Sudden death and sleeping history among Finnish men

Snoring during Bronchoscopy with Moderate Sedation Is a Predictor of Obstructive Sleep Apnea

Background

Snoring is the cardinal symptom of obstructive sleep apnea (OSA). Snoring and upper airway obstruction associated with major oxygen desaturation may occur in populations undergoing flexible bronchoscopy.

Methods

To evaluate the prevalence of patients at a high risk of having OSA among patients undergoing bronchoscopy with sedation and to investigate whether snoring during the procedure predicts patients who are at risk of OSA, we prospectively enrolled 517 consecutive patients who underwent the procedure with moderate sedation. Patients exhibiting audible snoring for any duration during the procedure were considered snorers. The STOP-Bang (Snoring, Tiredness, Observed apnea, high blood Pressure-Body mass index, Age, Neck circumference and Gender) questionnaire was used to identify patients at high (score ≥3 out of 8) or low risk (score <3) of OSA.

Results

Of the 517 patients, 165 (31.9%) snored during bronchoscopy under sedation. The prevalence of a STOP-Bang score ≥3 was 61.9% (320/517), whereas 200 of the 352 nonsnorers (56.8%) and 120 of the 165 snorers (72.7%) had a STOP-Bang score ≥3 (p=0.001). In multivariable analysis, snoring during bronchoscopy was significantly associated with a STOP-Bang score ≥3 after adjustment for the presence of diabetes mellitus, chronic obstructive pulmonary disease, chronic kidney disease, and stroke (adjusted odds ratio, 1.91; 95% confidence interval, 1.26–2.89; p=0.002).

Conclusion

Two-thirds of patients undergoing bronchoscopy with moderate sedation were at risk of OSA based on the screening questionnaire. Snoring during bronchoscopy was highly predictive of patients at high risk of OSA.

The Effects of Continuous Positive Airway Pressure on Premature Ventricular Contractions and Ventricular Wall Stress in Patients with Heart Failure and Sleep Apnea

Background

We aimed to investigate the effects of continuous positive airway pressure (CPAP) treatment on electrocardiography (ECG), premature ventricular contraction load on 24-hour Holter recordings, and implantable cardioverter defibrillator (ICD) shocks in patients with obstructive sleep apnea syndrome (OSAS) and heart failure.

Methods

Patients with heart failure and ICD and patients with newly diagnosed OSAS were divided into two groups according to CPAP treatment. To compare the impact of CPAP on ECG parameters, both baseline and 6-month ECG, 24-hour Holter ECG, ambulatory blood pressure monitoring, echocardiography, polysomnography, and laboratory parameters were collected.

Results

CPAP treatment significantly reduced the frequency of premature ventricular contractions, T-peak to T-end, corrected QT, corrected QT dispersion, and T-peak to T-end/corrected QT ratio in the study group (p < 0.001 for all). Although the baseline NT-pro-BNP levels were similar between study and control groups, after six months, the NT-pro-BNP levels of the study group were significantly lower than that of the control group (39.18 ± 7.57 versus 46.11 ± 7.65; p < 0.001).

Conclusions

CPAP treatment in patients with heart failure and ICD and in patients with newly diagnosed OSAS may have beneficial effects on premature ventricular contractions and electrocardiographic arrhythmia indices and NT-pro-BNP levels. However, these results are needed to be clarified with further studies.

Obstructive sleep apnoea-hypopnoea and arrhythmias: new updates

AIMS

Obstructive sleep apnoea-hypopnoea (OSAH) is a prevalent condition characterized by repetitive pharyngeal collapse during sleep, leading to hypoxemia, hypercapnia, and persistent inspiratory efforts against an occluded airway until arousal. Several studies demonstrated that OSAH exerts acute and chronic effects on the cardiovascular system. Thus, although being a respiratory problem, the most important consequences of OSAH are cardiovascular, among which there are arrhythmias. The purpose of this review is to systematically analyse what has been recently published about the relationship between OSAH and every cardiac arrhythmia separately.

METHODS

We searched Pubmed, Scopus, Web of Science and Cochrane Collaboration databases for 'OSAHS arrhythmias', 'OSAH arrhythmias' and 'OSA arrhythmias'. We analyse 1298 articles and meta-analyses, excluding already edited reviews.

RESULTS

Arrhythmias, especially of ventricular origin, are frequent in OSAH. Ventricular premature beats, couplets and ventricular tachycardia runs are even more frequent in patients suffering from heart failure. They may be due to left heart remodelling, overwork and ischaemia and can explain at least some sudden deaths occurring between midnight and 6 a.m. Sinus pauses and atrioventricular blocks are increased according to the severity of the disturbance and may be reduced by continuous positive airway pressure therapy, preventing pace-maker implantation. Finally, atrial fibrillation, resistance against antiarrhythmic drugs and recurrences after surgical procedures are strongly related to OSAH.

CONCLUSION

Arrhythmias are frequent in OSAH. Treatment of OSAH may reduce some of them. An implantable cardioverter-defibrillator and continuous positive airway pressure should be considered in some patients.

Screening and managing obstructive sleep apnoea in nocturnal heart block patients: an observational study

Background

Nocturnal heart block often occurs in patients with obstructive sleep apnoea (OSA). It is more likely to be undiagnosed in heart block patients who are ignorant of the symptoms of sleep disorder. Berlin Questionnaire (BQ) is a highly reliable way to discover the risk factors of OSA, whereas the validity in sleep-related heart block patients is uncertain. We performed an observational study to address these issues and confirmed the potential protective effect of continuous positive airway pressure (CPAP).

Methods

Patients who were previously diagnosed with nocturnal heart block with R-R pauses exceeding 2 seconds were retrospective screened from the ECG centre of Zhongshan hospital. These recruited participants completed Berlin Questionnaire and underwent polysomnography synchronously with 24-hour Holter monitoring. A cross-sectional analysis was performed to confirm the association between nocturnal arrhythmia and OSA, as well as to assess the diagnostic accuracy of the BQ. Subsequently, subjects diagnosed with OSA (apnoea-hypopnoea index > 5) underwent 3 consecutive days of CPAP therapy. On the third day, patients repeated 24-hour Holter monitoring within the institution of CPAP.

Results

The symptoms of disruptive snoring and hypersomnolence in 72 enrolled patients were more related to the occurrence of nocturnal heart block (r = 0.306, 0.226, respectively, p = 0.015, 0.019) than syncope (r = 0.134, p = 0.282) and palpitations (r = 0.106, p = 0.119), which were prominent trait of our study population. The sensitivity, specificity, positive and negative predictive value of the BQ at a cut-off point of 5 of AHI for detecting OSA in heart block patients was 81.0 %, 44.4 %, 91.07 % and 25 %. Nocturnal heart block does not appear to occur exclusively in severe sleep apnoea. The frequent occurrence of arrhythmias in prominent oxygen desaturation supports the correlation between them. CPAP therapy resulted in significant decrease in the average number of episodes of heart block, from 148.58 ± 379.44 to 16.07 ± 58.52 (p < 0.05), same to the change of the longest RR pausing time (from 4.38 ± 2.95 s to 0.57 ± 1.05 s, p = 0.169) in 51 patients. The optimal therapy pressure to make the observed arrhythmia disappeared is 12 cm H₂O.

Conclusion

Concerning high prevalence of OSA in heart block patients, BQ provided an economical and efficient screening method for OSA. For better management, CPAP therapy is feasible to prevent heart blocks avoiding unnecessary concomitant pacemaker implantation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0333-8) contains supplementary material, which is available to authorized users.

Cardiovascular complications of obstructive sleep apnea

Obstructive sleep apnea (OSA) is a common disorder with an increasing public health burden. It is characterized by repeated upper airway narrowing and closure, leading to apneas, hypopneas and increased respiratory effort-related arousals. Continuous positive airway pressure is an effective modality of treatment for OSA. Apart from being responsible for daytime sleepiness and cognitive impairment, OSA has been implicated in various systemic diseases, particularly of the cardiovascular system. This article reviews some of the extensive literature implicating OSA in the development of cardiovascular diseases and describes the intermediary pathophysiologic mechanisms involved. Repetitive nocturnal oxygen desaturation and reoxygenation and increased intrathoracic pressure changes related to OSA result in the intermediary pathophysiologic mechanisms that affect the neural, humoral, thrombotic, inflammatory and metabolic pathways responsible for the development of cardiovascular disorders. This review also examines evidence that suggests that OSA may be a specific cause of certain cardiovascular disorders.

THE RELATIONSHIP OF HRV TO SLEEP EEG AND SLEEP RHYTHM

Previous studies have shown that there exists a cycle of NREM (non-rapid eye movement)-REM (rapid eye movement) during normal human sleep, and heart rate variability (HRV) has a close relationship to sleep stages and sleep cycle. This article reports the relationship between the electroencephalographic activity and the HRV spectral power in several specific frequency bands. The authors discovered that relationships do exist between HRV and electroencephalogram (EEG) during sleep. In particular, it was found that, prior to the changes of EEG, the changes of HRV usually indicate the shift of sleep stages. HRV frequency analysis indicates that the very-low-frequency components of HRV are closely related to sleep EEG. Results show that the rhythm of the spectral power oscillations in some specific frequency bands of HRV is almost the same as the sleep cycle, which reflects the rhythm of sleep to a certain extent.

Heavy snoring is a risk factor for case fatality and poor short-term prognosis after a first acute myocardial infarction

STUDY OBJECTIVES

Sleep disordered breathing has been associated with an increased risk for developing coronary heart disease. Data on the effects of sleep disordered breathing on case fatality and prognosis of a myocardial infarction are sparse. The present study aimed to investigate a possible relationship of snoring and case fatality and mortality after an acute myocardial infarction. DESIGN, SETTINGS, PATIENTS, AND MEASUREMENTS: In this study, we enrolled 1660 first acute myocardial infarction cases and examined the effects of self- or relative-reported heavy snoring on case fatality and prognosis. The average follow-up time was 8 years, SD = 262 days.

RESULTS

There was a variation in the association between snoring and mortality with time, with a strong association in the first 28 days after infarction but not later during the follow-up. Occasional and regular heavy snorers, when compared to those never having heavy snoring, had a 2.04 (95% confidence interval, 1.50 to 2.79) and 3.30 (95% confidence interval, 2.37 to 4.58) hazard ratio for mortality within the first 28 days after controlling for age, gender, obesity, history of diabetes and hypertension, physical activity, smoking, and education, respectively. There was no association between snoring and new myocardial infarction, stroke, or hospitalization for heart failure during the follow-up.

CONCLUSIONS

Heavy snoring is associated with case fatality and short-term mortality in patients with a first acute myocardial infarction.

Obstructive Sleep Apnea and its Relationship to Cardiac Arrhythmias

Obstructive sleep apnea (OSA) affects approximately 4% of middle-aged men and 2% of middle-aged women. Cardiac arrhythmias are common problems in patients with OSA, even though the true prevalence and clinical relevance of cardiac arrhythmias remains to be determined. The presence and complexity of both tachyarrhythmias and bradyarrhythmias may influence morbidity, mortality, and the quality of life for OSA patients. Although the exact mechanisms underlying the link between OSA and cardiac arrhythmias are not well established, they could be partially the same proposed mechanisms relating OSA to different cardiovascular diseases. OSA is characterized by repetitive pharyngeal collapse during sleep that leads to markedly reduced or absent airflow, followed by oxyhemoglobin desaturation, persistent inspiratory efforts against an occluded airway, and termination by arousal from sleep. These mechanisms elicit a variety of autonomic, hemodynamic, humoral, and neuroendocrine responses that by themselves evoke acute and chronic changes in cardiovascular function. These effects may lead to the development of cardiac arrhythmias and any other form of cardiovascular disease linked to OSA. The aims of this review are to describe the essential cardiovascular pathophysiological aspects of OSA, to outline the relationship between OSA and both tachyarrhythmias and bradyarrhythmias and their possible influence in the natural history of OSA patients, and to assess the effects of OSA treatment on the presence of cardiac arrhythmias.

Home Sleep Testing in the Diagnosis and Treatment of Sleep Disordered Breathing

Sleep-disordered breathing is a growing public health concern and an integral part of head and neck surgery. Multichannel home sleep testing is a cost-effective, patient-friendly, scientifically valid technique of evaluating patients who present with symptoms of sleep-disordered breathing, typically snoring or daytime sleepiness. Home sleep tests can be dispensed from the physician's office. They have a 95% successful recording rate. Scoring can be autoscore or manual score. There are several protocols that can be followed based on diagnostic outcomes.

Radiofrequency tissue volume reduction of the soft palate and UPPP in the treatment of snoring

The purpose of this study was to evaluate the efficiency of radiofrequency tissue volume reduction (RFTVR) and uvulopalatopharyngoplasty (UPPP) in the treatment of snoring in a prospective clinical trial of 79 patients consecutively undergoing surgery for snoring. Seventy-nine patients with primary snoring or mild OSAS (obstructive sleep apnea syndrome) were enrolled in this clinical trial (66 males and 13 females). According to the anatomical findings (the size of the tonsils and uvula), the patients underwent UPPP/TE of the RFTVR of the soft palate. Forty-seven patients had UPPP/TE (age 45.81+/-12.11 years; median AHI: 8; range 1-29). Thirty-two patients were treated with RFTVR of the soft palate (age 48.10+/-10.92; median AHI: 5.0; range 0-26). The average number of treatments was 2.2. All patients underwent preoperative polysomnography to exclude severe OSAS. Pre- and postoperative snoring scores were evaluated from the patients with bed partners. Postoperative follow-up data were collected at a median of 4 months after treatment; 85.1% of the UPPP group and 53.1% of the RFTVR group underwent postoperative polysomnography. Subjective snoring scores of all study participants were evaluated. Preoperatively, there was no statistically significant difference of subjective symptoms, age and BMI between the two groups. The snoring scores improved statistically significantly in both groups (P <0.001 in the UPPP group; P =0.001 in the RFTVR group). After UPPP/TE snoring improved in 37 patients (78.7%), and 29 (61.7%) thereof were free of bothersome snoring; no change was found in 9 patients (19.2%), and 1 (2.1%) worsened. In the RFTVR group, snoring improved in 15 (46.9%), and 9 (28.1%) thereof were free of bothersome snoring; no change was found in 13 patients (50%), and 1 worsened (3.1%). Preoperative AHI was statistically higher (P =0.016) and mean minimal oxygen saturation significantly lower (P =0.002) in the UPPP group. In the UPPP group AHI and HI showed statistically significant improvement postoperatively (P =0.025 and P =0.034, respectively). After RFTVR, no statistically significant change of AHI, HI or oxygen saturation was found. Besides limited mucosal erosions (15%) after RFTVR and foreign body sensations (<10%) after UPPP/TE, no side effects were observed. The success rate of RFTVR of the soft palate is lower compared to the more invasive technique of UPPP. Due to its minimally invasive character, RFTVR is suitable as first-step treatment for snoring, but patients should be counseled about possible success rates and different treatment options.

Antioxidant responses to chronic hypoxia in the rat cerebellum and pons

Obstructive sleep apnea (OSA) is characterized by chronic intermittent hypoxia (CIH) and sleep fragmentation and deprivation. Exposure to CIH results in oxidative stress in the cortex, hippocampus and basal forebrain of rats and mice. We show that sustained and intermittent hypoxia induces antioxidant responses, an indicator of oxidative stress, in the rat cerebellum and pons. Increased glutathione reductase (GR) activity and thiobarbituric acid reactive substance (TBARS) levels were observed in the pons and cerebellum of rats exposed to CIH or chronic sustained hypoxia (CSH) compared with room air (RA) controls. Exposure to CIH or CSH increased GR activity in the pons, while exposure to CSH increased the level of TBARS in the cerebellum. The level of TBARS was increased to a greater extent after exposure to CSH than to CIH in the cerebellum and pons. Increased superoxide dismutase activity (SOD) and decreased total glutathione (GSHt) levels were observed after exposure to CIH compared with CSH only in the pons. We have previously shown that prolonged sleep deprivation decreased SOD activity in the rat hippocampus and brainstem, without affecting the cerebellum, cortex or hypothalamus. We therefore conclude that sleep deprivation and hypoxia differentially affect antioxidant responses in different brain regions.

Day-night pattern of sudden death in obstructive sleep apnea

BACKGROUND

The risk of sudden death from cardiac causes in the general population peaks from 6 a.m. to noon and has a nadir from midnight to 6 a.m. Obstructive sleep apnea is highly prevalent and associated with neurohormonal and electrophysiological abnormalities that may increase the risk of sudden death from cardiac causes, especially during sleep.

METHODS

We reviewed polysomnograms and the death certificates of 112 Minnesota residents who had undergone polysomnography and had died suddenly from cardiac causes between July 1987 and July 2003. For four intervals of the day, we compared the rates of sudden death from cardiac causes among people with obstructive sleep apnea and the following: the rates among people without obstructive sleep apnea, the rates in the general population, and the expectations according to chance. For each interval, we assessed the median apnea-hypopnea index and the relative risk of sudden death from cardiac causes. We similarly analyzed sudden death from cardiac causes during three time intervals that correlate with usual sleep-wake cycles.

RESULTS

From midnight to 6 a.m., sudden death from cardiac causes occurred in 46 percent of people with obstructive sleep apnea, as compared with 21 percent of people without obstructive sleep apnea (P=0.01), 16 percent of the general population (P<0.001), and the 25 percent expected by chance (P<0.001). People with sudden death from cardiac causes from midnight to 6 a.m. had a significantly higher apnea-hypopnea index than those with sudden death from cardiac causes during other intervals, and the apnea-hypopnea index correlated directly with the relative risk of sudden death from cardiac causes from midnight to 6 a.m. For people with obstructive sleep apnea, the relative risk of sudden death from cardiac causes from midnight to 6 a.m. was 2.57 (95 percent confidence interval, 1.87 to 3.52). The analysis of usual sleep-wake cycles showed similar results.

CONCLUSIONS

People with obstructive sleep apnea have a peak in sudden death from cardiac causes during the sleeping hours, which contrasts strikingly with the nadir of sudden death from cardiac causes during this period in people without obstructive sleep apnea and in the general population.

Sleep-disordered breathing: implications in cerebrovascular disease

Stroke and sleep-disordered breathing (SDB) are both common and are associated with significant morbidity and mortality. Several recent large epidemiologic studies have shown a strong association between these two disorders independent of known risk factors for stroke. This review will outline the scientific basis for this relationship and suggest SDB as a modifiable risk factor for stroke. Several studies have shown a characteristic circadian rhythmicity in stroke. The authors discussed the influence of normal sleep states as well as the effect of SDB on cerebral hemodynamics. The hemodynamic, metabolic, and hematologic changes during SDB in the form of decreased cerebral perfusion and increased coagulability are the possible pathogenetic mechanisms for stroke. There are accumulating lines of evidence that SDB may indeed cause diurnal hypertension. However, the increased risk of stroke in patients with SDB appears to be independent of coexisting hypertension, but the presence of hypertension would greatly increase the risk even further. Furthermore, several studies have documented high prevalence of sleep apnea in patients with transient ischemic attacks and stroke. SDB appears to contribute as a risk factor for stroke through hemodynamic and hematologic changes. Because of high prevalence of SDB in this population, patients with transient ischemic attacks and stroke should be screened for these disorders.

Nocturnal Arterial Oxygen Desaturation and Episodic Airway Obstruction After Ambulatory Surgery

Some patients experience disordered breathing during sleep and arterial oxygen desaturation after major inpatient surgery. We performed this study to determine whether similar events occur after ambulatory surgery. Forty-five ambulatory surgery patients received an unrestricted anesthetic. Continuous unattended nocturnal recordings of breathing pattern and oxygen saturation were made in the patients' homes before surgery and during the first and second postoperative nights. Nine patients had a respiratory disturbance index >10 and/or >1% of recording time with oxygen saturation <90% on at least one study night. These nine patients had a significantly older median age and a significantly larger median body mass index. Their median respiratory disturbance index and median percentage of time with oxygen saturation <90% were significantly higher on the first postoperative night than on the preoperative night.

Snoring as a cause of nocturia in men with lower urinary tract symptoms

OBJECTIVES

Snoring increases with increasing age and body mass, and repeated periods of hypoxia cause nocturnal polyuria. Accordingly, we examined the occurrence of snoring problems in patients scheduled for transurethral prostatic resection.

METHODS

Of 171 men scheduled for TUR-P, 41 were excluded due to cardiac disease, diabetes, or prostatic malignancy. Of the remaining 130 patients, 12% were troubled by snoring that disturbed their sleep. The severity of their snoring was evaluated by questionnaires, micturition charts, and determination of nocturnal capillary oxygen saturation (SaO(2)) and pulse rate. Plasma levels of cortisol, arginine vasopressin (AVP), and atrial natriuretic peptide (ANP) were measured in the morning and at 2 p.m. Fifteen non-snoring patients also scheduled for TUR-P served as controls.

RESULTS

Compared to controls, the snoring patients had a significantly higher body mass index (BMI), voided more frequently, and produced more urine at night. They also had a significantly larger number of hypoxic episodes at night, which, along with low SaO(2) levels, correlated with the nocturnal diuresis. Snorers did not differ significantly from controls in regard to excretion of cortisol and AVP, but they did have higher plasma levels of ANP.

CONCLUSIONS

We recommend that elderly obese men with urgency at night be questioned about snoring, and that micturition frequency and volume charts be completed before deciding to operate.

Sleep apnea syndrome in patients undergoing total joint arthroplasty

Sleep apnea syndrome (SAS) is a condition of repeated episodes of apnea and hypopnea during sleep. It can cause life-threatening morbidities, including cardiac arrhythmia and ischemia, hypertension, and respiratory arrest, and even death. In a retrospective study at our institution of patients who underwent hip or knee total joint arthroplasty (TJA) with a diagnosis of SAS, we hypothesized that avoiding factors that exacerbate SAS in the perioperative period would minimize adverse outcomes. There were 19 patients with a preoperative diagnosis of moderate or severe SAS; 15 patients received continuous positive airway pressure or bilevel positive airway pressure noninvasive ventilation, 1 patient experienced respiratory arrest secondary to intraoperative propafol, and 2 patients developed postoperative respiratory depression. Avoidance of opioids and sedative drugs, awareness of the possibility of acute airway obstruction, and close monitoring during and after surgery are vital in patients with SAS.

The occurrence of sleep-disordered breathing among patients with head and neck cancer

OBJECTIVE

To identify the incidence of obstructive sleep apnea (OSA) in patients treated for head and neck cancer. Obstructive sleep apnea is a relatively common and highly morbid condition that affects 9.1% of male and 4% of female middle-aged adults.1 Patients who have been successfully treated for head and neck cancer may often have a partially obstructed upper airway which is functional during the day, but collapses during sleep.

STUDY DESIGN/METHODS

Twenty-four patients successfully treated for tumors of the tongue-base, pharynx, or supraglottic larynx were enrolled. Through OSA-related questionnaires, physical examination, and polysomnography, the incidence of OSA in this patient population was determined and compared with that of the general population.

RESULTS

The incidence of OSA (91.7%) in this head and neck cancer patient population was found to be significantly (P =.001) higher than that of the general population. (In a random sampling of middle-aged adult males between the ages of 30 and 60 years old with a respiratory disturbance index (RDI) >15, the prevalence was previously reported to be 9.1%.1) Sixteen of 24 patients (72.7%) had clinically defined symptoms of sleep apnea. Ten of 24 patients (41.7%) received radiation therapy; all had an RDI >15. Eleven of the 14 patients (78.5%) who did not receive radiation therapy also had an RDI >15. Eight patients (33.3%) continue to regularly use continuous positive airway pressure with significant improvement in symptoms.

CONCLUSIONS

Identification and treatment of OSA may be an important factor in improving quality of life for patients with head and neck cancer.

Echocardiographic features of the right heart in sleep-disordered breathing: the Framingham Heart Study

The effect of sleep-disordered breathing (SDB) on right heart structure and function is controversial. Studies of patients referred for evaluation of possible sleep apnea have yielded conflicting results, and the impact of SDB on the right heart has not been investigated in the general population. We examined the echocardiographic features of subjects with SDB at the Framingham Heart Study site of the Sleep Heart Health Study. Of 1,001 polysomnography subjects, 90 with SDB defined as a respiratory disturbance index (RDI) score > 90th percentile (mean RDI = 42) were compared with 90 low-RDI subjects (mean RDI = 5) matched for age, sex, and body mass index. Right heart measurements, made without knowledge of clinical status, were compared between groups. The majority of the subjects were male (74%). After multivariable adjustment, right ventricle (RV) wall thickness was significantly greater (p = 0.005) in subjects with SDB (0.78 +/- 0.02 cm) than in the low-RDI subjects (0.68 +/- 0.02 cm). Right atrial dimensions, RV dimensions, and RV systolic function were not found to be significantly different between subjects with SDB and the low-RDI subjects. We conclude that in this community-based study of SDB and right heart echocardiographic features, RV wall thickness was increased in subjects with SDB. Whether the RV hypertrophy observed in persons with SDB is associated with increased morbidity and mortality remains unknown.

Sudden cardiac death with clozapine and sertraline combination

OBJECTIVE

To report a case of sudden cardiac death in a patient receiving combination therapy with clozapine and sertraline.

CASE SUMMARY

A 26-year-old white man was discovered dead at his residence. His medical history included chronic paranoid schizophrenia, obsessive-compulsive disorder, major depressive disorder, obstructive sleep apnea, and akathisia. He had no prior history of cardiovascular disease. His medication regimen included clozapine 100 mg twice daily (started 4 y prior to his death), risperidone 3 mg twice daily, sertraline 200 mg once daily, atenolol 50 mg twice daily, and lorazepam 0.5 mg four times daily. Autopsy and toxicology studies revealed cardiomegaly suggestive of idiopathic cardiomyopathy, single-vessel coronary artery disease, sertraline and clozapine blood concentrations in the expected range, undetectable lorazepam and risperidone blood concentrations, obesity, and moderate fatty changes to the liver. The most likely cause of death was sudden cardiac death due to acute cardiac arrhythmia.

DISCUSSION

Clozapine is structurally similar to the tricyclic antidepressants, which have type 1 A antiarrhythmic properties. Case reports have described electrocardiographic abnomalities, cardiomyopathy, and fatal myocarditis associated with its use. Unexplained death in patients on clozapine therapy has also been reported. Sertraline appears to have less cardiac effect; however, one report has observed clinically significant QT prolongation during sertraline therapy.

CONCLUSIONS

Clozapine-induced cardiomyopathy and cardiac arrhythmia from clozapine and/or sertraline use may have contributed to this man's death.

Sleep-related breathing disorders and risk of stroke

BACKGROUND

Stroke and sleep-related breathing disorders are both common and are associated with significant morbidity and mortality. Several recent large epidemiological studies have shown a strong association between these 2 disorders independent of known risk factors for stroke. This article will outline the scientific basis for this relationship and suggest sleep-related breathing disorders as modifiable risk factors for stroke.

SUMMARY OF REVIEW

Several studies have shown a characteristic circadian rhythmicity in stroke. We have discussed the influence of normal sleep states as well as the effect of sleep-related breathing disorders on cerebral hemodynamics. The hemodynamic, metabolic, and hematologic changes during sleep-related breathing disorders in the form of decreased cerebral perfusion and increased coagulability are possible pathogenetic mechanisms for stroke. There are accumulating lines of evidence that sleep apnea disorder may indeed cause diurnal hypertension. However, the increased risk of stroke in patients with sleep-related breathing disorders appears to be independent of coexisting hypertension; the presence of hypertension would increase the risk even further. Furthermore, several studies have documented high prevalence of sleep apnea disorders in patients with transient ischemic attacks and stroke.

CONCLUSIONS

Sleep-related breathing disorder appears to contribute as a risk factor for stroke through hemodynamic and hematologic changes. Because of the high prevalence of sleep apnea disorder in this population, patients with transient ischemic attacks and stroke should undergo evaluation for these disorders.

CLINICAL REVIEW ARTICLE: Epidemiology of sleep-related obstructive breathing

The diagnosis of obstructive sleep apnoea syndrome (OSAS) and upper airway resistance syndrome (UARS) is based both on a combination of laboratory findings from whole-night sleep recordings and daytime symptoms. Due to the recent interest in breathing disturbances during sleep many prevalence studies have been performed within this field. There are, however, methodological difficulties in characterizing these syndromes in large populations; many of the studies have therefore been unable to present an overview of the complete syndromes but rather have focused on specific characteristics. In epidemiological research snoring and/or daytime sleepiness have often been used as markers of OSAS, while other studies have looked only on the respiratory disturbances or oxygen desaturation. Studies on the prevalence of OSAS based on polysomnography are reviewed here, as well as investigations where associated factors such as cardiovascular diseases and mortality were analysed. The interrelationships between snoring, daytime symptoms and laboratory findings are discussed. Gender, age, obesity, smoking, alcohol and ethnicity are all factors that influence the prevalence of OSAS. The data on associations between OSAS and cardiovascular disease or mortality are sometimes unrelated. Much of the discrepancy between different studies can be explained by the methodological difficulties connected with the definition of OSAS and also by the fact that the association between sleep-disordered breathing and cardiovascular outcome seems to be age-dependent.

Habitual snoring in an outpatient population in Japan

In order to investigate the occurrence and history of sleep problems in Japan, the 11-Centre Collaborative Study on Sleep Problems (COSP) project was carried out. Complaints of snoring are examined, and its prevalence, risk factors and screening reliability are discussed. The subjects who participated in the study were 6445 new outpatients from a general hospital. They were asked to answer a sleep questionnaire that consisted of 34 items with seven demographic items; each item was composed of four grades of frequency. In order to offset possible seasonal variations in sleep habits, data were collected across four seasons. Sleep patterns, insomnia, hypersomnia, parasomnia and circadian rhythm sleep disorders were covered. Habitual snoring was seen in 16.0% of males and 6.5% of females. Male predominance was noted. From these data, the relationship between habitual snoring and sleep complaints was statistically analyzed. Habitual snorers (HS) were observed to wake up more frequently during sleep (17.8% of males, 21.5% of females) than were non-habitual snorers (NHS; 6.6% of males, 9.7% of females). Mid-sleep awakening of HS was also more frequent than it was for NHS; however, there were no differences in difficulty in falling asleep and early morning awakening. Body mass index, cigarette smoking and alcohol consumption were also correlated with habitual snoring.

Respiratory disturbance index: an independent predictor of mortality in coronary artery disease

Cardiovascular mortality was prospectively investigated in consecutive coronary artery disease (CAD) patients with versus without obstructive sleep apnea (OSA) during a follow-up period of 5 yr. An overnight sleep/ventilatory study was performed in patients requiring intensive care (n = 62, mean age 67.6 +/- 10.4 yr, range 44 to 86) during a stable condition (New York Heart Association [NYHA] functional class I-II) 4 to 21 mo after discharge from the hospital. OSA, defined as a respiratory disturbance index (RDI) of 10/h or more was found in 19 patients (mean RDI 17.5 +/- 8.3). Three OSA subjects who were successfully treated with continuous positive airway pressure (CPAP) during the observation period were excluded from the final analysis. There was no statistically significant difference (Fisher two-tailed exact test) between the OSA and non-OSA patient groups in terms of number of elderly subjects (age >/= 65 yr), gender, obesity (body mass index [BMI] >/= 30 kg/m(2)), smoking history, presence of hypertension, diabetes mellitus, hypercholesterolemia, or history of myocardial infarction at the study start. During the follow-up period, cardiovascular death occurred in six of 16 OSA patients (37.5%) compared with 4 (9.3%) in the non-OSA group (p = 0.018). The univariate predictors of cardiovascular mortality were RDI (p = 0.007), OSA (p = 0.014), age at baseline (p = 0.028), hypertension at baseline (p = 0.036), history of never-smoking (p = 0.031), and digoxin treatment during the follow-up period (p = 0.013). In a Cox multiple conditional regression model, RDI remained as an independent predictor of cardiovascular mortality (exp beta = 1.13, 95% confidence interval [CI] 1.05 to 1.21, two-sided p < 0.001). We conclude that untreated OSA is associated with an increased risk of cardiovascular mortality in patients with CAD. Furthermore, it appears appropriate that RDI is taken into consideration when evaluating secondary prevention models in CAD.

Sleep-related breathing disorders and cardiovascular disease

Sleep-related breathing disorders, ranging from habitual snoring to the increased upper airway resistance syndrome to sleep apnea, are now recognized as major health problems. The majority of patients have excessive daytime sleepiness and tiredness. Neuropsychological dysfunction results in poor work performance, memory impairment, and even depression. Until recently, the coexistence of cardiovascular and cerebrovascular diseases with sleep-related breathing disorders was thought to be the result of shared risk factors, such as age, sex, and obesity. However, in the past 5 years several epidemiologic studies have demonstrated that sleep-related breathing disorders are an independent risk factor for hypertension, probably resulting from a combination of intermittent hypoxia and hypercapnia, arousals, increased sympathetic tone, and altered baroreflex control during sleep. Sleep apnea may lead to the development of cardiomyopathy and pulmonary hypertension. Early recognition and treatment of sleep-related breathing disorders may improve cardiovascular function.

Circadian antidiuretic hormone variation in elderly men complaining of persistent nocturia after urinary flow obstruction removal

Persistence of nocturia after prostatic resection in healthy patients without symptoms referred to residual bladder instability and to pathological polyuria seems to be caused by an increased urine production at night. The more accreditate mechanism involved is the relevant decreased ADH secretion pattern which occurs at night. In our study, patients with nocturnal poliuria showed significantly low plasmatic vasopressin levels compared with a control group. The aim of this study was to evaluate whether the persistence of nocturia after prostatic resection in healthy patients, without symptoms referred due to residual bladder instability and important polyuria, could be due to a decrease or a lack of increase in antidiuretic hormone (ADH) nocturnal levels following increased urine production at night. Serum ADH, atrial natriuretic peptide (ANP) and osmolality were assessed at 4-h intervals in 12 patients complaining of residual nocturia (group A) and in a control group of 13 patients who had undergone a complete resolution of nocturia after prostate ablation (group B). In the 25 patients involved in the study (mean age 65.8 years), no significant differences were observed in the two groups concerning mean age (67.5 years for group A, 64 years for group B). Mean nocturnal urine volume (1080 +/- 490 ml) in group A patients was significantly higher than in group B (500 +/- 100 ml) (p < 0.001), while no significant differences were found in diurnal diuresis. Mean plasma vasopressin levels of the 12 patients showing an increased nocturnal micturition were found to be significantly lower at all 4-h intervals when compared with the control group (p < 0.05). Individual fluctuations in serum osmolality were slight and insignificant within the normal range in all patients. The diurnal variation of plasma atrial natriuretic peptide was within the reference limits for all subjects during the 24-h period. Our results lead us to believe that residual nocturia after prostatic resection seems to be caused by an increased urine production at night due to a decreased ADH secretion pattern.

Increased mortality among sleepy snorers: a prospective population based study

BACKGROUND

The long term health consequences of snoring and sleep apnoea syndrome are still uncertain. This study was conducted to assess the mortality risk associated with snoring and excessive daytime sleepiness (EDS), the two main symptoms of sleep apnoea syndrome, in men.

METHODS

In 1984 a sample of 3100 men aged 30-69 responded to a postal questionnaire including questions about snoring, EDS, and the prevalence of various diseases (response rate 77.1%). Mortality data for the period 1985-1995 were collected for the complete sample.

RESULTS

During the 10 year follow up period 213 men died, 88 of cardiovascular diseases. Compared with subjects with no snoring or EDS in 1984, men with isolated snoring or EDS displayed no significantly increased mortality. The combination of snoring and EDS was associated with a significant increase in mortality. However, the relative rates decreased with increasing age, and in men aged 60 and above no effect on mortality was found. Men below the age of 60 with both snoring and EDS had an age adjusted total death rate which was 2.7 times higher than men with no snoring or EDS (95% CI 1.6 to 4.5). The corresponding age adjusted hazard ratio for cardiovascular mortality was 2.9 (95% CI 1.3 to 6.7) for subjects with both snoring and EDS. Further adjustment for body mass index and reported hypertension, cardiac disease, and diabetes reduced the relative mortality risk associated with the combination of snoring and EDS to 2.2 (95% CI 1.3 to 3.8) and the relative risk of cardiovascular mortality to 2.0 (95% CI 0.8 to 4.7).

CONCLUSION

Snoring without EDS does not appear to carry an increased risk of mortality. The combination of snoring and EDS appears to be associated with an increased mortality rate, but the effects seems to be age dependent. The increased mortality is partly explained by an association between "snoring and EDS" and cardiovascular disease.

[Obstructive sleep apnea syndrome in the Community of Valencia: current situation, study of needs and future prospects]

To analyze the infrastructure needs for diagnosing sleep apnea syndrome (SAS) in the Community of Valencia, we studied available resources and the diagnostic approaches to SAS in departments of pneumology and neurophysiology in 23 of the 25 public hospitals by means of a telephone interview. Only 52% of pneumology departments and 56% of neurophysiology departments studied SAS at any level. Level I study (conventional polysomnography) was performed by 42% of the pneumology departments and 100% of the neurophysiology departments. The remaining pneumology units used nighttime oximetry (a level IV technique). A special unit and trained personnel were available at 40% of hospitals. Home studies were performed by only 17%. Although 2,000 studies are performed annually, only 1,100 are level I and large interdepartmental differences were detected. The average waiting period was 16 months. Relations between pneumology and neurophysiology units were few and only one hospital took an interdisciplinary approach. The ratio of polysomnographs to inhabitants was 0.52/250,000 and the prevalence of nasal continuous positive airway pressure treatment was 36/100,000, lower than in other communities. We conclude that Valencia is understaffed and under-equipped, and that in some cases resources are under-used. Interdisciplinary approaches are scarcely used by the various specialists involved and the waiting lists for diagnostic tests required for prescribing empirical treatment are long. To attend the approximately 100,000 SAS patients estimated to reside in Valencia, it would be necessary to have 14 polysomnograph devices rather than the 8 available now, as well as to increase staff to meet demand and shorten waiting lists.

An update on coronary risk factors

Epidemiologic research continues to produce additional independent risk factors, including small dense LDL, Lp(a), isolated systolic hypertension, the insulin-resistance syndrome, leucocyte count, plasma fibrinogen, homocystinemia, and sleep disturbance. Alcohol in moderation appears protective. Because the hazard posed by any particular risk factor is markedly influenced by other metabolically linked risk factors with which it tends to cluster, multivariate risk assessment provides a substantially better risk estimate than that based on single risk factors.

Daytime sleepiness, snoring and gastro-oesophageal reflux amongst young adults in three European countries

OBJECTIVES

To study the geographical variation in daytime sleepiness, snoring and disrupted breathing during sleep and to identify and compare risk factors using the same method in four European cities.

DESIGN

A cross-sectional, multicentre epidemiological survey.

SETTING

Reykjavik in Iceland, Uppsala and Göteborg in Sweden and Antwerp in Belgium.

PARTICIPANTS

A random population sample of 2202 subjects who participated in the European Community Respiratory Health Survey.

MAIN OUTCOME MEASURES

Sleep disturbances and daytime symptoms.

RESULTS

At all the centres, 5% of the men and 2-3% of the women reported snoring every night. Daytime sleepiness (DS) was more often reported in Uppsala [odds ratio (OR) and 95% confidence interval: 1.6 (1.2-2.1)] than in the other centres, whilst daytime tiredness (DT) was most common in Reykjavik [ OR 1.8 (1.4-2.1)]. Snoring was positively correlated with age, male gender and body-mass index in all areas. Symptoms of gastro-oesophageal reflux were associated with DS: OR 2.6 (1.5 4.4) and DT: OR 4.5 (2.7-7.6) and disrupted breathing: OR 3.8 (1.4-10). DS and DT were reported more often by women than by men.

CONCLUSION

The prevalence of snoring was about the same in all four areas, whilst there was a geographical variation in daytime sleepiness and tiredness. As complaints of DS and DT and disrupted breathing were more common in subjects who reported symptoms of gastro-oesophageal reflux, we suggest that polysomnographic studies comparing sleep patterns in adult patients with and without reflux should be conducted.

Snoring and cardiovascular risk factors

The association of snoring with some cardiovascular risk factors was studied cross-sectionally by a postal survey among 3750 males aged 40-59 years. In univariate analyses, snoring associated statistically significantly (P < 0.01) with hypertension, smoking, obesity, heavy alcohol use, physical inactivity, dyspnoea, hostility and morning tiredness. In a multiple logistic regression model adjusted by age, snoring associated significantly with smoking, obesity, physical inactivity, hostility and morning tiredness. When smoking was excluded from the multivariate model, alcohol use was also associated significantly with snoring. The association of snoring with smoking, and with obesity seemed to be almost independent from other studied correlates of snoring. Our results indicate that in further studies on predictive value of snoring with regard to coronary heart disease and stroke, the associations of snoring with hypertension, smoking, obesity, heavy alcohol use, physical inactivity and hostility have to be considered, as these risk characteristics may cause confounding effects.

Sleep apnea and cardiac arrhythmias. Is there a relationship?

To determine if there was a relationship between cardiac arrhythmias and sleep apnea, we studied the prevalence of arrhythmias in a consecutive series of patients referred to our clinic for assessment of this disorder. Two hundred of 263 physician-referred patients were eligible for the study and, of these, 173 (86.5%) had complete investigations. All patients underwent a full night of polysomnography and Holter monitoring. Sleep apnea was diagnosed if patients had more than 10 apneas and hypopneas per hour (AHI). In 76 patients (43.9%) sleep apnea was diagnosed (median AHI = 33). The prevalence of arrhythmias in patients with sleep apnea versus those without was, respectively: complex ventricular ectopy (including ventricular tachycardia), 1.3% (95% CI, 0.4 to 6.9) versus 4.1% (CI, 1.6 to 10.1); frequent ventricular premature beats (> 30/h), 2.6% (CI, 0.8 to 8.9) versus 6.2% (CI, 2.9 to 12.8); second-degree atrioventricular block, 1.3% (CI, 0.4 to 6.9) versus 4.1% (CI, 1.6 to 10.1); sinus arrest, 5.2% (CI, 2.2 to 12.6) versus 1.0% (CI, 0.2 to 5.6). None of these differences was statistically significant. We conclude that the prevalence of cardiac arrhythmias is low in patients without serious cardiac or respiratory comorbidity who are referred for assessment of sleep apnea. Furthermore, the presence or absence of arrhythmias in this group is unrelated to sleep apnea severity.

The occurrence of sleep-disordered breathing among middle-aged adults

BACKGROUND

Limited data have suggested that sleep-disordered breathing, a condition of repeated episodes of apnea and hypopnea during sleep, is prevalent among adults. Data from the Wisconsin Sleep Cohort Study, a longitudinal study of the natural history of cardiopulmonary disorders of sleep, were used to estimate the prevalence of undiagnosed sleep-disordered breathing among adults and address its importance to the public health.

METHODS

A random sample of 602 employed men and women 30 to 60 years old were studied by overnight polysomnography to determine the frequency of episodes of apnea and hypopnea per hour of sleep (the apnea-hypopnea score). We measured the age- and sex-specific prevalence of sleep-disordered breathing in this group using three cutoff points for the apnea-hypopnea score (> or = 5, > or = 10, and > or = 15); we used logistic regression to investigate risk factors.

RESULTS

The estimated prevalence of sleep-disordered breathing, defined as an apnea-hypopnea score of 5 or higher, was 9 percent for women and 24 percent for men. We estimated that 2 percent of women and 4 percent of men in the middle-aged work force meet the minimal diagnostic criteria for the sleep apnea syndrome (an apnea-hypopnea score of 5 or higher and daytime hypersomnolence). Male sex and obesity were strongly associated with the presence of sleep-disordered breathing. Habitual snorers, both men and women, tended to have a higher prevalence of apnea-hypopnea scores of 15 or higher.

CONCLUSIONS

The prevalence of undiagnosed sleep-disordered breathing is high among men and is much higher than previously suspected among women. Undiagnosed sleep-disordered breathing is associated with daytime hypersomnolence.

Adipose expression of tumor necrosis factor-alpha: direct role in obesity-linked insulin resistance

Tumor necrosis factor-alpha (TNF-alpha) has been shown to have certain catabolic effects on fat cells and whole animals. An induction of TNF-alpha messenger RNA expression was observed in adipose tissue from four different rodent models of obesity and diabetes. TNF-alpha protein was also elevated locally and systemically. Neutralization of TNF-alpha in obese fa/fa rats caused a significant increase in the peripheral uptake of glucose in response to insulin. These results indicate a role for TNF-alpha in obesity and particularly in the insulin resistance and diabetes that often accompany obesity.

Desmopressin in elderly subjects with increased nocturnal diuresis. A two-month treatment study

This study describes changes in diuresis during a two-month treatment with 40 micrograms desmopressin (Minirin) in a group of elderly persons with increased nocturnal diuresis and decreased ADH secretion. The average age of the men (n = 7) was 72 +/- 4 years and of the women (n = 14) 73 +/- 6 years. Nocturnal diuresis decreased after one and two months by 21% and 20% in the men and by 36% and 34% in the women, respectively. Half of the change persisted among the women but not among the men one month after the treatment. The decrease in nocturnal diuresis was greatest among those who, before the treatment, had a large part of their diuresis during the night. Diuresis during the day changed only insignificantly. Body weight did not change during treatment, nor did blood pressure, osmolality, sodium or potassium in serum. Sleep improved during treatment. In one case, side-effects were observed, with a feeling of swelling in the body and decreased diuresis in the morning.