Diagnosis of sleep-related breathing disorders by visual analysis of transthoracic impedance signals in pacemakers

Seasonal influence on sleep apnoea recorded daily by pacemakers

PURPOSE

Obstructive sleep apnoea (OSA) and cardiac conduction disorders are pathologies with a rising prevalence due to increased life expectancy. Upper airway patency is affected by environmental factors that may be associated with seasonal periods. The ability to record the degree of nocturnal apnoea on a daily basis may provide a more accurate picture of seasonal variability.

METHODS

This study used an observational, cross-sectional design recruiting consecutive patients with Sorin/Livanova/Microport® pacemakers. The study assessed the seasonal influence on the daily degree of nocturnal apnoea over a minimum period of 180 days. The respiratory events were recorded using a pacemaker-integrated detection algorithm based on transthoracic impedance variation. A generalised linear repeated measure mixed model was used to study the seasonal effect.

RESULTS

A sample of 101 subjects with a mean of 227 valid nights was compiled. Summer was associated with higher RDI (respiratory disturbance index) values and winter with lower values. The mean daily RDI ratio in summer was 1.099 times higher than in winter.

CONCLUSIONS

Slight seasonal influences on the degree of nocturnal apnoea were detected through the daily observation of an unselected sample of pacemaker wearers. The degree of apnoea is higher in warmer months and lower in colder months.

Implantable cardiac devices in sleep apnoea diagnosis: A systematic review and meta-analysis

BACKGROUND

A particularly high burden of sleep apnoea is reported in patients treated with cardiac implants such as pacemakers and defibrillators. Sleep apnoea diagnosis remains a complex procedure mainly based on sleep and respiratory indices captured by polysomnography (PSG) or respiratory polygraphy (PG).

AIM

We aimed to evaluate the performance of implantable cardiac devices for sleep apnoea diagnosis compared to reference methods.

METHOD

Systematic structured literature searches were performed in PubMed, Embase and. Cochrane Library was performed to identify relevant studies. Quantitative characteristics of the studies were summarized and a qualitative synthesis was performed by a randomized bivariate meta-analysis and completed by pre-specified sensitivity analyses for different implant types and brands.

RESULTS

16 studies involving 999 patients met inclusion criteria and were included in the meta-analysis. The majority of patients were men, of mean age of 64 ± 4.6 years. Sensitivity of cardiac implants for sleep apnoea diagnosis ranged from 60 to 100%, specificity from 50 to 100% with a prevalence of sleep apnoea varying from 22 to 91%. For an apnoea-hypopnoea index threshold ≥30 events/h during polysomnography (corresponding to severe sleep apnoea), the overall performance of the implants was relevant with a sensitivity of 78% and a specificity of 79%. Subgroup analyses on implant type and brand provided no additional information owing to the small number of studies.

CONCLUSION

The respiratory disturbance index provided by cardiac implants is clinically relevant and might improve access to sleep apnoea diagnosis in at-risk cardiovascular populations. PROSPERO Registration number: CRD42020181656.

Validation of an apnea and hypopnea detection algorithm implemented in implantable cardioverter defibrillators. The AIRLESS study

Diagnosis of sleep apnea (SA) using simple tools has the potential to improve the efficacy of cardiac implants in the prevention of cardiac arrhythmias. The aim of the present study was to validate a transthoracic impedance sensor for SA diagnosis in patients with cardiac implants. We compared the apnea-hypopnea index (AHI) obtained from polysomnography (AHI_PSG) with the AHI obtained from autoscoring algorithms of the ApneaScan implantable impedance respiration sensor (AHI_AS) three months after implantation of cardioverter-defibrillator (ICD) or cardiac resynchronization therapy-defibrillator (CRT-D) devices. Twenty-five patients with indications for implantation of ICD or CRT-D (INCEPTA; Boston Scientific) (24 men, 59.9 ± 14.4 years; LVEF 30.3 ± 6.4%; body mass index 25.9 ± 4.2 kg/m²) were included. Mean AHI-_PSG was 21.9 ± 19.1 events/hr. A significant correlation was found between AHI_PSG and AHI_AS especially for the most severe SA (Spearman correlation: 0.71, p < 0.001). Intraclass Correlation Coefficient (was in the expected range: 0.67, 95% CI: 0.39–0.84. The mean bias was 5.4 events per hour (mean AHI: 23.3 ± 14.6 versus 29.7 ± 13.7 for AHI-_PSG and AHI-_AS, respectively). An optimal cutoff value for the AHI_AS at 30 events/h was obtained from the Receiver Operator Characteristic (ROC) curve analysis, which yielded a sensitivity of 100%, a specificity of 80%, PPV = 67%, NPV = 100%. Using an advanced algorithm for autoscoring of transthoracic impedance included in ICDs is reliable to identify SA and has the potential to improve the management of patients with cardiac implants.

Successful screening of sleep-disordered breathing using a pacemaker-based algorithm in Japan

BACKGROUND

Recent pacemakers with transthoracic impedance sensors have a specific algorithm identifying sleep apnea (SA). Our aim was to evaluate the algorithm in Japanese patients.

METHODS

Consecutive patients implanted with a pacemaker with sleep apnea monitoring algorithm at our hospital were enrolled prospectively. After implantation, patients underwent polysomnography (PSG). The respiratory disturbance index measured by pacemaker (RDI-PM) was extracted in the morning after PSG.

RESULTS

Forty-five patients were recruited; 78% of patients underwent overnight PSG completely, and among them RDI-PM was invalid for one patient. Then the analysis was performed in 34 patients. Moderate/severe SA (apnea hypopnea index, AHI≥15events/h) and severe SA (AHI≥30events/h) by PSG were diagnosed in 65% and 41% of patients. The mean AHI-PSG and RDI-PM were 30.4±22.6 and 21.7±14.2events/h, respectively. There was a significant positive correlation between AHI-PSG and RDI-PM (r=0.543; p=0.001). The correlation was stronger in the severe SA group (r=0.664; p=0.010), in a group whose apnea index was higher than hypopnea index (r=0.822; p=0.002), and in a group whose central sleep apnea (CSA) index was higher than obstructive sleep apnea index (r=0.977; p<0.001). RDI-PM cut-off value for identifying severe SA was 22 (area under the curve, 0.682; sensitivity, 64%; specificity, 75%).

CONCLUSIONS

The pacemaker-based algorithm is a useful screening tool for SA in Japanese individuals, especially in the severe SA group, apnea-dominant group, and CSA-dominant group.

Sleep apnea detection by a cardiac resynchronization device integrated thoracic impedance sensor: A validation study against the gold standard polysomnography

BACKGROUND

Sleep disordered breathing is a common but often undiagnosed comorbidity in heart failure patients. Cardiac implantable electronic devices used for cardiac resynchronization therapy (CRT) may detect sleep apnea by use of a transthoracic impedance sensor. Validation of the AP scan® algorithm (Boston Scientific®) was performed by using the diagnostic gold standard polysomnography (PSG).

METHODS

Forty-one patients with impaired left ventricular ejection fraction, frequent right ventricular pacing due to atrioventricular block and heart failure symptoms despite optimal medical therapy underwent upgrading to biventricular pacing. Within one month after left ventricular lead implantation, sleep apnea was assessed by single-night PSG and AP scan® measurements.

RESULTS

AP scan® measurements were valid in only 21 of 41 (51.2%) patients in the index night of the PSG. The PSG determined apnea-hypopnea index did not correlate statistically significant with the AP scan® measurements (r = 0.41, 95% confidence interval -0.05-0.72, p = 0.07). The degree of overestimation is displayed by using the Bland-Altman method: mean difference -12.4, standard deviation ± 15.8, 95% confidence interval -43.3-18.6.

CONCLUSIONS

In heart failure patients receiving CRT upgrading, the AP scan® algorithm may need further improvement before it can be recommended for sleep apnea detection.

Rationale and Design for a Monocentric Prospective Study: Sleep Apnea Diagnosis Using a Novel Pacemaker Algorithm and Link With Aldosterone Plasma Level in Patients Presenting With Diastolic Dysfunction (SAPAAD Study)

Previous studies showed good agreement between pacemaker respiratory disturbance index (RDI) and polysomnography for diagnosis of severe sleep apnea (SA). The aim of this study is to investigate the diagnostic accuracy of RDI compared with apnea-hypopnea index (AHI) from a cardiorespiratory sleep study for the diagnosis of severe SA within patients requiring a pacemaker and meeting diastolic dysfunction criteria. Secondary objectives are as follows: correlation between plasma aldosterone level and SA severity, diagnostic accuracy of RDI for moderate SA, prevalence of SA among patients with diastolic dysfunction, occurrence of arrhythmias, and improvement of RDI with continuous positive airway pressure therapy. We designed a monocentric prospective nonrandomized study of prevalent cases to include 68 patients with a 6-month follow-up. Both RDI and AHI will be compared 2 months after implantation and after 1 month of continuous positive airway pressure treatment in patients with severe SA. This is the first study that examines diagnostic accuracy of pacemaker algorithm for the diagnosis of SA and correlation with plasma aldosterone levels in patients with diastolic dysfunction. Protocol version: V04. 04/04/2017 Trial registration: ClinicalTrials.gov NCT02751021.

Sleep-Disordered Breathing in Acute Ischemic Stroke: A Mechanistic Link to Peripheral Endothelial Dysfunction

BACKGROUND

Sleep-disordered breathing (SDB) after acute ischemic stroke is frequent and may be linked to stroke-induced autonomic imbalance. In the present study, the interaction between SDB and peripheral endothelial dysfunction (ED) was investigated in patients with acute ischemic stroke and at 1-year follow-up.

METHODS AND RESULTS

SDB was assessed by transthoracic impedance records in 101 patients with acute ischemic stroke (mean age, 69 years; 61% men; median National Institutes of Health Stroke Scale, 4) while being on the stroke unit. SDB was defined by apnea-hypopnea index ≥5 episodes per hour. Peripheral endothelial function was assessed using peripheral arterial tonometry (EndoPAT-2000). ED was defined by reactive hyperemia index ≤1.8. Forty-one stroke patients underwent 1-year follow-up (390±24 days) after stroke. SDB was observed in 57% patients with acute ischemic stroke. Compared with patients without SDB, ED was more prevalent in patients with SDB (32% versus 64%; P<0.01). After adjustment for multiple confounders, presence of SDB remained independently associated with ED (odds ratio, 3.1; [95% confidence interval, 1.2-7.9]; P<0.05). After 1 year, the prevalence of SDB decreased from 59% to 15% (P<0.001). Interestingly, peripheral endothelial function improved in stroke patients with normalized SDB, compared with patients with persisting SDB (P<0.05).

CONCLUSIONS

SDB was present in more than half of all patients with acute ischemic stroke and was independently associated with peripheral ED. Normalized ED in patients with normalized breathing pattern 1 year after stroke suggests a mechanistic link between SDB and ED.

CLINICAL TRIAL REGISTRATION

URL: https://drks-neu.uniklinik-freiburg.de. Unique identifier: DRKS00000514.

Cardiac or Other Implantable Electronic Devices and Sleep-disordered Breathing - Implications for Diagnosis and Therapy

Sleep-disordered breathing (SDB) is of growing interest in cardiology because SDB is a highly prevalent comorbidity in patients with a variety of cardiovascular diseases. The prevalence of SDB is particularly high in patients with cardiac dysrhythmias and/or heart failure. In this setting, many patients now have implantable cardiac devices, such as pacemakers, implantable cardioverter-defibrillators or implanted cardiac resynchronisation therapy devices (CRT). Treatment of SDB using implantable cardiac devices has been studied previously, with atrial pacing and CRT being shown not to bring about satisfactory results in SDB care. The latest generations of these devices have the capacity to determine transthoracic impedance, to detect and quantify breathing efforts and to identify SDB. The capability of implantable cardiac devices to detect SDB is of potential importance for patients with cardiovascular disease, allowing screening for SDB, monitoring of the course of SDB in relation to cardiac status, and documenting of the effects of treatment.

Cheyne-Stokes respiration in heart failure: cycle length is dependent on left ventricular ejection fraction

BACKGROUND

Cheyne-Stokes respiration (CSR) is common in patients with congestive heart failure (CHF) and is associated with poor prognosis. The aim of this study was to analyse the characteristics of CSR in patients with varying degrees of impaired left ventricular ejection fraction (LVEF).

METHODS

A total of 104 patients with CSR (apnea-hypopnea index [AHI]15/h) and exertional dyspnea were divided into FIVE groups according to their LVEF (<20% upto 50%). A subgroup of 22 patients was studied twice: 15 in whom LVEF improved between studies and 7 in whom LVEF deteriorated. Using cardiorespiratory polygraphy recordings, cycle length (CL), apnea length (AL), ventilation length (VL), time to peak ventilation (TTPV), circulatory delay (CD) and VL:AL ratio were determined.

RESULTS

There was no relationship between AHI and impairment of LVEF, but the characteristics of CSR were related to LV function. Comparing the groups with the best LVEF (>50%) and the worst LVEF (<20%), there were significant increases in CL (49+/-17-86+/-23s), AL (21+/-9-31+/-10s), VL (28+/-10-55+/-17s), TTPV (19+/-5-32+/-11s), VL:AL ratio (1.5+/-0.4-1.9+/-0.7s) and CD (29+/-8-49+/-16s). In the subgroup of patients who were studied twice, improvement in EF was associated with a decrease in these parameters.

CONCLUSION

The current classification of CSR in CHF patients using AHI may be overly simplistic. Parameters such as CL, VL, TTPV and CD are related to cardiac function and could potentially be used for disease monitoring.

Sleep disordered breathing in chronic heart failure

Heart failure is a growing problem, placing an increasing burden on public health resources and continuing to exert a high toll in mortality and morbidity. Sleep disordered breathing (SDB) is also a major public health problem and is associated with an increased risk of fatal and non-fatal cardiovascular events. Current evidence suggests SDB, particularly central SDB, is more prevalent in patients with chronic heart failure (CHF) than in the general population, but is under-diagnosed as SDB symptoms are less prevalent in CHF. This is further hampered by the absence of a simple and accurate screening tool and limited access to sleep facilities to diagnose SDB in the large numbers of patients with CHF. The presence of SDB in patients with CHF imposes increased haemodynamic burdens and results in autonomic abnormalities. Central SDB is an independent marker of worse prognosis, and evidence is increasing that obstructive SDB is also associated with higher mortality in patients with CHF. Optimal treatment of central SDB in these patients remains uncertain. While evidence of efficacy of positive pressure ventilation is stronger in obstructive SDB, improvement in survival for patients with both CHF and SDB awaits definitive trials. This paper summarizes our current understanding of the pathophysiology of SDB in CHF, and the cardiovascular consequences, and reviews the evidence for the beneficial effects of treatment of SDB in patients with CHF.

Feasibility of automated detection of advanced sleep disordered breathing utilizing an implantable pacemaker ventilation sensor

OBJECTIVES

This study tested the feasibility of automatically detecting advanced sleep disordered breathing (SDB) from a pacemaker trans-thoracic impedance sensor.

BACKGROUND

SDB is prevalent yet under-diagnosed in patients with cardiovascular disease. The potential for automated detection of SDB in patients receiving pacemakers with respiration sensors has not been fully explored. We hypothesized that the trans-thoracic impedance sensor could be utilized for automatic detection of advanced SDB.

METHODS

Patients underwent overnight polysomnography (PSG). The pacemaker trans-thoracic impedance signal was simultaneously recorded and time synchronized with the polysomnograph. Cardiovascular health variables were abstracted from medical records. Apnea was defined as cessation of inspiratory airflow lasting 10 seconds or longer. Hypopnea was defined as a reduction of tidal volume of at least 30% from baseline tidal volume, lasting 10 seconds or more. A computer algorithm (PM-A) was developed to automatically detect SDB from the pacemaker impedance sensor data. The performance of automated SDB detection was compared against PSG.

RESULTS

Sixty patients (aged 69 +/- 12 years, 45 males) were studied. Advanced SDB (moderate or severe) was diagnosed in 40 patients. Severe SDB (apnea-hypopnea index [AHI]> or = 30) was diagnosed in 32 patients (53%), but only 5 patients had prior diagnosis of the disease. Moderate SDB (30 > AHI > 15) was diagnosed in 8 patients of whom only two were previously diagnosed. Cardiovascular health variables did not predict the presence of advanced SDB. PM-A derived AHI correlated with that of the PSG (r = 0.80, P < 0.01). The algorithm identified patients with advanced SDB with 82% sensitivity and 88% specificity.

CONCLUSIONS

It is feasible to automatically measure SDB severity using a pacemaker trans-thoracic impedance sensor. Advanced SDB was frequently undiagnosed in this cohort of pacemaker patients.

Screening for sleep-related breathing disorders by transthoracic impedance recording integrated into a Holter ECG system

In patients with arrhythmias, coincidence with sleep-related breathing disorders (SRBD) is high and of clinical relevance. Electrocardiogram-derived (ECG) parameters have been developed for SRBD screening, but it has proved necessary to exclude patients with frequent arrhythmias. Holter-based screening tools, easy to use, are therefore warranted. The goal of our study was to evaluate the diagnostic accuracy, with respect to SRBD detection, of transthoracic impedance recording (TTIR) integrated into a Holter System. Our investigation consisted of 2 phases. In phase 1 we compared the performance of TTIR to that of in-hospital polysomnography (PSG) in 56 patients (46 male, mean age 57). In phase 2 we compared TTIR to results from an ambulatory polygraphy (PG) system in 180 patients (143 male, mean age 56). We scored apnea and hypopnea from P(S)G, and derived a respiratory-disturbance index (P(S)G-RDI). TTIR was analyzed semi-automatically. Reduction of the impedance amplitude by more than 50% over 10 s was scored as apnea/hypopnea, with consequent calculation of TTIR-RDI. In phase 1, 20 out of 56 patients revealed a PSG-RDI > 10 h(-1). TTIR-RDI in 19 patients from this group was >10 h(-1) (sensitivity 95%, specificity 97.2%, positive predictive value 95%, negative predictive value 97.2%, interclass correlation coefficient 0.98). In phase 2, 46 of 180 patients revealed a PSG-RDI > 10 h(-1). TTIR-RDI in 37 out of this group was >10 h(-1) (sensitivity 80.4%, specificity 92.5%, positive predictive value 78.7%, negative predictive value 93.2%, interclass correlation coefficient 0.92). TTIR integrated into a Holter ECG system and tested in a large patient cohort demonstrates acceptable high accuracy in detection of SRBD. Arrhythmia analysis and screening for SRBD can be performed in a single-step approch.

Cardiac pacing in sleep apnoea: diagnostic and therapeutic implications

The sleep apnoea syndrome is a particularly common health problem associated with increased cardiovascular morbidity and mortality, as well as harmful socioeconomical and familial complications. In this article, the diagnostic and therapeutic role of cardiac pacing in this syndrome is discussed.

Implantable cardiac arrhythmia devices--part I: pacemakers

Implantable cardiac devices have become firmly entrenched as important therapeutic tools for a variety of cardiac conditions. The first part of this two-part review will discuss the contemporary use and follow-up of pacemakers, while the second part will address the use of implantable cardioverter defibrillators and implantable loop recorders. Pacemakers are the only available treatment for symptomatic bradycardia not due to reversible causes. Large randomized studies have demonstrated a small but statistically significant reduction in atrial fibrillation associated with pacing modes that maintain atrioventricular synchrony. In contrast, pacing mode appears to have a less dramatic effect in patients with atrioventricular block. Cardiac resynchronization with specialized left ventricular leads has been shown to reduce symptoms and improve survival in patients with symptomatic heart failure, systolic dysfunction, and widened QRS complexes. For all patients, careful follow-up is necessary to ensure optimal therapeutic benefit of pacing systems.

Temas de actualidad en estimulación cardíaca 2005

Currently, three areas of active development in cardiac pacing are of particular interest to clinical cardiologists. Biventricular pacing is now considered a type-I indication for adjuvant treatment in advanced and refractory heart failure. Consequently, some changes in everyday clinical practice will be seen when patients with end-stage heart failure start to receive resynchronization therapy. Secondly, the Cardiac Pacing Working Group of the Spanish Society of Cardiology has developed a national consensus document on sleep apnea and cardiac rhythm abnormalities. It appears that a novel way of tackling the current growing epidemic could be to use permanent cardiac pacing in an attempt to modify the cardiac rhythm alterations, mainly bradyarrhythmias, related to sleep apnea. Finally, promising developments are taking place in systems designed to reduce the unwanted right ventricular stimulation sometimes observed with antibradycardia pacing modalities. These new systems are expected to minimize significantly the well-known deleterious hemodynamic effects sometimes seen in our patients.

Beyond heart rhythms: new directions for implantable devices

Implantable cardiac devices have become firmly entrenched as important therapeutic tools for a variety of conditions. Pacemakers are the only available treatment for symptomatic bradycardia not due to reversible causes. Large randomized studies have demonstrated a small but statistically significant reduction in atrial fibrillation associated with pacing modes that maintain atrioventricular synchrony. In contrast, pacing mode appears to have a less dramatic effect in patients with atrioventricular block. Cardiac resynchronization with specialized left ventricular leads has been shown to reduce symptoms and improve survival in patients with symptomatic heart failure, systolic dysfunction, and widened QRS complexes. The implantable cardioverter defibrillator has become the standard therapy for protecting patients against sudden cardiac death. Two recent trials, Multicenter Automatic Defibrillator Trial II (MADIT II) and the Sudden Cardiac Death Heart Failure Trial (SCD-HEFT), demonstrated that the ICD is associated with a significant survival benefit for patients with reduced ejection fraction (< 0.30-0.35) particularly if heart failure symptoms are present. Finally the implantable loop recorder has become an important diagnostic tool for the patient with unexplained syncope. This brief overview summarizes the indications and follow-up of the wide array of implantable cardiac devices available to the clinical cardiologist.

Oligomer-mediated modulation of hTERT alternative splicing induces telomerase inhibition and cell growth decline in human prostate cancer cells

The expression of telomerase in human cells is strictly controlled by multiple mechanisms including transcription and alternative splicing of telomerase reverse transcriptase (hTERT). In this study, we demonstrated the possibility of modulating the hTERT splicing pattern in DU145 human prostate carcinoma cells through the use of 2'-O-methyl-RNA phosphorothioate oligonucleotides targeting the splicing site located between intron 5 and exon 6 in the hTERT pre-mRNA. An 18-h oligonucleotide exposure induced a decrease in the full-length hTERT transcript and a concomitant increase in the alternatively spliced transcripts, which resulted in significant inhibition of telomerase catalytic activity. Moreover, exposure to the R7 oligomer (which induced the most pronounced modulation of the hTERT splicing pattern and the greatest telomerase inhibition) caused a marked reduction in DU145 cell growth and the induction of apoptosis starting 2 days after treatment. Such data support the concept that down-regulation of hTERT expression can cause short-term effects on tumour cell growth, which are telomere-shortening independent.