Feasibility and efficacy of real-time ultrasound-guided venous closure with suture-mediated vascular closure device

BACKGROUND

Venous vascular access complications are usually nonfatal but are the most common complications after transvenous catheter intervention. Vascular closure devices (VCDs) have recently become available for venous closure.

OBJECTIVE

This study aimed to evaluate the feasibility and efficacy of real-time ultrasound-guided venous closure with suture-mediated VCDs in patients who underwent catheter ablation.

METHODS

This single-center observational study enrolled 226 consecutive patients who underwent elective catheter ablation with femoral venipuncture. For hemostasis, vessel closure by VCD was performed with real-time ultrasound guidance after 2022 (n = 123) and without ultrasound guidance in 2021 (n = 103). The occurrence of venous access site-related complications (major, minor, or other) was compared.

RESULTS

The rate of device failure was significantly lower in patients with ultrasound guidance than in those without (1.6% vs 6.3%; P = .048). The occurrence of all venous access site-related complications was significantly lower in patients with ultrasound guidance than in those without (4.9% vs 18.4%; P = .001). Time to ambulation was shorter in patients with ultrasound guidance than in those without (2.0 ± 0.1 hours vs 2.2 ± 0.6 hours; P < .001).

CONCLUSION

Real-time ultrasound guidance can reduce device failure, access site-related complications, and time to ambulation in performing venous closure with a VCD.

Optimal ablation settings of TactiFlex SE laser-cut irrigated-tip catheter: comparison with ThermoCool SmartTouch SurroundFlow porous irrigated-tip catheter

BACKGROUND

The TactiFlex SE catheter (TFSE, Abbott) with a contact force (CF) sensor and a laser-cut irrigated-tip has recently become available but lacks a lesion quality marker. This study aimed to explore distinctions in lesion characteristics between the TFSE and the ThermoCool SmartTouch SurroundFlow catheter (STSF, Biosense Webster), which utilizes a porous irrigated tip, and to assess the most effective application settings for the TFSE.

METHODS

Lesions were generated using varying settings of radiofrequency power (30-50 W), CF (10-20 g), application duration (10-40 s), and catheter orientation (perpendicular or parallel) in an ex vivo porcine model. Comparative analysis between the TFSE and STSF was conducted for lesion characteristics and incidence of steam pops using predictive models in regression analyses.

RESULTS

Among 720 applications, the TFSE exhibited a significantly lower incidence of steam pops compared to the STSF (0.6% vs. 36.8%, P < 0.001). Moreover, coefficients of determination (R2) for the TFSE were higher than those for the STSF concerning lesion depth (0.710 vs. 0.541) and volume (0.723 vs. 0.618). The lesion size generated with the TFSE was notably smaller than that with the STSF under identical application settings. Additionally, to achieve a lesion depth ≥ 4.0 mm, the TFSE required an application duration 8-12 s longer than the STSF under similar settings.

CONCLUSIONS

The TFSE demonstrated a lower incidence of steam pops and superior predictability in lesion size compared to the STSF. However, the TFSE necessitated a longer application duration than the STSF to achieve an adequate lesion size.

Comparison of novel intrinsic versus conventional antitachycardia pacing for ventricular tachycardia among implantable cardioverter-defibrillator recipients

INTRODUCTION

Intrinsic antitachycardia pacing (iATP) is a novel automated antitachycardia pacing (ATP) that provides individual treatment to terminate ventricular tachycardia (VT). However, the clinical efficacy of iATP in comparison with conventional ATP is unknown. We aim to compare the termination rate of VT between iATP and conventional ATP in patients with implantable cardioverter-defibrillators using a unique setting of different sequential orders of both ATP algorisms.

METHODS

Patients with the iATP algorithm were assigned to iATP-first and conventional ATP-first groups sequentially. In the iATP-first group, a maximum of seven iATP sequences were delivered, followed by conventional burst and ramp pacing. In contrast, in the conventional ATP-first group, two bursts and ramp pacing were initially programmed, followed by iATP sequences. We compared the success rates of VT termination in the first and secondary programmed ATP zones between the two groups.

RESULTS

Fifty-eight and 56 patients were enrolled in the iATP-first and conventional ATP-first groups, and 67 and 44 VTs were analyzed in each group, respectively. At the first single ATP therapy, success rates were 64% and 70% in the iATP and conventional groups, respectively. At the end of the first iATP treatment zone, the success rate increased from 64% to 85%. Moreover, secondary iATP therapy following the failure of conventional ATPs increased the success rate from 80% to 93%. There was a significant benefit of alternative iATP for VT termination compared to secondary conventional ATP (100% vs. 33%, p = .028).

CONCLUSIONS

iATP may be beneficial as a secondary therapy after failure of conventional ATP to terminate VT.

Mechanisms of torsades de pointes: an update

Torsades de Pointes (TdP) refers to a polymorphic ventricular tachycardia (VT) with undulating QRS axis that occurs in long QT syndrome (LQTS), although the term has been used to describe polymorphic ventricular tachyarrhythmias in which QT intervals are not prolonged, such as short-coupled variant of TdP currently known as short-coupled ventricular fibrillation (VF) and Brugada syndrome. Extensive works on LQTS-related TdP over more than 50 years since it was first recognized by Dessertennes who coined the French term meaning "twisting of the points", have led to current understanding of the electrophysiological mechanism that TdP is initiated by triggered activity due to early afterdepolarization (EAD) and maintained by reentry within a substrate of inhomogeneous repolarization. While a recently emerging notion that steep voltage gradients rather than EADs are crucial to generate premature ventricular contractions provides additions to the initiation mode, the research to elucidate the maintenance mechanism hasn't made much progress. The reentrant activity that produces the specific form of VT is not well characterized. We have conducted optical mapping in a rabbit model of electrical storm by electrical remodeling (QT prolongation) due to chronic complete atrioventricular block and demonstrated that a tissue-island with prolonged refractoriness due to enhanced late Na+ current (INa-L) contributes to the generation of drifting rotors in a unique manner, which may explain the ECG characteristic of TdP. Moreover, we have proposed that the neural Na+ channel NaV1.8-mediated INa-L may be a new player to form the substrate for TdP. Here we discuss TdP mechanisms by comparing the findings in electrical storm rabbits with recently published studies by others in simulation models and human and animal models of LQTS.

Distributions and number of drivers on real-time phase mapping associated with successful atrial fibrillation termination during catheter ablation for non-paroxysmal atrial fibrillation

BACKGROUND

Real-time phase mapping (ExTRa™) is useful in determining the strategy of catheter ablation for non-paroxysmal atrial fibrillation (AF). This study aimed to investigate the features of drivers of AF associated with its termination during ablation.

METHODS

Thirty-six patients who underwent catheter ablation for non-paroxysmal AF using online real-time phase mapping (ExTRa™) were enrolled. A significant AF driver was defined as an area with a non-passively activated ratio of ≥ 50% on mapping analysis in the left atrium (LA). All drivers were simultaneously evaluated using a low-voltage area, complex fractionated atrial electrogram (CFAE), and rotational activity by unipolar electrogram analysis. The electrical characteristics of drivers were compared between patients with and without AF termination during the procedure.

RESULTS

Twelve patients achieved AF termination during the procedure. The total number of drivers detected on the mapping was significantly lower (4.4 ± 1.6 vs. 7.4 ± 3.8, p = 0.007), and the drivers were more concentrated in limited LA regions (2.8 ± 0.9 vs. 3.9 ± 1.4, p = 0.009) in the termination group than in the non-termination group. The presence of drivers 2-6 with limited (≤ 3) LA regions showed a tenfold increase in the likelihood of AF termination, with 83% specificity and 67% sensitivity. Among 231 AF drivers, the drivers related to termination exhibited a greater overlap of CFAE (56.8 ± 34.1% vs. 39.5 ± 30.4%, p = 0.004) than the non-related drivers. The termination group showed a trend toward a lower recurrence rate after ablation (p = 0.163).

CONCLUSIONS

Rotors responsible for AF maintenance may be characterized in cases with concentrated regions and fewer drivers on mapping.

Clinical outcomes and predictors of delayed echocardiographic response to cardiac resynchronization therapy

INTRODUCTION

The clinical outcomes and mechanisms of delayed responses to cardiac resynchronization therapy (CRT) remain unclear. We aimed to investigate the differences in outcomes and gain insight into the mechanisms of early and delayed responses to CRT.

METHODS

This retrospective study included 110 patients who underwent CRT implantation. Positive response to CRT was defined as ≥15% reduction of left ventricular (LV) end-systolic volume on echocardiography at 1 year (early phase) and 3 years (delayed phase) after implantation. The latest mechanical activation site (LMAS) of the LV was identified using two-dimensional speckle-tracking radial strain analysis.

RESULTS

Seventy-eight (71%) patients exhibited an early response 1 year after CRT implantation. Of 32 non-responders in the early phase, 12 (38%) demonstrated a delayed response, and 20 (62%) were classified as non-responders after 3 years. During the follow-up time of 10.3 ± 0.5 years, the delayed and early responders had a similar prognosis of mortality and heart failure (HF) hospitalization. In contrast, non-responders had a worse prognosis. Multivariate analysis revealed that a longer duration (months) between initial HF hospitalization and CRT (odds ratio [OR]: 1.126; 95% confidence interval [CI]: 1.036-1.222; p = .005), non-exact concordance of LV lead location with LMAS (OR: 32.744; 95% CI: 1.101-973.518; p = .044), and pre-QRS duration (OR: 0.901; 95% CI: 0.827-0.981; p = .016) were independent predictors of delayed response to CRT compared with early response.

CONCLUSION

The prognoses were similar regardless of the response time after CRT. A longer history of HF, suboptimal LV lead position, and shorter pre-QRS duration were related to delayed response than early response.

Triggers of Ventricular Fibrillation in Patients With Inferolateral J-Wave Syndrome

BACKGROUND

There are few data on ventricular fibrillation (VF) initiation in patients with inferolateral J waves.

OBJECTIVES

This multicenter study investigated the characteristics of triggers initiating spontaneous VF in inferolateral J-wave syndrome.

METHODS

A total of 31 patients (age 37 ± 14 years, 24 male) with spontaneous VF episodes associated with inferolateral J waves were evaluated to determine the origin and characteristics of triggers. The J-wave pattern was recorded in inferior leads in 11 patients, lateral leads in 3, and inferolateral leads in 17.

RESULTS

The VF triggers (n = 37) exhibited varying QRS durations (176 ± 21 milliseconds, range 119-219 milliseconds) and coupling intervals (339 ± 46 milliseconds, range 250-508 milliseconds) with a right (70%) or left (30%) bundle branch block (BBB) pattern. Trigger patterns were associated with J-wave location: left BBB triggers with inferior J waves and right BBB triggers with lateral J waves. Electrophysiologic study was performed for 22 VF triggers in 19 patients. They originated from the left or right Purkinje system in 6 and from the ventricular myocardium in 10 and were undetermined in 6. Purkinje vs myocardial triggers showed distinct electrocardiographic characteristics in coupling interval and QRS-complex duration and morphology. Abnormal epicardial substrate associated with fragmented electrograms was identified in 9 patients, with triggers originating from the same region in 7 patients. Catheter ablation resulted in VF suppression in 15 patients (79%).

CONCLUSIONS

VF initiation in inferolateral J-wave syndrome is associated with significant individual heterogeneity in trigger characteristics. Myocardial triggers have electrocardiographic features distinct from Purkinje triggers, and their origin often colocalizes with an abnormal epicardial substrate.

Stereotactic radiotherapy for ventricular tachycardia: A study protocol

Background

Currently, the standard curative treatment for ventricular tachycardia (VT) and ventricular fibrillation (VF) is radiofrequency catheter ablation. However, when the VT circuit is deep in the myocardium, the catheter may not be delivered, and a new, minimally invasive treatment using different energies is desired.

Methods

This is a protocol paper for a feasibility study designed to provide stereotactic radiotherapy for refractory VT not cured by catheter ablation after at least one catheter ablation. The primary end point is to evaluate the short-term safety of this treatment and the secondary endpoint is to evaluate its efficacy as assessed by the reduction in VT episode. Cyberknife M6 radiosurgery system will be used for treatment, and the prescribed dose to the target will be 25Gy in one fraction. The study will be conducted on three patients.

Conclusion

Since catheter ablation is the only treatment option for VT that is covered by insurance in Japan, there is currently no other treatment for VT/VF that cannot be cured by catheter ablation. We hope that this feasibility study will provide hope for patients who are currently under the stress of ICD activation.

Trial registration

The study has been registered in the Japan Registry of Clinical Trials (jRCTs042230030).

Association Between Catheter Ablation for Nonparoxysmal Atrial Fibrillation and Functional Mitral Regurgitation in Patients With Heart Failure With Preserved Ejection Fraction

Functional mitral regurgitation (FMR) often coexists with atrial fibrillation (AF) and may have a causal relation with AF persistence and exacerbation of heart failure (HF). The purpose of this study was to investigate the impact of FMR on AF catheter ablation (AFCA) outcomes and improvement in FMR after AFCA in patients with HF with preserved ejection fraction (HFpEF) and nonparoxysmal AF. Excluding patients with primary valve disease or post-mitral valve repair, 280 patients with HFpEF who underwent CA for nonparoxysmal AF were retrospectively included. All patients completed 1-year follow-up and were assessed for FMR, AF recurrence and HF parameters, including echocardiography. At baseline, FMR was present in 153 (54.6%) patients (mild, n = 112; moderate, n = 40; severe, n = 1), and these were decreased to 70 (25%) significantly 1 year after AFCA (mild, n = 64; moderate, n = 6), 119 patients (78%) had improvement in MR (a decrease of ≥1 level in the severity from baseline to 1 year on echocardiography). Overall, 274 patients (97.9%) had sinus rhythm at the 1-year examination, and recurrent AF-free survival did not differ in patients with and without MR improvement (83.2% vs 82.4%, p = 0.908). However, the MR improvement group had a significantly lower cardiothoracic ratio, left atrial diameter, E/e', and B-type natriuretic peptide levels after 1 year than those in the MR nonimprovement group. In conclusion, the majority of the HFpEF patients with nonparoxysmal AF had improvement of FMR after AFCA with the high maintenance of sinus rhythm, leading to a virtuous cycle of cardiac function.

Elevated liver fibrosis-4 index predicts recurrence after catheter ablation for atrial fibrillation in patients with heart failure

BACKGROUND

The fibrosis-4 (FIB-4) index is a noninvasive scoring system that is used to assess the progression of liver fibrosis. This study aimed to assess whether the FIB-4 index is associated with recurrent atrial fibrillation (AF) after catheter ablation in patients with and without heart failure (HF).

METHODS

We included 1,184 patients who underwent initial AF catheter ablation between 2016 and 2021. The patients were classified into low-risk (< 1.3), intermediate-risk (1.3-2.67), and high-risk (> 2.67) groups based on their FIB-4 indices at baseline. The patients were divided into HF (n = 552) and non-HF groups (n = 632); the HF group was further divided into paroxysmal AF (PAF) and non-PAF groups. AF recurrence after catheter ablation was then compared among the groups.

RESULTS

In the non-HF group, no significant differences in recurrence after ablation were observed between the low-(n = 219), intermediate-(n = 364), and high-risk (n = 49) groups. In contrast, in the HF group, the intermediate-(n = 341) and high-risk (n = 112) groups had significantly higher recurrence rates than the low-risk group (n = 99) (log-rank test, p = 0.005). This association remained significant after multivariate analysis (hazard ratio [HR]:1.374; p = 0.027). The FIB-4 index increased incrementally as the brain natriuretic peptide levels and severity of tricuspid regurgitation increased. The FIB-4 index was an independent predictor of recurrence in the non-PAF HF group (HR:1.498; p = 0.007) but not in the PAF group.

CONCLUSIONS

The FIB-4 index may be a useful predictor of AF recurrence after catheter ablation in patients with HF, particularly in those with non-PAF.

Initial multicenter clinical experience with the first-generation endoscopic guided laser balloon in Japan

BACKGROUND

Isolation of the pulmonary veins (PVs) is the golden standard for atrial fibrillation (AF) ablation. To achieve a permanent PV isolation, the endoscopic guided HeartLight laser balloon system was invented. We analyzed the safety and efficacy of this laser balloon system.

METHODS AND RESULTS

Three hundred four patients from 21 investigational sites inside Japan were enrolled in this study. One thousand sixty-two out of 1175 PVs (90.4%) were isolated using the HeartLight laser balloon. The isolation rate of the left superior, left inferior, right superior, and right inferior PVs was 87.8%, 91.3%, 91.6%, and 92.1%, respectively. The procedure time, defined as the time from the venous access to taking out the balloon, was 155 ± 39 min. The fluoroscopic time was 44 ± 25 min. The mean follow-up period was 309 ± 125 days. The freedom from AF recurrence at 3 months was 89.0% and at 12 months 82.1%. Adverse events occurred in 22 patients (7.2%) including phrenic nerve injury lasting more than 3 months in 1.6% and strokes in 1.0% of the patients.

CONCLUSIONS

This initial experience demonstrated that the laser balloon ablation was feasible for PV isolation in Japanese AF patients.

Lethal ventricular arrhythmia due to entrectinib-induced Brugada syndrome: a case report and literature review

Entrectinib, a multikinase inhibitor of ROS1 and tropomyosin receptor kinases, is recommended to treat ROS1-positive metastatic non-small cell lung cancer (NSCLC). In a previous study, entrectinib-related cardiotoxicity occurred in 2% of patients; however, lethal arrhythmias remain understudied. We encountered a case of fatal arrhythmia due to drug-induced Brugada syndrome caused by entrectinib. An 81-year-old Japanese male with lung adenocarcinoma harboring ROS1-fusion gene was treated with entrectinib. The patient developed lethal arrhythmias three days after drug initiation, including ventricular tachycardia with Brugada-like electrocardiogram changes. Echocardiography and coronary angiography revealed no evidence of acute coronary syndrome or myocarditis. Following the termination of entrectinib, the electrocardiogram abnormality improved within 12 days. Hence, paying special attention to and monitoring electrocardiogram changes is necessary. In addition, it is also necessary to consider early therapeutic interventions and discontinuation of the drug in cases of drug-induced Brugada syndrome.

Different time course effect of autonomic nervous modulation after cryoballoon and hotballoon catheter ablations for paroxysmal atrial fibrillation

BACKGROUND

Few studies have reported on the quantitative evaluation of autonomic nerve modification after balloon ablation. Therefore, this study aimed to evaluate the effects of cryoballoon and hotballoon ablations on the autonomic nervous system (ANS) and their relationship with prognosis.

METHODS

We included 234 patients who underwent cryoballoon ablation (n = 190) or hotballoon ablation (n = 44) for paroxysmal atrial fibrillation. Heart rate variability (HRV) analysis was performed on all patients using a 3-min electrocardiogram at baseline, 1, 3, 6, and 12 months after ablation. HRV parameters and prognoses were compared between the two balloon systems.

RESULTS

Ln low-frequency (LF), Ln high-frequency (HF), standard deviation of the R-R intervals (SDNN), and RR intervals significantly decreased after 1 month in both groups, but the changes were more pronounced in the cryoballoon group than in the hotballoon group. In contrast, HRV indices in the hotballoon ablation group decreased gradually and reached their lowest point 3-to-6 months after the procedure, which was later than in the cryoballoon ablation group. The recurrence rate did not differ between the two groups. HRV parameters changed similarly in the cryoballoon group, regardless of recurrence. However, patients with recurrence had significantly higher SDNN and Ln LF at 12 months than those without recurrence in the hotballoon group (41.2 ± 39.3 ms vs. 18.5 ± 12.6 ms, p = 0.006, and 2.2 ± 0.7 ms² vs. 1.5 ± 0.7 ms², p = 0.003, respectively).

CONCLUSIONS

The time course of HRV changes differed between cryoballoon and hotballoon ablations. Hence, the two balloon systems may have distinct effects on the ANS and its role in prognosis.

A rare case of delayed complete lead dislodgement after deep septal pacing: A hidden risk of the specific procedure

Deep septal ventricular pacing is a recently developed physiological pacing modality with good efficacy; however, it has a potential risk of unusual complications. Here, we report a patient with pacing failure and spontaneous, complete lead dislodgement after >2 years of deep septal pacing, possibly caused by systemic bacterial infection and specific lead behavior in the septal myocardium. This case report may implicate a hidden risk of unusual complications in deep septal pacing.

A novel practical algorithm using machine learning to differentiate outflow tract ventricular arrhythmia origins

INTRODUCTION

Diagnosis of outflow tract ventricular arrhythmia (OTVA) localization by an electrocardiographic complex is key to successful catheter ablation for OTVA. However, diagnosing the origin of OTVA with a precordial transition in lead V3 (V3TZ) is challenging. This study aimed to create the best practical electrocardiogram algorithm to differentiate the left ventricular outflow tract (LVOT) from the right ventricular outflow tract (RVOT) of OTVA origin with V3TZ using machine learning.

METHODS

Of 498 consecutive patients undergoing catheter ablation for OTVA, we included 104 patients who underwent ablation for OTVA with V3TZ and identified the origin of LVOT (n = 62) and RVOT (n = 42) from the results. We analyzed the standard 12-lead electrocardiogram preoperatively and measured 128 elements in each case. The study population was randomly divided into training group (70%) and testing group (30%), and decision tree analysis was performed using the measured elements as features. The performance of the algorithm created in the training group was verified in the testing group.

RESULTS

Four measurements were identified as important features: the aVF/II R-wave ratio, the V2S/V3R index, the QRS amplitude in lead V3, and the R-wave deflection slope in lead V3. Among them, the aVF/II R-wave ratio and the V2S/V3R index had a particularly strong influence on the algorithm. The performance of this algorithm was extremely high, with an accuracy of 94.4%, precision of 91.5%, recall of 100%, and an F1-score of 0.96.

CONCLUSIONS

The novel algorithm created using machine learning is useful in diagnosing the origin of OTVA with V3TZ.

HotBalloon Pulmonary Vein Isolation Registry Study - Real-World Efficacy and Safety of HotBalloon Ablation

BACKGROUND

Radiofrequency hotballoon (RHB) is an ablation device used for atrial fibrillation (AF) treatment. The efficacy and safety of RHB-based pulmonary vein isolation (PVI) in real-world practice are unknown.Methods and Results: A multicenter, prospective registry study (UMIN000029567) enrolled AF patients who underwent RHB-PVI. The primary endpoint was the AF recurrence-free survival rate at 12 months after PVI. Of the 679 patients enrolled, 613 (90.3%; paroxysmal AF, n=370; persistent AF, n=136; long-standing AF, n=107) underwent initial RHB-PVI. Acute isolation using only the RHB was successful for 55.6% of patients and 83.5% of pulmonary veins (PVs). The acute isolation rate was higher for patients with paroxysmal AF and more experienced centers. Antiarrhythmic drugs were prescribed after 3 months for 47.5% of patients. The AF recurrence-free survival rate at 12 months was 83.7%. Procedure-related complications including atrio-esophageal fistula (n=1) and phrenic nerve injury (persistent; n=4, permanent; n=2) were observed in 19 (3.1%) patients. Five (1.7%) of the 302 patients who underwent pre-procedural and post-procedural multidetector computed tomography had severe PV stenosis.

CONCLUSIONS

The size-adjustable RHB has been used for the treatment of various AF types. The arrhythmia recurrence-free rate at 12 months, with the use of antiarrhythmic drugs in approximately half of the patients, was acceptable, but the acute isolation rate using the RHB requires further improvement.

A case of successful catheter ablation of blocked atrial bigeminy and bradycardia with the recovery of normal sinus rhythm and myocardial reverse remodeling

A 69-year-old man presented bradycardia with a constant blocked atrial bigeminy and heart failure. Successful catheter ablation of blocked atrial bigeminy with bradycardia resulted in myocardial reverse remodeling and restoration of the normal sinus rhythm from the ectopic atrial rhythm.

Efficacy and feasibility of cryoballoon ablation for atrial fibrillation in patients with heart failure: A large-scale multicenter study

INTRODUCTION

Data are limited regarding outcomes of cryoballoon ablation for atrial fibrillation (AF) in patients with heart failure (HF). This large-scale multicenter study aimed to evaluate the prognosis of patients with HF after cryoballoon ablation for AF.

METHODS

Among 3655 patients undergoing cryoballoon ablation at 17 institutions, 549 patients (15%) (391 with paroxysmal AF and 158 with persistent AF) diagnosed with HF preoperatively were analyzed. Clinical endpoints were recurrence, mortality, and HF hospitalization after ablation.

RESULTS

Most patients had a preserved left ventricular ejection fraction (LVEF) ≥ 50%. During a mean follow-up period of 25.7 months, recurrence, all-cause death, and HF hospitalization occurred in 29%, 4.0%, and 4.8%, respectively. Cardiac function on echocardiography and B-type natriuretic peptide (BNP) levels significantly improved postoperatively, and the effect was more pronounced in the nonrecurrence group. Major complications occurred in 33 patients (6.0%), but most complications were phrenic nerve palsy (3.6%). Although death and HF hospitalization occurred more frequently in patients with LVEF ≤ 40% (n = 73) and New York Heart Association (NYHA) class III-IV (n = 19) than other subgroups, the BNP levels, and LVEF significantly improved after ablation in all LVEF and NYHA class subgroups. High BNP levels, NHYA class, CHADS₂ score, and structural heart disease, but not postablation recurrence, independently predicted death, and HF hospitalization on multivariate analysis. The patients with tachycardia-induced cardiomyopathy had better recovery of BNP levels and LVEF after ablation than those with structural heart disease.

CONCLUSIONS

Cryoballoon ablation for AF in HF patients is feasible and leads to significantly improved cardiac function.

Evaluation of the direction and extent of ice formation during cryoballoon ablation: an experimental study

BACKGROUND

The distal hemisphere of a balloon is generally cooled during cryoapplication. However, a wide ablation area can be acquired after cryoballoon ablation. This study aimed to evaluate the extent of ice formation on two types of balloon surfaces through experimental and simulation studies.

METHODS

A standard cryoballoon (SCB; Arctic Front Advance Pro, Medtronic) and novel cryoballoon (NCB; POLARx, Boston Scientific) were frozen for 240 s in 36 °C normal saline solution to observe ice formation on the balloon surface. Pieces of porcine tissue were placed between the upper and lower sides of the balloon, and the balloon was frozen in the horizontal direction for 240 s in 20 attempts (10 for SCB and NCB each). The measured areas of ice formation were evaluated and compared between the upper and lower sides of each balloon.

RESULTS

Ice formation was greater on the lower side of the balloon than on the upper side. A larger area of ice formation in the tissue slab was observed on the lower side than on the upper side in both balloons, and the ice formation extended to the proximal hemisphere on the lower side of the balloon. The ice formation area in the NCB was significantly larger than that in SCB.

CONCLUSIONS

Ice formation was significantly greater on the lower side of the cryoballoon than on the upper side and extended to the proximal hemisphere of the balloon, which might facilitate the acquisition of a wide ablation area on the left atrial posterior wall after cryoballoon ablation. Different ice formation after cryoballoon ablation Greater ice formation on the lower side of cryoballoon and an extensive ice formation in the proximal hemisphere, especially in novel cryoballoon.

Regional left atrial conduction velocity in the anterior wall is associated with clinical recurrence of atrial fibrillation after catheter ablation: efficacy in combination with the ipsilateral low voltage area

Background

Left atrial (LA) conduction velocity (CV) is an electrical remodeling parameter of atrial fibrillation (AF) substrate. However, the pathophysiological substrate of LA-CV and its impact on outcomes after catheter ablation for AF have not been well evaluated.

Methods

We retrospectively evaluated 119 patients with AF who underwent catheter ablation and electroanatomical mapping during sinus rhythm. To measure regional LA-CV, we took triplet sites (A, B, and C) on the activation map and calculated the magnitude of the matched orthogonal projection vector between vector-AB and vector-AC, indicating two-dimensional CV. The median of the LA-CVs from four triad sites in both the anterior and posterior walls was set as the ‘model LA-CV’. We evaluated the impact of the model LA-CV on recurrence after ablation and relationship between the model LA-CV and LA-low voltage area (LVA) of < 0.5 mV.

Results

During the 12-month follow-up, 29 patients experienced recurrence. The LA-CV model was significantly correlated with ipsilateral LVA. The lower anterior model LA-CV was significantly associated with recurrence, with the cut-off value of 0.80 m/s having a sensitivity of 72% and specificity of 67%. Multivariable analysis revealed that the anterior model LA-CV (hazard ratio, 0.09; 95% confidence interval, 0.01–0.94; p = 0.043) and anterior LA-LVA (hazard ratio, 1.06; 95% confidence interval, 1.00–1.11; p = 0.033) were independently associated with AF recurrence. The anterior LA-LVA was mildly correlated with the anterior model LA-CV (r = -0.358; p < 0.001), and patients with both lower LA-CV and greater anterior LA-LVA based on each cut-off value had the worst prognosis. However, decreased LA-CV was more likely to be affected by the distribution pattern of the LVA rather than the total size of the LVA.

Conclusion

Decreased anterior LA-CV was a significant predictor of AF recurrence and was a useful electrical parameter in addition to LA-LVA for estimating AF arrhythmogenicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02881-6.

The ridge line of left pulmonary vein isolation from left atrial appendage can subsequently increase the completion rate of the mitral isthmus block line

BACKGROUND AND OBJECTIVES

Mitral isthmus (MI) ablation for mitral flutter is technically difficult, and incomplete block line is not uncommon. The objective of this study is to investigate the effect of the ridge line of left pulmonary vein isolation (LPVI) from left atrial appendage (LAA) on completion rate of mitral isthmus (MI) block line and recurrence rate of atrial tachycardia (AT) or atrial flutter (AFL) after the first MI ablation.

METHODS

We identified 611 patients who underwent first MI ablation for mitral flutter during the study period. Finally, 559 patients were enrolled and divided into two groups according to the method of ridge line ablation of LPVI (LAA group, n = 467, conventional group, n = 92). Outcome measures were the completion of MI block line by first MI ablation, the recurrence of AT/AFL, and repeat MI ablation after the first MI ablation.

RESULTS

The first MI block line completion rate was significantly higher in the LAA group than the conventional group (95% vs. 85%, p < 0.001). The recurrence rate of AT/AFL after 3 months from first MI ablation was significantly lower in the LAA group. The requirement of additional MI ablation tended to be lower in the LAA group.

CONCLUSIONS

Our novel approach of ablating LPV-LAA ridge from the LAA side during PVI can increase the success rate of MI block line completion, and reduce the recurrence rate of AT/AFL and the need for additional MI block line ablation. Graphical abstract Ablation of the left pulmonary vein-left atrial appendage ridge from the left atrial appendage side during PVI increased the success rate of mitral isthmus block line completion.

Depolarization and repolarization dynamics after His-bundle pacing: Comparison with right ventricular pacing and native ventricular conduction

Background

The current study aimed to evaluate changes in electrical depolarization and repolarization parameters after His‐bundle pacing (HBP) compared with right ventricular pacing (RVP) and its association with ventricular arrhythmia (VA).

Methods

Forty‐one patients (13 with HBP, 14 with RVP, and 14 controls [AAI mode]) were evaluated. After continuous pacing algorithm, QRS duration, QT interval, QTc, JT interval, T‐peak to T‐end (Tpe), and Tpe/QT ratio were measured on electrocardiography at baseline and 1 week, 1 month, and 6 months postoperatively. We investigated VA occurrence and adverse events after implantation.

Results

At 6 months, QRS duration was significantly shorter in the HBP (121.6 ± 15.6 ms) than in the RVP (150.1 ± 14.9 ms) group. The QT intervals were lower in the HBP (424.0 ± 40.9 ms) and control (405.9 ± 23.0 ms) groups than in the RVP (453.0 ± 40.2 ms) group. The Tpe and Tpe/QT ratios at 6 months differed significantly between the HBP and RVP groups (Tpe, 69.8 ± 19.7 ms vs 87.4 ± 11.9 ms and Tpe/QT, 0.16 ± 0.03 vs 0.19 ± 0.02, respectively). The Tpe and Tpe/QT ratios were similarly shortened in the HBP and control groups. VA occurred less frequently in the HBP (15%) and control (7.1%) groups than in the RVP (50%) group (p = 0.020). The non‐RVP group showed significantly lower rates of VA and major adverse events than the RVP group. Patients with VA demonstrated significantly longer QRS duration, QT interval, Tpe, and Tpe/QT at 6 months than those without VA.

Conclusion

HBP showed better depolarization and repolarization stability than RVP.

Higher F-wave frequency associates with poor procedural success rate after Maze procedure

OBJECTIVES

Persistent atrial fibrillation (AF) causes atrial remodeling, which causes myocardial fibrosis and micro-reentry. Fibrosis may reduce wave voltage and micro-reentry may enhance the dominant frequency (DF) of the F-wave. We investigated whether the DF predicts procedural success by the Maze procedure.

METHODS

In 138 consecutive patients who underwent mitral valve surgery and a modified Cox-Maze III procedure for persistent AF in Nagoya University in 2002-2018, 96 (70%) were successfully cardioverted (group S); 42 had persistent or relapsed AF after surgery (group F). Patient data were compared between the groups. Cut-off values were determined by an ROC analysis and predictors of procedural success were evaluated. The DF was obtained from the F-wave of V1 by a high-speed Fourier analysis using the CEPAS software program.

RESULTS

Group F showed a significantly larger LA diameter, better LVEF, lower F-wave voltage, higher DF, and longer duration of AF. The cut-off values were as follows: LA diameter, 56 mm; EF, 64.5%; F-wave voltage, 0.13 mV; DF, 7.3 Hz; and duration of AF, 44 months. Each factor showed statistical significance in a univariate analysis; DF lost significance in the multivariate analysis. The higher (DF ≥ 7.3 Hz) and lower voltage group (≤ 0.13 mV) showed the worst procedural success rate (36%), while the lower DF (< 7.3 Hz) and higher voltage group (> 0.13 mV) showed a good rate (86%).

CONCLUSIONS

The DF of the F-wave is a useful predictor of procedural success after the Maze procedure in addition to the voltage of F-wave.

Septal coronary artery fistula after left bundle branch area pacing assessed by multi-imaging modalities and shunt volume quantification

Septal coronary artery fistula is a rare but concerning complication of left bundle branch area pacing (LBBAP). We report the case of an 82-year-old man who was indicated for cardiac resynchronization therapy and underwent LBBAP. The patient had no chest symptoms during or after implantation. Postoperative echocardiography demonstrated a new abnormal tunnel inside the interventricular septum (IVS) and shunt flow from the IVS toward the right ventricle. Coronary angiography confirmed a septal coronary artery fistula, which might have been formed by failed deep screw attempts. Since the shunt volume assessed by the Q_p /Q_s was small, the patient was treated conservatively.

Evaluation of the Novel Automated Anti-Tachycardia Pacing Algorithm Successfully Terminating Sustained Monomorphic Ventricular Tachycardia in an Electrophysiology Study

We report the usefulness of novel automated anti-tachycardia pacing (ATP) for ventricular tachycardia (VT) termination evaluated in an electrophysiology study. This intrinsic, automated ATP with an implanted cardiac resynchronization therapy-defibrillator successfully terminated the sustained VT, which had not been suppressed by repetitive burst pacing from the electrode catheter. The reproduction of programed pacing of the automated ATP by a right ventricular electrode catheter was effective in terminating VT, and this termination was absolute and reproducible. Further detailed assessment in an electrophysiology study could highlight the algorithm of the automated ATP and its possible benefit in terminating the reentrant VT.

＜Editors' Choice＞ Very long-term clinical outcomes after percutaneous coronary intervention for complex vs non-complex lesions: 10-year outcomes following sirolimus-eluting stent implantation

Few studies have reported the long-term outcomes (>10 years) following first-generation drug-eluting stent implantation. In this single-center retrospective study, we investigated the very long-term clinical outcomes after first-generation sirolimus-eluting stent (SES) implantation in patients with complex lesions. The study included 383 consecutive patients who underwent initial SES implantation between July 2004 and January 2006; 84 and 299 of these patients reported a history of percutaneous coronary intervention (PCI) for complex and noncomplex lesions, respectively. Complex PCI was defined as having at least one of the following features: left main trunk PCI, implantation of ≥3 stents, bifurcation lesions with implantation of 2 stents, total stent length >60 mm, or chronic total occlusion. The target lesion revascularization (TLR) rate was significantly higher in the complex PCI than in the noncomplex PCI group (29.4% vs 13.0%, P=0.001), and we observed a significant intergroup difference in the late TLR (>1 year) rates (21.6% vs 9.5%, P=0.008). Late TLR continued over 10 years at a rate of 2.4%/year in the complex PCI and 1.1%/year in the noncomplex PCI group. Cox regression analysis revealed that complex PCI was related to TLR both over 10 years (hazard ratio 2.29, P=0.003) and beyond 1 year (hazard ratio 2.32, P=0.01). Cardiac death was more common in the complex PCI than in the noncomplex PCI group, particularly 4 years after PCI (15.8% vs 7.5%, P=0.031). Sudden death was the major cause of cardiac death beyond 4 years in the complex PCI group. These data indicate that long-term careful follow-up is essential for patients implanted with SES, especially those treated for complex lesions.

Comparison of the empirical linear ablation and low voltage area-guided ablation in addition to pulmonary vein isolation in patients with persistent atrial fibrillation: a propensity score-matched analysis

Background

The efficacy of pulmonary vein isolation (PVI) alone is not guaranteed for persistent atrial fibrillation (PeAF), and it is unclear which type of ablation approach should be applied in addition to PVI. This study aimed to compare outcomes and prognosis between empirical linear ablation and low-voltage area (LVA) ablation after PVI for PeAF.

Methods

We enrolled 128 patients with PeAF who were assigned to the linear ablation group (n = 64) and the LVA ablation group (n = 64) using a propensity score-matched model. After PVI and cardioversion, the patients underwent either empirical linear ablation or LVA ablation during sinus rhythm. All patients in the linear ablation group underwent both roof line and mitral valve isthmus (MVI) ablations. An electrical-guided ablation targeting LVA (< 0.5 mV) was performed in the LVA group. When there was no LVA in the LVA group, only PVI was applied. We compared the procedural outcomes and recurrence after ablation between the two groups.

Results

The baseline characteristics were well-balanced between the two groups. Fifty patients had LVA (22 and 28 patients in the linear and LVA groups). The roof and MVI lines were completed in 100% and 96.9% of the patients. During the mean follow-up of 279.5 ± 161.3 days, the LVA group had significantly lower recurrence than the linear group (15 patients [23%] vs. 29 patients [45%], p = 0.014). Thirty-five patients were prescribed antiarrhythmic drugs during the follow-up period (linear group, n = 17; LVA group, n = 18); amiodarone and bepridil were administered to most of the patients (15 and 17 patients, respectively). The difference in the prognosis was relevant among the patients with LVA, while this trend was not observed in those without LVA. The LVA ablation group demonstrated significantly lower radiofrequency energy and shorter procedural time compared to the linear ablation group. The recurrence of atrial flutter was more likely to occur in the linear group than in the LVA group (14 [22%] vs. 6 [9.4%], p = 0.052).

Conclusion

The electrophysiological-guided LVA ablation is more effective than empirical linear ablation in PeAF patients with LVA. Unnecessary empirical linear ablation might have a risk of iatrogenic gap and atrial flutter recurrence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02460-9.

Short coupling interval with high burden of atrial ectopy predicts recurrence after atrial fibrillation ablation

Atrial ectopy (AE) with a short coupling interval (S-AE) causes atrial fibrillation (AF). A higher burden of AE is associated with recurrence after AF ablation. However, a few reports have evaluated the prognostic impact of both AE burden and S-AE after the acute phase of ablation. This study aimed to assess the characteristics of AE beyond the blanking period in predicting the recurrence. We retrospectively analyzed 173 patients who underwent first catheter ablation for AF and 24-h Holter recording following a 3-month blanking period. AE was defined as a narrow QRS complex occurring < 75% earlier than the prior reference R-R interval. We investigated the relationship between the AE's characteristics in Holter recordings and atrial arrhythmia recurrence. Forty-two patients (24%) had a recurrence during a median 488-day follow-up. Patients with S-AE (minimum coupling interval ratio of AE ≤ 45%) had a higher recurrence rate than those without S-AE (44.9% vs. 16.1%, p < 0.001). Moreover, patients with AE ≥ 241/day exhibited a significantly higher recurrence rate than those with AE < 241/day (44.3% vs. 10.7%, p < 0.001). In multivariate analysis, S-AE with a higher AE burden was an independent predictor of recurrence (hazard ratio 5.82, 95% confidence interval: 2.64-12.82, p < 0.001). Kaplan-Meier analysis showed that patients with S-AE and a higher AE burden had the worst prognosis for recurrence (p < 0.001). The combination of a higher AE burden with S-AE could be an efficient predictor of recurrence. These results can help to develop follow-up strategies after AF ablation.

Cryoballoon ablation for atrial fibrillation without the use of a contrast medium: a combination of the intracardiac echocardiography and pressure wave monitoring guided approach

In cryoballoon ablation (CBA), a contrast medium is commonly used to confirm balloon occlusion of the pulmonary veins (PVs). However, a contrast medium cannot always be used in patients with renal dysfunction and allergy. The present study aimed to assess the efficacy and safety of CBA without the use of a contrast medium. We retrospectively examined consecutive patients with paroxysmal atrial fibrillation (PAF) who underwent first-time CBA. We compared the procedural results and outcomes in patients for whom a contrast medium was used (contrast group) and those from whom a contrast medium was not used (non-contrast group). In the non-contrast group, we used saline injection on the intracardiac echocardiography and pressure wave monitoring for PV occlusion. Fifty patients (200 PVs) and 22 patients (88 PVs) underwent CBA with and without a contrast medium, respectively. The success rate of PV isolation with CBA alone was 93% and 90% in the non-contrast and contrast groups, respectively (p = 0.40). The fluoroscopy time and nadir temperature were significantly lower in the non-contrast group as compared to that in the contrast group. The recurrence rate 1 year after ablation did not differ between the two groups (18% vs. 18%, p > 0.99). Furthermore, the number of reconnected PVs in patients with recurrence was significantly lower in the non-contrast group than in the contrast group (6% vs. 36%, p = 0.017). In conclusion, CBA using the intracardiac echocardiography and pressure monitoring approach without the use of a contrast medium was safe and efficient.

Earliest pulmonary vein potential-guided cryoballoon ablation is associated with better clinical outcomes than conventional cryoballoon ablation: A result from two randomized clinical studies

INTRODUCTION

With regard to short-term outcome in atrial fibrillation (AF), the benefit of cryoballoon ablation (CBA) by pressing a balloon against the earliest pulmonary vein (PV) potential site during PV isolation (earliest potential [EP]-guided CBA) has been previously demonstrated. The present study aimed to evaluate the long-term outcome of the EP-guided CBA.

METHODS AND RESULTS

This study included 136 patients from two randomized studies, who underwent CBA for paroxysmal AF for the first time. Patients were randomly assigned to the EP-guided and conventional CBA groups in each study. In the EP-guided CBA group, we pressed a balloon against the EP site when the time-to-isolation (TTI) after cryoapplication exceeded 60 and 45 s in the first and second studies, respectively. We compared the clinical outcomes for 1 year after the procedure between the EP-guided CBA group (68 patients) and the conventional CBA group (68 patients). The primary endpoint was the recurrence of atrial arrhythmia after ablation. No significant differences in baseline characteristics were observed between the two groups. Compared with the conventional CBA group, the EP-guided CBA group had a significantly higher success rate at TTI ≤ 90 s (98.5% vs. 90.0%, p < .001); lower touch-up rate and total cryoapplication; and shorter procedure time, and fluoroscopy time. The recurrence at 1 year after ablation was significantly lower in the EP-guided CBA group than in the conventional CBA group (6.0% vs. 19.4%; p = .019).

CONCLUSIONS

The EP-guided CBA approach can facilitate the ablation procedure and achieve low recurrence at 1 year after ablation.

Permanent His-bundle pacing using distal His-bundle electrogram-guided approach in patients with atrioventricular block

BACKGROUND

Permanent His-bundle pacing (HBP) is effective and safe; however, the success rate of HBP is low, especially in patients with infranodal block. This study aimed to assess the efficacy and feasibility of HBP implantation using an electrophysiological guided approach targeting a distal His-bundle electrogram (HBE) in patients with atrioventricular block (AVB).

METHODS

Thirty-four consecutive patients with AVB (infranodal block in 28 patients) who underwent HBP were enrolled. During implantation, we attempted to target the distal part of the HBE (distal HBE) beyond the block site based on unipolar mapping. The His-capture threshold was evaluated for 1 year after implantation.

RESULTS

HBP was achieved in 26 patients and in 21 patients (75%) with infranodal block. Detection of distal HBE was significantly higher in the successful HBP group than in the HBP failure group (65.4% vs. 0%, p = .001). Among 15 patients with intra-Hisian block, 14 patients (93%) successfully achieved HBP with distal HBE detection. During the 1-year follow-up period, an increase in His-capture threshold by ≥1.0 V at 1.0 ms occurred in five (19.2%) of 26 patients. The increased His-capture threshold group exhibited significantly less detection of distal HBE (20% vs. 76.2%; odds ratio 0.078, 95% confidence interval 0.07-0.87, p = .038) and a higher His-capture threshold at implantation (2.0 ± 1.1 V vs. 1.1 ± 0.9 V; odds ratio 1.702, 95% confidence interval 1.025-2.825, p = 0.04) than the non-increased His-capture threshold group.

CONCLUSION

HBP implantation guided by distal HBE approach may be feasible with subsequent stable pacing in patients with intra-Hisian and atrioventricular nodal block.

Incidence of Left Atrial Thrombus Development and Imaging Approach in Patients Scheduled for Repeat Catheter Ablation for Atrial Fibrillation

The risk for developing left atrial (LA) thrombi after initial catheter ablation for atrial fibrillation (AF) and requirements for imaging evaluation for thrombi screening at repeat ablation is unclear. This study aimed to assess the occurrence of thrombus development and frequency of any imaging study evaluating thrombus formation during repeat ablation for AF. Of 2,066 patients undergoing initial catheter ablation for AF with uninterrupted oral anticoagulation, 615 patients underwent repeat ablation after 258.0 (105.0-882.0) days. We investigated the factors associated with safety outcomes and requirements for thrombus screening. All patients underwent at least one imaging examination to screen for thrombi in the initial session; however, the examination rate decreased to 476 patients (77%) before the repeat session. The frequency of imaging evaluations was 5.0%, 11%, 21%, 84%, and 91% for transesophageal echocardiography and 18%, 33%, 49%, 98%, and 99% for any imaging modality at repeat ablation performed ≤60 days, ≤90 days, ≤180 days, >180 days, and >1 year after the initial session, respectively. Three patients (0.5%) developed LA thrombi at repeat ablation due to identifiable causes, and no patients experienced thromboembolic events when no imaging evaluation was performed. Multivariate analysis revealed that repeat ablation performed after >180 days, non-paroxysmal atrial arrhythmias, and lower left ventricular ejection fraction were predictors of thrombus development and severe spontaneous echocardiography contrast. In conclusion, the risk for thrombus development at repeat ablation for AF was low. There needs to be a risk stratification of the imaging screening for thrombi at repeat ablation.

Impact of Preoperative Nutritional Status on the Outcome of Catheter Ablation for Atrial Fibrillation

BACKGROUND

The relationship between nutritional status and the incidence or prognosis of atrial fibrillation (AF) has been reported, but no studies have described the relationship between the outcomes of AF catheter ablation (CA) and nutritional status as assessed by various scoring tools. We aimed to verify the hypothesis that preoperative nutritional status is associated with arrhythmia recurrence after CA for AF.Methods and Results:We evaluated 913 patients (age, 67±10 years; men, 72%; paroxysmal AF, 56%) who underwent CA for AF between November 2011 and November 2017. Patients were systematically followed with an endpoint of atrial tachyarrhythmia recurrence, the predictive value of which was compared among 3 scoring tools (Controlling Nutritional Status [CONUT] score / Geriatric Nutritional Risk Index [GNRI] / Prognostic Nutritional Index [PNI]). Patients were divided into normal nutrition (CONUT <2 [n=637] / GNRI >98 [n=836] / PNI >38 [n=910]) and undernutrition (CONUT ≥2 [n=276] / GNRI ≤98 [n=77] / PNI ≤3 [n=3]) groups. AF recurred in 274 patients (mean follow-up, 2.3±0.8 years). The AF recurrence rate was higher in patients with undernutrition than in those with normal nutrition (CONUT/GNRI) status. Multivariate Cox regression analysis identified undernutrition status (GNRI ≤98) as an independent predictor of atrial tachyarrhythmia recurrence.

CONCLUSIONS

The AF recurrence rate after CA was higher in patients with undernutrition than in those with normal nutrition as stratified by the nutrition scoring tools.

Dynamic Changes in Electrocardiogram Parameters After Epicardial Substrate Catheter Ablation of Brugada Syndrome

BACKGROUND

Catheter ablation (CA) is effective for recurrent episodes of ventricular fibrillation (VF) in Brugada syndrome (BrS). VF development in BrS is associated with several electrocardiogram (ECG) abnormalities. This study investigated changes in ECG parameters in high-risk BrS patients who underwent epicardial CA.Methods and Results:In all, 27 BrS patients were implanted with an implantable cardioverter-defibrillator (ICD). Patients were divided into 2 groups: (1) an ablation group (n=11) that underwent epicardial CA because of VF recurrence; and (2) a primary prevention (PP) group (n=16) with ICD implantation only. ECG parameters were evaluated before and 12 months after CA and compared with ECG parameters in the PP group. The T wave peak-to-end interval was significantly longer and the number of abnormal spikes in leads V1-V3 at the second, third, and fourth intercostal spaces was greater in the ablation than PP group. After ablation, ST levels and the sum of abnormal spikes in leads V1-V3 were significantly decreased. The mean (±SD) number of ICD shocks decreased markedly during a mean follow-up period of 42.0 months (from 3.8±3.7 to 0.2±0.4/year). Four patients had an ICD shock following the ablation procedure. Greater reductions in ST-segment elevation and abnormal spikes were observed in the group without than with VF recurrence.

CONCLUSIONS

Improvements in surface ECG parameters appear to be associated with successful ablation in high-risk BrS patients.

Defibrillation threshold of internal cardioversion prior to ablation predicts atrial fibrillation recurrence

BACKGROUND

Many studies have reported the predictors of atrial fibrillation (AF) recurrence after persistent AF (peAF) ablation. However, the correlation between the atrial defibrillation threshold (DFT) for internal cardioversion (IC) and AF recurrence rate is unknown. Here we investigated the relationship between the DFT prior to catheter ablation for peAF and AF recurrence.

HYPOTHESIS

DFT prior to ablation was the predictive factor for AF recurrence after peAF ablation.

METHODS

From June 2016 to May 2019, we enrolled 82 consecutive patients (mean age, 65.0 ± 12.4 years), including 45 with peAF and 37 with long-standing peAF, at Hamamatsu Medical Center. To assess the DFT, we performed IC with gradually increasing energy prior to radiofrequency application.

RESULTS

Forty-nine and 33 patients showed DFT values less than or equal to 10 J (group A) and greater than 10 J or unsuccessful defibrillation (group B). During the mean follow-up duration of 20.5 ± 13.1 months, patients in group B showed significantly higher AF recurrence rates than those in group A after the ablation procedure (p = .017). Multivariate analysis revealed that DFT was the only predictive factor for AF recurrence (odds ratio, 1.07; 95% CI, 1.00-1.13, p = .047).

CONCLUSIONS

The DFT for IC was among the strongest prognostic factors in the peAF ablation procedure.