Effective ablation of atrial tachycardia with an epicardial circuit-insights from endocardial scars sites: a case study.

A previous study reported primary macroreentrant atrial tachycardia (AT) in the left atrium (LA), including the epicardial circuit on a left atrial anterior wall (LAAW) scar, without any prior cardiac intervention (Miyazawa et al. in J Cardiovasc Electrophysiol 2019; 30: 263-264). However, determining the target for terminating macroreentrant ATs is challenging. The mapping revealed a centrifugal pattern but did not fully elucidate the AT circuit. The reentrant mechanism of these ATs was confirmed using entrainment pacing. The earliest excitation site (EES) was traditionally selected as the ablation site, typically located in healthy tissue. However, our two cases provide new insights into AT termination, including the epicardial bridge across the endocardial LAAW scar, using minimum ablation points, without the need to ablate the healthy EES.

Acute impact of atrial fibrillation on pacemaker lead-induced tricuspid regurgitation: Case report.

We report a case of worsening lead-induced tricuspid regurgitation (TR) after new-onset atrial fibrillation (AF) evaluated using three-dimensional (3D) transthoracic echocardiography (TTE) from admission through TR improvement. An 84-year-old man experienced worsening lead-induced TR with new-onset AF, acutely resulting in low output syndrome. Less invasive interventions, such as rhythm control therapy and diuretics administration worked effectively. However, 3DTTE revealed consistent restricted motion of the septal leaflet with lead impingement. Right heart dilatation due to AF and worsened TR led to incomplete closure of other leaflets and tricuspid annular dilatation, which caused further deterioration of the TR. According to the course of our case, new-onset AF can cause acute worsening of lead-induced TR and low output syndrome in patients with cardiac implantable electronic devices (CIED). Our findings emphasize the importance of understanding the TR etiology in patients with CIED, which may prevent unnecessary CIED lead extraction. Learning objective: Lead-induced tricuspid regurgitation (TR) can acutely deteriorate after new onset of atrial fibrillation (AF). AF-induced deterioration of TR may not depend on restricted motion of a leaflet with lead impingement but on incomplete closure of other leaflets caused by right heart and tricuspid annular dilatation. Rhythm control therapy and diuretics administration may improve AF-induced deterioration of lead-induced TR, and should be considered before performing invasive lead extractions.

Predictors of implantation failure in left bundle branch area pacing using a lumenless lead in patients with bradycardia.

Background: Left bundle branch area pacing (LBBAP) is a novel conduction system pacing technique. In this multicenter study, we aimed to evaluate the procedural success, safety, and preoperative predictors of procedural failure of LBBAP. Methods: LBBAP was attempted in 285 patients with pacemaker indications for bradyarrhythmia, which were mainly atrioventricular block (AVB) (68.1%) and sick sinus syndrome (26.7%). Procedural success and electrophysiological and echocardiographic parameters were evaluated. Results: LBBAP was successful in 247 (86.7%) patients. Left bundle branch (LBB) capture was confirmed in 54.7% of the population. The primary reasons for procedural failure were the inability of the pacemaker lead to penetrate deep into the septum (76.3%) and failure to achieve shortening of stimulus to left ventricular (LV) activation time in lead V6 (18.4%). Thickened interventricular septum (odds ratio [OR], 2.48; 95% confidence interval [CI], 1.15-5.35), severe tricuspid regurgitation (OR, 8.84; 95% CI, 1.22-64.06), and intraventricular conduction delay (OR, 8.16; 95% CI, 2.32-28.75) were preoperative predictors of procedural failure. The capture threshold and ventricular amplitude remained stable, and no major complications occurred throughout the 2-year follow-up. In patients with ventricular pacing burden >40%, the LV ejection fraction remained high regardless of LBB capture. Conclusions: Successful LBBAP was affected by abnormal cardiac anatomy and intraventricular conduction. LBBAP is feasible and safe as a primary strategy for patients with AVB, depending on ventricular pacing.

Utility of Routine Transthoracic Echocardiographic Parameters to Predict Functional Recovery after Catheter Ablation Therapy in Patients with Atrial Fibrillation and Left Ventricular Systolic Dysfunction.

Arrhythmia-induced cardiomyopathy (AIC) occurring in patients with atrial fibrillation (AF) is a reversible form of cardiomyopathy characterized by LV systolic dysfunction. However, it is difficult to predict the reversibility before rhythm control therapy. We performed this study to develop a parameter for the identification of AIC in routine transthoracic echocardiography (TTE) in patients with presumptive AIC due to AF.We retrospectively studied 72 patients treated with catheter ablation therapy for persistent AF, and LV ejection fraction (LVEF) ≤ 45%. The patients were divided into 2 groups by follow-up TTE performed within 12 ± 6 months postoperatively. Patients with ≥ 15% improvement in LVEF or ≥ 10% improvement and ≥ 50% in LVEF were classified as the AIC group, and the others were classified as the non-AIC group.A total of 57 (79%) patients were classified as the AIC group. In the stepwise multivariate logistic regression model, LV end-diastolic dimension (LVDd) and e' (septal) were independent predictors of AIC. The sensitivities of LVDd ≤ 53 mm and e' (septal) ≥ 6.3 cm/second were 60% and 75%, respectively. Their specificities were 80% and 67%, respectively. The presence of either LVDd ≤ 53 mm or e' (septal) ≥ 6.3 cm/second had a higher sensitivity (90%); their co-occurrence had a higher specificity (93%) in predicting AIC.The functional recovery in patients with AIC can occur in LV systolic dysfunction without remodeling and impairment of relaxation. The combination of LVDd and e' (septal) is useful in predicting AIC due to AF with routine TTE.

Is narrowest QRS the best? A case of cardiac resynchronization therapy in a patient with left anterior fascicular block.

The efficacy of cardiac resynchronization therapy (CRT) in patients with a narrow QRS duration has not been established. We present a patient with a narrow QRS duration and left anterior fascicular block in which CRT was effective. Left ventricular lead implantation at the optimal site and appropriately-timed left ventricular pacing (LVP) resulted in left ventricle reverse remodeling. Left ventricular dyssynchrony did not improve with LVP at a timing that resulted in narrower QRS than an intrinsic QRS duration. The optimization of LVP timing in CRT for patients with a narrow QRS duration is discussed.

Risk factors of pacing-induced cardiomyopathy-Insights from lead position.

There was no significant difference in the incidence of pacing-induced cardiomyopathy between right ventricular apex pacing group and OpenCurlyQuote;true CloseCurlyQuote; mid-right ventricular septum pacing group. The preoperative left ventricular end-systolic diameter and paced QRS duration were independent predictors of PICM.

Achievement rate and learning curve of left bundle branch capture in left bundle branch area pacing procedure performed to demonstrate output-dependent QRS transition.

INTRODUCTION: Recently, output-dependent QRS transition was reported to be required to confirm left bundle branch (LBB) capture in LBB area pacing (LBBAP) procedure. This study aimed to evaluate the achievement rate and the learning curve of LBB capture in LBBAP procedure performed with the goal of demonstrating output-dependent QRS transition, and investigate predictors of LBB capture. METHODS AND RESULTS: The LBBAP procedure was performed in 126 patients with bradyarrhythmia. LBB capture was defined as a demonstration of output-dependent QRS transition. The following pacing definitions were used for evaluation: (1) LBBAP, which met the previously reported LBBAP criteria, (2) LBB pacing (LBBP), LBB capture was confirmed, and (3) available LBBP, LBB threshold was clinically usable (<3 V at 0.4 ms). The learning curve was evaluated by division into three time-periods. The achievement rates of LBBAP, LBBP, and available LBBP were 88.1%, 41.2%, and 35.7%, respectively. The achievement rates of all three pacing definitions significantly increased with experience (p < .01), but the achievement rate of available LBBP was still 50% in the third period. As predictors of LBB capture, the interval between LBB-Purkinje potential and QRS onset ≥22 ms had high specificity of 98.3%, while R wave peak time in V6 < 68 ms had insufficient sensitivity of 79% and specificity of 68%. CONCLUSION: Even if LBB capture was aimed in LBBAP procedure, it was not easy to achieve, and there was a clear learning curve. Much of LBBAP may be left ventricular septal pacing that does not capture LBB.

Severe sphincter of Oddi spasm after cryoballoon ablation: a case report of an unusual complication after atrial fibrillation ablation.

BACKGROUND: Perioesophageal vagal nerve (VN) injury after atrial fibrillation (AF) ablation remains an important complication. The VN provides parasympathetic innervation to the majority of the abdominal organs-including the stomach and the sphincter of Oddi (SO)-and regulates smooth muscle contraction. We present an unusual case of SO spasm induced by VN injury after cryoballoon ablation (CBA). CASE SUMMARY: A 71-year-old woman presented to our institution with paroxysmal AF. The patient had a history of cholecystectomy and SO dysfunction. She had undergone CBA for AF. Immediately after the procedure, the patient developed epigastric pain. Computed tomography showed dilation of the intra- and extrahepatic bile ducts, with the diameter of the common bile duct measuring ∼15.6 mm. Blood tests on postoperative Day 1 revealed severely elevated aminotransferase levels (aspartate aminotransferase, 3156 U/L; alanine aminotransferase, 2084 U/L; lactate dehydrogenase, 2279 U/L; total bilirubin 1.7 mg/dL). DISCUSSION: It is known that VN denervation induces SO spasms. The right and left vagal trunks descend alongside the oesophagus, forming a perioesophageal plexus and innervating most of the gastrointestinal organs. In our case, SO spasm was induced as a result of the perioesophageal plexus injury caused by CBA. Underlying SO dysfunction and post-cholecystectomy also played an important role. Coupled with the absence of the gallbladder, which is the reservoir of bile juice and coordinator of SO, SO spasm caused severe elevation of the bile duct pressure. Care should be taken when performing AF ablation with regards to the stomach and the SO.

Differences in the durability of left atrial posterior wall isolation based on the isolation process.

PURPOSE: The best strategy for durable left atrial posterior wall isolation (PWI) after completion of pulmonary vein isolation (PVI) is not yet determined. This study aimed to examine the differences in the durability of PWI based on the isolation process and the predictors of the reconduction of PWI. METHODS: Among the 221 patients (mean age, 65 ± 11 years) with consecutive non-paroxysmal atrial fibrillation (AF) who completed PVI and PWI, 50 patients undergoing repeat AF ablation were enrolled and divided into the following groups based on how PWI was achieved at the initial procedure: by only the first line on the roof and floor line (group A), by additional gap ablation to the first line or second liner ablation next to the first line (group B), and by adjunct ablation inside the PW revealing the earliest activation (group C). RESULTS: Reconduction of PWI occurred in 24 of the 50 patients (48%). The durability of PWI in groups A, B, and C was 81% (17 of 21 patients), 75% (6 of 8 patients), and 14% (3 of 21 patients), respectively (p < 0.01). In a multivariate analysis, the ablation inside the PW for PWI was the independent predictor of the reconduction of PWI (p < 0.001). CONCLUSION: PWI achieved by the ablation inside the PW resulted in a high rate of reconduction. It may be necessary to aim to achieve the PWI without ablating the inside of the PW to prevent reconduction.

Bachmann's bundle-ridge related biatrial tachycardia with a long epicardial circuit.

Biatrial tachycardia (BiAT), involving Bachmann's bundle in the circuit, has sometimes been observed after mitral anterior line ablation. In this article, we present a case of BiAT, involving a long epicardial circuit, composed of Bachmann's bundle and the left atrial ridge (LAR). We discuss the optimal ablation technique for this tachycardia based on our experience in addition to the relationship between Bachmann's bundle and the LAR. Furthermore, the evaluation method for the mitral anterior block line is also discussed.

The Impact of Aorto-Mitral Angle on New-Onset Atrial Arrhythmia after Mitral Valve Repair in Patients with Mitral Regurgitation.

In this study, we hypothesized that post-operative aorto-mitral angle might be associated to the occurrence of post-operative atrial arrhythmia (AA), including atrial fibrillation and atrial tachycardia, after mitral valve repair in patients with mitral regurgitation (MR). Thus, this present study aims to determine the effects of post-operative aorto-mitral angle on new-onset AA after mitral valve repair with mitral annuloplasty for the treatment of MR.In total, 172 patients without any history of AA underwent mitral valve repair with mitral annuloplasty in our institution between 2008 and 2017. Patient information, including medical records and echocardiographic data, were retrospectively studied.As per our findings, AA occurred in 15 (8.7%) patients during the follow-up period (median, 35.7 months; range, 0.5-132 months). The patients with AA were noted to have a longer cardiopulmonary bypass time and a smaller aorto-mitral angle at post-operative TTE than the others (119 ± 6° versus 125 ± 10°, P = 0.003). No significant difference was noted in the degree of post-operative residual MR or functional MS between the groups. In a multivariate Cox proportional hazards analysis, the longer cardiopulmonary bypass time and the smaller post-operative aorto-mitral angle were independent predictors of the occurrence of AA during the follow-up period (odds ratio per 10 minutes 1.11; 95% CI 1.02-1.22, P = 0.019: odds ratio 0.91; 95% CI 0.85-0.98, P = 0.012).A small aorto-mitral angle at post-operative TTE was determined to be a predictor of new-onset AA after a mitral valve repair for treating MR.

Characteristics and proposed mechanisms of QRS morphology observed during the left bundle branch pacing procedure.

BACKGROUND: In performing left bundle branch pacing (LBBP), various QRS morphologies are observed as the lead penetrates the ventricular septum (VS). This study aimed to evaluate these characteristics and infer the mechanism underlying each QRS morphology. METHODS: In 19 patients who met the strict criteria for LBB capture, we classified the QRS morphologies observed during the LBBP procedure into seven patterns, the first five of which were determined by the depth of penetration: right ventricular septal pacing (RVSP), intraventricular septal pacing (IVSP1 and IVSP2), endocardial side of left ventricular septal pacing (LVSeP), nonselective LBBP (NS-LBBP), selective LBBP (S-LBBP), and NS-LBBP with anodal capture. The parameters of the QRS morphologies in these seven patterns were evaluated. RESULTS: Among the first five patterns, stimulus-QRSend duration (s-QRSend) was the narrowest in IVSP1 rather than in NS-LBBP, and stimulus-to-peak of R wave in V6 (s-LVAT) was significantly shortened in two steps, from RVSP to IVSP1 (96 ± 11; 82 ± 8 ms, p < .01) and from LVSeP to NS-LBBP (76 ± 7; 60 ± 4 ms, p < .01). The late-R duration in V1 was significantly prolonged in the order of LVSeP, NS-LBBP, and S-LBBP (45 ± 7; 53 ± 10; 71 ± 15 ms, respectively, p < .01). CONCLUSIONS: s-QRSend was the narrowest in IVSP1 rather than in NS-LBBP among the QRS morphologies observed during lead penetration through the VS. The prolonged late-R duration in V1 and abrupt shortening of the s-LVAT in V6 may help determine LBB capture during lead penetration.

Impact of a poor functional capacity on the clinical outcomes in patients with a pacemaker implantation -Results from the Japanese Heart Rhythm Society Registry.

BACKGROUND: Functional capacity (FC) correlates with mortality in various cardiovascular diseases. The aim of this study was to examine whether cardiac pacemaker implantations improve the FC and affect the prognosis. METHODS AND RESULTS: We prospectively enrolled 621 de novo pacemaker recipients (age 76 ± 9 years, 50.7% male). The FC was assessed by metabolic equivalents (METs) during the implantation and periodically thereafter. The patients were a priori classified into poor FC (<2 METs, n = 40), moderate FC (2 ≤ METs < 4, n = 239), and good FC (≥4 METs, n = 342). Three months after the pacemaker implantation, poor FC or moderate FC patients improved to a good FC by 43%. The distribution of the three FCs remained at those levels until after 1 year of follow-up (P = .18). During a median follow-up of 2.4 years, 71 patients (11%) had cardiovascular hospitalizations and 35 (5.6%) all-cause death. A multivariate Cox analysis revealed that a poor FC at baseline was an independent predictor of both cardiovascular hospitalization (hazard ratio [HR] 2.494, P = .012) and all-cause death (HR 3.338, P = .016). One year after the pacemaker implantation, the eight who remained with a poor FC had a high mortality rate of 37.5% (P < .01). CONCLUSION: Approximately half of the poor or moderate FC patients improved to good FC 3 months after the pacemaker implantation. The baseline FC predicted the prognosis, and patients with an improved FC after the pacemaker implantation had a better prognosis.

Intracardiac conduction time as a predictor of cardiac resynchronization therapy response: Results of the BIO|SELECT pilot study.

BACKGROUND: Quadripolar left ventricular (LV) leads are capable of sensing and pacing the left ventricle from 4 different electrodes, which may potentially improve patient response to cardiac resynchronization therapy (CRT). OBJECTIVE: We measured 3 different time intervals: right ventricular (RV)-sensed to LV-sensed during intrinsic rhythm (RVs-LVs), RV-paced to LV-sensed (RVp-LVs), and LV-paced to LV-sensed (LVp-LVs, between distal [LV1] and proximal pole on a quadripolar LV lead), and assessed their association with CRT response in terms of LV end-systolic volume (LVESV) and a composite benefit index (CBI) comprising LVESV, LV ejection fraction (LVEF), brain natriuretic peptide level, and NYHA class. METHODS: A CRT-defibrillator system with quadripolar LV lead was implanted in 196 patients (mean age 69 years, mean LVEF 30%, left bundle-branch block [LBBB] 58%). Conduction intervals were measured before hospital discharge. At baseline and 7-month follow-up, echocardiographic and other components of CBI were determined. RESULTS: The mean RVs-LV1s, RVp-LV1s, and LVp-LVs delays were 68 ± 38 ms, 132 ± 34 ms, and 99 ± 31 ms, respectively. From baseline to 7 months, LVESV decreased by 17.3% ± 28.6%. The RVs-LV1s interval correlated stronger with CBI (R2 = 0.12, P < .00001) than with LVESV change (R2 = 0.05, P = .006). In contrast, RVp-LV1s did not correlate and LVp-LVs correlated only weakly with CRT response. The subgroup of patients (44%) with LBBB and RVs-LV1s above the lower quartile (≥34 ms) showed the greatest response to CRT. CONCLUSION: The RVs-LVs interval during intrinsic rhythm is relevant for CRT success, whereas RVp-LVs and LVp-LVs intervals did not predict CRT response.

What is the mechanism of narrow paced QRS duration during left bundle branch area pacing? A case report.

BACKGROUND: Although left bundle branch area pacing (LBBAP) can capture the His-Purkinje conduction system and create a narrower paced QRS duration, its mechanism has not been investigated. In this case report, ventricular activation patterns were evaluated using three-dimensional electroanatomical mapping during LBBAP and right ventricular septal pacing (RVSP). CASE SUMMARY: An 81-year-old woman with sick sinus syndrome received LBBAP, followed 4 months later with atrial fibrillation ablation. We compared ventricular activation patterns during RVSP and LBBAP using a three-dimensional electro-anatomical mapping system. Paced QRS durations during RVSP and LBBAP were 163 ms and 115 ms, respectively. The activation pattern and the total left ventricular (LV) activation time were similar during RVSP and LBBAP (86 and 73 ms, respectively), despite the conduction system capture during LBBAP. The stimulus interval to the latest LV activation point during RVSP was 117 ms, and transseptal conduction time was 31 ms (117 - 86 ms). DISCUSSION: Although LBBAP could capture the His-Purkinje conduction system, neither ventricular activation patterns nor total activation time changed dramatically. The mechanism of narrower paced QRS duration during LBBAP compared to that during RVSP can be attributable to passing over the slow transseptal conduction.