Machine learning-based detection of sleep-disordered breathing in hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is often concomitant with sleep-disordered breathing (SDB), which can cause adverse cardiovascular events. Although an appropriate approach to SDB prevents cardiac remodelling, detection of concomitant SDB in patients with HCM remains suboptimal. Thus, we aimed to develop a machine learning-based discriminant model for SDB in HCM. METHODS: In the present multicentre study, we consecutively registered patients with HCM and performed nocturnal oximetry. The outcome was a high Oxygen Desaturation Index (ODI), defined as 3% ODI >10, which significantly correlated with the presence of moderate or severe SDB. We randomly divided the whole participants into a training set (80%) and a test set (20%). With data from the training set, we developed a random forest discriminant model for high ODI based on clinical parameters. We tested the ability of the discriminant model on the test set and compared it with a previous logistic regression model for distinguishing SDB in patients with HCM. RESULTS: Among 369 patients with HCM, 228 (61.8%) had high ODI. In the test set, the area under the receiver operating characteristic curve of the discriminant model was 0.86 (95% CI 0.77 to 0.94). The sensitivity was 0.91 (95% CI 0.79 to 0.98) and specificity was 0.68 (95% CI 0.48 to 0.84). When the test set was divided into low-probability and high-probability groups, the high-probability group had a higher prevalence of high ODI than the low-probability group (82.4% vs 17.4%, OR 20.9 (95% CI 5.3 to 105.8), Fisher's exact test p<0.001). The discriminant model significantly outperformed the previous logistic regression model (DeLong test p=0.03). CONCLUSIONS: Our study serves as the first to develop a machine learning-based discriminant model for the concomitance of SDB in patients with HCM. The discriminant model may facilitate cost-effective screening tests and treatments for SDB in the population with HCM.

Comparison of the left ventricular dyssynchrony between stylet-driven and lumen-less lead technique in left bundle branch area pacing using myocardial perfusion scintigraphy.

Background: Left bundle branch area pacing (LBBAP) has emerged as a novel physiological pacing method to reduce left ventricular (LV) dyssynchrony due to ventricular pacing. Only lumen-less pacing leads (LLLs) with fixed helixes could achieve LBBAP previously, but recently, LBBAP has been performed using stylet-driven leads (SDLs). This study aimed to evaluate the LV dyssynchrony between SDLs and LLLs techniques in LBBAP. Methods: We retrospectively evaluated patients who underwent LBBAP with either SDLs or LLLs. We compared both groups' electrocardiogram (ECG) findings and LV dyssynchrony parameters derived from myocardial perfusion scintigraphy. LV dyssynchrony parameters consisted of phase analysis and regional wall motion analysis. We evaluated bandwidth, phase standard deviation (PSD), and entropy in the phase analysis. The time to the end-systolic frame (TES) was calculated in regional wall motion analysis using single-photon emission computed tomography (SPECT). We also evaluated the maximum differences between segmental TES (MDTES), the standard deviation of TES (SDTES), and the difference in the TES between the lateral wall and septum (DTES-LS). Results: In total, 97 patients were enrolled. The success rate of LBBAP did not differ between the groups [SDLs: 47/48 patients (98%) vs. LLLs: 47/51 patients (92%), P=0.36]. The paced QRS duration and the stimulus to the peak LV activation time (stim-LVAT) also did not differ between SDL and LLL groups (122±10 vs. 119±12 ms, P=0.206; 69±12 vs. 66±13 ms, P=0.31, respectively). There were no differences in bandwidth, PSD, and entropy between SDL and LLL groups (73°±37° vs. 86°±47°, P=0.18; 19°±8.5° vs. 21°±9.7°, P=0.19; 0.57±0.08 vs. 0.59±0.08, P=0.17, respectively). The regional wall motion analysis parameters MDTES, SDTES, and DTES-LS also did not differ between SDL and LLL groups (19%±10% vs. 20%±10%, P=0.885; 5.0%±2.5% vs. 5.0%±2.5%, P=0.995; 5.0%±3.7% vs. 4.8%±4.2%, P=0.78, respectively). Conclusions: LBBAP using SDLs was comparable to LV electrical and mechanical synchrony with LLLs.

Feasibility of Short-Term Aggressive Lipid-Lowering Therapy with the PCSK9 Antibody in Acute Coronary Syndrome.

BACKGROUND: The guideline-recommended low-density lipoprotein cholesterol target level of <70 mg/dL may not be achieved with statin administration in some patients with acute coronary syndrome (ACS). Therefore, the proprotein convertase subtilisin-kexin type 9 (PCSK9) antibody can be added to high-risk patients with ACS. Nevertheless, the optimal duration of PCSK9 antibody administration remains unclear. METHODS AND RESULTS: Patients were randomized to receive either 3 months of lipid lowering therapy (LLT) with the PCSK9 antibody followed by conventional LLT (with-PCSK9-antibody group) or 12 months of conventional LLT alone (without-PCSK9-antibody group). The primary endpoint was the composite of all-cause death, myocardial infarction, stroke, unstable angina, and ischemia-driven revascularization. A total of 124 patients treated with percutaneous coronary intervention (PCI) were randomly assigned to the two groups (n = 62 in each). The primary composite outcome occurred in 9.7% and 14.5% of the patients in the with- and without-PCSK9-antibody groups, respectively (hazard ratio: 0.70; 95% confidence interval: 0.25 to 1.97; p = 0.498). The two groups showed no significant differences in hospitalization for worsening heart failure and adverse events. CONCLUSIONS: In ACS patients who underwent PCI, short-term PCSK9 antibody therapy with conventional LLT was feasible in this pilot clinical trial. Long-term follow-up in a larger scale clinical trial is warranted.

Clinical utility of the "balloon lever technique" in the right inferior pulmonary vein cryoballoon ablation.

Background: The acute success rate of pulmonary vein isolation (PVI) with cryoballoon (CB) is reported to be lower in the right inferior pulmonary vein (RIPV). This study aimed to investigate the utility of the "balloon lever technique (BLT)" for RIPV CB ablation. Methods: We retrospectively studied consecutive patients who underwent CB-PVI for atrial fibrillation between February 21, 2020 and June 3, 2022. RIPV cryoablation was performed according to a specific protocol. The patients underwent RIPV cryoablation using the conventional method. If the method was found ineffective, BLT cryoablation was performed. The acute success rate of RIPV CB ablation was examined. We also investigated the RIPV isolation rate and procedural parameters during conventional and BLT cryoablation. Results: Ninety-three patients were included in the analysis. RIPV isolation was achieved in 89.2% (83/93) of the patients using conventional method and subsequent BLT cryoablation. Meanwhile, 68 patients underwent BLT cryoablation because the conventional method was ineffective. RIPV was isolated with BLT in 85.3% (58/68) of patients. Additionally, BLT was found to be superior to conventional cryoablation in terms of nadir balloon temperature, freezing time, and thawing time to a specific temperature in patients who underwent both conventional and BLT cryoablations. Conclusions: BLT is useful in RIPV cryoablation when the conventional method is ineffective. BLT cryoablation may be helpful, mainly because of the BLT-mediated contact of the balloon with the bottom of the RIPV, which leads to optimal RIPV occlusion.

A successful treatment of ganglionated plexi ablation for vagally mediated nocturnal atrioventricular block.

Patients suffering from sleep-related bradyarrhythmias are often underdiagnosed, due to the presence of asymptomatic cases. Although the consequence of increased nocturnal parasympathetic nerve activities and decreased sympathetic nerve activity during sleep are associated with nocturnal bradyarrhythmias, the detailed mechanisms are still unknown. It is well known that ganglionated plexi (GP) ablation is an effective therapeutic approach to modify autonomic nerve functions. Here, we report a case of successful treatment for the vagally mediated long ventricular pauses during sleep using autonomic modulation through GP ablation. Learning objective: Sleep-related bradyarrhythmias unrelated to sleep apnea or hypopnea are rare sleep disorders. Treatment of this disorder has not been established. High-frequency stimulation guided ganglionated plexi ablation could be an effective therapeutic approach to achieve long-term vagal attenuation to prevent vagally induced nocturnal bradyarrhythmias.

Ectopic discharge originating from the ostium of the inferior vena cava that is likely to cause atrial fibrillation.

It has been established that the initiation of paroxysmal atrial fibrillation (AF) is frequently associated with ectopic beats inside the thoracic veins, including the pulmonary veins, superior vena cava, coronary sinus, and/or vein of Marshall. However, similar arrhythmogenic ectopic discharge or premature atrial contractions (PACs) originating from the inferior vena cava (IVC) have been rarely described. We present the case of a 51-year-old man with paroxysmal AF undergoing electrophysiological study. Twelve-lead electrocardiography demonstrated PACs with negative P waves in the inferior leads. Ectopic beats originating from the ostium of the IVC, which were likely to initiate AF, were observed. Furthermore, the origin of the PAC was visualized using an electroanatomical local activation timing (LAT) map and located close to the fibrotic tissue of the vasculature. Radiofrequency catheter ablation was performed at the earliest activation site, and ectopic beats were not observed after the procedure. This is the first report to demonstrate a LAT contact map of ectopic discharge arising from the IVC. If PACs with negative P waves in the inferior leads are found in a patient with AF, the IVC should be investigated for possible focal ectopic discharges. Learning objective: Non-pulmonary vein foci play a significant role in the pathogenesis of atrial fibrillation (AF). However, inferior vena cava (IVC) triggers that initiate AF have rarely been described. Premature atrial contractions with negative P waves in the inferior leads may be associated with ectopic discharges originating from the IVC, which contribute to the initiation of AF.

Usefulness of P-wave peak time as an electrocardiographic parameter in predicting left ventricular diastolic dysfunction in patients with mitral regurgitation.

INTRODUCTION: Conventional Doppler measurements have limitations in predicting left ventricular diastolic dysfunction (LVDD) in patients with mitral regurgitation (MR). Recently, electrocardiographic P-wave peak time (PWPT) has been proposed as a parameter of detecting LVDD. This study aimed to evaluate the association between PWPT and left ventricular end-diastolic pressure (LVEDP) in patients with MR. METHODS: We performed echocardiography and cardiac catheterization in 82 patients with moderate or severe MR. We classified patients into two groups: low LVEDP group (L-LVEDP) (LVEDP <16 mmHg, n = 40) and high LVEDP group (H-LVEDP) (LVEDP ≥16 mmHg, n = 42). We evaluated LVDD and PWPT based on echocardiographic and electrocardiographic findings in both groups. RESULTS: The PWPT in lead II (PWPTII ) was significantly longer in patients in the H-LVEDP group than in those in the L-LVEDP group (67 vs. 47 ms, p < .001). Using correlation analysis, LVEDP was positively correlated with PWPTII (r = .577, p < .001). Using multivariate analysis, PWPTII was found to be an independent predictor of increased LVEDP (95% CI: 0.1030-0.110; p < .001). Using receiver operating characteristic (ROC) curve analysis, the optimal cutoff value of PWPTII for predicting elevated LVEDP was 58.9 ms, with a sensitivity of 80.0% and a specificity of 73.8% (area under curve: 0.809, 95% CI: 0.713-0.905). CONCLUSION: To the best of our knowledge, this is the first study to assess the effect of a significant valvular disease on PWPT in lead II. These findings suggest that prolonged PWPTII may be an independent predictor of increased LVEDP in patients with moderate or severe MR.

Assessing cardiac mechanical dyssynchrony in left bundle branch area pacing and right ventricular septal pacing using myocardial perfusion scintigraphy in the acute phase of pacemaker implantation.

INTRODUCTION: Left bundle branch area pacing (LBBAP) has recently been reported to be a new, clinically feasible and safe physiological pacing strategy. The present study aims to investigate the usefulness of LBBAP in reducing mechanical dyssynchrony compared with right ventricular septal pacing (RVSP). METHODS AND RESULTS: A total of 39 LBBAP patients, 42 RVSP patients, and 93 healthy control participants were retrospectively evaluated. We compared phase analysis- (bandwidth, phase standard deviation [PSD], entropy) and regional wall motion analysis parameters. Wall motion analysis parameters included the time to the end-systolic frame (TES) assessed using single-photon emission computed tomography analysis. The maximum differences between segmental TES (MDTES), the standard deviation of TES (SDTES), and the TES difference between the lateral and septal segments (DTES-LS) were obtained. All phase analysis parameters were significantly smaller in the LBBAP group than in the RVSP group (bandwidth: LBBAP, 74 ± 31° vs. RVSP, 102 ± 59°, p = .009; PSD: LBBAP, 19 ± 6.7° vs. RVSP, 26 ± 15°, p = .007; entropy: LBBAP, 0.57 ± 0.07 vs. RVSP, 0.62 ± 0.11 p = .009). The regional wall motion analysis parameters were also smaller in the LBBAP group than in the RVSP group (MDTES:LBBAP, 17 ± 7.1% vs. RVSP, 25 ± 14%, p = .004; SDTES:LBBAP, 4.5 ± 1.7% vs. RVSP, 6.0 ± 3.5%, p = .015; DTES-LS: LBBAP, 4.1 ± 3.4% vs. RVSP, 7.1 ± 5.4%, p = .004). All phase analysis and wall motion analysis parameters were same in the LBBAP and control groups. CONCLUSION: LBBAP may reduce mechanical dyssynchrony and achieve greater physiological ventricular activation than RVSP.

Impact of the Degree of Wire Bias in the Vessel's Healthy Portion on Coronary Perivascular Trauma in Rotational Atherectomy.

BACKGROUND: In rotational atherectomy (RA), the risk of coronary perforation is considered to increase when the wire is in contact with the healthy portion of the vessel. However, the relationship between the extent of wire bias in the healthy portion of the vessel and the risk of coronary perivascular trauma (CPT) has not been reported. METHODS: We examined 90 consecutive cases wherein intravascular ultrasound (IVUS) was performed before and after RA. The IVUS catheter in contact with the healthy region of the vessel was defined as the healthy portion wire bias (HWB), of which we measured the bias diameter, defined as the media-to-media length between the site where the IVUS catheter was in contact and the opposite side of the vessel. The bias ratio was defined as the ratio of the bias diameter to the short diameter at the region where the wire bias was the strongest. The relationship between the bias ratio and the CPT risk was evaluated. RESULTS: CPT was significantly higher in the HWB group than in the non-HWB group (9% vs. 0%, P = 0.048). In the HWB group, the bias ratio was significantly greater in the CPT group than in the non-CPT group (1.31 ±â€¯0.09 vs. 1.06 ±â€¯0.06; P < 0.0001). The cutoff value of the bias ratio for CPT was 1.2, which was the maximum value of the sum of sensitivity 100% and specificity 97%. CONCLUSIONS: Lesions without HWB had no CPT. CPT risk increased when the bias ratio exceeded 1.2.

Four-dimensional flow magnetic resonance imaging visualizes reverse vortex pattern and energy loss increase in left bundle branch block.

AIMS: This study aimed to investigate the intraventricular blood flow pattern of patients with left bundle branch block (LBBB) using four-dimensional flow magnetic resonance imaging (4D-flow MRI). METHODS AND RESULTS: We performed 4D-flow MRI for 16 LBBB patients (LBBB group) and 16 propensity score-matched patients with a normal QRS duration (non-LBBB group). The energy loss (EL) in the left ventricle was evaluated. In both groups, blood flow from the mitral valve to the apex of the heart and left ventricular (LV) outflow tract during LV diastole were observed. Vortices were also observed in both groups. There were two patterns of vortices: unidirectional clockwise rotation and counterclockwise rotation taking place from the mid-diastole to the systole (reverse pattern). The reverse pattern was observed significantly more frequently in the LBBB group (LBBB 94% vs. non-LBBB 19%, P < 0.001). The interobserver agreement for the streamline analysis was good (kappa = 0.68). The maximum EL was significantly higher in the LBBB group [LBBB 12 (11-15) mW vs. non-LBBB 8.0 (6.2-9.7) mW, P < 0.001]. CONCLUSION: Left bundle branch block patients may suffer from inefficient LV haemodynamics reflected by non-physiological counterclockwise vortices and increased EL. Thus, the shape of the vortices and EL in the left ventricle can serve as markers of LV mechanical dyssynchrony in LBBB patients and could be investigated as predictors of response to cardiac resynchronization therapy.

Association of device-measured physical activity with peak oxygen consumption measured by cardiopulmonary exercise testing in patients with cardiac implantable electronic devices.

PURPOSE: Cardiac implantable electronic devices (CIEDs) offer diagnostic information such as device-measured physical activity (PA). Peak oxygen consumption (VO2) measured by cardiopulmonary exercise testing (CPET) is the most objective variable showing exercise capacity. The purpose of this study was to investigate the relationship between these 2 variables. METHODS: We retrospectively studied consecutive patients with CIEDs undergoing CPET between April 1, 2018, and January 31, 2021. These patients were divided into 2 groups: patients with peak VO2 ≤ 14 ml/kg/min (low peak VO2 group) and those showing peak VO2 > 14 ml/kg/min (high peak VO2 group). The peak device-measured PA was compared between the 2 groups. The relationship between the peak device-measured PA and peak VO2 was also investigated. RESULTS: There were 50 and 51 patients in the low and high peak VO2 groups, respectively. The peak device-measured PA, which was expressed in units of hours/day, was significantly lower in the low peak VO2 group than in the high peak VO2 group (3.06, interquartile range [2.43-4.00] vs. 5.50, interquartile range [4.04-6.70] p < 0.01). The peak device-measured PA and peak VO2 showed a significant positive correlation (Spearman's ρ = 0.53; p < 0.01). Furthermore, receiver operating characteristic curve analysis showed that a peak device-measured PA > 3.87 h/day could predict high peak VO2 (80.4%, sensitivity; 72.0%, specificity). In multivariate linear regression analysis, peak device-measured PA was an independent predictor of peak VO2 (regression coefficient, 0.61; 95% confidence interval, 0.33-0.89; p < 0.01). CONCLUSIONS: Peak device-measured PA was significantly associated with peak VO2.

Concomitant Pulmonary and Cerebral Tumor Embolism and Intracardiac Metastasis from Bladder Cancer.

An 82-year-old woman with a history of bladder cancer presented with dyspnea and loss of consciousness. Contrast-enhanced computed tomography revealed pulmonary embolism, and emergency thrombus aspiration therapy was performed, but the thrombus was not aspirated. Echocardiography showed mobile masses in the heart and a right-to-left shunt due to a patent foramen ovale (PFO). Magnetic resonance imaging showed multiple cerebral infarctions. Surgical thrombectomy and PFO closure were performed, and the patient was diagnosed with intracardiac metastasis of bladder cancer based on intraoperative histopathology. This is a rare case of concomitant pulmonary and cerebral tumor embolism and intracardiac metastasis from bladder cancer.

An Autopsy Case of Antibody-negative Immune-mediated Necrotizing Myopathy with Severe Cardiac Involvement.

A 41-year-old man was admitted with a chief complaint of dyspnea. Echocardiography showed diffuse severe hypokinesis in the left ventricle. Although his heart failure improved, high creatine kinase levels persisted. A muscle biopsy of the biceps brachii showed necrotic and regenerating fibers along with positive findings for major histocompatibility complex class I and membrane attack complex. He was diagnosed with antibody-negative immune-mediated necrotizing myopathy (IMNM). Steroid therapy was started, but he died due to ventricular fibrillation. Autopsy findings revealed CD68-positive macrophages in the myocardium and quadriceps. To our knowledge, this is the first case of antibody-negative IMNM with cardiac involvement.

Clinical utility of CorVue intrathoracic impedance alert with device-measured physical activity in predicting heart failure events.

Cardiac implantable electronic devices (CIEDs) offer heart failure (HF) diagnostic information, including intrathoracic impedance (ITI) or physical activity (PA). However, few studies have evaluated the utility of these parameters measured by CIEDs with CorVue algorithm. The purpose of this study was to investigate the relationship between ITI alerts triggered by the CorVue algorithm and HF development. We also examined the association between device-measured PA and ITI alerts associated with HF development. We retrospectively studied consecutive patients with CIEDs equipped with CorVue algorithm, which were implanted between June 1, 2011 and August 31, 2019. These patients were divided into two groups: patients with decreased ITI followed by the ITI alerts (ITI alert group) and those without the alerts (non-ITI alert group). There were 35 and 14 patients in the ITI and non-ITI alert groups, respectively. A total of 96 ITI alerts were observed. ITI alerts associated with HF development were observed in 21% (20/96); whereas, ITI alerts not associated with HF development were observed in 79% (76/96). Accurate device-measured PA was confirmed in 76 ITI alerts, which consisted of 30 alerts with lower PA and 46 alerts without lower PA. ITI alerts associated with HF development were observed in 30% (9/30) of the alerts with lower PA, whereas observed only in 6.5% (3/46) of the alerts without lower PA. In conclusion, the CorVue ITI alerts indicated a high false-positive rate. However, device-measured PA may be useful to determine whether ITI alerts are associated with HF development or not, which was attributed to the high negative predictive value.

The usefulness of a delivery catheter system for right ventricular "true" septal pacing.

Right ventricular (RV) septum is an alternate site for the placement of RV lead tip instead of RV apex. Recent studies have demonstrated that less than half of the RV leads targeted for septal implantation are placed on the RV septum using a conventional stylet system; new guiding catheter systems have become available for RV lead placement. This study aimed to investigate the usefulness of the delivery catheter system in lead placement on the RV septum when compared with the stylet system. We retrospectively evaluated 198 patients who underwent fluoroscopically guided pacemaker implantation with RV leads targeted to be placed in the RV septum and in whom computed tomography was incidentally and subsequently performed. A delivery catheter was used in 16 patients, and a stylet in 182 patients. The primary endpoint of this study was the success rate of RV lead placement on the RV septum. The proportion of RV lead placement on the RV septum was higher in the delivery catheter group than in the stylet group (100% vs. 44%; p < 0.001). In the stylet group, the lead tips were placed at the hinge in 92 cases (51%) and on the free wall in 9 cases (5%). Paced QRS duration was narrower in the delivery catheter group than in the stylet group (128 ± 16 vs. 150 ± 21 ms, p < 0.01). The delivery catheter system designated for pacing leads may aid in selecting RV septal sites and achieve good physiologic ventricular activation.

Technology Applications of Capnography Waveform Analytics for Evaluation of Heart Failure Severity.

This study aimed to elucidate the influential parameter, acquired from the analyses of nasal capnography waveforms, for the elevated plasma brain natriuretic peptide (BNP) levels in patients (n = 34) with heart failure (HF). The capnography waveforms were analyzed to evaluate changes in end-tidal CO2 (ETCO2) values and expiratory and inspiratory durations. The relationship between these parameters, estimated from capnography analyses and plasma BNP, was then evaluated. Mean ETCO2 values and BNP levels showed a strong negative correlation (R2 = 0.6355, p < 0.0001) in HF patients with chronic kidney disease (CKD) (R2 = 0.6355, p < 0.0001). The ETCO2 value was the most influential parameter that indicated elevated BNP levels in HF patients with CKD (ß = - 0.577; p = 0.031). The mean ETCO2 level could be a potentially influential parameter reflecting elevated BNP levels in HF patients, especially in HF patients with CKD. Respiratory parameters, acquired from detailed nasal capnography analyses, might be reasonable for evaluating the severity of HF. Graphical abstract.

Laryngeal mask versus facemask in the respiratory management during catheter ablation.

BACKGROUND: The purpose of this study is to investigate if a laryngeal mask could improve respiratory condition during radiofrequency catheter ablation (RFCA). METHODS: Twenty-four consecutive patients who underwent RFCA for atrial fibrillation were divided into two groups (Facemask group; n = 10, Laryngeal mask group; n = 14). All patients were completely sedated under intravenous anesthesia and fitted with artificial respirators during the RFCA. The capnography waveforms and their differential coefficients were analyzed to evaluate the changes of end-tidal CO2 (ETCO2) values, respiratory intervals, expiratory durations, and inspiratory durations. RESULTS: During the RFCA, ETCO2 values of the laryngeal mask group were higher than those of the facemask group (36.0 vs. 29.2 mmHg, p = 0.005). The respiratory interval was significantly longer in the laryngeal mask group than those in the facemask group (4.28 s vs.5.25 s, p < 0.001). In both expiratory and inspiratory phases, the mean of the maximum and minimum values of CO2 was significantly higher when using a laryngeal mask than when using a facemask. The inspiratory-expiratory ratio of the laryngeal mask group was significantly larger than that of the facemask group (1.59 vs. 1.27, p < 0.001). The total procedure duration, fluoroscopic duration and the ablation energy were significantly lower in the laryngeal mask group than in the facemask group. The ETCO2 value is the most influential parameter on the fluoroscopic duration during the RFCA procedure (ß = - 0.477, p = 0.029). CONCLUSIONS: The use of a laryngeal mask could stabilize respiration during intravenous anesthesia, which could improve the efficiency of RFCA.

Increased respiratory disturbance index measured using an advanced device algorithm is associated with heart failure development.

Previous studies suggested that sleep-disordered breathing was associated with cardiovascular diseases such as heart failure (HF). Recently, algorithms of cardiac implantable electronic devices (CIEDs) have been developed to detect advanced sleep apnea (SA); the Apnea Scan (AP Scan) being an example. The purpose of this study was to investigate the association between respiratory disturbance index (RDI) measured using the AP Scan algorithm and HF development. We retrospectively studied consecutive patients with CIEDs equipped with the AP Scan algorithm which were implanted between December 1, 2011 and March 31, 2019. These patients were divided into 2 groups according to the trends of RDI: patients with a continually high RDI > 30 (severe SA group) and those without a continually high RDI (non-severe SA group). There were 16 and 46 patients in the severe and non-severe SA groups, respectively. Increased left ventricular end-diastolic and end-systolic dimensions were observed in the severe SA group. Regarding cardiovascular events, HF was observed in 8 patients (50.0%) in the severe SA group and 1 patient (2.2%) in the non-severe SA group; thus, there was a significantly higher proportion of patients with HF in the severe SA group. In conclusion, continually high RDI was associated with HF development in patients with CIEDs equipped with the AP Scan algorithm. Therefore, an elevated RDI may be a risk factor for the development of HF in patients with CIEDs.