Shen, Win‐Kuang

Aims:Increased left ventricular (LV) wall thickness is frequently encountered in transthoracic echocardiography (TTE). While accurate and early diagnosis is clinically important, given the differences in available therapeutic options and prognosis, an extensive workup is often required to establish the diagnosis. We propose the first echo-based, automated deep learning model with a fusion architecture to facilitate the evaluation and diagnosis of increased left ventricular (LV) wall thickness. Methods and Results: Patients with an established diagnosis of increased LV wall thickness (hypertrophic cardiomyopathy (HCM), cardiac amyloidosis (CA), and hypertensive heart disease (HTN)/others) between 1/2015 and 11/2019 at Mayo Clinic Arizona were identified. The cohort was divided into 80%/10%/10% for training, validation, and testing sets, respectively. Six baseline TTE views were used to optimize a pre-trained InceptionResnetV2 model. Each model output was used to train a meta-learner under a fusion architecture. Model performance was assessed by multiclass area under the receiver operating characteristic curve (AUROC). A total of 586 patients were used for the final analysis (194 HCM, 201 CA, and 191 HTN/others). The mean age was 55.0 years, and 57.8% were male. Among the individual view-dependent models, the apical 4-chamber model had the best performance (AUROC: HCM: 0.94, CA: 0.73, and HTN/other: 0.87). The final fusion model outperformed all the view-dependent models (AUROC: HCM: 0.93, CA: 0.90, and HTN/other: 0.92). Conclusion: The echo-based InceptionResnetV2 fusion model can accurately classify the main etiologies of increased LV wall thickness and can facilitate the process of diagnosis and workup.

AbstractIntroductionBrugada syndrome is an inherited arrhythmic disease associated with major arrhythmic events (MAE). The importance of primary prevention of sudden cardiac death (SCD) in Brugada syndrome is well recognized; however, ventricular arrhythmia risk stratification remains challenging and controversial. We aimed to assess the association of type of syncope with MAE via systematic review and meta‐analysis.MethodsWe comprehensively searched the databases of MEDLINE and EMBASE from inception to December 2021. Included studies were cohort (prospective or retrospective) studies that reported the types of syncope (cardiac, unexplained, vasovagal, and undifferentiated) and MAE. Data from each study were combined using the random‐effects, generic inverse variance method of DerSimonian and Laird to calculate the odds ratio (OR) and 95% confidence intervals (CIs).ResultsSeventeen studies from 2005 to 2019 were included in this meta‐analysis involving 4355 Brugada syndrome patients. Overall, syncope was significantly associated with an increased risk of MAE in Brugada syndrome (OR = 3.90, 95% CI: 2.22–6.85, p < .001, I2 = 76.0%). By syncope type, cardiac (OR = 4.48, 95% CI: 2.87–7.01, p < .001, I2 = 0.0%) and unexplained (OR = 4.71, 95% CI: 1.34–16.57, p = .016, I2 = 37.3%) syncope was significantly associated with increased risk of MAE in Brugada syndrome. Vasovagal (OR = 2.90, 95% CI: 0.09–98.45, p = .554, I2 = 70.9%) and undifferentiated syncope (OR = 2.01, 95% CI: 1.00–4.03, p = .050, I2 = 64.6%, respectively) were not.ConclusionOur study demonstrated that cardiac and unexplained syncope was associated with MAE risk in Brugada syndrome populations but not in vasovagal syncope and undifferentiated syncope. Unexplained syncope is associated with a similar increased risk of MAE compared to cardiac syncope.

Aims Increased LV wall thickness is frequently encountered in transthoracic echocardiography (TTE). While accurate and early diagnosis is clinically important, given the differences in available therapeutic options and prognosis, an extensive workup is often required to establish the diagnosis. We propose the first echo-based, automated deep learning model with a fusion architecture to facilitate the evaluation and diagnosis of increased left ventricular (LV) wall thickness. Methods and Results Patients with an established diagnosis of increased LV wall thickness (hypertrophic cardiomyopathy (HCM), cardiac amyloidosis (CA), and hypertensive heart disease (HTN)/others) between 1/2015 to 11/2019 at Mayo Clinic Arizona were identified. The cohort was divided into 80%/10%/10% for training, validation, and testing sets, respectively. Six baseline TTE views were used to optimize a pre-trained InceptionResnetV2 model. Each model output was used to train a meta-learner under a fusion architecture. Model performance was assessed by multiclass area under the receiver operating characteristic curve (AUROC). A total of 586 patients were used for the final analysis (194 HCM, 201 CA, and 191 HTN/others). The mean age was 55.0 years, and 57.8% were male. Among the individual view-dependent models, the apical 4 chamber model had the best performance (AUROC: HCM: 0.94, CA: 0.73, and HTN/other: 0.87). The final fusion model outperformed all the view-dependent models (AUROC: CA: 0.90, HCM: 0.93, and HTN/other: 0.92). Conclusion The echo-based InceptionResnetV2 fusion model can accurately classify the main etiologies of increased LV wall thickness and can facilitate the process of diagnosis and workup.

AbstractIntroductionAtrial fibrillation (AF) is the most common cardiac arrhythmia with a high stroke and mortality rate. The video‐assisted thoracoscopic radiofrequency pulmonary vein ablation is a treatment option for patients who fail catheter ablation. Randomized data comparing surgical versus catheter ablation are limited. We performed a meta‐analysis of randomized control trials to explore the outcome efficacy between surgical and catheter radiofrequency pulmonary vein ablation in patients with AF.MethodsWe comprehensively searched the databases of MEDLINE and EMBASE from inception to December 2020. Included studies were published randomized control trials that compared video‐assisted thoracoscopic and catheter radiofrequency pulmonary vein ablation. Data from each study were combined using the fixed‐effects, generic inverse variance method of DerSimonian, and Laird to calculate odds ratios and 95% confidence intervals.ResultsSix studies from November 2013 to 2020 were included in this meta‐analysis involving 511 AF patients (79% paroxysmal) with 263 catheter ablation (mean age 56 ± 3 years) and 248 surgical ablations (mean age 52 ± 4 years). Catheter ablation was associated with increased atrial arrhythmias recurrence when compared to surgical ablation (pooled relative risk = 1.85, 95% confidence interval: 1.44−2.39, p < .001, I2 = 0.0%) but associated with less total major adverse events (pooled relative risk = 0.29, 95% confidence interval: 0.16−0.53, p < .001, I2 = 0.0%). In subgroup analysis, catheter ablation was associated with increased AF recurrence in refractory paroxysmal AF when compared to surgical ablation (pooled relative risk = 2.47, 95% confidence interval: 1.31−4.65, p = .005, I2 = 0.0%) but not in persistent AF (relative risk = 1.09, 95% confidence interval: 0.60−2.0, p = .773).ConclusionCatheter ablation was associated with higher atrial arrhythmia recurrence when compared with surgical ablation. However, our study suggests that the benefit of surgical ablation in patients with persistent AF is unclear. More studies and alternative ablation strategies investigation in persistent AF are warranted.

AbstractAimsThe MicraTM transcatheter pacing system (TPS) (Medtronic) is the only leadless pacemaker that promotes atrioventricular (AV) synchrony via accelerometer‐based atrial sensing. Data regarding the real‐world experience with this novel system are scarce. We sought to characterize patients undergoing MicraTM‐AV implants, describe percentage AV synchrony achieved, and analyze the causes for suboptimal AV synchrony.MethodsIn this retrospective cohort study, electronic medical records from 56 consecutive patients undergoing MicraTM‐AV implants at the Mayo Clinic sites in Minnesota, Florida, and Arizona with a minimum follow‐up of 3 months were reviewed. Demographic data, comorbidities, echocardiographic data, and clinical outcomes were compared among patients with and without atrial synchronous ventricular pacing (AsVP) ≥ 70%.ResultsSixty‐five percent of patients achieved AsVP ≥ 70%. Patients with adequate AsVP had smaller body mass indices, a lower proportion of congestive heart failure, and prior cardiac surgery. Echocardiographic parameters and procedural characteristics were similar across the two groups. Active device troubleshooting was associated with higher AsVP. The likely reasons for low AsVP were small A4‐wave amplitude, high ventricular pacing burden, and inadequate device reprogramming. Importantly, in patients with low AsVP, subjective clinical worsening was not noted during follow‐up.ConclusionWith the increasing popularity of leadless pacemakers, it is paramount for device implanting teams to be familiar with common predictors of AV synchrony and troubleshooting with MicraTM‐AV devices.

Aims: The MicraTM transcatheter pacing system (TPS) (Medtronic) is the only leadless pacemaker that promotes atrioventricular (AV) synchrony via accelerometer-based atrial sensing. Data regarding the real-world experience with this novel system are currently lacking. We sought to characterize patients undergoing MicraTM -AV implants, describe percentage AV synchrony achieved, and analyze the causes for suboptimal AV synchrony. Methods: In this retrospective cohort study, electronic medical records from 56 consecutive patients undergoing MicraTM -AV implants at the Mayo Clinic sites in Minnesota, Florida, and Arizona with a minimum follow-up of 3 months were reviewed. Demographic data, comorbidities, echocardiographic data, and clinical outcomes were compared among patients with and without atrial synchronous-ventricular pacing (AsVP) ≥70%. Results: Fifty-six percent of patients achieved AsVP ≥70%. Patients with adequate AsVP had smaller body mass indices, a lower proportion of congestive heart failure and pulmonary hypertension. Echocardiographic parameters and procedural characteristics were similar across the two groups. Active device troubleshooting was associated with higher AsVP. The likely reasons for low AsVP were persistent atrial arrhythmias, small A4-wave amplitude, and inadequate device reprogramming. Importantly, in patients with low AsVP, subjective clinical worsening was not noted during follow-up. Conclusion: With the increasing popularity of leadless PM, it is paramount for device implanting teams to be familiar with common predictors of AV synchrony and troubleshooting with MicraTM -AV devices.

Background and Objectives: Knowledge of the incidence and time frames of the adverse events of patients presenting syncope at the ED is essential for developing effective management strategies. The aim of the present study was to perform a meta-analysis of the incidence and time frames of adverse events of syncope patients. Materials and Methods: We combined individual patients’ data from prospective observational studies including adult patients who presented syncope at the ED. We assessed the pooled rate of adverse events at 24 h, 72 h, 7–10 days, 1 month and 1 year after ED evaluation. Results: We included nine studies that enrolled 12,269 patients. The mean age varied between 53 and 73 years, with 42% to 57% females. The pooled rate of adverse events was 5.1% (95% CI 3.4% to 7.7%) at 24 h, 7.0% (95% CI 4.9% to 9.9%) at 72 h, 8.4% (95% CI 6.2% to 11.3%) at 7–10 days, 10.3% (95% CI 7.8% to 13.3%) at 1 month and 21.3% (95% CI 15.8% to 28.0%) at 1 year. The pooled death rate was 0.2% (95% CI 0.1% to 0.5%) at 24 h, 0.3% (95% CI 0.1% to 0.7%) at 72 h, 0.5% (95% CI 0.3% to 0.9%) at 7–10 days, 1% (95% CI 0.6% to 1.7%) at 1 month and 5.9% (95% CI 4.5% to 7.7%) at 1 year. The most common adverse event was arrhythmia, for which its rate was 3.1% (95% CI 2.0% to 4.9%) at 24 h, 4.8% (95% CI 3.5% to 6.7%) at 72 h, 5.8% (95% CI 4.2% to 7.9%) at 7–10 days, 6.9% (95% CI 5.3% to 9.1%) at 1 month and 9.9% (95% CI 5.5% to 17) at 1 year. Ventricular arrhythmia was rare. Conclusions: The risk of death or life-threatening adverse event is rare in patients presenting syncope at the ED. The most common adverse events are brady and supraventricular arrhythmias, which occur during the first 3 days. Prolonged ECG monitoring in the ED in a short stay unit with ECG monitoring facilities may, therefore, be beneficial.

Background: The hallmark of Long QT Syndrome (LQTS) is a prolongation of the ventricular electrical action potential caused by mutations involving key cardiac ion channels on the surface membrane of ventricular myocytes. Different mutations are associated with specific modes of arrhythmia initiation and distinct changes in cardiac rhythm prior to these events. We hypothesized that some LQTS-causing mutations might involve the sinus node, leading to aberrations in cardiac rhythm. To test this hypothesis, we examined the features of cardiac rhythm in 23 genotyped patients with LQTS and 14 matched controls (C) using Holter ECG data (6hrs). Methods: QRS-complexes were identified using custom software and verified by an experienced ECG reader; series of sinus beats were extracted and gaps in time series were linearly interpolated. The mean, max, and min heart rate (HR), the time (SD, SDNN, SDANN, RMSSD, pNN50) and frequency-domain (Total (TP), Very low (VLF), Low (LF), High (HF) frequency powers, and LF/HF) indices of heart rate variability (HRV) were calculated in each 5-min interval and over the entire recording. The short-long-short irregularity was examined using the novel multiscale rhythmogenetic analysis (MRA), which quantifies changes in the HRV indices during the transition from one time-scale window to another. Results: The maximum heart rate was slower in LQTS than in C (101±13 and 119±19bpm, p=0.001). The high-frequency power (HF) was lower in LQTS than in C (80±76 and 113±58ms 2 , p<0.05). However, the short-term irregularity (quantified by the difference in RMSSD between the 75ms and 2000ms time scales) was 4 times greater in LQTS compared to C (p=0.003). Inclusion or exclusion of two patents who were on β-blockers did not change the results. Conclusions: LQTS is associated with specific changes in cardiac rhythm, including: diminished acceleration capacity, decreased high-frequency power, and enhanced short-long-short irregularity. This suggests that LQTS involves channel modifications in the sinus node, which might contribute to arrhythmogenesis. Rhythm characterization in genetic sub-types of LQTS might improve arrhythmia risk stratification in this heterogeneous patient population.

Introduction Optivol (Medtronic Inc.) thoracic impedance (ZT) provides preemptive disease status information in heart failure (HF). It remains unclear how pulmonary‐capillary blood volume (Vc), lung volume (Lvol), and interstitial fluid influence ZT. Hypothesis Positional change and exercise result in increased Vc and/or lung interstitial fluid and ZT tracks fluctuation in these variables. Methods 12 HF patients (age 63±8yr, LVEF 41±14%) were recruited. Measures were taken at rest, exercise, recovery. This included: spirometry, ZT, diffusing capacity of the lungs for CO and NO (DLCO, DLNO), alveolar‐capillary conductance (Dm, interstitial fluid index), and Vc. Inspiratory capacity was obtained to provide consistent lung volumes for assessing ZT. Results Positional change (upright‐supine) resulted in an increased ZT (5±4%, p<0.01), while the change in Lvol (RV‐TLC) resulted in a 7±2 ohm swing in ZT (0.2±0.1ohm change/100ml change in Lvol). After 30min supine, Vc increased 28±39% (p<0.05) while Dm/Vc and Lvol decreased (29±11% and 17±3%, p<0.05). During exercise compared to baseline, Vc increased 56±44% (p<0.01), DmCO/Vc decreased 25±7% (p<0.05), and ZT did not change. During recovery measures normalized except DmCO/Vc. Conclusion Positional changes and fluctuations in Lvol influence ZT yet measures of lung fluid minimally impact this measure despite significant fluctuations.