Cha, Yong-Mei

Abstract Background and Aims Prior reports have demonstrated a favourable safety and efficacy profile of the Micra leadless pacemaker over mid-term follow-up; however, long-term outcomes in real-world clinical practice remain unknown. Updated performance of the Micra VR leadless pacemaker through five years from the worldwide post-approval registry (PAR) was assessed. Methods All Micra PAR patients undergoing implant attempts were included. Endpoints included system- or procedure-related major complications and system revision rate for any cause through 60 months post-implant. Rates were compared through 36 months post-implant to a reference dataset of 2667 transvenous pacemaker patients using Fine–Gray competing risk models. Results 1809 patients were enrolled between July 2015 and March 2018 and underwent implant attempts from 179 centres in 23 countries with a median follow-up period of 51.1 months (IQR: 21.6–64.2). The major complication rate at 60 months was 4.5% [95% confidence interval (CI): 3.6%–5.5%] and was 4.1% at 36 months, which was significantly lower than the 8.5% rate observed for transvenous systems (HR: .47, 95% CI: .36–.61; P < .001). The all-cause system revision rate at 60 months was 4.9% (95% CI: 3.9%–6.1%). System revisions among Micra patients were mostly for device upgrades (41.2%) or elevated thresholds (30.6%). There were no Micra removals due to infection noted over the duration of follow-up. At 36 months, the system revision rate was significantly lower with Micra vs. transvenous systems (3.2% vs. 6.6%, P < .001). Conclusions Long-term outcomes with the Micra leadless pacemaker continue to demonstrate low rates of major complications and system revisions and an extremely low incidence of infection.

AbstractIntroductionLeft bundle branch area pacing (LBBP) is a novel conduction system pacing method to achieve effective physiological pacing and an alternative to cardiac resynchronization therapy (CRT) with biventricular pacing (BVP) for patients with heart failure with reduced ejection fraction (HFrEF). We conduted this meta‐analysis and systemic review to review current data comparing BVP and LBBP in patients with HFrEF and indications for CRT.MethodsWe searched PubMed/Medline, Web of Science, and Cochrane Library from the inception of the database to November 2022. All studies that compared LBBP with BVP in patients with HFrEF and indications for CRT were included. Two reviewers performed study selection, data abstraction, and risk of bias assessment. We calculated risk ratios (RRs) with the Mantel–Haenszel method and mean difference (MD) with inverse variance using random effect models. We assessed heterogeneity using the I2 index, with I2 > 50% indicating significant heterogeneity.ResultsTen studies (9 observational studies and 1 randomized controlled trial; 616 patients; 15 centers) published between 2020 and 2022 were included. We observed a shorter fluoroscopy time (MD: 9.68, 95% confidence interval [CI]: 4.49–14.87, I2 = 95%, p < .01, minutes) as well as a shorter procedural time (MD 33.68, 95% CI: 17.80–49.55, I2 = 73%, p < .01, minutes) during the implantation of LBBP CRT compared to conventional BVP CRT. LBBP was shown to have a greater reduction in QRS duration (MD 25.13, 95% CI: 20.06–30.20, I2 = 51%, p < .01, milliseconds), a greater left ventricular ejection fraction improvement (MD: 5.80, 95% CI: 4.81–6.78, I2 = 0%, p < .01, percentage), and a greater left ventricular end‐diastolic diameter reduction (MD: 2.11, 95% CI: 0.12–4.10, I2 = 18%, p = .04, millimeter). There was a greater improvement in New York Heart Association function class with LBBP (MD: 0.37, 95% CI: 0.05–0.68, I2 = 61%, p = .02). LBBP was also associated with a lower risk of a composite of heart failure hospitalizations (HFH) and all‐cause mortality (RR: 0.48, 95% CI: 0.25–0.90, I2 = 0%, p = .02) driven by reduced HFH (RR: 0.39, 95% CI: 0.19–0.82, I2 = 0%, p = .01). However, all‐cause mortality rates were low in both groups (1.52% vs. 1.13%) and similar (RR: 0.98, 95% CI: 0.21–4.68, I2 = 0%, p = .87).ConclusionThis meta‐analysis of primarily nonrandomized studies suggests that LBBP is associated with a greater improvement in left ventricular systolic function and a lower rate of HFH compared to BVP. There was uniformity of these findings in all of the included studies. However, it would be premature to conclude based solely on the current meta‐analysis alone, given the limitations stated. Dedicated, well‐designed, randomized controlled trials and observational studies are needed to elucidate better the comparative long‐term efficacy and safety of LBBP CRT versus BIV CRT.

AbstractIntroductionData regarding ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation in patients with aortic valve (AV) intervention (AVI) is limited. Catheter ablation (CA) can be challenging given perivalvular substrate in the setting of prosthetic valves. We sought to investigate the characteristics, safety, and outcomes of CA in patients with prior AVI and ventricular arrhythmias (VA).MethodsWe identified consecutive patients with prior AVI (replacement or repair) who underwent CA for VT or PVC between 2013 and 2018. We investigated the mechanism of arrhythmia, ablation approach, perioperative complications, and outcomes.ResultsWe included 34 patients (88% men, mean age 64 ± 10.4 years, left ventricular (LV) ejection fraction 35.2 ± 15.0%) with prior AVI who underwent CA (22 VT; 12 PVC). LV access was obtained through trans‐septal approach in all patients except one patient who had percutaneous transapical access. One patient had combined retrograde aortic and trans‐septal approach. Scar‐related reentry was the dominant mechanism of induced VTs. Two patients had bundle branch reentry VTs. In the VT group, substrate mapping demonstrated heterogeneous scar that involved the peri‐AV area in 95%. Despite that, the site of successful ablation included the periaortic region only in 6 (27%) patients. In the PVC group, signal abnormalities consistent with scar in the periaortic area were noted in 4 (33%) patients. In 8 (67%) patients, the successful site of ablation was unrelated to the periaortic area. No procedure‐related complications occurred. The survival and recurrence‐free survival rate at 1 year tended to be lower in VT group than in PVC group (p = .06 and p = .05, respectively) with a 1‐year recurrence‐free survival rate of 52.8% and 91.7%, respectively. No arrhythmia‐related death was documented on long‐term follow‐up.ConclusionCA of VAs can be performed safely and effectively in patients with prior AVI.

AbstractAimsIntraoperative defibrillation testing (DT) during implant or replacement of implantable cardioverter-defibrillators (ICDs) has been a matter of debate for many years. This debate was put to rest by the Simple and Nordic ICD trials, and the practice of testing during new implantations has essentially been almost abandoned. Old registries demonstrated an increased incidence of significant findings in DT during replacements. The aim of the present study was to evaluate frequency of significant findings and safety of DT in subjects undergoing device replacement.Methods and resultsA prospective observational multi-centre study included consecutive patients undergoing ICD generator replacement. The primary outcome was a failure to terminate induced ventricular fibrillation (VF) with a single shock 10 J below the maximal capacity of the device. Secondary outcomes included complications of DT. Patients were followed-up at 1- and 6-months post-procedure. A total of 92 patients were eligible, and consented to the study, of which 84 underwent DT during battery replacement. The median age was 68 years and 79.8% were males. Induction of VF was successful in 84 patients as was a successful conversion on the first attempt in all. There were no procedure-related complications. During follow up one patient had two appropriate ICD shock events. In four patients, ICD programming was changed. None suffered inappropriate shock. There was no evidence of lead malfunction. Two deaths occurred, none of which was related to arrhythmia.ConclusionThe present study found DT was not associated with complications in patients undergoing ICD generator replacement but produced no clinically important information.

AbstractIntroductionA wearable cardioverter defibrillator (WCD) is indicated in appropriate patients to reduce the risk for sudden cardiac death. Challenges for patients wearing a WCD have been frequent false shock alarms primarily due to electrocardiogram noise and wear discomfort. The objective of this study was to test a contemporary WCD designed for reduced false shock alarms and improved comfort.MethodsOne hundred and thirty patients with left ventricular ejection fraction ≤40% and an active implantable cardioverter defibrillator (ICD) were fitted with the ASSURE WCD (Kestra Medical Technologies) and followed for 30 days. WCD detection was enabled and shock alarm markers recorded, but shocks and shock alarms were disabled. All WCD episodes and ICD ventricular tachycardia/ventricular fibrillation (VT/VF) episodes were adjudicated. The primary endpoint was the false‐positive shock alarm rate with a performance goal of 1 every 3.4 days (0.29 per patient‐day).ResultsOf 163 WCD episodes, 4 were VT/VF and 159 non‐VT/VF (121 rhythms with noise, 32 uncertain with noise, 6 atrial flutter without noise). Only three false‐positive shock alarm markers were recorded; one false‐positive shock alarm every 1333 patient‐days (0.00075 per patient‐day, 95% confidence interval: 0.00015–0.00361; p < .001). No ICD recorded VT/VF episodes meeting WCD detection criteria (≥170 bpm for ≥20 s) were missed by the WCD during 3501 patient‐days of use. Median wear was 31.0 days (interquartile range [IQR] 2.0) and median daily use 23.0 h (IQR 1.7). Adverse events were mostly mild: skin irritation (19.4%) and musculoskeletal discomfort (8.5%).ConclusionThe ASSURE WCD demonstrated a low false‐positive shock alarm rate, low patient‐reported discomfort, and no serious adverse events.

AbstractBackgroundWhile ventricular tachycardia (VT) in the setting of postmyocardial infarction left ventricular aneurysms (LVA) is not uncommonly encountered, there is a scarcity of data regarding the safety, efficacy, and outcomes of ablation of VT in this subset of patients.MethodsOur study included consecutive patients aged 18 years or older with postmyocardial infarction LVA who presented to Mayo Clinic for catheter ablation of VT between 2002 and 2018.ResultsOf 34 patients, the mean age was 70.4 ± 9.1 years; 91% were male. Mean LVEF was 29 ± 9.7% and left ventricular end‐diastolic dimension was 64.9 ± 6.6 mm. The site of the LVA was apical in 21 patients (62%). Fifteen patients (44%) presented with electrical storm or incessant VT. Nine patients (26%) had a history of intracardiac thrombus. All except for one patient had at least one VT originating from the aneurysm. The mean number of VTs was 2.9 ± 1.7. All patients underwent ablation at the site of the aneurysm. Ablation outside the aneurysm was performed in 13 patients (38%). Low‐voltage fractionated potentials and/or late potentials at the aneurysmal site were present in all cases. Complete elimination of all VTs was achieved in 18 (53%), while the elimination of the clinical VT with continued inducibility of nonclinical VTs was achieved in a further 11 patients (32%). Two patients developed cardiac tamponade requiring pericardiocentesis. During a mean follow‐up period of 2.3 ± 2.4 years, 11 patients (32%) experienced VT recurrence. Freedom from all‐cause mortality at 1‐year follow‐up was 94%.ConclusionRadiofrequency catheter ablation targeting the aneurysmal site is a feasible and reasonably effective management strategy for clinical VTs in patients with postinfarction LVA.

AbstractIntroductionThe efficacy of cardiac resynchronization therapy (CRT) has been widely studied in the medical literature; however, about 30% of candidates fail to respond to this treatment strategy. Smart computational approaches based on clinical data can help expose hidden patterns useful for identifying CRT responders.MethodsWe retrospectively analyzed the electronic health records of 1664 patients who underwent CRT procedures from January 1, 2002 to December 31, 2017. An ensemble of ensemble (EoE) machine learning (ML) system composed of a supervised and an unsupervised ML layers was developed to generate a prediction model for CRT response.ResultsWe compared the performance of EoE against traditional ML methods and the state‐of‐the‐art convolutional neural network (CNN) model trained on raw electrocardiographic (ECG) waveforms. We observed that the models exhibited improvement in performance as more features were incrementally used for training. Using the most comprehensive set of predictors, the performance of the EoE model in terms of the area under the receiver operating characteristic curve and F1‐score were 0.76 and 0.73, respectively. Direct application of the CNN model on the raw ECG waveforms did not generate promising results.ConclusionThe proposed CRT risk calculator effectively discriminates which heart failure (HF) patient is likely to respond to CRT significantly better than using clinical guidelines and traditional ML methods, thus suggesting that the tool can enhanced care management of HF patients by helping to identify high‐risk patients.

AbstractBackgroundOptimal timing of cardiovascular implantable electronic device (CIED) re‐implantation following device removal due to infection is undefined. Multinational guidelines reflect this and include no specific recommendation for this timing, while others have recommended waiting at least 14 days in cases of CIED related infective endocarditis (CIED‐IE). The current work seeks to clarify this issue.MethodsWe retrospectively reviewed institutional data at Mayo Clinic, Minnesota of patients aged ≥ 18 years who developed CIED‐IE from January 1, 1991 to February 1, 2016. CIED‐IE was defined as echocardiogram reported device lead or valvular vegetation. Regression analyses were used to relate the risk of clinical outcomes to the interval between CIED removal and re‐implantation and the location of vegetations.ResultsA total of 109 patients met study inclusion criteria. A majority (68.8%) of patients were men and the median age was 68.0 years. Transoesophageal echocardiogram (TEE) was performed in 95.4% of patients, with valve vegetations detected in 33.9% (n = 37). Survival analysis comparing patients in whom device re‐implantation was < 14 days vs. ≥14 days, and further categorized by those with and without valve vegetation, showed a significant difference (P = 0.028); patients with valve vegetation and reimplantation interval < 14 days had the lowest (58.7%) 12‐month survival. When adjusted for valve vegetation, longer time interval for reimplantation trended toward increased hospital length of stay (P = 0.079).ConclusionOur findings suggest that the recommended 14‐day delay between CIED extraction and re‐implantation in CIED‐IE patients is associated with a survival benefit, but longer length of hospital stay following re‐implantation.

AbstractBackgroundThe subcutaneous implantable cardioverter‐defibrillator (S‐ICD) has a larger generator and its implantation involves more dissection and tunneling compared to traditional transvenous defibrillator system. Liposomal bupivacaine, an extended‐release bupivacaine with 72 h of duration has been used for postoperative pain management in patients undergoing S‐ICD implantation. Our aim was to compare postoperative pain and opioid prescription patterns among patients undergoing S‐ICD implantation who received intraprocedural liposomal bupivacaine and those who did not.MethodsWe performed a retrospective analysis of all patients who underwent subcutaneous ICD implantation from January 1, 2013 to March 30, 2018 at the Mayo Clinic in Rochester, Minnesota. Patients were categorized into those who received liposomal bupivacaine and those who did not. Data on inpatient pain score, outpatient opioid prescription rates at discharge, and doses based on oral morphine equivalents (OME) were collected.ResultsA total of 104 patients underwent S‐ICD implantation. Intraprocedural liposomal bupivacaine was used in 69% of patients. Patients who received intraprocedural liposomal bupivacaine had similar mean inpatient pain scores (2.9 vs. 2.9, p = .786). There was also no difference in the rate of inpatient opioid administration (79.2% vs. 87.5%, p = .4139), outpatient opioid prescription (23.6% vs. 12.5%, p = .29), or mean OME (41.7‐mg vs. 16.6‐mg, p = .188) when comparing patients those who received intraprocedural liposomal bupivacaine and those who did not.ConclusionIntraprocedural liposomal bupivacaine administration was not associated with any significant impact on postoperative pain scores, inpatient opioid administration, and outpatient opioid prescription rates or OME amounts at discharge.