A Dual-Chamber Leadless Pacemaker.

BACKGROUND: Single-chamber ventricular leadless pacemakers do not support atrial pacing or consistent atrioventricular synchrony. A dual-chamber leadless pacemaker system consisting of two devices implanted percutaneously, one in the right atrium and one in the right ventricle, would make leadless pacemaker therapy a treatment option for a wider range of indications. METHODS: We conducted a prospective, multicenter, single-group study to evaluate the safety and performance of a dual-chamber leadless pacemaker system. Patients with a conventional indication for dual-chamber pacing were eligible for participation. The primary safety end point was freedom from complications (i.e., device- or procedure-related serious adverse events) at 90 days. The first primary performance end point was a combination of adequate atrial capture threshold and sensing amplitude at 3 months. The second primary performance end point was at least 70% atrioventricular synchrony at 3 months while the patient was sitting. RESULTS: Among the 300 patients enrolled, 190 (63.3%) had sinus-node dysfunction and 100 (33.3%) had atrioventricular block as the primary pacing indication. The implantation procedure was successful (i.e., two functioning leadless pacemakers were implanted and had established implant-to-implant communication) in 295 patients (98.3%). A total of 35 device- or procedure-related serious adverse events occurred in 29 patients. The primary safety end point was met in 271 patients (90.3%; 95% confidence interval [CI], 87.0 to 93.7), which exceeded the performance goal of 78% (P<0.001). The first primary performance end point was met in 90.2% of the patients (95% CI, 86.8 to 93.6), which exceeded the performance goal of 82.5% (P<0.001). The mean (±SD) atrial capture threshold was 0.82±0.70 V, and the mean P-wave amplitude was 3.58±1.88 mV. Of the 21 patients (7%) with a P-wave amplitude of less than 1.0 mV, none required device revision for inadequate sensing. At least 70% atrioventricular synchrony was achieved in 97.3% of the patients (95% CI, 95.4 to 99.3), which exceeded the performance goal of 83% (P<0.001). CONCLUSIONS: The dual-chamber leadless pacemaker system met the primary safety end point and provided atrial pacing and reliable atrioventricular synchrony for 3 months after implantation. (Funded by Abbott Medical; Aveir DR i2i ClinicalTrials.gov number, NCT05252702.).

Atrioventricular Synchrony Delivered by a Dual-Chamber Leadless Pacemaker System.

BACKGROUND: A dual-chamber leadless pacemaker system has been designed for atrioventricular synchronous pacing using wireless, beat-to-beat, implant-to-implant (i2i) communication between distinct atrial and ventricular leadless pacemakers. The atrioventricular synchrony achieved across various ambulatory scenarios has yet to be systematically evaluated. METHODS: A prospective, single-arm, unblinded, multicenter, international clinical trial of the leadless pacemaker system was conducted in patients with a conventional dual-chamber pacing indication enrolled from February 2022 to March 2023. Leadless pacemaker systems were implanted, and 12-lead Holter electrocardiographic recordings were collected 3 months after implantation over various postures/activities: sitting, supine, left lateral recumbent, right lateral recumbent, standing, normal walk, and fast walk. An independent Holter core laboratory performed a manual adjudication of the percent of atrioventricular synchronous beats using the standard 300-millisecond PR interval limit. Atrium-to-ventricle and ventricle-to-atrium i2i communication success rates were also assessed. Post hoc summary statistics describing the relationships between atrioventricular synchrony and i2i success, posture/activity, implantation indication, atrioventricular event, and heart rate were calculated. RESULTS: In the evaluable population (n=384 of 464 enrolled [83%]; 61% male; age, 70 years; weight, 82 kg; 60% ejection fraction; 95% of beats evaluable), the mean atrioventricular synchrony of 98% of beats observed across all postures using the standard 300-millisecond limit was greater than both atrial-to-ventricular i2i (94%) and ventricular-to-atrial i2i (94%; P<0.001), exceeding both i2i values in 95% of patients. Atrioventricular synchrony was achieved in >95% of evaluable beats across all postures/activities, implantation indications, atrioventricular paced/sensed event combinations, and heart rate ranges (including >100 bpm). CONCLUSIONS: This dual-chamber leadless pacemaker system demonstrated atrioventricular synchrony in 98% of evaluable beats at 3 months after implantation. Atrioventricular synchrony was maintained across postures/activities and remained robust for heart rates >100 bpm.

Effect of empagliflozin on ventricular arrhythmias in patients with type 2 diabetes treated with an implantable cardioverter-defibrillator: the EMPA-ICD trial.

BACKGROUND: Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of hospitalization for heart failure and cardiovascular death with type 2 diabetes; however, their effect on arrhythmias is unclear. The purpose of this study was to investigate the effects of empagliflozin on ventricular arrhythmias in patients with type 2 diabetes. METHODS: A total of 150 patients with type 2 diabetes who were treated with an implantable cardioverter-defibrillator or cardiac resynchronization therapy defibrillator (ICD/CRT-D) were randomized to once-daily empagliflozin or placebo for 24 weeks. The primary endpoint was the change in the number of ventricular arrhythmias from the 24 weeks before to the 24 weeks during treatment. Secondary endpoints included the change in the number of appropriate device discharges and other values. RESULTS: In the empagliflozin group, the number of ventricular arrhythmias recorded by ICD/CRT-D decreased by 1.69 during treatment compared to before treatment, while in the placebo group, the number increased by 1.79. The coefficient for the between-group difference was - 1.07 (95% confidence interval [CI] - 1.29 to - 0.86; P < 0.001). The change in the number of appropriate device discharges during and before treatment was 0.06 in the empagliflozin group and 0.27 in the placebo group, with no significant difference between the groups (P = 0.204). Empagliflozin was associated with an increase in blood ketones and hematocrit and a decrease in blood brain natriuretic peptide and body weight. CONCLUSIONS: In patients with type 2 diabetes treated with ICD/CRT-D, empagliflozin reduces the number of ventricular arrhythmias compared with placebo. Trial registration jRCTs031180120.

His-Bundle Pacing for Pulmonary Hypertension With Bradycardia in Congenital Heart Disease: A Case Report.

Bradycardia, atrial tachyarrhythmia, heart failure, residual shunts, and pulmonary hypertension (PH) are significant problems after congenital heart disease surgery. We performed His-bundle pacing (HBP) for drug-resistant PH with bradycardia in a woman post-total anomalous pulmonary venous return repair complicated by bradycardia, hypertension, PH, residual atrial shunts, and heart failure. Significant improvement in PH post-HBP was achieved without exacerbation of left ventricular function. We successfully closed the atrial shunts 12 months after HBP.

A mutually communicable external system resource in remote monitoring for cardiovascular implantable electronic devices.

BACKGROUND: Using third-party resources to manage remote monitoring (RM) data from implantable cardiac electronic devices (CIEDs) can assist in device clinic workflows. However, each hospital-acquired data is not used for further analysis as big data. METHODS AND RESULTS: We developed a real-time and automatically centralized system of CIED information from multiple hospitals. If the extensive data-based analysis suggests individual problems, it can be returned to each hospital. To show its feasibility, we prospectively analyzed data from six hospitals. For example, unexpected abnormal battery levels were easily illustrated without recall information. CONCLUSIONS: The centralized RM system could be a new platform that promotes the utilization of device data as big data, and that information could be used for each patient's practice.

Outcome of transvenous lead extraction in nonagenarians: A single-center retrospective study.

BACKGROUND: Transvenous lead extraction (TLE) for cardiovascular implantable electronic device (CIED)-related infections has increased. The incidence of TLE in nonagenarians is low, with limited reports outlining the outcomes of this procedure. Therefore, in this study, we aimed to clarify the outcomes of TLE in nonagenarians. METHODS: Patients with TLE treated at our hospital between 2014 and 2023 were retrospectively examined; patient characteristics, device type, indications, procedures, complications, and clinical data of nonagenarians were analyzed. RESULTS: Of 12 patients with 24 leads (active fixation lead, n = 11; passive fixation lead, n = 13) who underwent TLE, the indication for TLE was infection (pocket infection, n = 8; sepsis, n = 4). Methicillin-resistant Staphylococcus epidermidis was the most frequently identified causative agent (n = 4). The median patient age was 91 years; five patients were female. The median lead dwell time was 9 years. Excimer laser sheath (16 leads), mechanical sheath (five leads), Evolution RL (one lead), and manual traction (two leads) were employed in TLE. The procedure was successful in all patients, and only one had a minor complication. Six patients required CIED re-implantation, and leadless pacemakers were selected for five patients. The 30-day mortality after TLE was 0%. CONCLUSION: TLE can be safely performed in nonagenarians. The decision to perform TLE should not be based on old age alone; the suitability of removing infected CIEDs should be determined based on each patient's condition.

Metabolome analysis in patients with heart failure and implantable cardioverter defibrillators.

Heart failure (HF) is a complex, heterogeneous syndrome with several comorbidities, often life-threatening and requires urgent therapy. In HF, metabolic alterations that can be assessed using comprehensive plasma, and tissue profiling will help establish new biomarkers and therapeutic targets. Metabolomic analysis of sudden death in HF cases remains unresolved. We prospectively evaluated 19 patients who underwent implantable cardioverter defibrillator (ICD) placement for the primary prevention of sudden cardiac death (SCD). Metabolomic analysis was performed using plasma samples before ICD implantation. Ventricular arrhythmia (VA)/SCD was defined as VA with an appropriate ICD therapy or SCD. During a median follow-up of 29 months (range, 13-35 months), four patients developed VA and one patient developed SCD. Using metabolomic analysis, arginine, lysine, and valine were significantly reduced in patients with VA/SCD (n = 5) compared with those without VA/SCD (n = 14). The molecules involved in energy metabolism might be associated with VA/SCD, thus requiring further investigation as a predictive value of metabolomic analysis of VA/SCD.

Comparative analysis of recurrence predictors and outcomes for atrial tachyarrhythmia following atrial fibrillation ablation: high-power short-duration vs. conventional pulmonary vein isolation.

Atrial fibrillation (AF) is a common cardiac arrhythmia, with structural and electrical remodeling being significant risk factors for recurrence post-catheter ablation. The advent of high-power short-duration pulmonary vein isolation (HPSD-PVI) presents a novel approach, potentially enhancing procedural success rates through the creation of transmural lesions without overheating. This study investigates the predictors of atrial tachyarrhythmia (ATA) recurrence and compares outcomes between HPSD-PVI and conventional PVI techniques. A total of 1005 patients undergoing radiofrequency catheter ablation (RFA) for AF were retrospectively analyzed in this study. The cohort was divided based on the ablation strategy: conventional PVI from February 2013 to September 2018, and HPSD-PVI from October 2018 onwards. The primary objective was to compare the predictors of ATA recurrence and the outcome between the two groups. Among 969 patients analyzed after exclusions, independent predictors of recurrence differed between groups; higher CHADS2/CHA2DS2-VASc scores and lower left ventricular ejection fraction (LVEF) were significant in the HPSD-PVI group, while non-paroxysmal AF, larger left atrial volume index (LAVI), and longer AF history were predictors in the conventional PVI group. The HPSD-PVI group showed a trend toward lower ATA recurrence rates compared to the conventional PVI group in the propensity-score-matched (PSM) cohort (log-rank test, p = 0.06). Higher CHADS2/CHA2DS2-VASc scores and lower LVEF were also independent predictors of ATA recurrence in the PSM cohort.

Prolonged T-peak to T-end Interval Predicts Implantable Cardioverter Defibrillator Therapy in Patients With Cardiac Sarcoidosis.

BACKGROUND: The association between the T-peak to T-end interval (Tp-e) and ventricular arrhythmia (VA) events in cardiac sarcoidosis (CS) is unknown. The purpose of this study was to investigate whether Tp-e was associated with VA events in CS patients with implantable cardioverter defibrillators (ICDs) or cardiac resynchronization therapy defibrillators (CRT-Ds).Methods and Results: We retrospectively studied 50 patients (16 men; mean [±SD] age 56.3±10.5 years) with CS and ICD/CRT-D. The maximum Tp-e in the precordial leads recorded by a 12-lead electrocardiogram after ICD/CRT-D implantation was evaluated. The clinical endpoint was defined as appropriate ICD therapy. During a median follow-up period of 85.0 months, 22 patients underwent appropriate therapy and 10 patients died. Kaplan-Meier analysis revealed that the probability of the clinical endpoint was 28.3% at 2 years and 35.3% at 4 years. The optimal cut-off value of the Tp-e for the prediction of the clinical endpoint was 91 ms, with a sensitivity of 72.7% and a specificity of 87.0% (area under the curve=0.81). Multivariate Cox regression analysis showed that Tp-e ≥91 ms (hazard ratio [HR] 5.10; 95% confidence interval [CI] 1.99-13.1; P<0.001) and a histological diagnosis of CS (HR 3.84; 95% CI 1.28-11.5; P=0.016) were significantly associated with the clinical endpoint. CONCLUSIONS: Tp-e ≥91 ms was a significant predictor of VA events in patients with CS and ICD/CRT-D.

Safety and Performance of the Micra VR Leadless Pacemaker in a Japanese Cohort　- Comparison With Global Studies.

BACKGROUND: The Micra leadless pacemaker has demonstrated favorable outcomes in global trials, but its real-world performance and safety in a Japan-specific population is unknown.Methods and Results: Micra Acute Performance (MAP) Japan enrolled 300 patients undergoing Micra VR leadless pacemaker implantation in 15 centers. The primary endpoint was the acute (30-day) major complication rate. The 30-day and 6-month major complication rates were compared to global Micra studies. All patients underwent successful implantation with an average follow-up of 7.23±2.83 months. Compared with previous Micra studies, Japanese patients were older, smaller, more frequently female, and had a higher pericardial effusion risk score. 11 acute major complications were reported in 10 patients for an acute complication rate of 3.33% (95% confidence interval: 1.61-6.04%), which was in line with global Micra trials. Pericardial effusion occurred in 4 patients (1.33%; 3 major, 1 minor). No procedure or device-related deaths occurred. Frailty significantly improved from baseline to follow-up as assessed by Japan Cardiovascular Health Study criteria. CONCLUSIONS: In a Japanese cohort, implantation of the Micra leadless pacemaker had a high success rate and low major complication rate. Despite the Japan cohort being older, smaller, and at higher risk, the safety and performance was in line with global Micra trials.

Lead switching to resolve undersensing of ventricular tachycardia by a cardiac resynchronization therapy defibrillator.

A 63-year-old man was admitted to the hospital due to ventricular tachycardia (VT) undersensing, caused by decreased R-wave amplitude in a cardiac resynchronization therapy defibrillator. The R-wave amplitude of VT sensed by the left ventricular (LV) lead was markedly higher than that by the right ventricular (RV) lead; therefore, we reconnected the IS-1 RV lead to the LV IS-1 port and the IS-1 LV lead to the RV IS-1 port to resolve this issue. After discharge, it was confirmed that VT was successfully terminated by the second sequence of intrinsic ATP (iATP, Medtronic, Minneapolis, MN, USA) from the LV lead.

Impact of the timing of first appropriate shock on outcomes in patients with an implantable cardioverter-defibrillator: Early versus late.

BACKGROUND: Appropriate implantable cardioverter-defibrillator (ICD) shocks are associated with an increased risk of mortality and heart failure (HF) events. The first appropriate shock may occur late after implantation. However, whether the timing of the first appropriate shock influences prognosis is unknown. This study aimed to evaluate the clinical significance of the timing of the first appropriate shock in patients with ICD. METHODS: This retrospective and observational study enrolled 565 consecutive ICD patients. Patients who received an appropriate shock were divided into the early group (first appropriate shock <1 year after ICD implantation) and late group (first appropriate shock ≥1 year after ICD implantation). All-cause mortality was compared between the two groups. RESULTS: Over a median follow-up of 5.6 years, 112 (19.8%) patients received an appropriate shock, including 32 patients (28.6%) in the early group and 80 patients (71.4%) in the late group. Comparisons of baseline characteristics at ICD implantation revealed that the late group was more likely to receive cardiac resynchronization therapy (66.3% vs. 31.3%, p < 0.001), ICD for primary prevention (60.0% vs. 31.3%, p = 0.001), and angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker treatment (88.8% vs. 71.9%, p = 0.028). Survival after shock was significantly worse in the late group than in the early group (p = 0.027). In multivariable Cox proportional hazards analysis, the late group had an increased risk of all-cause mortality compared with the early group (HR: 2.22; 95% CI 1.01-4.53; p = 0.029). In both groups, the most common cause of death was HF. CONCLUSIONS: Late occurrence of the first appropriate ICD shock was associated with a worse prognosis compared with early occurrence of the first appropriate shock. Cardiac death was the most common cause of death in patients who experienced late occurrence of the first appropriate ICD shock, resulting from HF in most cases.

Prognostic significance of cardiorenal dysfunction within 1 year after atrial fibrillation ablation in patients with systolic dysfunction.

Atrial fibrillation (AF) ablation can improve left ventricular ejection fraction (LVEF) and renal function and can even reduce mortality in patients with impaired LVEF. However, the effect of post-ablation cardiorenal dysfunction on the prognosis of patients with impaired LVEF who underwent AF ablation remains unclear. Of the 1243 consecutive patients undergoing AF ablation, the prognosis of 163 non-dialysis patients who underwent AF ablation with < 50% LVEF was evaluated. The primary outcome was a composite of all-cause mortality, heart failure hospitalization, and a need for modification of the treatment for heart failure. During the median follow-up of 4.2 years after the first AF ablation procedure, the primary outcome occurred in 30 of 163 patients (18%). The receiver operating characteristic curve analysis demonstrated that the post-LVEF (LVEF within 1 year after the procedure, and before the occurrence of primary outcome) had larger areas under the curve (0.70) than the pre-LVEF (LVEF before the procedure), and the most optimal cutoff value was LVEF ≤ 42%. Multivariate analysis demonstrated that patients with post-LVEF ≤ 42% and worsening renal function (WRF; an absolute increase in serum creatinine [SCr] ≥ 0.3 mg/dL compared with the SCr at baseline within 1 year after the procedure and before the occurrence of primary outcome) had a 3.4- to 4.3-fold and 3.4- to 3.7-fold higher risk of the primary outcome compared with those without these predictors, respectively. Patients were categorized using post-LVEF ≤ 42% and WRF as follows: group 1 (post-LVEF > 42% without WRF), group 2 (post-LVEF ≤ 42% without WRF), group 3 (post-LVEF > 42% with WRF), and group 4 (post-LVEF ≤ 42% with WRF). Group 4 had a 15.8-fold (P = 0.0001) higher risk of the primary outcome compared with group 1 after adjusting for pre-procedural factors. In patients with impaired LVEF undergoing AF ablation, post-LVEF ≤ 42% and WRF were independent predictors of poor prognosis. The combination of post-LVEF ≤ 42% and WRF is strongly associated with a poor prognosis in patients with AF undergoing ablation, who with these post-ablation cardiorenal dysfunction may have to be treated more intensively after AF ablation.

Impact of signal-averaged electrocardiography findings on appropriate shocks in prophylactic implantable cardioverter defibrillator patients with nonischemic systolic heart failure.

BACKGROUND: Appropriate shock therapy is associated with subsequent all-cause death in heart failure (HF) patients who receive an implantable cardioverter defibrillator (ICD) for the primary prevention of sudden cardiac death. To evaluate the impact of signal-averaged electrocardiography (SAECG) findings on appropriate shocks in prophylactic ICD patients with nonischemic systolic HF. METHODS: We studied 86 patients with nonischemic HF and a left ventricular ejection fraction ≤ 35% who underwent new ICD implantation for the primary prevention of sudden cardiac death. We excluded patients who had a previously implanted permanent pacemaker and patients who received cardiac resynchronization therapy with an ICD. SAECG was performed before implantation. Abnormal SAECG findings were defined if 2 of the following 3 conditions were identified: filtered QRS duration (fQRS) ≥ 114 ms, root-mean-square voltage during the last 40 ms of the fQRS (RMS 40) < 20 µV, and duration of the low-amplitude potentials < 40 µV (LAS 40) > 38 ms; additionally, patients with a QRS complex ≥ 120 ms who met both the RMS 40 and LAS 40 criteria were also considered to have abnormal SAECG findings. The primary outcome was the first occurrence of appropriate shock after implantation of the ICD. The secondary outcomes were the first occurrence of inappropriate shock and all-cause mortality. RESULTS: Forty-two patients met the criteria for abnormal SAECG findings (49%). During a median follow-up period of 61 months, 17 patients (20%) died, 24 (28%) received appropriate shock therapy, and 19 (22%) received inappropriate shock therapy. There was a significantly higher incidence of appropriate shocks in patients with abnormal SAECG findings than in those with normal SAECG findings (log-rank test, p = 0.025). Multivariate analysis revealed that abnormal SAECG findings were independently associated with the occurrence of appropriate shock (hazard ratio 2.67, 95% confidential interval 1.14-6.26). However, abnormal SAECG findings were not related to inappropriate shock. There was no difference in the incidence of all-cause death between patients with abnormal and normal SAECG findings. CONCLUSIONS: Our results suggest that abnormal SAECG findings are associated with a high probability of appropriate shocks in prophylactic ICD patients with nonischemic systolic HF.

Efficacy of catheter ablation for patients with atrial fibrillation and atrial septal defect.

INTRODUCTION: Given that few studies investigated the efficacy of catheter ablation (CA) in patients with paroxysmal atrial fibrillation (AF) and atrial septal defect (ASD), this study evaluated its effectiveness in patients with paroxysmal AF and ASD. METHODS AND RESULTS: Of the 216 patients who underwent ASD device closure at two hospitals, 36 patients had paroxysmal AF. After April 2012, CA for AF was performed before ASD device closure (ASD-CA group; n = 20). The ASD-CA group had a significantly higher AF-free survival rate after ASD device closure compared to patients without CA for AF before ASD device closure (ASD-non-CA group; n = 16) (ASD-CA group: 2 patients vs. ASD-non-CA group: 9 patients; follow-up period: 4.2 ± 2.5 years; log-rank p = .01). In addition, the AF-free survival rates were similar between the ASD-CA group and 80 paroxysmal AF patients who underwent CA without any detectable structural heart disease (non-SHD-CA group). The two groups were matched by propensity scores for age, sex, and left atrium dimension (ASD-CA group: 2 patients vs. non-SHD-CA group: 5 patients; follow-up period: 3.3 ± 1.8 years; log-rank p = .28). CONCLUSION: CA for AF before ASD device closure might be an effective treatment option for patients with paroxysmal AF and ASD.

Technical Features and Clinical Outcomes of Coronary Venous Left Ventricular Lead Removal and Reimplantation.

BACKGROUND: The number of patients undergoing cardiac resynchronization therapy has increased. Consequently, there is increased frequency in the removal and reimplantation of coronary venous (CV) leads due to infection or malfunction.Methods and Results:A total of 345 consecutive patients referred for lead(s) extraction were reviewed. Of these, 34 patients who underwent a CV lead removal were investigated. The indications for CV leads removal were device-related infections in 29 patients and lead malfunctions in 5 patients. The average duration of the CV leads was 4.1±3.8 years. All CV leads were successfully removed without any major complications, except for 1 in-hospital death. Successful CV lead removal by simple traction (ST) was achieved in 21 patients (62%), whereas extraction tools were required in 13 patients (38%). Local infection and CV lead dwell time were significantly associated with successful ST (P=0.04 and P=0.014, respectively). CV lead re-implantation was successfully performed in 25 patients; however, a right-side approach was required in 92%, and occlusion/stenosis of the previous CV was observed in 80% of the patients. CONCLUSIONS: CV lead removal is relatively successful and safe. The presence of local infection and a shorter lead duration may enable successful ST of a CV lead. However, the re-implantation procedure should be well prepared for the complexity related to the right-side approach and occlusion/stenosis of the previous CV.

Left intraventricular pressure gradient in hypertrophic cardiomyopathy patients receiving implantable cardioverter-defibrillators for primary prevention.

BACKGROUND: Conventional risk factors for sudden cardiac death (SCD) justify primary prevention through implantable cardioverter-defibrillator (ICD) implantation in hypertrophic cardiomyopathy (HCM) patients. However, the positive predictive values for these conventional SCD risk factors are low. Left ventricular outflow tract obstruction (LVOTO) and midventricular obstruction (MVO) are potential risk modifiers for SCD. The aims of this study were to evaluate whether an elevated intraventricular pressure gradient (IVPG), including LVOTO or MVO, is a potential risk modifier for SCD and ventricular arrhythmias requiring ICD interventions in addition to the conventional risk factors among HCM patients receiving ICDs for primary prevention. METHODS: We retrospectively studied 60 HCM patients who received ICDs for primary prevention. An elevated IVPG was defined as a peak instantaneous gradient ≥ 30 mmHg at rest, as detected by continuous-wave Doppler echocardiography. The main outcome was a composite of SCD and appropriate ICD interventions, which were defined as an antitachycardia pacing or shock therapy for ventricular tachycardia or fibrillation. The Cox proportional hazards model was used to assess the relationships between risk factors and the occurrence of SCD and appropriate ICD interventions. RESULTS: Thirty patients met the criteria of elevated IVPG (50%). During the median follow-up period of 66 months, 2 patients experienced SCD, and 10 patients received appropriate ICD interventions. Kaplan-Meier curves showed that the incidence of the main outcome was higher in patients with an IVPG ≥ 30 mmHg than in those without an IVPG ≥ 30 mmHg (log-rank P = 0.03). There were no differences in the main outcome between patients with LVOTO and patients with MVO. The combination of nonsustained ventricular tachycardia (NSVT) and IVPG ≥ 30 mmHg was found to significantly increase the risk of the main outcome (HR 6.31, 95% CI 1.36-29.25, P = 0.02). Five patients experienced ICD implant-related complications. CONCLUSIONS: Our findings showed that a baseline IVPG ≥ 30 mmHg was associated with an increased risk of experiencing SCD or appropriate ICD interventions among HCM patients who received ICDs for primary prevention. Combined with NSVT, which is a conventional risk factor, a baseline IVPG ≥ 30 mmHg may be a potential modifier of SCD risk in HCM patients.

Transaortic cryoablation of uncommon atrioventricular nodal reentrant tachycardia after Senning and Rastelli operations.

A 36-years-old woman with a congenital corrected transposition of the great arteries, who underwent Senning and Rastelli operations, was admitted with a symptomatic supraventricular tachycardia. During an electrophysiological study, uncommon atrioventricular (AV) nodal reentrant tachycardia was induced. The coronary veins and coronary sinus did not connect to the systemic venous atrium. The His bundle electrogram (HBE) was recorded at the anterior septum of the mitral valve via the aorta. The target of ablation was the site of the earliest atrial activation during the tachycardia, 5 mm posterior to the AV node, and a successful cryoablation was performed using a transaortic approach. Both the antegrade and retrograde conduction of the slow AV nodal pathway was eliminated.

Transvenous shock-only implantable cardioverter defibrillator after an atrio-pulmonary Fontan surgery.

A 42-year-old woman with tricuspid atresia who underwent a Fontan surgery (atrio-pulmonary connection) was admitted to our hospital due to symptomatic ventricular tachycardia (VT). A defibrillation lead was implanted in a distal site of a coronary vein since there was no usual entry to the ventricle. Ventricular pacing was impossible due to the high threshold, however, good sensing was obtained. Three years later, she felt palpitations and a subsequent shock therapy while climbing stairs. The cardioverter data showed that an appropriate cardioversion therapy successfully converted VT to normal rhythm.

Safe and effective transvenous lead extraction for elderly patients utilizing non-laser and laser tools: a single-center experience in Japan.

Transvenous lead extraction (TLE) for cardiac implantable electric device (CIED) infection is becoming increasingly common, but is believed to be particularly risky in elderly patients. This study aimed to clarify the safety and effectiveness of TLE in the elderly, evaluating the use of both non-laser and laser extraction tools. We retrospectively analyzed the characteristics, device type, indications, procedures, and clinical results in younger (YG; age: 15-79 years; n = 48) and elderly groups (EG; age: ≥ 80 years; n = 27) of patients who underwent percutaneous TLE between April 2014 and December 2019 at our hospital. The average age was 68 and 88 years in the YG and EG, respectively. Indications for TLE were infection in 33 (68.8%) patients and other in 15 (30.6%) patients in the YG, and infection in all 27 (100%) EG patients. Bloodstream infection was detected in 9 and 4 patients in the YG and EG, respectively, with methicillin-resistant Staphylococcus epidermidis being the most common causative pathogen. All TLE procedures were performed under general anesthesia in an operating room with cardiovascular surgeon backup. An excimer laser sheath (76 leads), a laser followed by a mechanical sheath (45 leads), Evolution RL® (17 leads), a mechanical sheath (9 leads), and manual traction (one lead) were employed to extract a total of 148 leads (98 and 50 in the YG and EG, respectively). A mechanical sheath or Evolution RL® was more frequently used in the YG. The respective average implantation durations in the YG and EG were 5.3 and 5.0 years, respectively, which were comparable (p = 0.46). Procedural success rates were identical between the YG and EG (99% vs. 100%, respectively). There was only one procedure-related complication in the entire cohort (cardiac tamponade in a YG patient). Taken together, the success rates of TLE were high in the EG, with no complications, with extraction being the indication for infection in all EG patients. Percutaneous TLE was safe and effective in elderly patients using both non-laser and laser techniques.