Association between implantable defibrillator-detected sleep apnea and atrial fibrillation: The DASAP-HF study.

INTRODUCTION: The Respiratory Disturbance Index (RDI) computed by an implantable cardioverter defibrillator (ICD) algorithm accurately identifies severe sleep apnea (SA). In the present analysis, we tested the hypothesis that RDI could also predict atrial fibrillation (AF) burden. METHODS: Patients with ejection fraction ≤35% implanted with an ICD were enrolled and followed up for 24 months. One month after implantation, patients underwent a polysomnographic study. The weekly mean RDI value was considered, as calculated during the entire follow-up period and over a 1-week period preceding the sleep study. The endpoints were as follows: daily AF burden of ≥5 min, ≥6 h, ≥23 h. RESULTS: Here, 164 patients had usable RDI values during the entire follow-up period. Severe SA (RDI ≥ 30 episodes/h) was diagnosed in 92 (56%) patients at the time of the sleep study. During follow-up, AF burden ≥ 5 min/day was documented in 70 (43%), ≥6 h/day in 48 (29%), and ≥23 h/day in 33 (20%) patients. Device-detected RDI ≥ 30 episodes/h at the time of the polygraphy, as well as the polygraphy-measured apnea hypopnea index ≥ 30 episodes/h, were not associated with the occurrence of the endpoints, using a Cox regression model. However, using a time-dependent model, continuously measured weekly mean RDI ≥ 30 episodes/h was independently associated with AF burden ≥ 5 min/day (hazard ratio [HR]: 2.13, 95% confidence interval [CI]: 1.24-3.65, p = .006), ≥6 h/day (HR: 2.75, 95% CI: 1.37-5.49, p = .004), and ≥23 h/day (HR: 2.26, 95% CI: 1.05-4.86, p = .037). CONCLUSIONS: In heart failure patients, ICD-diagnosed severe SA on follow-up data review identifies patients who are from two- to three-fold more likely to experience an AF episode, according to various thresholds of daily AF burden.

Prognostic value of implantable defibrillator-computed respiratory disturbance index: The DASAP-HF study.

BACKGROUND: Sleep apnea, as measured by polysomnography, is associated with adverse outcomes in heart failure. The DASAP-HF (Diagnosis and Treatment of Sleep Apnea in Patient With Heart Failure) study previously demonstrated that the respiratory disturbance index (RDI) computed by the ApneaScan algorithm (Boston Scientific) accurately identifies severe sleep apnea in implantable cardioverter-defibrillator (ICD) patients. OBJECTIVE: The purpose of the long-term study phase was to assess the incidence of clinical events after 24 months and investigate the association with RDI values. METHODS: Patients with left ventricular ejection fraction ≤35% implanted with an ICD were enrolled and followed-up for 24 months. The RDI calculated at 1 month after implantation was used to stratify patients (below or above 30 episodes/h). The endpoints were all-cause death and a combination of all-cause death or cardiovascular hospitalization. RESULTS: Of the 265 enrolled patients, 224 had usable RDI values. Severe sleep apnea (RDI ≥30 episodes/h) was diagnosed in 115 patients (51%). These patients were more frequently male (84% vs 72%; P = .030) and had higher creatinine levels. During median follow-up of 25 months, 19 patients (8%) died. Cardiovascular hospitalizations were reported in 19 patients (8%). The risk of all-cause death was higher in patients with RDI ≥30 episodes/h (hazard ratio [HR] 3.33; 95% confidence interval [CI] 1.35-8.21; P = .023), as well as the risk of all-cause death or cardiovascular hospitalization (HR 1.94; 95% CI 1.01-3.76; P = .048). At multivariate analysis, independent predictors of death were RDI ≥30 episodes/h (HR 4.02; 95% CI 1.16-13.97; P = .029) and creatinine levels (HR 2.36; 95% CI 1.26-4.42; P = .008). CONCLUSION: In heart failure patients implanted with an ICD, higher RDI values are associated with death and cardiovascular hospitalizations. Device-detected severe sleep apnea independently predicts death.

Implantable cardioverter-defibrillator-computed respiratory disturbance index accurately identifies severe sleep apnea: The DASAP-HF study.

BACKGROUND: Sleep apnea (SA) is a relevant issue in the management of patients with heart failure for risk stratification and for implementing treatment strategies. OBJECTIVE: The purpose of this study was to evaluate in patients with implantable cardioverter-defibrillators (ICDs) the performance of the respiratory disturbance index (RDI) computed by the ApneaScan algorithm (Boston Scientific Inc., Natick, MA) as a discriminator of severe SA. METHODS: ICD-indicated patients with left ventricular ejection fraction ≤35% were enrolled. One month after implantation, patients underwent a polysomnographic study. We evaluated the accuracy of the RDI for the prediction of severe SA (apnea-hypopnea index [AHI] ≥30 episodes/h) and the agreement between RDI and AHI during the sleep study night. RESULTS: Two hundred sixty-five patients were enrolled to obtain the required sample of 173 patients with AHI and RDI data for analysis. The mean AHI was 21 ± 15 episodes/h and severe SA was diagnosed in 38 patients (22%), while the mean RDI was 33 ± 13 episodes/h. On the basis of the receiver operating characteristic curve analysis of RDI values, the area under the curve was 0.77 (95% confidence interval [CI] 0.70-0.83; P < .001). At an RDI value of 31 episodes/h, severe SA was detected with 87% (95% CI 72%-96%) sensitivity and 56% (95% CI 48%-66%) specificity. RDI closely correlated with AHI recorded during the same night (r = 0.74; 95% CI 0.57-0.84; P < .001), and the Bland-Altman agreement analysis revealed a bias of 11 episodes/h, with limits of agreement being -10 to 32 episodes/h. CONCLUSION: The RDI accurately identified severe SA and demonstrated good agreement with AHI. Therefore, it may serve as an efficient tool for screening patients at risk of SA.

Economic impact of remote monitoring after implantable defibrillators implantation in heart failure patients: an analysis from the EFFECT study.

AIMS: Heart failure (HF) patients with implantable cardioverter-defibrillators (ICD) require admissions for disease management and out-patient visits for disease management and assessment of device performance. These admissions place a significant burden on the National Health Service. Remote monitoring (RM) is an effective alternative to frequent hospital visits. The EFFECT study was a multicentre observational investigation aiming to evaluate the clinical effectiveness of RM compared with in-office visits standard management (SM). The present analysis is an economic evaluation of the results of the EFFECT trial. METHODS AND RESULTS: The present analysis considered the direct consumption of healthcare resources over 12-month follow-up. Standard tariffs were applied to hospitalizations, in-office visits and remote device interrogations. Economic comparisons were also carried out by means of propensity score (PS) analysis to take into account the lack of randomization in the study design. The analysis involved 858 patients with ICD or CRT-D. Of these, 401 (47%) were followed up via an SM approach, while 457 (53%) were assigned to RM. The rate of hospitalizations was 0.27/year in the SM group and 0.16/year in the RM group (risk reduction =0.59; P = 0.0004). In the non-adjusted analysis, the annual cost for each patient was €817 in the SM group and €604 in the RM group (P = 0.014). Propensity score analysis, in which 292 RM patients were matched with 292 SM patients, confirmed the results of the non-adjusted analysis (€872 in the SM group vs. €757 in the RM group; P < 0.0001). CONCLUSION: There is a reduction in direct healthcare costs of RM for HF patients with ICDs, particularly CRT-D, compared with standard monitoring. CLINICAL TRIAL REGISTRATION: http://clinicaltrials.gov/Identifier, NCT01723865.

Comparison between IEGM-based approach and echocardiography in AV/PV and VV delay optimization in CRT-D recipients (Quicksept study).

BACKGROUND: AtrioVentricular (AV) and InterVentricular (VV) delay optimization can improve ventricular function in Cardiac Resynchronization Therapy (CRT) and is usually performed by means of echocardiography. St Jude Medical has developed an automated algorhythm which calculates the optimal AV and VV delays (QuickOpt™) based on Intracardiac ElectroGrams, (IEGM), within 2 min. So far, the efficacy of the algorhythm has been tested acutely with standard lead position at right ventricular (RV) apex. Aim of this project is to evaluate the algorhythm performance in the mid- and long-term with RV lead located in mid-septum. METHODS: AV and VV delays optimization data were collected in 13 centers using both echocardiographic and QuickOpt™ guidance in CRTD implanted patients provided with this algorhythm. Measurements of the aortic Velocity Time Integral (aVTI) were performed with both methods in a random order at pre-discharge, 6-month and 12-month follow-up. RESULTS: Fifty-three patients were studied (46 males; age 68 ± 10y; EF 28 ± 7%). Maximum aVTI obtained by echocardiography at different AV delays, were compared with aVTI acquired at AV delays suggested by QuickOpt. The AV Pearson correlations were 0.96 at pre-discharge, 0.95 and 0,98 at 6- and 12- month follow-up respectively. After programming optimal AV, the same approach was used to compare echocardiographic aVTI with aVTI corresponding to the VV values provided by QuickOpt. The VV Pearson Correlation were 0,92 at pre-discharge, 0,88 and 0.90 at 6-month and 12- month follow-up respectively. CONCLUSIONS: IEGM-based optimization provides comparable results with echocardiographic method (maximum aVTI) used as reference with mid-septum RV lead location.

Diagnosis of paroxysmal atrial fibrillation in patients with implanted pacemakers: relationship to symptoms and other variables.

BACKGROUND: Atrial fibrillation (AF) is not always accompanied by clear-cut symptoms and symptoms suggestive of AF may not correspond to a genuine AF episode. The study prospectively evaluated the burden of asymptomatic AF episodes in pacemaker patients (for sick sinus syndrome) with a history of documented paroxysmal AF. METHODS: Consecutive patients were enrolled and implanted with dual-chamber pacemakers equipped with diagnostic features for AF monitoring. Each patient was instructed about typical AF symptoms and was asked to keep a detailed log of symptoms. Stored pacemaker data were analyzed using only AF episodes >30 s. RESULTS: The mean follow-up was 16 +/- 6 months and 102 patients were enrolled (73 +/- 7 years, 59 M). Thirteen patients (13%) dropped out with the development of permanent AF and their data were discarded. Twenty-three patients (26%) without device-stored AF episodes all reported at least one annotated AF episode. There were 1,245 device-stored AF episodes in 66 (74%) out of 89 patients. Patients reported 1,141 episodes of AF-related symptoms. Only 240 (21%) corresponded to a genuine device-stored AF event. The sensitivity and positive predictive value of symptoms to detect AF were respectively 19% and 21%. Episode duration, rate increase at the onset of the arrhythmia, heart disease, or antiarrhythmic drug therapy showed no statistically significant differences comparing symptomatic and asymptomatic episodes. CONCLUSIONS: Many pacemaker patients with paroxysmal AF can develop AF-like symptoms in the absence of device-stored AF. AF-related symptoms have low sensitivity and low positive predictive value in patients with permanent pacemakers.