Recurrent episodes of atrioventricular nodal reentrant tachycardia: Sites of ablation success, ablation endpoint, and primary culprits for recurrence.

Background: Atrioventricular nodal reentrant tachycardia (AVNRT) sometimes recurs even after anatomical slow pathway (SP) ablation targeting the rightward inferior extension (RIE). This multicenter study aimed to determine the reasons for AVNRT recurrence. Methods and Results: Forty-six patients were treated successfully for recurrent AVNRT. Initial treatment was for 38 slow-fast AVNRTs, 3 fast-slow AVNRTs, 2 slow-slow AVNRTs, 2 slow-fast and fast-slow AVNRTs, and 1 noninducible AVNRT. All initial treatments were of RF application to the RIE; SP elimination was achieved in 11, dual AVN physiology was seen in 29, and AVNRT remained inducible in 5. The recurrent AVNRTs included 34 slow-fast AVNRTs, 6 fast-slow AVNRTs, 3 slow-slow AVNRTs, 2 slow-fast and fast-slow AVNRTs, and 1 slow-fast and slow-slow AVNRTs. Successful ablation site was within the RIE in 39 and left inferior extension in 7. In 30 of 39, the successful RIE site was in the same area or higher than that of the initial procedure. Conclusion: For a high majority (around 85%) of patients in whom AVNRT recurs after initial ablation success, the site of a second successful procedure will be within the RIE even though the RIE was originally targeted. Furthermore, a high majority (around 86%) of sites of successful ablation will be higher than those originally targeted.

Clinical characteristics and analysis of prognostic factors in methicillin-resistant Staphylococcus aureus endocarditis: A retrospective multicenter study in Japan.

BACKGROUND: Infective endocarditis (IE) caused by MRSA (methicillin-resistant Staphylococcus aureus) is associated with a high mortality rate. This study aimed to elucidate the characteristics of patients with MRSA-IE in Japan and identify the factors associated with prognosis. METHODS: This retrospective study included patients with a confirmed diagnosis of IE caused by MRSA, between January 2015 and April 2019. RESULTS: A total of 65 patients from 19 centers were included, with a mean age of 67 years and 26 % were female. Fifty percent of the patients with IE were had nosocomial infections and 25 % had prosthetic valve involvement. The most common comorbidities were hemodialysis (20 %) and diabetes (20 %). Congestive heart failure was present in 86 % of patients (NYHA class I, II: 48 %; III, IV: 38 %). The 30-day and in-hospital mortality rates were 29 % and 46 %, respectively. Multi-organ failure was the primary cause of death, accounting for 43 % of all causes of death. Prognostic factors for in-hospital mortality were age, disseminated intravascular coagulation, daptomycin and/or linezolid as initial antibiotic therapy, and surgery. Surgical treatment was associated with a lower mortality rate (odds ratio [OR], 0.026; 95 % confidence interval [CI], 0.002-0.382; p = 0.008 for 30-day mortality and OR, 0.130; 95 % CI; 0.029-0.584; p = 0.008 for in-hospital mortality). CONCLUSION: Mortality due to MRSA-IE remains high. Surgical treatment is a significant prognostic predictor of MRSA-IE.

Outcomes of left bundle branch area pacing compared to His bundle pacing and right ventricular apical pacing in Japanese patients with bradycardia.

Background: His bundle pacing (HBP) and left bundle branch area pacing (LBBAP) emerge as better alternatives to right ventricular apical pacing (RVAP) in patients with bradycardia requiring permanent cardiac pacing. We aimed to compare the clinical outcomes of LBBAP, HBP, and RVAP in Japanese patients with bradycardia. Methods: A total of 424 patients who underwent successful pacemaker implantation (HBP, n = 53; LBBAP, n = 75; and RVAP, n = 296) were retrospectively enrolled in this study. The primary study endpoint was the cumulative incidence of heart failure hospitalization (HFH) during the follow-up. Results: The success rate for implantation was higher in the LBBAP group than in the HBP group (94.9% and 81.5%, respectively). Capture threshold increase >1V during the follow-up occurred in the HBP and RVAP groups (9.4% and 5.1%, respectively), while it did not in the LBBAP group. The cumulative incidence of HFH was significantly lower in the LBBAP group than the RVAP (adjusted hazard ratio, 0.12 [95% confidence interval: 0.02-0.86]; p = .034); it did not differ between the HBP and RVAP groups (adjusted hazard ratio, 0.48 [95% confidence interval: 0.17-1.34]; p = .16). Advanced age, mean percent right ventricular pacing (per 10% increase), left ventricular ejection fraction <50%, and RVAP were associated with HFH. Conclusions: Compared to RVAP and HBP, LBBAP appeared more feasible and effective in patients with bradycardia requiring permanent cardiac pacing.

Antimicrobial therapy and outcome of methicillin-resistant Staphylococcus aureus endocarditis: A retrospective multicenter study in Japan.

BACKGROUND: MRSA (methicillin-resistant Staphylococcus aureus)-infective endocarditis (IE) is associated with high morbidity and mortality. This study aimed to assess data from patients with MRSA-IE across multiple facilities in Japan, with a specific focus on antimicrobial therapy and prognosis. METHODS: This retrospective study enrolled patients with a confirmed diagnosis of IE attributed to MRSA, spanning the period from January 2015 to April 2019. RESULTS: Sixty-four patients from 19 centers were included, with a median age of 67 years. The overall mortality rate was 28.1% at 30 days, with an in-hospital mortality of 45.3%. The most frequently chosen initial anti-MRSA agents were glycopeptide in 67.2% of cases. Daptomycin and linezolid were selected as initial therapy in 23.4% and 17.2% of cases, respectively. Approximately 40% of all patients underwent medication changes due to difficulty in controlling infection or drug-related side effects. Significant prognostic factors by multivariable analysis were DIC for 30-day mortality and surgical treatment for 30-day and in-hospital mortality. For vancomycin as initial monotherapy, there was a trend toward a worse prognosis for 30-day and in-hospital mortality (OR, 6.29; 95%CI, 1.00-39.65; p = 0.050, OR, 3.61; 95%CI, 0.93-14.00; p = 0.064). Regarding the choice of initial antibiotic therapy, statistical analysis did not show significant differences in prognosis. CONCLUSION: Glycopeptide and daptomycin were the preferred antibiotics for the initial therapy of MRSA-IE. Antimicrobial regimens were changed for various reasons. Prognosis was not significantly affected by choice of antibiotic therapy (glycopeptide, daptomycin, linezolid), but further studies are needed to determine which antimicrobials are optimal as first-line agents.

Initial results of transcatheter modification of left atrial appendage by obliteration with device in patients with nonvalvular atrial fibrillation: Real-world data from the TERMINATOR registry.

BACKGROUND: Percutaneous left atrial appendage closure (LAAC) has increased for those who need alternative to long-term anticoagulation with non-valvular atrial fibrillation (NVAF). METHODS AND RESULTS: From September 2019, after initiating WATCHMAN (Boston Scientific, Maple Grove, MN, USA) device implantation, we established Transcatheter Modification of Left Atrial Appendage by Obliteration with Device in Patients from the NVAF (TERMINATOR) registry. Utilizing 729 patients' data until January 2022, we analyzed percutaneous LAAC data regarding this real-world multicenter prospective registry. A total of 729 patients were enrolled. Average age was 74.9 years and 28.5 % were female. Paroxysmal AF was 37.9 % with average CHADS2 3.2, CHA2DS2-VASc 4.7, and HAS-BLED score of 3.4. WATCHMAN implantation was successful in 99.0 %. All-cause deaths were 3.2 %, and 1.2 % cardiovascular or unexplained deaths occurred during follow-up [median 222, interquartile range (IQR: 93-464) days]. Stroke occurred in 2.2 %, and the composite endpoint which included cardiovascular or unexplained death, stroke, and systemic embolism were counted as 3.4 % [median 221, (IQR: 93-464) days]. Major bleeding defined as BARC type 3 or 5 was seen in 3.7 %, and there was 8.6 % of all bleeding events in total [median 219, (IQR: 93-464) days]. CONCLUSIONS: These preliminary data demonstrated percutaneous LAAC with WATCHMAN device might have a potential to reduce stroke and bleeding events for patients with NVAF. Further investigation is mandatory to confirm the long-term results of this strategy using this transcatheter local therapy instead of life-long systemic anticoagulation.

Influence of the irrigation flow pattern and catheter tip design on the lesion formation: an ex vivo experimental model.

BACKGROUND: Lesion formation during catheter ablation is influenced by the power, contact force (CF), time, and catheter stability. However, the influence of the irrigation effects on lesion formation remains unknown. METHODS: An ex vivo experiment using conductive gel was performed. Using three different catheter designs (TactiFlex ™ SE [TF], IntellaNav MiFi ™ OI [MiFi], QDOT MICRO™ [QDOT]), a cross-sectional analysis of the lesion size and surface lesion type of 10g/40W lesions with a combination of various ablation times was performed in protocol 1. A longitudinal analysis (combination of various powers [30, 40, and 50W] and various ablation times with a 10g setting) was performed to investigate the influence of the auto-regulated irrigation system (QDOT) on lesion formation in protocol 2. RESULTS: The lesion formation with the QDOT catheter tended to create larger ablation lesions, while that with the TF catheter created smaller lesions than the other catheters. The lesion surface characteristics were divided into two patterns: ring (MiFi catheter and QDOT) and crescent (TF) patterns. The auto-regulated irrigation system did not influence the lesion formation, and the relationship between the lesion formation and RF energy exhibited similar changes regardless of the ablation power setting. CONCLUSION: The lesion formation and lesion surface characteristics differed among the different irrigation tip designs. An auto-regulated irrigation system did not affect the lesion creation or surface lesion characteristics. Care should be given to the inter-product differences in the lesion characteristics during RF catheter ablation, partly due to the irrigation flow control and tip design.

Zero-Contrast Left Atrial Appendage Closure in Patients With Chronic Kidney Disease.

BACKGROUND: Left atrial appendage closure (LAAC) usually requires contrast medium during the procedure. However, patients with chronic kidney disease (CKD) are at high risk of developing contrast nephropathy. This study aimed to assess the safety and feasibility of zero-contrast LAAC in patients with CKD.Methods and Results: Zero-contrast LAAC was attempted in 15 patients with CKD Stages 3b-5 who were not on hemodialysis. All procedures were performed successfully, without any periprocedural complications. At the 45-day follow-up, no device-related complications or acute kidney disease were observed. CONCLUSIONS: The strategy of zero-contrast LAAC in patients with CKD can be an acceptable option.

Acute Effect of Atrial Fibrillation on Circulating Natriuretic Peptides: The Influence of Heart Rate, Rhythm Irregularity, and Left Atrial Pressure Overload.

Plasma natriuretic peptides (NPs) are increased in patients with atrial fibrillation (AF) compared with the patients with sinus rhythm. This study investigated whether this phenomenon is intrinsic to heart rhythm irregularity and independent of the heart rate and left atrial pressure (LAP) overload. We investigated 46 patients (age: 59 ± 10 years, male gender: 77%) with non-valvular paroxysmal AF who were scheduled for catheter ablation and had documented stable sinus rhythm for at least 18 hours before the procedure. All patients underwent direct measurement of right atrial pressure and LAP, simultaneously with assessment of plasma B-type NP, N-terminal pro-brain NP, and mid-regional pro-atrial NP. The baseline measurement was followed by induction of AF by rapid atrial pacing in the first 24 patients and by regular pacing from the coronary sinus at 100/min (corresponding to the mean heart rate during induced AF) in the latter 22 patients. Hemodynamic assessment and blood sampling were repeated after 20 min of the ongoing AF or fast regular paging. The baseline characteristics and hemodynamic measurements were comparable between study groups; however, patients in the regular atrial pacing group had a higher body mass index and a larger left atrial diameter compared with the induced AF group. Plasma levels of all 3 NPs increased significantly during induced AF but not during fast regular pacing, and the increase of NPs was independent of right atrial pressure and LAP. Baseline concentrations of NPs and heart rhythm irregularity were the only independent predictors of increased NPs.

A novel ablation strategy for recurrent atrial fibrillation: Fractionated signal area in the atrial muscle ablation 1-year follow-up.

INTRODUCTION: Treatment of recurrent atrial fibrillation (AF) is sometimes challenging due to non-pulmonary vein (PV) foci. Fractionated signal area in the atrial muscle (FAAM) is a valid predictor of the location of non-PV foci. FAAM ablation has the potential to decrease the recurrence rate of atrial tachyarrhythmia in patients with recurrent AF. We compared the clinical impact of FAAM ablation for recurrent AF, using 1 year follow up date. METHODS: A total of 230 consecutive patients with symptomatic recurrent AF who underwent catheter ablation specifically targeting non-PV foci as FAAM-guided ablation (n = 113) and non-FAAM-guided ablation (n = 117) were retrospectively analyzed. FAAM was assigned a parameter (peaks slider, which indicates the number of components of fractionated signals), ranging from 1 to 15, indicating the location of the FAAM (1: largest, 15: smallest). FAAM-guided ablation was performed by ablating FAAM until none inducibility of non-PV foci. On the other hand, non-FAAM-guided ablation was performed via linear ablation, complex fractionated atrial electrogram ablation, superior vena cava isolation, and focal ablation according to the location of the non-PV foci. The RHYTHMIA system was used to perform all the procedures. The primary endpoints were AF recurrence, atrial flutter, and/or atrial tachycardia. RESULTS: After a 1-year follow up, freedom from atrial tachyarrhythmia was achieved in 90.3% and 75.2% of patients in the FAAM and non-FAAM groups, respectively (hazard ratio = 0.438 [95% confidence interval: 0.243-0.788], p = .005). CONCLUSIONS: FAAM ablation showed a promising decrease in the recurrence rate of atrial tachyarrhythmia in patients with recurrent AF during a 1-year follow-up.

Subcutaneous ICDs implantation following removal of normally functioning non-infected transvenous ICDs in two young patients.

In young patients with transvenous implantable cardioverter defibrillations (TV-ICDs), the possibility of device infection or lead fracture would be high in their long lifetimes. Furthermore, the risk of lead removal will gradually increase over the years. We reported two cases of subcutaneous ICDs implantation following removal of TV-ICDs. Patient 1, 35-year-old man, underwent TV-ICD implantation 9 years ago for idiopathic ventricular fibrillation, and Patient 2, 46-year-old man, underwent TV-ICD implantation 8 years ago for asymptomatic Brugada syndrome. In both cases, the electrical performance was stable, and there was no incidence of arrythmia or no pacing demand during the follow-up duration. Considering future risk of device infection or lead fracture, and difficulty in future lead removal, TV-ICDs were removed with sufficient informed consent, and then, subcutaneous ICDs (S-ICDs) implantation were performed as an alternative to them. Although indication of the TV-ICD removal should be carefully considered in individual cases, long-term risks leaving it in place should be also considered in the management of young patient. Learning objective: In young patient with TV-ICD, even for a normally functioning non-infected lead, S-ICD implantation following removal of the TV-ICD would represent a strategy associated with less long-term risks than leaving it in place.

Efficacy of SubcutAneous implantable cardioVErter-defibrillators in ≤18 year-old CHILDREN: SAVE-CHILDREN registry.

BACKGROUND: In adult patients, subcutaneous implantable cardioverter defibrillators (S-ICDs) have been reported to be non-inferior to transvenous ICDs with respect to the incidence of device-related complications and inappropriate shocks. Only a few reports have investigated the efficacy of S-ICDs in the pediatric field. This study aimed to investigate the utility and safety of S-ICDs in patients ≤18 years old. METHODS: This study was a multicenter, observational, retrospective study on S-ICD implantations. Patients <18 years old who underwent S-ICD implantations were enrolled. The detailed data on the device implantations and eligibility tests, incidence of appropriate- and inappropriate shocks, and follow-up data were assessed. RESULTS: A total of 62 patients were enrolled from 30 centers. The patients ranged in age from 3 to 18 (median 14 years old [IQR 11.0-16.0 years]). During a median follow up of 27 months (13.3-35.8), a total of 16 patients (26.2%) received appropriate shocks and 13 (21.3%) received inappropriate shocks. The common causes of the inappropriate shocks were sinus tachycardia (n = 4, 30.8%) and T-wave oversensing (n = 4, 30.8%). In spite of the physical growth, the number of suitable sensing vectors did not change during the follow up. No one had any lead fractures or device infections in the chronic phase. CONCLUSIONS: Our study suggested that S-ICDs can prevent sudden cardiac death in the pediatric population with a low incidence of lead complications or device infections. The number of suitable sensing vectors did not change during the patients' growth.

Clinical outcome for heart failure hospitalizations in patients with leadless pacemaker.

Introduction: The long-term performance of leadless pacemaker (LPM) has not been well evaluated. Methods: Between September 2017 and January 2021, 929 consecutive patients who underwent pacemaker implantation were grouped according to the types of pacemakers: LPM (LPM group, n = 368) and conventional pacemaker (PM group, n = 561). Results: The median follow-up duration was 1.7 years (interquartile range 0.8-2.6 years). Hospitalization rate for heart failure in the LPM group was 9.3%, 15.6%, and 21.6% at 1, 2, 3 years, respectively. The LPM group had a significantly higher adjusted heart failure hospitalization risk than the PM group [hazard ratio (HR) 1.70, 95% confidence interval (CI) 1.09-2.64, p = .01]. More patients with symptomatic bradycardia caused by sinus node dysfunction (SND) in the LPM group (n = 150) were admitted to the hospital for heart failure compared to those in the PM group (n = 219) (HR 2.02, 95%CI 1.04-3.90, p = .03), whereas no significant difference was observed between the two groups in the patients with bradycardia caused by atrial fibrillation (LPM group, n = 71; PM group, n = 18) or atrioventricular block (LPM group, n = 147; PM group, n = 324). Conclusions: Patients who received LPM implantation had greater hospitalization risk for heart failure, compared to those who received conventional pacemaker implantation. The increased risk was mainly attributed to patients with SND.

The hemodynamic effect of simulated atrial fibrillation on left ventricular function.

INTRODUCTION: Atrial fibrillation (AF) is the most common sustained arrhythmia in humans. The onset of the arrhythmia can significantly impair cardiac function. This hemodynamic deterioration has been explained by several mechanisms such as the loss of atrial contraction, shortening of ventricular filling, or heart rhythm irregularity. This study sought to evaluate the relative hemodynamic contribution of each of these components during in vivo simulated human AF. METHODS: Twelve patients undergoing catheter ablation for paroxysmal AF were paced simultaneously from the proximal coronary sinus and the His bundle region according to prescribed sequences of irregular R-R intervals with the average rate of 90 and 130 bpm, which were extracted from the database of digital ECG recordings of AF from other patients. The simulated AF was compared to regular atrial pacing with spontaneous atrioventricular conduction and regular simultaneous atrioventricular pacing at the same heart rate. Beat-by-beat left atrial and left ventricular pressures, including LV dP/dT and Tau index were assessed by direct invasive measurement; beat-by-beat stroke volume and cardiac output (index) were assessed by simultaneous pulse-wave doppler intracardiac echocardiography. RESULTS: Simulated AF led to significant impairment of left ventricular systolic and diastolic function. Both loss of atrial contraction and heart rate irregularity significantly contributed to hemodynamic impairment. This effect was pronounced with increasing heart rate. CONCLUSION: Our findings strengthen the rationale for therapeutic strategies aiming at rhythm control and heart rate regularization in patients with AF.

Initial practice of left atrial appendage closure device in Japan; single-center experience.

BACKGROUND: The left atrial appendage closure (LAAC) device for patients with nonvalvular atrial fibrillation (NVAF) has recently been introduced in Japan. However, clinical data of Japanese patients are insufficient. METHODS: In this single-center study, 55 consecutive patients (mean age, 74 years) who received LAAC therapy from September 2019 to December 2020 were analyzed. The WATCHMAN implant procedure (Boston Scientific, St. Paul, MN, USA) was performed under transesophageal echocardiography and general anesthesia for all cases. RESULTS: The baseline CHA2DS2-VASc score was 4.6 ± 1.4, and the baseline HAS-BLED score was 3.8 ± 0.9. All procedures (98.2%) were successful, except for one, and no procedure-related complications were observed. After the procedures, various antithrombotic regimens were employed according to the bleeding risk of each patient; warfarin was used in 27 patients (49%), direct oral anticoagulants (DOACs) were used in 22 patients (40%), and dual antiplatelet therapy (DAPT) was employed in 6 patients. During a mean follow-up of 360 days, three cases of device-related thrombus (DRT) were detected. One DRT case was related to ischemic stroke. Nine patients had major bleeding during follow-up: two patients received DOACs, six patients received DAPT, and one patient received aspirin. CONCLUSIONS: In this initial Japanese experience, LAAC therapy for high bleeding risk patients with NVAF seems feasible. Optimal antithrombotic regimens are warranted for better clinical outcomes.

Percutaneous Left Atrial Appendage Closure in a Patient with Diffuse Alveolar Hemorrhaging Associated with Anticoagulant Therapy and Atrial Fibrillation.

Diffuse alveolar hemorrhaging (DAH) due to oral anticoagulation (OAC) is a life-threatening condition that leads to severe respiratory failure. There is a clinical dilemma in that OAC-induced DAH often forces the discontinuation of OAC therapy and the administration of high-dose corticosteroids, which increases the risk of stroke and cardiovascular events. We herein report the first case of OAC-induced DAH and atrial fibrillation (AF) in a patient who completely discontinued OAC therapy and high-dose corticosteroids after experiencing percutaneous left atrial appendage (LAA) occlusion. This case suggests that percutaneous LAA closure may aid in the management of OAC-induced DAH and AF.

Predictors of lead break during transvenous lead extraction.

BACKGROUND: The incidence, predictors, and clinical impact of lead break during transvenous lead extraction (TLE) were previously unknown. METHODS: We included consecutive patients who underwent TLE between September 2013 and July 2019 at our institute. Lead break during removal was defined as lead stretching and becoming misshapen, as assessed by fluoroscopy. RESULTS: A total of 246 patients underwent TLE for 501 leads. At a patient level, complete success was achieved in 226 patients (91.9%). At a lead level, 481 leads (96.0%) were completely removed and 101 leads (20.1%) were broken during the procedure. Of 392 identified pacemaker leads, 71 (18.3%) were broken during the TLE procedure. A multivariable analysis confirmed high lead age (odds ratio [OR] 1.12, 95% confidence interval (CI) 1.07-1.17; P < .001), passive leads (OR 2.29 95% CI 1.09-4.80; P = .028), coradial leads (OR 3.45 95% CI 1.72-6.92; P < .001), and insulators made of nonpolyurethane (OR 2.38 95% CI 1.03-5.26; P = .04) as predictors of lead break. Broken leads needed longer procedure times and were associated with a higher rate of cardiac tamponade. CONCLUSIONS: Lead age, coradial bipolar leads, passive leads, and leads without polyurethane insulation were predictors of lead break and could increase the difficulty of lead extraction.