Heart failure promotes multimorbidity through innate immune memory

Patients with heart failure (HF) often experience repeated acute decompensation and develop comorbidities such as chronic kidney disease and frailty syndrome. Although this suggests pathological interaction among comorbidities, the mechanisms linking them are poorly understood. Here, we identified alterations in hematopoietic stem cells (HSCs) as a critical driver of recurrent HF and associated comorbidities. Bone marrow transplantation from HF-experienced mice resulted in spontaneous cardiac dysfunction and fibrosis in recipient mice, as well as increased vulnerability to kidney and skeletal muscle insults. HF enhanced the capacity of HSCs to generate proinflammatory macrophages. In HF mice, global chromatin accessibility analysis and single-cell RNA-seq showed that transforming growth factor-β (TGF-β) signaling was suppressed in HSCs, which corresponded with repressed sympathetic nervous activity in bone marrow. Transplantation of bone marrow from mice in which TGF-β signaling was inhibited similarly exacerbated cardiac dysfunction. Collectively, these results suggest that cardiac stress modulates the epigenome of HSCs, which in turn alters their capacity to generate cardiac macrophage subpopulations. This change in HSCs may be a common driver of repeated HF events and comorbidity by serving as a key carrier of "stress memory."

One-shot screening: Utilization of a two-dimensional convolutional neural network for automatic detection of left ventricular hypertrophy using electrocardiograms

BACKGROUND AND OBJECTIVE

Left ventricular hypertrophy (LVH) can impair ejection function and elevate the risk of heart failure. Therefore, early detection through screening is crucial. This study aimed to propose a novel method to enhance LVH detection using 12-lead electrocardiogram (ECG) waveforms with a two-dimensional (2D) convolutional neural network (CNN).

METHODS

Utilizing 42,127 pairs of ECG-transthoracic echocardiogram data, we pre-processed raw data into single-shot images derived from each ECG lead and conducted lead selection to optimize LVH diagnosis. Our proposed one-shot screening method, implemented during pre-processing, enables the superimposition of waveform source data of any length onto a single-frame image, thereby addressing the limitations of the one-dimensional (1D) approach. We developed a deep learning model with a 2D-CNN structure and machine learning models for LVH detection. To assess our method, we also compared our results with conventional ECG criteria and those of a prior study that used a 1D-CNN approach, utilizing the same dataset from the University of Tokyo Hospital for LVH diagnosis.

RESULTS

For LVH detection, the average area under the receiver operating characteristic curve (AUROC) was 0.916 for the 2D-CNN model, which was significantly higher than that obtained using logistic regression and random forest methods, as well as the two conventional ECG criteria (AUROC of 0.766, 0.790, 0.599, and 0.622, respectively). Incorporating additional metadata, such as ECG measurement data, further improved the average AUROC to 0.921. The model's performance remained stable across two different annotation criteria and demonstrated significant superiority over the performance of the 1D-CNN model used in a previous study (AUROC of 0.807).

CONCLUSIONS

This study introduces a robust and computationally efficient method that outperforms 1D-CNN models utilized in previous studies for LVH detection. Our method can transform waveforms of any length into fixed-size images and leverage the selected lead of the ECG, ensuring adaptability in environments with limited computational resources. The proposed method holds promise for integration into clinical practice as a tool for early diagnosis, potentially enhancing patient outcomes by facilitating earlier treatment and management.

Prediction of pacemaker-induced cardiomyopathy using a convolutional neural network based on clinical findings prior to pacemaker implantation

Risk factors for pacemaker-induced cardiomyopathy (PICM) have been previously reported, including a high burden of right ventricular pacing, lower left ventricular ejection fraction, a wide QRS duration, and left bundle branch block before pacemaker implantation (PMI). However, predicting the development of PICM remains challenging. This study aimed to use a convolutional neural network (CNN) model, based on clinical findings before PMI, to predict the development of PICM. Out of a total of 561 patients with dual-chamber PMI, 165 (mean age 71.6 years, 89 men [53.9%]) who underwent echocardiography both before and after dual-chamber PMI were enrolled. During a mean follow-up period of 1.7 years, 47 patients developed PICM. A CNN algorithm for prediction of the development of PICM was constructed based on a dataset prior to PMI that included 31 variables such as age, sex, body mass index, left ventricular ejection fraction, left ventricular end-diastolic diameter, left ventricular end-systolic diameter, left atrial diameter, severity of mitral regurgitation, severity of tricuspid regurgitation, ischemic heart disease, diabetes mellitus, hypertension, heart failure, New York Heart Association class, atrial fibrillation, the etiology of bradycardia (sick sinus syndrome or atrioventricular block) , right ventricular (RV) lead tip position (apex, septum, left bundle, His bundle, RV outflow tract), left bundle branch block, QRS duration, white blood cell count, haemoglobin, platelet count, serum total protein, albumin, aspartate transaminase, alanine transaminase, estimated glomerular filtration rate, sodium, potassium, C-reactive protein, and brain natriuretic peptide. The accuracy, sensitivity, specificity, and area under the curve of the CNN model were 75.8%, 55.6%, 83.3% and 0.78 respectively. The CNN model could accurately predict the development of PICM using clinical findings before PMI. This model could be useful for screening patients at risk of developing PICM, ensuring timely upgrades to physiological pacing to avoid missing the optimal intervention window.

Removal of central venous catheter using Evolution® Rotating Dilator

We experienced the first case of a difficult-to-extract central venous catheter removed with a pacemaker lead removal system: a 14-year-old boy with Hirschsprung's disease who had repeated catheter infections that could not be removed by traction. Because the catheter lumen was occluded, a suture was tied around the end of the catheter and the catheter was removed with a rotating dilator.

Association of Atrial Fibrillation Progression With Left Atrial Functional Reserve and Its Reversibility

BACKGROUND

Atrial fibrillation (AF) progression is closely related to heart failure occurrence, and catheter ablation carries a beneficial effect for heart failure prevention. Recently, particular attention has been given to left atrial (LA) function and functional reserve in the pathogenesis linking AF and heart failure, although its significance and reversibility is not well studied.

METHODS AND RESULTS

We prospectively investigated 164 patients with AF with normal left ventricular systolic function and free from heart failure who underwent first catheter ablation and pre-/postprocedural echocardiography. Conventional and speckle-tracking echocardiography were performed at rest and during passive leg lifting to assess LA size, LA reservoir strain (LARS), and functional reserve calculated as passive leg lifting-LARS - rest-LARS. Patients were categorized into 3 AF subtypes: paroxysmal AF (N=95), persistent AF (PeAF; N=50), and long-standing persistent AF (LS-PeAF; N=19). The PeAF and LS-PeAF groups had larger LA size and reduced LARS compared with the paroxysmal AF group (all P<0.05). LA functional reserve was significantly impaired in the LS-PeAF group (P=0.003). In multivariable analysis, LS-PeAF and advanced age were significantly associated with impaired LA functional reserve. Among 149 patients with sinus rhythm 1 to 2 days after catheter ablation, LARS was significantly improved in both PeAF and LS-PeAF groups but was still lower than that in the paroxysmal AF group. Sinus rhythm restoration also led to amelioration of LA functional reserve in patients with LS-PeAF.

CONCLUSIONS

AF progression was related to impaired LARS and LA functional reserve, and restoration of sinus rhythm might contribute to early LA reverse remodeling.

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.

Cryoballoon ablation for paroxysmal atrial fibrillation mildly improves lung function: An observational study

Atrial fibrillation (AF) is the most common arrhythmia and a major public health burden. Catheter ablation (CA) is an effective treatment of AF. Although radiofrequency catheter ablation (RFCA) is the standard practice, cryoballoon ablation (CBA) has become increasingly popular. Pulmonary dysfunction is also associated with AF. As CA targets the pulmonary vasculature, it poses a risk to lung function. However, the effect of CA on respiration in patients with paroxysmal atrial fibrillation (PAF) post-ablation has not yet been assessed. We assessed pulmonary function after CA in a cohort of patients with AF. This prospective, single-center study included 26 patients with symptomatic PAF and 18 patients without PAF. CA techniques include RFCA, CBA, hot balloon ablation, and laser balloon-mediated ablation. Spirometry parameters included vital capacity (VC), forced vital capacity (FVC), forced expiratory volume (FEV1), and peak expiratory flow, which were all measured 6 months post-ablation. AF ablation significantly improved VC (P = .04), FVC (P = .01), and peak expiratory flow (P = .006) in all the patients. In the patients with PAF, we observed a significant increase in FEV1 (P = .04). CBA significantly improved VC (P = .012) and FVC (P = .013). A significant improvement in these pulmonary parameters was achieved, specifically in patients with PAF treated with an ablation protocol with CBA, but not with RFCA or hot balloon ablation. A significant decrease in FEV1 was observed with hot balloon ablation (P = .035). Significant improvement in pulmonary parameters was observed specifically in patients with PAF who underwent CBA. CBA may be a more suitable treatment strategy for patients with PAF, particularly those with compromised pulmonary function.

The estimated glomerular filtration rate predicts pacemaker-induced cardiomyopathy

Clinical predictors for pacemaker-induced cardiomyopathy (PICM) (e.g., a wide QRS duration and left bundle branch block at baseline) have been reported. However, factors involved in the development of PICM in patients with preserved left ventricular ejection fraction (LVEF) remain unknown. This study aimed to determine the risk factors for PICM in patients with preserved LVEF. The data of 113 patients (average age: 71.3 years; men: 54.9%) who had echocardiography before and after pacemaker implantation (PMI) among 465 patients undergoing dual-chamber PMI were retrospectively analyzed. Thirty-three patients were diagnosed with PICM (18.0/100 person-years; 95% CI 12.8-25.2). A univariate Cox regression analysis showed that an estimated glomerular filtration rate (eGFR) ≤ 30 mL/min/1.73 m2 (HR 3.47; 95% CI 1.48-8.16) and a past medical history of coronary artery disease (CAD) (HR 2.76; 95% CI 1.36-5.60) were significantly associated with the onset of PICM. After adjusting for clinical variables, an eGFR ≤ 30 mL/min/1.73 m2 (HR 2.62; 95% CI 1.09-6.29) and a medical history of CAD (HR 2.32; 95% CI 1.13-4.80) were independent risk factors for developing PICM. A medical history of CAD and low eGFR are independent risk factors for PICM in patients with preserved LVEF at baseline. These results could be helpful in predicting a decreased LVEF by ventricular pacing before PMI. Close follow-up by echocardiography is recommended to avoid a delay in upgrading to physiological pacing, such as cardiac resynchronization therapy or conduction system pacing.

Prevalence, Associated Factors, and Echocardiographic Estimation of Left Atrial Hypertension in Patients With Atrial Fibrillation

Background Elevated left atrial (LA) pressure predisposes individuals to the initiation and persistence of atrial fibrillation (AF), and LA hypertension is associated with AF recurrence after catheter ablation (CA). However, the exact frequency and factors associated with LA hypertension are unknown, and its noninvasive estimation is challenging. This study aimed to investigate the prevalence and determinants of LA hypertension in patients with AF who underwent first CA. Methods and Results We examined 183 patients with AF who underwent conventional and speckle-tracking echocardiography before CA to assess LA size, reservoir strain, and stiffness. Direct LA pressure was measured at the time of CA, and LA hypertension was defined as mean LA pressure >15 mm Hg. Thirty-three (18.0%) patients exhibited LA hypertension. Patients with LA hypertension had a significantly larger LA volume index (40.2 [28.4-52.1] versus 34.1 [26.9-42.4] mL/m2, P=0.025), reduced LA reservoir strain (15.1 [10.4-21.7] versus 22.7 [14.4-32.3] %, P=0.002) and increased LA stiffness (0.69 [0.34-0.99] versus 0.36 [0.24-0.54], P<0.001). Multivariable analyses showed that waist circumference, C-reactive protein level, LA reservoir strain, and LA stiffness were independently associated with LA hypertension (all P<0.05), while LA volume and E/e' ratio were not. Among echocardiographic parameters, receiver operating characteristic curve analysis identified LA stiffness as the best predictor of LA hypertension. Conclusions Approximately 20% of patients with AF who underwent CA had LA hypertension. Central obesity and inflammation might be involved in the pathophysiological mechanisms of LA hypertension, and echocardiography-derived LA stiffness may have clinical utility for the detection of LA hypertension before CA.

Prevalence of glucose metabolism disorders and its association with left atrial remodelling before and after catheter ablation in patients with atrial fibrillation

AIMS

To investigate the exact prevalence of glucose metabolism disorders, and their impact on left atrial (LA) remodelling and reversibility in patients with atrial fibrillation (AF).

METHODS AND RESULTS

We examined 204 consecutive patients with AF who underwent their first catheter ablation (CA). Oral glucose tolerance test was used to evaluate glucose metabolism disorders in 157 patients without known diabetes mellitus (DM). Echocardiography was performed before and 6 months after CA. Oral glucose tolerance test identified abnormal glucose metabolism in 86 patients [11 with newly diagnosed DM, 74 with impaired glucose tolerance (IGT) and 1 with impaired fasting glucose (IFG)]. Ultimately, 65.2% of patients had abnormal glucose metabolism. Diabetes mellitus group had the worst LA reservoir strain and LA stiffness (both P < 0.05), while there was no significant difference in baseline LA parameters between normal glucose tolerance (NGT) group and IGT/IFG group. The prevalence of LA reverse remodelling (≥15% decrease in the LA volume index at 6 months after CA) was significantly higher in NGT group compared with IGT/IFG and DM group (64.1 vs. 38.6 vs. 41.5%, P = 0.006). Both DM and IFG/IGT carry a significant risk of lack of LA reverse remodelling independent of baseline LA size and AF recurrence.

CONCLUSION

Approximately 65% of patients with AF who underwent their first CA had abnormal glucose metabolism. Patients with DM had significantly impaired LA function compared with non-DM patients. Impaired glucose tolerance/IFG as well as DM carries significant risk of unfavourable LA reverse remodelling. Our observations may provide valuable information regarding the mechanisms and therapeutic strategies of glucose metabolism-related AF.

Prediction of Atrial Fibrillation Being Asymptomatic at First Onset by Cardiac Pacing

Asymptomatic or silent atrial fibrillation (AF) has long been a clinical problem due to the incidence of ischemic stroke. A method is needed to predict the development of silent AF before the occurrence of ischemic stroke. This study was focused on the symptoms of AF, especially palpitation, in pacemaker patients. We assessed the hypothesis that absence of palpitation during rapid ventricular pacing could be a predictor of future onset AF being asymptomatic.In this study, we assessed the presence of symptoms during RV pacing and AF symptoms on 145 pacemaker patients at the outpatient clinic by VVI pacing at 120 ppm. The relationship between symptoms during RV pacing and symptom during AF was assessed. The predictive value of absence of symptom during RV pacing on AF being asymptomatic was assessed.Of 145 patients, 74 had previous AF episode. Among the AF patients, absence of symptom during VVI pacing was associated with AF being asymptomatic.Of 145 patients, 71 had no previous AF events. There were 14 patients who had new-onset AF or atrial flutter (AFL) after the device implantation. Four of the 14 patients (28.6%) were symptomatic during first AF/AFL episode, and 10 (71.4%) were asymptomatic during first-onset AF. All ten patients who were asymptomatic during cardiac pacing test were asymptomatic during their initial episodes of AF as well.This study showed that absence of symptoms during rapid ventricular pacing was associated with first-onset AF being asymptomatic.

Uninterrupted Direct Oral Anticoagulants Without a Change in Regimen for Catheter Ablation for Atrial Fibrillation Is an Acceptable Protocol

Background: In patients undergoing catheter ablation (CA) for atrial fibrillation (AF), the use of uninterrupted direct oral anticoagulants (DOACs) is the current protocol. This study evaluated bleeding complications following the uninterrupted use of 4 DOACs in patients undergoing CA for AF without any change in the dosing regimen. Moreover, we assessed differences between once- and twice-daily DOAC dosing in patients undergoing CA for AF who continued on DOACs without any change in the dosing regimen.

Methods and Results: This study was a retrospective single-center cohort study of consecutive patients. All patients continued DOACs without interruption or changes to the dosing schedule, even in the case of morning procedures. The primary endpoint was the incidence of major bleeding events within the first 30 days after CA. In all, 710 consecutive patients were included in the study. Bleeding complications were less frequent in the uninterrupted twice- than once-daily DOACs group. However, the incidence of cardiac tamponade across all DOACs was low (0.98%; 7/710), suggesting that uninterrupted DOACs without changes to the dosing regimen may be an acceptable strategy. The rate of total bleeding events, including minor bleeding (12/710; 1.6%), was also satisfactory.

Conclusions: Uninterrupted DOACs without any change in dosing regimen for patients undergoing CA for AF is acceptable. Bleeding complications may be less frequent in patients receiving DOACs twice rather than once daily.

Pseudo-elevation of conduction system pacing threshold through parallel connection of an intracardiac electrogram recording system

Parallel connection of an electrophysiology recording system (EP system) to equipment for conduction system pacing (CSP) has been widely used for fine monitoring of intracardiac electrograms and pacing evaluation. We experienced a case showing unexpected pacing threshold exacerbation under specific conditions when the EP system was connected in parallel. We evaluated the underlying mechanism using an ex vivo model. An ex vivo pacing and intracardiac electrogram monitoring model was generated using an oscilloscope, pacing system analyzer (PSA), EP system, and simulated heart. The discrepancy between expected output at the PSA and the actual measured output value at the simulated heart was measured under various conditions and using various combinations of pacing equipment. Parallel connection of the EP system was associated with reduced electrical output from the PSA as recorded at the simulated heart. The unexpected adverse effects were particularly noticeable when using an RMC-5000 EP system with the pacing function on. The trouble is completely resolved by simply turning off the pacing function of the system. There is a possibility that the EP system might increase the pacing threshold in CSP when the PSA and EP system is are deployed in parallel. The issue may provoke pseudo failure of CSP due to the high pacing threshold. When the RMC-5000 is used for conduction system pacing in parallel with a PSA for the pacing test, the pacing function of RMC-5000 should be turned off.

Cardiac macrophages prevent sudden death during heart stress

Cardiac arrhythmias are a primary contributor to sudden cardiac death, a major unmet medical need. Because right ventricular (RV) dysfunction increases the risk for sudden cardiac death, we examined responses to RV stress in mice. Among immune cells accumulated in the RV after pressure overload-induced by pulmonary artery banding, interfering with macrophages caused sudden death from severe arrhythmias. We show that cardiac macrophages crucially maintain cardiac impulse conduction by facilitating myocardial intercellular communication through gap junctions. Amphiregulin (AREG) produced by cardiac macrophages is a key mediator that controls connexin 43 phosphorylation and translocation in cardiomyocytes. Deletion of Areg from macrophages led to disorganization of gap junctions and, in turn, lethal arrhythmias during acute stresses, including RV pressure overload and β-adrenergic receptor stimulation. These results suggest that AREG from cardiac resident macrophages is a critical regulator of cardiac impulse conduction and may be a useful therapeutic target for the prevention of sudden death.

Uninterrupted twice-daily direct oral anticoagulants are safer than once-daily ones for atrial fibrillation catheter ablation

Background

In patients undergoing AF catheter ablation (CA), uninterpreted DOACs reduced bleeding events without increasing ischemic events compared with vitamin K antagonist, and the continuation of anticoagulants is recommended for AF ablation. However, in the past studies, patients received once-daily DOACs in the evening, not in the morning of the procedure day. Moreover, there has been no study comparing uninterrupted 4 DOACs; therefore, the safety and effect of uninterpreted DOACs taken just in the morning of AF ablation is unknown.

Objective

The purpose of this study was to compare bleeding complications and thromboembolism events between 4 DOACs in patients undergoing AF ablation.

Method

This study was the retrospective single-center cohort study of consecutive patients who underwent AF ablation between April 2014 to July 2019. All patients continued DOAC uninterruptedly including just in the morning of the procedure. The primary endpoint included major bleeding events within the first 30 days after CA. The secondary endpoints included the composite events of ischemic stroke, systemic embolism, myocardial infarction, and vascular death.

Result

A total of 713 patients (mean age 64±12 years, 72% male) were included in this analysis; enrolled patients were 88, 238, 218, and 169 respectively in dabigatran, rivaroxaban, apixaban and edoxaban group. At the baseline, the ratio of age ≥75 years and CHADS2 score was higher in apixaban group, though all other baseline variables were similar between them.

The primary endpoint was observed 0%, 2.1%, 0.45%, and 4.7% respectively in dabigatran, rivaroxaban, apixaban, and edoxaban group (P=0.013) without significant difference about secondary endpoint between them (P=0.3).

Comparing twice-daily vs once-daily DOACs, the primary endpoint was observed significantly lower in the twice-daily group than in once-daily group (0.32% and 3.2% respectively, P=0.0054), without any significant difference about secondary endpoint (0% and 0.73% respectively, P=0.26).

Conclusion

Taking DOACs also in the morning of AF ablation, uninterrupted twice-daily DOACs are safer than once-daily DOACs without increasing ischemic event, although twice-daily DOACs, especially apixaban, were used in higher aged patients.

Figure 1

Funding Acknowledgement

Type of funding source: None

Fluoroless and contrast-free catheter ablation without a lead apron in routine clinical practice

The technique of catheter ablation has been improved within the past few decades, especially by three-dimensional (3D) mapping system. 3D mapping system has reduced radiation exposure but ablation procedures still require fluoroscopy. Our previous study showed the safety and efficacy of catheter ablation based on intracardiac echogram combined with CARTOSOUND/CARTO3 system, however fluoroscopy use for an average of 16 min is required for this procedure. The present study was aimed to reduce radiation exposure to zero and establish a radiation free catheter ablation method with the goal of utilizing it in routine clinical practice. We conducted single center, retrospective study during 2019 April to 2020 February. Consecutive 76 patients were enrolled. In the first 18 cases, the previously reported procedure (CARTOSOUND/CARTO3 method) was used. The remaining 58 cases were transitioned to fluoroless catheter ablation. The procedure time, success rates and complication rates were analyzed. Not only AF patients but atrial flutter (AFL), paroxysmal supraventricular tachycardia (PSVT) and ventricular arrhythmia patients were included. Catheter positioning, catheter visualization and collecting the geometry of each camber of the heart were conducted by using contact force and ICE based geometry on CARTO system without either prior computed tomography (CT) or magnetic resonance image (MRI). In fluoroless group, all catheter ablations were successfully performed without lead aprons. No complications occurred in either group. There were no significant differences in procedure time in any type of procedure (Total procedure time Fluoro-group; 149 ± 51 min vs. Fluoroless-group; 162 ± 43 min, N.S.), (PSVT 170 ± 53 min vs. 162 ± 29 min, N.S.), (AFL 110 ± 70 min vs. 123 ± 43 min, N.S.), (AF 162 ± 43 min vs. 163 ± 32 min, N.S.). The total radiation time was reduced to zero in fluoroless group. Catheter ablation with ICE and 3D mapping system guide without fluoroscopy could be safely performed with a high success rate, without any prior CT/MRI 3D images. Radiation was reduced completely for patients and staff, negating the need for protective wear for operators.

Hybrid Lead Extraction Technique: Combined Transatrial Laser Lead Extraction and Surgical Removal of Calcified Lesions

This report presents a new hybrid lead extraction technique combined with transatrial laser lead extraction and surgical removal of calcified lesions in a 50-year-old man with superior vena cava syndrome and bilateral subclavian vein occlusion caused by an abandoned lead, which had been infected for 11 years. (Level of Difficulty: Intermediate.).

Longitudinal dissociation and transition in thickness of the His-Purkinje system cause various QRS waveforms of surface ECG under His bundle pacing: A simulation study based on clinical observations

AIMS

His bundle pacing (HBP) is a feasible and reliable alternative to conventional right ventricular pacing (RVP), but associated ECG (electrocardiogram) changes have not been well-studied. This study aimed to determine the mechanisms underlying ECG changes associated with HBP using patient-specific multiscale heart simulations.

METHODS

ECGs were recorded in two patients who were treated by HBP under a native rhythm and HBP at high and low voltages. We created patient-specific multiscale simulation heart models of these patients and performed ECG simulation under these conditions. Using these results and detailed information on the electrical field around the pacing lead, we investigated mechanisms underlying the observed ECG changes.

RESULTS

Heart simulations successfully reproduced ECGs under a native rhythm for both cases. In case 1, nonselective HBP produced a left bundle branch (LBB) block pattern, which was reproduced as a selective right bundle branch (RBB) pacing. However, in case 2, ECG under nonselective HBP showed an RBB block pattern, which could not be reproduced by the commonly used framework. Findings on the electrical field and anatomy of the His bundle and its branches suggested that longitudinal dissociation of the His bundle and transition of thickness in the stem of the LBB caused a conduction delay in the RBB to produce these ECG changes in this patient.

CONCLUSION

Variations in the anatomy of the His bundle and its branches may underlie the diverse ECG responses to HBP. These variations should be taken into account when performing this therapy.

Feasibility of a T-Shirt-Type Wearable Electrocardiography Monitor for Detection of Covert Atrial Fibrillation in Young Healthy Adults

Covert atrial fibrillation (AF) accounts for cryptogenic stroke aetiology in elderly patients and in younger populations. However, asymptomatic AF is difficult to diagnose based on a short electrocardiography (ECG) recording. We evaluated the feasibility of a self-applied continuous ECG monitoring device that can record automatically, easily, and noninvasively in a younger population. We investigated community screening for asymptomatic AF using a wireless single-lead ECG with an electrode embedded in a T-shirt. One hundred men with a CHADS2 score ≥1 who were free from AF and <65 years of age were enrolled. We instructed the participants to wear ECG monitoring devices for at least 4 days/week over 2 months. The proportion of participants with newly detected AF (NDAF) and the monitoring time were evaluated. The mean CHADS2 score was 1.43 ± 0.62. The mean patient age was 52.5 ± 5.4 years. The mean monitoring time was 222 ± 199 hours. NDAF continuing for >30 seconds was detected in 10 participants (10.0%). AF continuing for >6 minutes was detected in 2 participants (2.0%). The T-shirt-type wearable ECG monitoring system was suitable for continuous, daily long-term use among young people with high physical activity, and it had the distinct capability of identifying covert AF.

Impacts of Left Bundle/Peri-Left Bundle Pacing on Left Ventricular Contraction

BACKGROUND

His-bundle pacing is an emerging routine technique that avoids pacing-dependent side effects. However, the success rate of His-bundle pacing is not 100%.Methods and Results:Left bundle pacing or peri-left bundle pacing (LBP/peri-LBP) are recently developed techniques that directly capture the left bundle or ventricular tissue near the left bundle. We evaluated the success rate of LBP/peri-LBP in patients whose treatment with His-bundle pacing failed. In addition, we evaluated left ventricular contraction and desynchrony after LBP/peri-LBP.

CONCLUSIONS

LBP/peri-LBP is an alternative ventricular pacing method in atrioventricular block in patients with failure of His-bundle pacing.

Novel extraction technique of retained pacemaker and defibrillator lead during heart transplantation

Background

Removal of cardiac implantable electronic devices (CIEDs) by manual traction during orthotopic heart transplantation (OHT) sometimes results in retained lead fragments. Moreover, abandoned leads and retained lead fragments are a contraindication for magnetic resonance imaging (MRI) and may be a cause of CIED infection.

Objective

To eliminate complications of retained lead fragments, we completely removed residual leads using an excimer laser sheath technique during OHT. We report our clinical experience and high success rate of lead extraction using the excimer laser sheath compared with manual traction during OHT.

Methods and results

We obtained data on 84 consecutive patients receiving OHT between August 2007 and August 2017. Thirty-nine of 84 patients had undergone CIED implantation before OHT and removal of all their leads was attempted during OHT. From 2007 to 2014, defibrillator and pacemaker leads were extracted by manual traction in all patients (N = 22). After 2015, all leads were extracted with the excimer laser sheath, and surgical assistance was prepared for the procedure (N = 17). Complete procedural success was achieved in 100% of patients in the excimer laser group and 77% of patients in the manual traction group.

Conclusion

Extraction of abandoned leads using the excimer laser sheath system during OHT is novel and safe technique, and has a higher success rate than extraction using manual traction during OHT.

A Case of a Cardiac Resynchronization Therapy-Defibrillator Exhibiting a Lower and Alternately Variable Basic Rate

A cardiac resynchronization therapy defibrillator (CRT-D) (Medtronic Inc. Protecta XT) was implanted in a 67-year-old man who had cardiac sarcoidosis with extremely low cardiac function. He had ventricular tachycardia which was controlled by catheter ablation, medication and pacing. The programmed mode was DDI, lower rate was 90 beats/minute, paced AV delay was 150 ms, and the noncompetitive atrial pacing (NCAP) function was programmed as 300 ms.After his admission for pneumonia and heart failure, we changed his DDI mode to a DDD mode because he had atrial tachycardia, which led to inadequate bi-ventricular pacing. After a while, there were cycle lengths which were longer than his device setting and alternately varied. We were able to avoid this phenomenon with AV delay of 120 ms and NCAP of 200 ms.NCAP is an algorithm which creates a gap above a certain period after the detection of an atrial signal during the postventricular atrial refractory period of the pacemaker. This is to prevent atrial tachycardia and repetitive non-reentrant ventriculoatrial (VA) synchrony in the presence of retrograde VA conduction. But in this case, NCAP algorithm induced much lower rate than the programmed basic lower rate. This situation produced some arrhythmias and exacerbated symptoms of heart failure. This had to be paid attention to, especially when the device was programmed at high basic heart rate.

Direct left atrial ICE imaging guided ablation for atrial fibrillation without employing contrast medium

BACKGROUND

Preoperative and intraoperative use of a contrast medium is unavoidable in catheter ablation for atrial fibrillation, which can become a particularly significant issue for patients suffering from renal impairment.

OBJECTIVE

The purpose of this study is to investigate the feasibility and safety of a technique for atrial fibrillation ablation without a contrast medium via intra-cardiac ultrasound imaging only.

METHODS

We prepared the geometry of the pulmonary vein and left atrium via a SOUNDSTAR catheter from inside the left atrium, without preoperative and intraoperative investigations using contrast mediums, for computed tomography or magnetic resonance imaging and pulmonary venography. This was followed by retrospective investigation of the success rate and complications observed in 200 successive paroxysmal and persistent atrial fibrillation cases that underwent catheter ablation from January 2011 to November 2012. The outcomes were assessed after the one-year follow-up.

RESULTS

Inserting a SOUNDSTAR catheter into the left atrium was successful in all cases, wherein rendering of all pulmonary veins and the left atrium was possible, and extensive encircling pulmonary vein isolation was successful in all cases. The sinus rhythm maintenance rate one year after the procedure was 90.4% for paroxysmal atrial fibrillation and 76.0% for persistent atrial fibrillation. The major complication rate was 0.5% (cardiac tamponade), with no cases presenting aggravation of renal function.

CONCLUSION

Atrial fibrillation ablation using an intra-cardiac ultrasound from the left atrium without employing a contrast medium was safe, with no adverse effects on renal function.

Nickel-free stainless steel avoids neointima formation following coronary stent implantation

SUS316L stainless steel and cobalt-chromium and platinum-chromium alloys are widely used platforms for coronary stents. These alloys also contain nickel (Ni), which reportedly induces allergic reactions in some subjects and is known to have various cellular effects. The effects of Ni on neointima formation after stent implantation remain unknown, however. We developed coronary stents made of Ni-free high-nitrogen austenitic stainless steel prepared using a N₂-gas pressurized electroslag remelting (P-ESR) process. Neointima formation and inflammatory responses following stent implantation in porcine coronary arteries were then compared between the Ni-free and SUS316L stainless steel stents. We found significantly less neointima formation and inflammation in arteries implanted with Ni-free stents, as compared to SUS316L stents. Notably, Ni²⁺ was eluted into the medium from SUS316L but not from Ni-free stainless steel. Mechanistically, Ni²⁺ increased levels of hypoxia inducible factor protein-1α (HIF-1α) and its target genes in cultured smooth muscle cells. HIF-1α and their target gene levels were also increased in the vascular wall at SUS316L stent sites but not at Ni-free stent sites. The Ni-free stainless steel coronary stent reduces neointima formation, in part by avoiding activation of inflammatory processes via the Ni-HIF pathway. The Ni-free-stainless steel stent is a promising new coronary stent platform.

Preliminary report of tolvaptan treatment in Japanese patients with heart failure

While diuretic drugs are commonly used in patients with congestive heart failure, the efficacy of their long-term use still remains controversial. Recently, a new class of diuretics, vasopressin receptor 2 antagonists, has been launched, and tolvaptan is one such drug. We describe our initial experience with this novel agent. Tolvaptan is potentially useful for treatment of heart failure patients with fluid overload who are refractory to conventional diuretic therapies.

Diagnostic efficacy of coronary CT angiography as a follow-up modality for procedure-related coronary dissection

Procedure-related coronary dissection is associated with an increased risk of major adverse cardiovascular events after percutaneous coronary intervention (PCI). In most patients with such an iatrogenic complication, further PCI or bypass surgery aimed at complete revascularization is performed. Moreover, conventional coronary angiography has been used as a standard modality in the follow-up of such patients. The present report describes a 70 year old female patient who was complicated by catheter-related extensive coronary dissection in the right coronary artery (RCA) when treated for an acute myocardial infarction. Although RCA flow was insufficient, we decided against revascularization and followed her medically without additional revascularization procedures. Her clinical course had been uneventful for 4 years. However, symptoms of effort angina developed and re-examinations were performed at approximately 5 years after the myocardial infarction. Although conventional coronary angiography failed to show the culprit lesion responsible for the angina symptoms, the superior spatial resolution of the coronary CT angiography clearly identified significant progression of the stenotic lesion in the true lumen of the dissected RCA. Thus, coronary CT angiography might be considered as a possible first-line follow-up modality in patients with procedure-related coronary dissection.

Long-Term Outcome of First-Generation Metallic Coronary Stent Implantation in Patients With Coronary Artery Disease Observational Study Over a Decade

BACKGROUND

In the era of drug-eluting stents, percutaneous coronary intervention (PCI) has been considered an established therapeutic modality for patients with coronary artery disease (CAD). However, little is known about the long-term prognosis.

METHODS AND RESULTS

Using data obtained from a single-center registry for cases of first-generation bare metallic stent (BMS) implantation, a 10-year follow-up study in patients with CAD was performed. Data for 125 serial patients (aged 62+/-9 years, 104 males) in whom a BMS was successfully implanted was analyzed. Cardiac death (n=16 [12.8%]), including sudden cardiac death (n=9 [7.2%]), non-cardiac death (n=17 [13.6%]) and non-fatal acute myocardial infarction (n=16 [12.8%]) were documented. At 10 years, cumulative probabilities of target and non-target lesion revascularization were 20.5% and 41.5%, respectively, and only 39.2% of the patients were free from cardiac events (cardiac death/myocardial infarction/unplanned revascularization). Age and left ventricular ejection fraction (LVEF) were significant predictors of total death, and LVEF and the use of diuretics were predictors of cardiac events.

CONCLUSIONS

Stabilization of the initial stented site was relatively good and the majority of cardiac events might have originated in non-target lesions. Prevention of systemic arteriosclerosis progression is important for patients with CAD, even after successful PCI.