Effects of cardiac rehabilitation with motion assistance from a wearable cyborg hybrid assistive limb on patients with chronic heart failure: a randomized controlled trial with a one-year follow-up.

[Purpose] We have recently reported that using a wearable cyborg hybrid assistive limb improved the isometric knee extensor muscle strength of patients with chronic heart failure. Here, we investigated the long-term effects of a lumbar-type hybrid assistive limb for patients with chronic heart failure. [Participants and Methods] A total of 28 hospitalized patients with chronic heart failure (mean age, 73.1 ± 13.8 years) were randomly assigned to two groups: the hybrid assistive limb group or the control group, in which they performed a sit-to-stand exercise with or without the hybrid assistive limb, respectively. The cardiac rehabilitation therapy included this intervention, which was performed as many times as possible for 5-30 minutes per day for 6-10 days. Clinical assessments like lower-limb muscle strength, walking ability, etc., were measured before and after the intervention. Cardiac events were followed up for up to a year after discharge. [Results] No adverse events occurred during the study period in either group. In terms of long-term effects, the incidence of cardiac events was 23% and 45% in the hybrid assistive limb and the control groups, respectively. [Conclusion] Hybrid assistive limb-assisted exercise therapy may be a safe and feasible cardiac rehabilitation tool in patients with chronic heart failure. The lumbar-type wearable cyborg hybrid assistive limb may have a positive effect on heart failure prognosis by adding long-term exercise therapy.

Disposable Nitric Oxide Generator Based on a Structurally Deformed Nitrite-Type Layered Double Hydroxide.

The inhalation of nitric oxide (NO), which acts as a selective vasodilator of pulmonary blood vessels, is an established medical treatment. However, its wide adoption has been limited by the lack of a convenient delivery technique of this unstable gas. Here we report that a solid mixture of FeIISO4·7H2O and a layered double hydroxide (LDH) containing nitrite (NO2-) in the interlayer spaces (NLDH) stably generates NO at a therapeutic level (∼40 ppm over 12 h from freshly mixed solids; ∼80 ppm for 5-10 h from premixed solids) under air flow (0.25 L min-1) if the NLDH has been prepared by using a reconstruction method. Mg/Al-type LDH was calcined at 550 °C to remove interlayer CO32- and then treated with NaNO2 in water to reconstruct the NLDH. This one-pot, organic solvent-free process can be performed at large scales and is suitable for mass production. Humid air promotes anion exchange between NO2- and SO42- in the solid mixture, resulting in persistent interactions of NO2- and Fe2+, generating NO. In contrast to the previously reported NLDH prepared using an anion-exchange method, the reconstructed NLDH exhibits stable and persistent generation of NO because of partial deformation of the layered structures (e.g., particle aggregation, reduced crystallinity, and enhanced basicity). Degradation of the solid mixture is suppressed under dry conditions, so that a portable cartridge column that is readily available as an NO source for emergency situations can be prepared. This work demonstrates that the interlayer nanospace of LDH serves as a reaction mediator for excellent controllability of solid-state reactions. This inexpensive and disposable NO generator will facilitate NO inhalation therapy in developing countries and nonhospital locations.

Effects of Cardiac Rehabilitation With Lumbar-Type Hybrid Assistive Limb on Muscle Strength in Patients With Chronic Heart Failure　- A Randomized Controlled Trial.

BACKGROUND: Aiming to establish an effective tool in new cardiac rehabilitation programs, we investigated the use of a lumbar-type hybrid assistive limb (HAL) in patients with heart failure (HF) who had difficulty in walking at the usual speed of healthy subjects (≈80 m/min).Methods and Results:We randomly assigned 28 HF patients (age, 73.1±13.8 years) to perform a sit-to-stand exercise with or without HAL. The sit-to-stand exercise was repeated as many times as possible as cardiac rehabilitation therapy over a period of 6-10 days. We measured 5 parameters before and after the completion of cardiac rehabilitation: B-type natriuretic peptide, Short Physical Performance Battery (SPPB), 6-min walking distance (6MWD), 30-s chair-stand test (CS-30), and isometric knee extensor muscle strength. The SPPB and 6MWD were significantly improved, and the CS-30 score was somewhat improved, after the exercise therapy in both the HAL and non-HAL groups. The knee extensor muscle strength improved significantly in the HAL group (0.29±0.11 to 0.35±0.11 kgf/kg, P<0.01), but showed no change in the non-HAL group (0.35±0.11 to 0.35±0.13 kgf/kg, P=0.40). CONCLUSIONS: The improved knee extensor muscle strength in the HAL group suggests that the lumbar-type HAL may be an effective tool for cardiac rehabilitation in HF patients with frailty, which is a predictor of poor prognosis in HF.

Preprocedural restoration of sinus rhythm and left atrial strain predict outcomes of catheter ablation for long-standing persistent atrial fibrillation.

INTRODUCTION: Catheter ablation (CA) for long-standing persistent atrial fibrillation (LS-AF) remains challenging. We aimed to explore whether sinus rhythm (SR) restoration and left atrium (LA) function after pretreatment with antiarrhythmic drugs (AAD's) and electrical cardioversion (ECV) predict procedural outcomes. METHODS AND RESULTS: We included 100 consecutive patients with LS-AF who were treated with AAD/ECV for at least 3 months before CA. The echocardiographic LA strain during reservoir phase (LASr) was assessed after pretreatment as a marker of LA fibrosis. The recurrence was recorded for ≥1 year after the last procedure. During a 34 ± 16-month follow-up period, the single and multiple procedures and pharmaceutically assisted success rates were 40% and 71%, respectively. Patients with preprocedural SR restoration and higher LASr showed a significantly higher recurrence-free probability after the last CA (logrank P = .001 and P < .001, respectively). Failure of preprocedural SR restoration and LASr ≤8.6% were independently associated with recurrence after the last CA (hazard ratio [HR]: 3.13, 95% confidence interval [CI]: 1.42-6.91, P = .005; HR: 3.89, 95% CI: 1.65-9.17, P = .002, respectively). These parameters added incrementally to the predictive value of AF duration and LA dilatation (P = .03 and P = .002, respectively) and improved the recurrence-risk stratification (net reclassification improvement = 0.39; 95% CI = 0.13-0.65; P = .003). CONCLUSION: In patients with LS-AF, the inability to restore SR and lower LASr after AAD/ECV treatment independently and incrementally predicts the recurrence after CA. These findings might be useful for determining LS-AF ablation candidates.

Audiovisual telesupport system for cardiovascular catheter interventions: A preliminary report on the clinical implications.

OBJECTIVES: This study aimed to validate the clinical implications of audiovisual telesupport system use. BACKGROUND: An audiovisual telesupport system with supervisors has been effective in guiding procedures when surgeons have limited experience with the technique. However, cardiovascular catheter interventions using an audiovisual telesupport system has not been previously reported. METHODS: Starting in September 2017, two cardiologists in Kamisu Saiseikai Hospital (Kamisu, Japan, with limited cardiologists) began performing cardiovascular catheter interventions using an audiovisual telesupport system. This system enabled them to perform catheter interventions with the support of advisors in the University of Tsukuba (Tsukuba, Japan). We retrospectively assessed procedure time and complications of percutaneous coronary intervention (PCI) and catheter ablation (CA). RESULTS: In the first 10 months, 21 patients with coronary artery disease underwent PCI using this system. The mean procedure duration of PCI was 42 ± 10 min. Nine patients with tachyarrhythmia including supraventricular tachycardia (SVT), ventricular premature contraction (VPC), common atrial flutter, and paroxysmal atrial fibrillation (AF) underwent CA using this system. The mean CA procedure time was 134 ± 31 min for SVT, 100 ± 14 min for VPC, and 200 min for AF. All PCI and CA procedures were successfully performed without any complications. CONCLUSIONS: The audiovisual telesupport system enabled cardiologists with limited human resources to provide safe and high-quality catheter interventions.

Fragmented QRS Is a Novel Risk Factor for Ventricular Arrhythmic Events After Receiving Cardiac Resynchronization Therapy in Nonischemic Cardiomyopathy.

INTRODUCTION: A fragmented QRS (fQRS) is reported to be associated with a poor prognosis or sudden cardiac death (SCD) in patients with Brugada syndrome or ischemic heart disease. However, no studies have clarified the impact of the presence of an fQRS on SCD or ventricular arrhythmic events in patients receiving cardiac resynchronization therapy (CRT). This study aimed to clarify this point in patients with nonischemic cardiomyopathy. METHODS AND RESULTS: This study included 137 heart failure patients with nonischemic cardiomyopathy who received CRT (NYHA functional class: II/III/IV = 25/84/28). The 12-lead ECGs before and after CRT were analyzed. The presence of an fQRS was decided in accordance with the definition in previous papers. Before the CRT, an fQRS was observed in 67 patients (fQRS-pre; 49%). However, it was masked in 35 (52% of fQRS-pre) patients after the CRT. Inversely, in 70 patients in whom an fQRS was absent before the CRT, it appeared after the CRT in 15 (21%) patients. As a result, 47 patients (34%) had an fQRS after the CRT (fQRS-post), and it was less than that before the CRT (P = 0.014). During 18 months of follow-up, SCD or ventricular arrhythmic events were observed more frequently in patients with an fQRS-post than in those without (36.2% vs. 3.3%, P < 0.001). A Cox regression analysis revealed that an fQRS-post was significantly associated with those events (hazard ratio = 9.18; 95% confidence interval = 2.45-34.48, P = 0.001). CONCLUSION: In patients with nonischemic cardiomyopathy who received CRT, an fQRS-post was independently associated with SCD or ventricular arrhythmic events.

Electrophysiological Characteristics and Radiofrequency Catheter Ablation Treatment of Idiopathic Ventricular Arrhythmias Successfully Ablated From the Ostium of the Coronary Sinus.

BACKGROUND: Idiopathic ventricular arrhythmias (VAs) rarely arise from the epicardium at the crux of the heart. However, the electrophysiological characteristics of VAs successfully ablated from the ostium of the coronary sinus (CSO) have not yet been documented.Methods and Results:Electrocardiographic and electrophysiological data were analyzed in patients with idiopathic VAs successfully ablated from the CSO.Among 309 patients with idiopathic VAs treated with radiofrequency catheter ablation (RFCA), 6 (1.94%; 3 men; age: 66.3±9.7 years) had VAs successfully ablated from the CSO. Only 1 patient had sustained ventricular tachycardia. The morphology of the QRS showed a left superior axis and QS pattern in leads III and aVF. Furthermore, the precordial maximum deflection index was >0.55 in all patients and a right bundle branch block pattern was recorded in 5 of 6 patients. All VAs were successfully eliminated by RFCA within the CSO. Intracardiac ECGs at sites where VAs were eliminated by RFCA showed clear atrial and ventricular potentials (atrial amplitude: 0.21±0.11 mV; ventricular amplitude: 0.43±0.24 mV), except in 1 case of atrial fibrillation. No patients had recurrence during the 3.4±1.8-year follow-up period. CONCLUSIONS: The idiopathic VAs in our study were eliminated by RFCA within the CS, where a clear atrial amplitude was recorded.

Efficacy of Intensive Radiofrequency Energy Delivery to the Localized Dense Scar Area in Post-Infarction Ventricular Tachycardia Ablation　- A Comparative Study With Standard Strategy Targeting the Infarcted Border Zone.

BACKGROUND: Several reports have demonstrated the importance of severely low voltage areas as arrhythmogenic substrates of ventricular tachycardia (VT). However, a comparative study of dense scar-targeted and infarcted border zone-targeted strategies has not been reported.Methods and Results:We divided 109 consecutive patients with VT post-infarction from 6 centers into 2 groups according to the ablation strategy used: dense scar-targeted ablation (DS ablation, 48%) or border zone-targeted ablation (BZ ablation, 52%). During DS ablation, we attempted to identify VT isthmuses in the dense scar areas (≤0.6 mV) using detailed pace mapping, and linear ablation lesions were applied mainly to those areas. During BZ ablation, linear ablation of standard low voltage areas (0.5-1.5 mV) was performed along with good pace map sites of the clinical VT. Acute success was defined as complete success (no VTs inducible) or partial success (clinical VT was noninducible). The acute complete success rate was significantly higher for DS ablation than for BZ ablation (62% vs. 42%, P=0.043). During a median follow-up of 37 months, the VT-free survival rate was significantly higher for DS ablation than for BZ ablation (80% vs. 58% at 48 months; log-rank P=0.038). CONCLUSIONS: DS ablation may be a more effective therapy for post-infarction VT than BZ ablation in terms of the acute complete success rate and long-term follow-up.

J Waves Are Associated With the Increased Occurrence of Life-Threatening Ventricular Tachyarrhythmia in Patients With Nonischemic Cardiomyopathy.

INTRODUCTION: Recent studies showed that J waves were associated with higher incidence of ventricular tachyarrhythmia (VT/VF) in patients with idiopathic ventricular fibrillation (VF) and myocardial infarction. We sought to assess the association between J waves and VT/VF in patients with nonischemic cardiomyopathy (NICM). METHODS AND RESULTS: We retrospectively enrolled 109 patients (79 men; mean age, 60 ± 15 years) with NICM who underwent implantable cardioverter defibrillator (ICD) implantation. The primary endpoint of this study was the occurrence of appropriate device therapy due to sustained VT/VF. The J wave was electrocardiographically defined as an elevation of the terminal portion of the QRS complex of >0.1 mV in at least 2 contiguous inferior or lateral leads. Among the 109 patients, 37 (34%) experienced an episode of appropriate device therapy during a median follow-up period of 25.9 (IQR 11.5-54.3) months. Kaplan-Meier curves showed that the presence of J waves on the 12-lead ECG obtained before device implantation was associated with an increased occurrence of appropriate device therapy (P < 0.001). Multivariate Cox proportional regression analysis revealed that the presence of J waves (HR 2.95; 95% CI 1.31-6.64; P = 0.009) was an independent predictor for the occurrence of appropriate device therapy. In the subgroup analysis of the patients with dilated or hypertrophic cardiomyopathy, J wave tended to increase the occurrence of appropriate device therapy (P = 0.056 and P = 0.092, respectively). CONCLUSIONS: The presence of J waves was an independent predictor for the occurrence of appropriate device therapy in patients with NICM who underwent ICD implantation.

The QRS morphology pattern in V5R is a novel and simple parameter for differentiating the origin of idiopathic outflow tract ventricular arrhythmias.

AIMS: There are many reports on the ECG characteristics of idiopathic outflow tract ventricular arrhythmias (OT-VAs) to predict their origin. However, differentiating near regions using 12-lead ECGs is still complicated. The synthesized 18-lead ECG derived from the 12-lead ECG can provide virtual waveforms of the right-sided chest leads (V3R, V4R, and V5R) and back leads (V7, V8, and V9). The aim of this study was to develop a simple and useful parameter for differentiating OT-VA origins using the 18-lead ECG. METHODS AND RESULTS: We studied 28 and 73 patients with idiopathic VAs in a pacemapping study and validation cohort, respectively. In the pacemapping study, several sites out of five different sites were paced in each patient: the anterior and posterior right ventricular OT (RVOT-ant and RVOT-post), right and left coronary cusps (RCC and LCC), and junction of both cusps (RLJ). The 18-lead ECGs during pacemapping among the five sites were compared for establishing a simple parameter to predict VA origins. A novel parameter using 18-lead ECGs was tested prospectively in 73 patients. In the pacemapping study, the dominant QRS morphology pattern in the synthesized V5R significantly differed among those sites (RVOT-ant:Rs, RVOT-post:rS, RCC:QS, RLJ:qR, and LCC:R). The patients in the validation cohort were divided into five groups depending on those QRS morphology patterns during VAs in the synthesized V5R. Each V5R QRS morphology pattern could predict a precise origin of the OT-VAs with an overall accuracy of 75%. CONCLUSION: The QRS morphology pattern in V5R was a simple and useful parameter for differentiating detailed OT-VA origins.

Hybrid epicardial and endocardial ablation of a persistent atrial tachycardia arising from the marshall bundle: the importance of a detailed analysis of the local potentials.

Radiofrequency catheter ablation of an atrial tachycardia (AT) and atrial fibrillation (AF) was performed in a patient with a history of pulmonary vein isolation for paroxysmal AF. The AT exhibited a centrifugal pattern with the posterolateral LA as the earliest activation site. The AT was not terminated by ablation at the endocardial earliest site, but its cycle length was prolonged by ablation at an opposite site within the Vein of Marshall. Finally, the AT was terminated by an energy application at a site 7 mm posteroinferior to the initial earliest activation site. We analyzed the local potentials of each energy delivery site in detail.

Counterclockwise heart rotation affects variation in successful ablation line position in common atrial flutter.

BACKGROUND: Linear ablation of atrial flutter usually targets a 6 o'clock position on the cavotricuspid isthmus on left anterior oblique view, but the difficulty of the ablation often requires a variation in successful ablation line position from 5 to 7 o'clock. METHODS AND RESULTS: This study included 94 patients without structural heart disease. A linear lesion was created in turn at the 6, 7, and 5 o'clock positions until bidirectional block of the isthmus was completed; the final lesion was defined as the successful ablation line. The degree of counterclockwise heart rotation (CCW-HR) was evaluated in a blinded fashion according to the angle between the vertical line crossing the His bundle catheter and the line connecting the His bundle catheter and coronary sinus ostium. Successful ablation lines were obtained at the 6 o'clock position in 59 patients (63%); the 7 o'clock position in 19 patients (20%; the oldest group with a moderate radiofrequency burden); and the 5 o'clock position in the remaining 16 (17%; the youngest group with the largest radiofrequency burden). Age-related increase in CCW-HR was the only independent predictor of a more septal successful ablation line (OR, 7.1; 95% CI: 3.3-14.3; P<0.01). CONCLUSIONS: Variation in successful ablation line position was affected by age-related CCW-HR; its evaluation might reduce radiofrequency burden, especially in the young and elderly.

Significant improvement of left atrial and left atrial appendage function after catheter ablation for persistent atrial fibrillation.

BACKGROUND: The long-term effects of catheter ablation (CA) on the left atrium and left atrial appendage (LAA) are unknown in persistent atrial fibrillation (AF). This study investigated left atrial (LA) reverse remodeling and evolution of LA/LAA function after successful CA for persistent AF and identified predictors for maintenance of sinus rhythm (SR) and LA reverse remodeling. METHODS AND RESULTS: CA was performed in 123 patients with persistent AF. LA volumes, LA strain and LAA wall velocity were assessed both at baseline and at 12 months after ablation. Patients who maintained SR were divided into 2 groups according to whether LA volume decreased by ≥15% at follow-up (responders) or not (non-responders). During a follow-up period of 18±2 months, AF recurred in 45 patients (37%). Of the remaining 78 patients (63%) without recurrent AF, 62 patients (79%) were classified as responders. LA/LAA function significantly improved and the prevalence of spontaneous echo contrast decreased only in responders at follow-up. LA systolic strain and LAA wall velocity were independent predictors of both maintenance of SR (odds ratio [OR], 2.57; P=0.003; OR, 3.02; P=0.002, respectively) and LA reverse remodeling (OR, 4.44; P=0.007; OR, 3.52; P=0.01, respectively). CONCLUSIONS: Successful CA is associated with LA reverse remodeling and LA/LAA functional recovery in patients with persistent AF. LA systolic strain and LAA wall velocity at baseline predicted both maintenance of SR and LA reverse remodeling.

Differential relationship between decreased muscle oxygenation and blood pressure recovery during supraventricular and ventricular tachycardia.

Vasoconstriction during tachyarrhythmia contributes to maintenance of arterial pressure (AP) by decreasing peripheral blood flow. This cross-sectional observational study aimed to ascertain whether the relationship between peripheral blood flow and AP recovery occurs during both paroxysmal supraventricular (PSVT, n = 19) and ventricular tachycardias (VT, n = 17). Peripheral blood flow was evaluated using forearm tissue oxygen index (TOI), and mean AP (MAP) was measured using a catheter inserted in the brachial or femoral artery during an electrophysiological study. PSVT and VT rapidly decreased MAP with a comparable heart rate (P = 0.194). MAP recovered to the baseline level at 40 s from PSVT onset, but not VT. The forearm TOI decreased during both tachyarrhythmias (P ≤ 0.029). The TOI response was correlated with MAPrecovery (i.e., MAP recovery from the initial rapid decrease) at 20-60 s from PSVT onset (r = -- 0.652 to - 0.814, P ≤ 0.0298); however, this association was not observed during VT. These findings persisted even after excluding patients who had taken vasoactive drugs. Thus, restricting peripheral blood flow was associated with MAP recovery during PSVT, but not VT. This indicates that AP recovery depends on the type of tachyarrhythmia: different cardiac output and/or vasoconstriction ability during tachyarrhythmia.

Randomized crossover trial of 2-week Garment electrocardiogram with dry textile electrode to reveal instances of post-ablation recurrence of atrial fibrillation underdiagnosed during 24-hour Holter monitoring.

BACKGROUND: Atrial fibrillation (AF) is the most common arrhythmia and often recurs despite catheter ablation. The recurrence of AF is often underdiagnosed by standard 24-hour electrocardiogram (ECG) because of its transient and silent nature. A garment-style ECG with a highly conductive textile electrode made of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)(PEDOTPSS) and nanofiber (Garment ECG) has been developed that can provide longer-term continuous monitoring. This study investigated whether 2-week Garment ECG can reveal instances of AF recurrence in patients who are diagnosed as remaining in sinus rhythm by 24-hour Holter ECG. METHODS: The open-label randomized crossover study enrolled 67 patients (63.1±10.6 years old, 53 men) who had undergone initial AF ablation. Three months after ablation, patients were randomly assigned to group 1 (n = 35), 2-week Garment ECG followed by 24-hour Holter ECG, or group 2 (n = 32), 24-hour Holter ECG followed by 2-week Garment ECG. The detection of AF recurrence was compared between the two devices. RESULTS: The Garment ECG showed AF recurrence in 12 patients (18%) compared to 4 patients for the Holter ECG (6%, p = 0.008). The ECG acquisition rate was higher for Holter ECG than for Garment ECG (100.0% [interquartile range 100.0-100.0%] versus 82.4% [71.1-91.0%], p<0.001), but the Garment ECG provided longer total analysis time (11.0 days [9.0-12.2 days] for Garment; 1.0 day [1.0-1.0 day] for Holter, p<0.001). CONCLUSIONS: Despite the lower ECG acquisition rate, the 2-week Garment ECG revealed instances of AF recurrence after ablation in patients who were underdiagnosed by 24-hour Holter ECG. TRIAL REGISTRATION: Clinical Trial Registration: URL: https://jrct.niph.go.jp/en-latest-detail/jRCTs032180018 Unique Identifier: jRCTs032180018.

Electrocardiographic determinants of the polymorphic QRS morphology in idiopathic right ventricular outflow tract tachycardia.

INTRODUCTION: Premature ventricular contractions (PVCs) arising from the right ventricular outflow tract (RVOT) can trigger polymorphic ventricular tachycardia (PVT) or ventricular fibrillation (VF) in patients with no structural heart disease. We aimed to clarify the ECG determinants of the polymorphic QRS morphology in idiopathic RVOT PVT/VF. METHODS AND RESULTS: The ECG parameters were compared between 18 patients with idiopathic PVT/VF (PVT-group) and 21 with monomorphic VT arising from the RVOT (MVT-group). The coupling interval (CI) of the first VT beat was comparable between the 2 groups. However, the prematurity index (PI) of the first VT beat was smaller in the PVT-group than in the MVT-group (P < 0.001). Furthermore, the QT index, defined as the ratio of the CI to the QT interval of the preceding sinus complex, was also smaller for the PVT/VF in the PVT-group than that for the VT in the MVT-group (P < 0.01). In the PVT-group, the CI of the first VT beat was comparable between that of VT and isolated PVCs, but the PI of the first VT beat was shorter for VT than isolated PVCs (P < 0.05). The PI was the only independent determinant of the polymorphic QRS morphology (odd ratio = 2.198; 95% confidence interval = 1.321-3.659; P = 0.002). CONCLUSION: The smaller PIs of the first VT beat may result in a polymorphic QRS morphology.

Radiofrequency catheter ablation of persistent atrial fibrillation decreases a sleep-disordered breathing parameter during a short follow-up period.

BACKGROUND: Obstructive sleep apnea (OSA) is often associated with atrial fibrillation (AF), but the impact of radiofrequency catheter ablation (RFCA) for AF on sleep apnea syndrome is unknown. METHODS AND RESULTS: A total of 25 patients (3 women; 61 ± 6 years) with sleep apnea syndrome who underwent RFCA for drug-refractory, persistent AF were studied. Polysomnography was also performed 1 day before and 1 week after RFCA in all patients. The total number of central or OSA or hypopnea events was analyzed and compared. Among the 25 patients who all predominantly had obstructive apnea, the apnea-hypopnea index (AHI; median, 21, interquartile range [IQR]: 11-38 to median 15, IQR: 7-23; P=0.002) and obstructive type of apnea (median 10, IQR: 6-19 to median 7, IQR: 2-14; P=0.003) decreased after RFCA. In patients in whom sinus rhythm was restored and maintained after RFCA, the AHI decreased after RFCA (median 22, IQR: 15-38 to median 15, IQR: 7-23; P<0.01), but it did not in those who had AF recurrence (median 10, IQR: 9-11 to median 11, IQR: 10-16; P<0.05). There was a significant correlation between the outcome of RFCA and % change in the AHI (rs=0.569, P=0.003). CONCLUSIONS: In patients with sleep apnea syndrome and AF, restoring sinus rhythm by RFCA was significantly associated with a decrease in AHI (Clinical Trial Registration: Trial number, UMIN000005538).

Prevalence and influence of hyperthyroidism on the long-term outcome of catheter ablation for drug-refractory atrial fibrillation.

BACKGROUND: Hyperthyroidism is usually regarded as a reversible cause of atrial fibrillation (AF); however, one-third of patients remain in AF despite euthyroid restoration. We hypothesized that a significant number of AF patients with hyperthyroidism (Hyperthyroid-AF) as well as those without (Non-thyroid-AF) would benefit from catheter ablation of AF (AF ablation). This study aimed to clarify the prevalence of hyperthyroidism in candidates for AF ablation and to compare the long-term outcome of AF ablation between the Hyperthyroid-AF and Non-thyroid-AF groups. METHODS AND RESULTS: This study enrolled 337 consecutive patients with AF who underwent a first AF ablation that mainly involved extensive encircling pulmonary vein isolation. Sixteen (4.7%) patients had hyperthyroidism; the remaining 321 (95.3%) did not. In the Hyperthyroid-AF patients, a euthyroid state had been restored for at least 3 months before the ablation. During a mean follow-up period of 4±1 years after ablation, AF recurred in 7 patients (44%) with Hyperthyroid-AF and in 139 patients (43%) with Non-thyroid-AF (P=0.91 by the log-rank test). In the multivariate Cox regression models, the presence of hyperthyroidism was not associated with a higher risk of AF recurrence (hazard ratio, 0.87; 95% confidence interval, 0.40-1.88; P=0.73). CONCLUSIONS: In the AF ablation candidates without structural heart disease, hyperthyroidism was not rare. After euthyroid restoration on pharmacological treatment, hyperthyroidism was not associated with a higher risk of AF recurrence.