apnea-Hypopnea-Index (AHI) ≥ 5/h. Treated patients completed in-laboratory CPAP titration study. A 24-h ECG Holter was performed at baseline and at 3 and 6 months after CPAP treatment.

RESULTS

One hundred patients (70% males) with AF were included in the final analysis. OSA was diagnosed in 85% of patients. There were no significant changes in mean 24-h heart rate in patients with paroxysmal or permanent AF at 3 and 6 months of treatment compared to baseline. In patients with paroxysmal AF (n = 29), atrial and ventricular ectopy counts/24 h significantly decreased at 3 months compared to baseline (median (IQR) 351 (2049) to 57 (182), P = 0.002; 68 (105) to 16 (133), P = 0.01 respectively). At 6 months follow-up, the atrial ectopy count/24 h significantly decreased in patients with paroxysmal AF compared to baseline (median (IQR) 351 (2049) to 31 (113), P = 0.016, n = 14). In patients with permanent AF (n = 15), there was a significant reduction in ventricular ectopy count/24 h at 3 months compared to baseline (median (IQR) 100 (1116) to 33 (418), P = 0.02).

CONCLUSIONS

There is a significant decrease in atrial and ventricular ectopy count/24 h in patients with AF and OSA at 3 and 6 months of CPAP treatment compared to baseline.

Contribution of systemic vascular effects to fMRI activity in white matter

To investigate a potential contribution of systemic physiology to recently reported BOLD fMRI signals in white matter, we compared photo-plethysmography (PPG) and whole-brain fMRI signals recorded simultaneously during long resting-state scans from an overnight sleep study. We found that intermittent drops in the amplitude of the PPG signal exhibited strong and widespread correlations with the fMRI signal, both in white matter (WM) and in gray matter (GM). The WM signal pattern resembled that seen in previous resting-state fMRI studies and closely tracked the location of medullary veins. Its temporal cross-correlation with the PPG amplitude was bipolar, with an early negative value. In GM, the correlation was consistently positive. Consistent with previous studies comparing physiological signals with fMRI, these findings point to a systemic vascular contribution to WM fMRI signals. The PPG drops are interpreted as systemic vasoconstrictive events, possibly related to intermittent increases in sympathetic tone related to fluctuations in arousal state. The counter-intuitive polarity of the WM signal is explained by long blood transit times in the medullary vasculature of WM, which cause blood oxygenation loss and a substantial timing mismatch between blood volume and blood oxygenation effects. A similar mechanism may explain previous findings of negative WM signals around large draining veins during both task- and resting-state fMRI.

Physiological consequences of CPAP therapy withdrawal in patients with obstructive sleep apnoea-an opportunity for an efficient experimental model

Randomised controlled trials (RCTs) of continuous positive airway pressure (CPAP) in obstructive sleep apnoea (OSA) are time consuming, and their findings often inconclusive or limited due to suboptimal CPAP adherence in CPAP-naïve patients with OSA. Short-term CPAP withdrawal in patients with prior optimal CPAP adherence results in recurrence of OSA and its consequences. Thus, this experimental model serves as an efficient tool to investigate both the consequences of untreated OSA, and potential treatment alternatives to CPAP. The CPAP withdrawal protocol has been thoroughly validated, and applied in several RCTs focusing on cardiovascular and metabolic consequences of untreated OSA, as well as the assessment of treatment alternatives to CPAP.

Prevalence of Cardiac Arrhythmias in Asian Patients With Obstructive Sleep Apnea: A Singapore Sleep Center Experience

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is associated with increased cardiovascular morbidity and mortality. Cardiac arrhythmias are common in patients with OSA. However, the prevalence and significance of cardiac arrhythmias in Asian patients with OSA are not well studied. The aim of this study is to determine the prevalence of cardiac arrhythmias in patients with OSA in Singapore and to evaluate possible factors that may predispose patients with OSA to arrhythmias.

METHODS

A retrospective study of 2,019 patients was carried out from January 2011 to December 2012 at a sleep center in a tertiary medical center. Of the population, 1,457 patients were found to have OSA and 144 patients were found to have cardiac arrhythmias. Data collected included patient demographics, comorbidities, and polysomnogram parameters.

RESULTS

The prevalence of cardiac arrhythmias in our OSA population is 8.0%, compared to that of primary snorers at 4.8% (P = .015). The univariate analysis revealed that older age, higher body mass index, comorbidities, and severity of OSA, including apnea-hypopnea index (AHI), lowest oxygen saturation (LSAT) and hypoxic time were correlated with a higher prevalence of cardiac arrhythmias (P < .05). However, the multivariate analysis showed that only age and body mass index were significantly correlated with arrhythmias. AHI, LSAT, and hypoxic time were no longer statistically significant.

CONCLUSIONS

Our study demonstrated that cardiac arrhythmias are common in patients with OSA in Singapore. It also suggests that given the different demographics of our population, ethnicity may play a significant role in the development of cardiovascular disease among patients with OSA.

COMMENTARY

A commentary on this article appears in this issue on page 1229.

Repercusiones cardiovasculares del síndrome de apnea-hipopnea obstructiva del sueño (SAHOS)

En la población de sujetos con síndrome de apnea-hipopnea obstructiva del sueño se describen entidades clínicas cardiovasculares asociadas con esta entidad y que afectan su curso y pronóstico. Dentro de estas se encuentran hipertensión arterial, arritmias, enfermedad coronaria, insuficiencia cardíaca, hipertensión pulmonar y tromboembolismo venoso. Del mismo modo, se describen los mecanismos fisiopatológicos de estas asociaciones, su prevalencia e impacto. Dado que afectan el curso de la enfermedad y, por tanto, la severidad de la misma, estas entidades juegan un papel muy importante en la toma de decisiones al momento de ofrecer el mejor manejo en cada caso, el cual debe ser abordado de forma multidisciplinaria.

Sleep-Disordered Breathing and Arrhythmia in Heart Failure Patients

Heart failure (HF) treatment remains complex and challenging, with current recommendations aiming at consideration and treatment of comorbidities in patients with HF. Sleep-disordered breathing (SDB) and arrhythmia come into play, as both are associated with quality of life deterioration, and morbidity and mortality increase in patients with HF. Interactions of these diseases are versatile and may appear intransparent in daily practice. Nevertheless, because of their importance for patients' condition and prognosis, SDB and arrhythmia individually, but also through interaction on one another, necessitate attention, following the fact that treatment is requested and desired considering latest research findings and outcomes.

Biomarkers of cardiovascular injury and stress are associated with increased frequency of ventricular ectopy: a population-based study

BACKGROUND

Asymptomatic ventricular arrhythmias are common and associated with increased risk of cardiovascular mortality. Cardiac troponins, natriuretic peptides and C-reactive protein (CRP) are also predictive of adverse cardiovascular events in the general population, but limited information is available on the relationship between these biomarkers and ventricular ectopy in a community-based population. The objectives were to evaluate the associations between ventricular ectopic activity and N-terminal pro-B-type natriuretic peptide (NT-proBNP), high sensitivity-troponin I (hs-TnI) and hs-CRP in a community-based setting.

METHODS

We performed a 24 h Holter-recording and blood sampling in 498 subjects. Premature ventricular complexes (PVC) were classified as frequent at >5/h and the presence of any bigeminy, trigeminy or non-sustained ventricular tachycardia were classified as complex ventricular ectopy. The associations between biomarkers and ventricular arrhythmias were investigated by univariate and multivariate logistic regression analyses.

RESULTS

Frequent PVC's and complex ventricular ectopy were detected in 46 (9%) and 47 (9%) participants respectively, and were associated with significantly (p < 0.001) higher concentrations of NT-proBNP and hs-TnI. The association between NT-proBNP and both frequent PVC's (p = 0.020) and complex ventricular ectopy (p = 0.001) remained significant after adjusting for conventional risk markers in multivariate analyses.

CONCLUSION

Increased level of NT-proBNP was independently associated with ventricular ectopy, whereas no independent association was observed between hs-TnI and hs-CRP levels and ventricular ectopy in this community-based sample.

A Narrative Review of How Sleep-Related Breathing Disorders and Cardiovascular Diseases Are Linked: An Update for Advanced Practice Registered Nurses

PURPOSE/OBJECTIVES

Sleep-related breathing disorders (SRBDs), including obstructive sleep apnea and central sleep apnea, are common among patients with cardiovascular disease (CVD), but clinicians often do not pay enough attention to SRBDs. The purpose of this narrative review is to update advanced practice registered nurses on the literature focusing on the relationship between SRBDs and CVD (eg, hypertension, heart failure, coronary artery disease, arrhythmias, and stroke) and on treatments that can improve SRBDs in patients with CVD.

DESCRIPTION OF THE PROJECT

We conducted an electronic search of the literature published between 1980 and 2016 from PubMed, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Academic Search Premier, and related health resource Web sites to address the aims of this study.

OUTCOMES

Fifty-six primary research articles (42 observational studies and 14 experimental and quasi-experimental studies) were selected based on our study aims and inclusion criteria. The studies revealed that individuals with CVD are at a greater risk for SRBDs and that SRBDs can worsen CVD. The findings from the studies also suggest that positive airway treatment could improve both SRBDs and CVD.

CONCLUSIONS

This review found a close relationship between SRBDs and CVD. Advanced practice registered nurses are in key positions to identify and help patients manage SRBDs. In particular, advanced practice registered nurses can educate staff and establish standards of practice to improve outcomes for patients with CVD.

Clinical manifestations of sleep apnea

Obstructive sleep apnea (OSA) may manifest in a number of ways from subtle intrusion into daily life to profound sleepiness, snoring, witnessed apneas and other classic symptoms. Although there is increasing evidence suggesting OSA can adversely affect health in a variety of ways, this disorder remains underdiagnosed. The most well-escribed health consequences of OSA relate to the cardiovascular system. Hypertension and arrhythmias have a strong association with OSA, and evidence suggests that treatment of OSA in patients with refractory hypertension and in patients planning cardioversion for atrial fibrillation may be of particularly importance. Significant associations between heart failure and OSA as well as complex sleep apnea have also been well-described. Cerebrovascular insult, impaired neurocognition, and poorly controlled mood disorder are also associated with in OSA. Therapy for OSA may ameliorate atherosclerotic progression and improve outcomes post-cerebrovascular accident (CVA). OSA should be considered in patients complaining of poor concentration at work, actual or near-miss motor vehicle accidents, and patients with severe sleepiness as a component of their co-morbid mood disorders. The metabolic impact of OSA has also been studied, particularly in relation to glucose homeostasis. Also of interest is the potential impact OSA has on lipid metabolism. The adverse effect untreated OSA has on glucose tolerance and lipid levels has led to the suggestion that OSA is yet another constituent of the metabolic syndrome. Some of these metabolic derangements may be related to the adverse effects untreated OSA has on hepatic health. The cardiovascular, neurocognitive, and metabolic manifestations of OSA can have a significant impact on patient health and quality of life. In many instances, evidence exists that therapy not only improves outcomes in general, but also modifies the severity of co-morbid disease. To mitigate the long-term sequela of this disease, providers should be aware of the subtle manifestations of OSA and order appropriate testing as necessary.

Sleep-Disordered Breathing and Cardiac Arrhythmias

Over the past few years sleep-disordered breathing has been identified as an important factor in arrhythmogenesis and a potential target of therapy to prevent cardiac arrhythmias in selected patients. In this review we highlight the role of obstructive sleep apnea and Cheyne-Stokes respiration in the pathophysiology of arrhythmias, address their clinical effect in supraventricular and ventricular tachyarrhythmias, and in conduction disturbances, and address the role of current treatment options for sleep-disordered breathing in the primary and secondary prevention of arrhythmic events.

Association between obstructive sleep apnea and premature supraventricular contractions

OBJECTIVE

The exact association between obstructive sleep apnea (OSA) and premature supraventricular contractions (PSVCs) has not been established.

METHODS

We prospectively performed polysomnography together with 24-hour Holter electrocardiography in 431 patients who were clinically suspected of having OSA and examined the association between OSA severity and PSVCs during wakefulness and sleep. The patients were classified into 4 groups according to the apnea-hypopnea index (AHI) quartiles (Q1=patients with AHI<13.8, Q2=those with 13.8≤AHI<28.8, Q3=those with 28.8≤AHI<48.1, Q4=those with AHI≥48.1).

RESULTS

The number of PSVCs/hour during sleep differed significantly among the 4 groups, but the number of PSVCs/hour during wakefulness did not. The prevalence of PSVC≥5/hour during sleep was significantly higher in Q4 (21.0%) than the other 3 groups (Q1, 9.0%; Q2, 8.0%; Q3, 6.0%; all p<0.05 for Q4), but the prevalence of PSVC≥5/hour during wakefulness did not differ among the 4 groups. A multivariate logistic regression analysis showed that the highest AHI quartile was significantly associated with PSVC≥5/hour during sleep (odds ratio 3.04, 95% confidence interval 1.44-6.42, p=0.004).

CONCLUSIONS

Severe OSA can cause PSVCs during sleep, but its effect appears not to be strong. Further studies are needed to clarify the clinical significance of this small but significant increase in PSVCs during sleep in severe OSA patients.

Sleep disordered breathing as a risk of cardiac events in subjects with diabetes mellitus and normal exercise echocardiographic findings

Sleep disordered breathing (SDB) is associated with type 2 diabetes mellitus (T2DM) and cardiovascular disease; however, the contribution of SDB to incident heart failure (HF), coronary artery disease (CAD), and atrial fibrillation (AF) in patients with T2DM is unknown. We followed up 834 consecutive asymptomatic patients with T2DM (age 56 ± 11 years, 369 women) with normal exercise echocardiographic findings for ≤8 years using electronic health records. The demographics, cardiac risk factors, symptoms, diagnoses, and medications were collected at the echocardiography and validated from the electronic health records. SDB was confirmed by a comprehensive sleep evaluation and/or polysomnography before echocardiography. SDB was diagnosed in 188 patients (21%) at baseline; 116 were untreated. During a median follow-up of 4.9 years (interquartile range 3.9 to 6.1), 22 congestive HF, 72 CAD, and 40 AF incident events were observed. In the Cox proportional hazards models, SDB was associated with incident CAD (hazard ratio 1.8, 95% confidence interval 1.1 to 3.0, p = 0.01; adjusted hazard ratio 1.9, 95% confidence interval 1.2 to 3.2, p <0.01) and AF (hazard ratio 2.6, 95% confidence interval 1.4 to 4.7, p = 0.01; adjusted hazard ratio 2.9, 95% confidence interval 1.5 to 5.9, p <0.01). Limiting SDB to only those patients diagnosed using polysomnography (n = 132), SDB was associated with incident CAD (hazard ratio 1.9, 95% confidence interval 1.1 to 3.3, p = 0.03; adjusted hazard ratio 2.2, 95% confidence interval 1.2 to 3.9, p = 0.01) and HF (hazard ratio 2.7, 95% confidence interval 1.1 to 7.0, p = 0.03; adjusted hazard ratio 3.5, 95% confidence interval 1.4 to 9.0, p <0.01). Female gender, age, elevated blood pressure, and left ventricular mass were additional correlates of CAD in those with asymptomatic T2DM. In conclusion, the association of SDB with incident CAD, AF, and HF in patients with T2DM justifies more liberal screening for SDB in patients with T2DM, realizing that SDB is a potentially modifiable risk factor.

Tae-eum type as an independent risk factor for obstructive sleep apnea

Obstructive sleep apnea (OSA) is prevalent and associated with several kinds of chronic diseases. There has been evidence that a specific type of Sasang constitution is a risk factor for metabolic and cardiovascular diseases that can be found in patients with OSA, but there are no studies that address the association between the Sasang constitution type (SCT) and OSA. The purpose of this study was to investigate the association between the SCT and OSA. A total of 652 participants were included. All participants were examined for demographic information, medical history, and completed an interviewer-administered questionnaire on life style and sleep-related variables. Biochemical analyses were performed to determine the glucose and lipid profiles. An objective recording of OSA was done with an unattended home PSG using an Embla portable device. The apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) were significantly higher in the Tae-eum (TE) type as compared to the So-eum (SE) and the So-yang (SY) types. Even after adjusting for confounding variables, the TE type still had a 2.34-fold (95% CI, 1.11–4.94; P = 0.0262) increased risk for OSA. This population-based cohort study found that the TE constitutional type is an independent risk factor for the development of OSA.

[Sleep-disordered breathing and cardiac arrhythmias]

Sleep-disordered breathing (SDB) is an important comorbidity in patients with cardiac arrhythmias. Previous studies confirmed associations between supraventricular and ventricular arrhythmias and SDB. In heart failure patients, SDB was also found independently associated with a shorter event-free survival to the occurrence of malignant ventricular arrhythmias requiring appropriate cardioverter-defibrillator therapy. In obstructive sleep apnea, repetitive hypoxemia, mechanical stress (wall tension), arousals from sleep, and activation of the sympathetic nervous system promote cardiac arrhythmias. Pathophysiological concepts for the link between Cheyne-Stokes respiration and malignant arrhythmias are not fully understood and require further research. In addition, large-scale, randomized, controlled trials are awaited to prove whether adequate treatment of SDB is associated with a risk reduction for the occurrence of arrhythmias, in general, and malignant ventricular arrhythmias, in particular, in these patients.

Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio are prolonged in patients with moderate and severe obstructive sleep apnea

BACKGROUND

Prolongation of the peak and the end of T wave (Tp-e) has been reported to be associated with ventricular arrhythmias. Tp-e/QT ratio and Tp-e/QTc ratio are used as an index of ventricular arrhythmogenesis. An increased incidence of ventricular arrhythmias has been reported in patients with obstructive sleep apnea (OSA). The aim of this study was to assess ventricular repolarization in patients with OSA by using Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio.

METHODS

We have studied 72 patients who underwent overnight polysomnography (PSG) between the years 2010-2011 at our institution. Patients with moderate and severe OSA (23 patients; mean age: 45±10), according to the apnea-hypopnea index, constituted the study group. Patients with normal PSG (23 patients; mean age: 42±11) were used as the control group. In all patients, Tp-e interval, Tp-e/QT ratio, Tp-e/QTc ratio, as well as some other electrocardiogram intervals were measured. Independent samples t-tests were used for comparison of continuous and categorical variables and correlations were calculated by Spearman rank correlation.

RESULTS

Although QT and QTc intervals were not different between the groups, mean Tp-e interval (81.6±11.1 msn; 63.9±7.3 msn; respectively; P < 0.001), Tp-e/QT ratio (0.21±0.03; 0.17±0.02; respectively; P < 0.001), and Tp-e/QTc ratio (0.20±0.03; 0.16±0.02; respectively; P < 0.001) were prolonged in the study group compared to the control group. Correlation analysis showed a significant positive correlation between the presence of moderate and severe OSA and Tp-e interval (r = 0.72; P < 0.001), Tpe/QT ratio (r = 0.70; P < 0.001), and Tp-e/QTc ratio (r = 0.70; P < 0.001).

CONCLUSIONS

Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio are prolonged in patients with moderate and severe OSA patients. There is a positive correlation between the presence of OSA and Tp-e interval, Tp-e/QT ratio, and Tp-e/QTc ratio.