Beware of atrial pacing-induced ventricular depolarization: A case of lead malfunction.

Although ventricular capture during the atrial threshold test is possible, there are rare reports on the insulation defect and inactive leads thereof. In this case, we present a pacemaker-dependent patient with a history of pacemaker generator replacements. The patient experienced ventricular capture induced by atrial pacing due to adhesion of the atrial and ventricular leads with an insulation defect. The atrial lead was abandoned and a new lead was implanted. However, there was a significant decrease in ventricular impedance detected shortly after the new lead was implanted. When observing the phenomenon of atrial pacing-induced ventricular depolarization, one uncommon reason to consider is lead adhesive wear. It is important to pay attention to the contact and bending sites of the leads.

Long duration of atrial high-rate episode is more favorable in predicting ischemic stroke than high CHA2 DS2 -VASc score.

OBJECTIVE: This study aimed to explore the roles of duration and burden of atrial high-rate episode (AHRE) on ischemic stroke in patients with pacemaker implantation. METHODS: Patients with pacemaker implantation for bradycardia from 2013 to 2017 were consecutively enrolled. Data such as gender, age, combined diseases, type of AF, left atrial size, left ventricular size, left ventricular ejection fraction, CHA2 DS2 -VASc score, and anticoagulants were collected. The burden and duration of AHRE based on different interval partition were also recorded in detail to evaluate the impacts on ischemic stroke. Cox regression analysis with time-dependent covariates was conducted. RESULTS: A total of 220 patients with AHRE were enrolled. The average follow-up time was 48.42 ± 17.20 months. Univariate regression analysis showed that diabetes (p = .024), high CHA2 DS2 -VASc score (≥ 2) (p = .021), long mean AHRE burden (p = .011), long maximal AHRE burden (p = .015), long AHRE duration lasting≥48 h (p = .001) or 24 h (p = .001) or 12 h (p = .005) were prone to ischemic stroke. Further multivariate regression analysis showed that long duration of AHRE (≥48 h) (HR 10.77; 95% CI 3.22-55.12; p = .030) were significantly correlated with stroke in patients with paroxysmal AF. There was no significant correlation between the type of AF and stroke (p = .927). CONCLUSION: The longer duration of AHRE (≥48 h) was more favorable in predicting ischemic stroke than high CHA2 DS2 -VASc score (≥2).

Predictors of pacing-induced cardiomyopathy detection and outcomes demonstration after conduction system pacing upgrade on patients with long-term persistent atrial fibrillation.

OBJECTIVE: To identify the predictors of pacing-induced cardiomyopathy (PICM) and illustrate the safety and feasibility of conduction system pacing (CSP) upgrade on patients with long-term persistent atrial fibrillation (AF). METHODS: All patients with long-term persistent AF and normal left ventricular ejection fraction (LVEF) ≥50% were consecutively enrolled from January 2008 to December 2017, and all the patients with atrioventricular block (AVB) and high right ventricular pacing (RVP) percentage of at least 40%. The predictors of PICM were identified, and patients with PICM were followed up for at least 1 year regardless of CSP upgrade. Cardiac performances and lead outcomes were investigated in all patients before and after CSP upgrade. RESULTS: The present study included 139 patients, out of which 37 (26.62%) developed PICM, resulting in a significant decrease in the left ventricular ejection fraction (LVEF) from 56.11 ± 2.56% to 38.10 ± 5.81% (p< .01). The median duration for the development of PICM was 5.43 years. Lower LVEF (≤52.50%), longer paced QRS duration (≥175 ms), and higher RVP percentage (≥96.80%) were identified as independent predictors of PICM. Furthermore, the morbidity of PICM progressively increased with an increased number of predictors. The paced QRS duration (183.90 ± 22.34 ms vs. 136.57 ± 20.71 ms, p < .01), LVEF (39.35 ± 2.71% vs. 47.50 ± 7.43%, p < .01), and left ventricular end-diastolic diameter (LVEDD) (55.53 ± 5.67 mm vs. 53.20 ± 5.78 mm, p = .03) improved significantly on patients accepting CSP upgrade. CSP responses and complete reverse remodeling (LVEF ≥50% and LVEDD < 50 mm) were detected in 80.95% (17/21) and 42.9% (9/21) of patients. The pacing threshold (1.52 ± 0.78 V/0.4 ms vs. 1.27 ± 0.59 V/0.4 ms, p = .16) was stable after follow-up. CONCLUSION: PICM is very common in patients with long-term persistent AF, and CSP upgrade was favorable for better cardiac performance in this patient population.

Conduction system pacing following septal myectomy: Insights into site of conduction block.

INTRODUCTION: Septal myectomy for obstructive hypertrophic cardiomyopathy (HCM) is associated with conduction block; however, the electrophysiological characteristics of conduction block have not been well characterized. The aim of study was to assess the feasibility and safety of His bundle pacing (HBP) and left bundle branch area pacing (LBBAP) in patients with septal myectomy-associated conduction block. METHODS AND RESULTS: Patients with HCM and indications for pacing or cardiac resynchronization therapy after septal myectomy were included. Electrophysiological mapping was performed to identify the site of block. The success rates and pacing characteristics of HBP and LBBAP were also recorded. The echocardiographic data and complications were documented and tracked during follow-up. Ten patients with atrioventricular block (AVB) or left bundle branch block (LBBB) post-myectomy were included in the study. The site of block was infranodal in the nine patients with AVB. HBP failed due to the lack of distal His bundle capture (N = 7) or LBBB correction (N = 3). LBBAP was successful in nine patients and failed in one. QRS duration narrowed from 163.3 ± 16.6 ms after surgery to 123.6 ± 15.8 ms during LBBAP (p < .001). The mean depth of the leads was 13.3 ± 4.0 mm (range from 10 to 20 mm). At a mean follow-up of 5.3 ± 3.9 months, pacing parameters and left ventricular ejection fraction remained stable. CONCLUSIONS: Electrophysiological mapping revealed that the site of block was infra-Hisian and not correctable with HBP in patients with HCM post-myectomy. LBBAP appears to be a more feasible physiological strategy for these patients.

Decreased estimated glomerular filtration rate predicts long-term recurrence after catheter ablation of atrial fibrillation in mild to moderate renal insufficiency.

BACKGROUND: Catheter ablation is an established therapy for atrial fibrillation (AF), but recurrence after ablation remains a great challenge. Additionally, little is known about the effect of renal function on the efficiency of AF ablation. This study aimed to evaluate the predictors of the prognosis of catheter ablation for AF, especially the effect of renal function. METHODS: A total of 306 drug-refractory symptomatic patients with AF who underwent first-time catheter ablation were enrolled in the present study. Individuals underwent circumferential pulmonary vein isolation for paroxysmal AF and stepwise ablation for persistent AF. RESULTS: The follow-up time was 27.2 ± 19.5 months, 202 patients (66.01%) were free of atrial tachyarrhythmia (non-recurrence group), and the other 104 patients experienced recurrence (recurrence group). The recurrence group had a larger left atrial diameter (LAD) and left atrial volume (LAV), a higher LAV index (LAVI) (both, p < 0.01), and a lower estimated glomerular filtration rate (eGFR) (53.5 ± 14.4 vs. 65.5 ± 13.3 ml/min/1.732, p < 0.001) and creatinine clearance rate (CCr) (85.2 ± 26.1 vs. 101.5 ± 29.4 ml/min, p < 0.05). Multivariate logistic regression indicated both eGFR (p = 0.002) and LAVI (p < 0.001) as independent associated factors for long-term recurrence after single catheter ablation; multivariate Cox proportional hazard regression with backward feature selection identified both eGFR (HR: 0.93, 95% CI: 0.91-0.95, p < 0.001) and LAVI (HR: 1.32, 95% CI: 1.25-1.40, p < 0.001) as independent prognostic factors for recurrence when adjusting other clinical variables. CONCLUSIONS: Decreased eGFR and elevated LAVI may facilitate the long-term recurrence of atrial tachyarrhythmia after catheter ablation for AF.

Appropriate intraprocedural initial heparin dosing in patients undergoing catheter ablation for atrial fibrillation receiving uninterrupted non-vitamin-K antagonist oral anticoagulant treatment.

BACKGROUND: To clarify the appropriate initial dosage of heparin during radiofrequency catheter ablation (RFCA) in patients with atrial fibrillation (AF) receiving uninterrupted nonvitamin K antagonist oral anticoagulant (NOAC) treatment. METHODS: A total of 187 consecutive AF patients who underwent their first RFCA in our center were included. In the warfarin group (WG), an initial heparin dose of 100 U/kg was administered (control group: n = 38). The patients who were on NOACs were randomly divided into 3 NOAC groups (NG: n = 149), NG110, NG120, and NG130, and were administered initial heparin doses of 110 U/kg, 120 U/kg, and 130 U/kg, respectively. During RFCA, the activated clotting time (ACT) was measured every 15 min, and the target ACT was maintained at 250-350 s by intermittent heparin infusion. The baseline ACT and ACTs at each 15-min interval, the average percentage of measurements at the target ACT, and the incidence of periprocedural bleeding and thromboembolic complications were recorded and analyzed. RESULTS: There was no significant difference in sex, age, weight, or baseline ACT among the four groups. The 15 min-ACT, 30 min-ACT, and 45 min-ACT were significantly longer in the WG than in NG110 and NG120. However, no significant difference in 60 min-ACT or 75 min-ACT was detected. The average percentages of measurements at the target ACT in NG120 (82.2 ± 23.6%) and NG130 (84.8 ± 23.7%) were remarkably higher than those in the WG (63.4 ± 36.2%, p = 0.007, 0.003, respectively). These differences were independent of the type of NOAC. The proportion of ACTs in 300-350 s in NG130 was higher than in WG (32.4 ± 31.8 vs. 34.7 ± 30.6, p = 0.735). Severe periprocedural thromboembolic and bleeding complications were not observed. CONCLUSIONS: For patients with AF receiving uninterrupted NOAC treatment who underwent RFCA, an initial heparin dosage of 120 U/kg or 130 U/kg can provide an adequate intraprocedural anticoagulant effect, and 130 U/kg allowed ACT to reach the target earlier. TRIAL REGISTRATION: Registration number: ChiCTR1800016491, First Registration Date: 04/06/2018 (Chinese Clinical Trial Registry http://www.chictr.org.cn/index.aspx ).

Brady-arrhythmias in patients with atrial fibrillation and heart failure of reduced ejection fraction: is his-bundle pacing superior to biventricular pacing？.

OBJECTIVE: To investigate the efficacy and safety of His-bundle pacing (HBP) compared with the traditional biventricular pacing (BVP) on patients with brady-arrhythmias, who suffer from permanent atrial fibrillation (AF) and heart failure with reduced ejection fraction (HFrEF). METHODS: All patients with brady-arrhythmias, permanent AF and HFrEF were continuously enrolled from January 2017 to July 2019 and followed up for at least 12 months. The differences in QRS duration (QRSd), New York Heart Association (NYHA) classification, left ventricular ejection fraction (LVEF), tricuspid regurgitation grade, mitral regurgitation grade, left ventricular end-diastolic diameter (LVEDD), and left atrial size were compared. RESULTS: A total of 52 patients were enrolled: 37 patients were with HBP and 15 patients with BVP. There was no electrode dislodged, perforation, infection or thrombosis during the follow-up of 18.12 ± 4.45 months. The success rate for HBP implantation was 88.10%. The capture threshold of his-bundle and the threshold of the left ventricular lead remained stable during follow-up. LVEF increased to higher than 50% in 11 patients with HBP (29.73%). The NYHA classification (both p < .001), LVEF (both p < .001) and LVEDD improved significantly during the follow-up in both groups. NYHA (p = .030), LVEF (p = .013), and LVEDD (p = .003) improved in patients with HBP compared with BVP. CONCLUSION: HBP was safe and more effective in improving the cardiac function and remodeling in patients with brady-arrhythmias, permanent AF and HFrEF compared with BVP.

High efficiency and workflow of His bundle pacing and atrioventricular node ablation guided by three-dimensional mapping system.

BACKGROUND: Atrioventricular node (AVN) ablation combined with His bundle pacing is an effective strategy for permanent atrial fibrillation (AF) with rapid ventricular rate refractory to pharmacological therapy. We aimed to access the feasibility and efficiency of His bundle pacing and AVN ablation guided by three-dimensional (3-D) mapping system throughout the procedure. METHODS: Eighteen patients with permanent AF with refractory rate and symptoms were referred for His bundle pacing and AVN ablation guided by 3-D mapping (CARTO3). Electroanatomic 3-D mapping of the right atrium and right ventricle was performed by the ablation catheter with CARTO 3 system, followed by the visualization of the leads for implantation and AVN ablation. RESULTS: Implantation of His bundle and ventricular leads and AVN ablation were achieved successfully with the help of 3-D mapping in 17 patients. Selective His bundle pacing was achieved in five patients (29.4%), and the other (70.6%) were nonselective His bundle pacing. The mean procedure duration was 99.4 ± 16.4 minutes. The mean fluoroscopy time was 7.0 ± 2.6 minutes. The time spent on His lead implantation was 6.1 ± 3.2 minutes. One patient experienced AVN ablation from left side under aortic valves due to no effect of ablation in right atrium. CONCLUSION: His bundle pacing and AVN ablation guided by throughout real-time 3-D mapping system are of high-efficiency and feasibility.

Outcomes of Upgrading to LBBP in CRT Nonresponders: A Prospective, Multicenter, Nonrandomized, Case-Control Study.

BACKGROUND: Cardiac resynchronization therapy (CRT) nonresponders account for nearly 30% of CRT candidates. Left-bundle branch pacing (LBBP) is an alternative to CRT. OBJECTIVES: This study aimed to evaluate the feasibility, clinical efficacy, and outcomes of upgrading to LBBP in CRT nonresponders, using propensity-score matching (PSM) analysis. METHODS: CRT nonresponders were defined as those with an implantable CRT-pacemaker or CRT-defibrillator for more than 12 months who remained nonresponsive (a decrease in left ventricular end-systolic volume of <15% or a left ventricular ejection fraction [LVEF] absolute increase of <5%) after optimal medical therapy and device optimization compared with baseline. In total, 145 CRT nonresponders were prospectively enrolled and randomly divided into 2 groups: upgraded to LBBP (n = 48), and continuing biventricular pacing (BVP) (control; n = 97). PSM was performed at a 1:1 ratio, and clinical evaluation and echocardiographic assessments were compared at baseline and follow-up in paired cohorts. The primary composite endpoint for clinical outcomes (heart failure-related rehospitalization events, all-cause death, or heart transplantation) was analyzed. RESULTS: Successful upgrading to LBBP was achieved in 48/49 patients (97.96%), with a significant decrease in QRS duration (P < 0.001). In the paired LBBP group, LVEF significantly increased (baseline: 29.75% ± 7.79%; 6 months: 37.78% ± 9.25% [P < 0.001]; 12 months: 38.84% ± 12.13% [P < 0.001]) with 21/44 patients (47.73%) classified as echocardiographically responsive, whereas in the BVP control group, no significant improvement was observed (29.55% ± 6.74% vs 29.22% ± 8.10%; P = 0.840). In a multivariate logistic regression model, LV end-diastolic volume and baseline LBBB QRS morphology were independent predictors of echocardiographic response after upgrading to LBBP. At a median 24 months, the primary composite endpoint was significantly lower in the LBBP group (HR: 0.31; 95% CI: 0.14-0.72; log-rank P = 0.007). CONCLUSIONS: Upgrading to LBBP is feasible and effective in achieving significant heart function improvement and better clinical outcomes in CRT nonresponders, making it a reasonable and promising pacing strategy. (LBBP in CRT Non-Response patients; ChiCTR1900028131).

Denervation as a common mechanism underlying different pulmonary vein isolation strategies for paroxysmal atrial fibrillation: evidenced by heart rate variability after ablation.

BACKGROUNDS: Segmental and circumferential pulmonary vein isolations (SPVI and CPVI) have been demonstrated to be effective therapies for paroxysmal atrial fibrillation (PAF). PVI is well established as the endpoint of different ablation techniques, whereas it may not completely account for the long-term success. METHODS: 181 drug-refractory symptomatic PAF patients were referred for segmental or circumferential PVI (SPVI = 67; CPVI = 114). Heart rate variability (HRV) was assessed before and after the final ablation. RESULTS: After following up for 62.23 ± 12.75 months, patients underwent 1.41 ± 0.68 procedures in average, and the success rates in SPVI and CPVI groups were comparable. 119 patients were free from AF recurrence (SPVI-S, n = 43; CPVI-S, n = 76). 56 patients had recurrent episodes (SPVI-R, n = 21; CPVI-R, n = 35). Either ablation technique decreased HRV significantly. Postablation SDNN and rMSSD were significantly lower in SPVI-S and CPVI-S subgroups than in SPVI-R and CPVI-R subgroups (SPVI-S versus SPVI-R: SDNN 91.8 ± 32.6 versus 111.5 ± 36.2 ms, rMSSD 47.4 ± 32.3 versus 55.2 ± 35.2 ms; CPVI-S versus CPVI-R: SDNN 83.0 ± 35.6 versus 101.0 ± 40.7 ms, rMSSD 41.1 ± 22.9 versus 59.2 ± 44.8 ms; all P < 0.05). Attenuation of SDNN and rMSSD remained for 12 months in SPVI-S and CPVI-S subgroups, whereas it recovered earlier in SPVI-R and CPVI-R subgroups. Multivariate logistic regression analysis identified SDNN as the only predictor of long-term success. CONCLUSIONS: Beyond PVI, denervation may be a common mechanism underlying different ablation strategies for PAF.

[Long term outcome of atrial fibrillation patients with KCNA5 and NPPA mutations post circumferential pulmonary vein ablation].

OBJECTIVE: The outcome of atrial fibrillation patients with genetic mutations post ablation was not well evaluated. METHODS AND RESULTS: Three atrial fibrillation patients with evidence of mutations in KCNA5 and NPPA post successful circumferential pulmonary vein ablation were included. Mutation in KCNA5 was found in one male patient with paroxysmal atrial fibrillation. He was free of atrial fibrillation post ablation after 46 months follow-up. Mutations in NPPA were found in two male patients with persistent atrial fibrillation and they were free from atrial fibrillation after 64 months and 38 months follow-up post circumferential pulmonary vein ablation, roof line and mitral isthmus line ablation. CONCLUSION: Satisfactory long term results are observed in atrial fibrillation patients with KCNA5 and NPPA mutations post circumferential pulmonary vein ablation.

The feasibility and safety of his-purkinje conduction system pacing in patients with heart failure with severely reduced ejection fraction.

Objective: The purpose of this study was to evaluate the feasibility and outcomes of conduction system pacing (CSP) in patients with heart failure (HF) who had a severely reduced left ventricular ejection fraction (LVEF) of less than 30% (HFsrEF). Methods: Between January 2018 and December 2020, all consecutive HF patients with LVEF < 30% who underwent CSP at our center were evaluated. Clinical outcomes and echocardiographic data [LVEF and left ventricular end-systolic volume (LVESV)], and complications were all recorded. In addition, clinical and echocardiographic (≥5% improvement in LVEF or ≥15% decrease in LVESV) responses were assessed. The patients were classified into a complete left bundle branch block (CLBBB) morphology group and a non-CLBBB morphology group according to the baseline QRS configuration. Results: Seventy patients (66 ± 8.84 years; 55.7% male) with a mean LVEF of 23.2 ± 3.23%, LVEDd of 67.33 ± 7.47 mm and LVESV of 212.08 ± 39.74 ml were included. QRS configuration at baseline was CLBBB in 67.1% (47/70) of patients and non-CLBBB in 32.9%. At implantation, the CSP threshold was 0.6 ± 0.3 V @ 0.4 ms and remained stable during a mean follow-up of 23.43 ± 11.44 months. CSP resulted in significant LVEF improvement from 23.2 ± 3.23% to 34.93 ± 10.34% (P < 0.001) and significant QRS narrowing from 154.99 ± 34.42 to 130.81 ± 25.18 ms (P < 0.001). Clinical and echocardiographic responses were observed in 91.4% (64/70) and 77.1% (54/70) of patients. Super-response to CSP (≥15% improvement in LVEF or ≥30% decrease in LVESV) was observed in 52.9% (37/70) of patients. One patient died due to acute HF and following severe metabolic disorders. Baseline BNP (odds ratio: 0.969; 95% confidence interval: 0.939-0.989; P = 0.045) was associated with echocardiographic response. The proportions of clinical and echocardiographic responses in the CLBBB group were higher than those in the non-CLBBB group but without significant statistical differences. Conclusions: CSP is feasible and safe in patients with HFsrEF. CSP is associated with a significant improvement in clinical and echocardiographic outcomes, even for patients with non-CLBBB widened QRS.

Conduction system pacing improves the outcomes on patients with high percentage of ventricular pacing and heart failure with mildly reduced ejection fraction.

Aims: This study aimed to investigate the efficacy and safety of CSP in patients with a high percentage of ventricular pacing and heart failure with HFmrEF. Methods: Patients who underwent CSP for HFmrEF and ventricular pacing >40% were consecutively enrolled from January 2018 to May 2021. All participants were followed up at least 12 months. Clinical data including cardiac performance and lead outcomes were compared before and after the procedure. Left ventricular ejection fraction (LVEF) was measured using the biplane Simpson's method. HFmrEF was defined as heart failure with the LVEF ranging from 41%-49%. Results: CSP was successfully performed in 64 cases (96.97%), which included 16 cases of left bundle branch pacing (LBBP) and 48 cases of His bundle pacing (HBP). After a mean of 23.12 ± 8.17 months follow-up, NYHA classification (P < 0.001), LVEF (42.45 ± 1.84% vs. 49.97 ± 3.57%, P < 0.001) and left ventricular end diastolic diameter (LVEDD) (55.59 ± 6.17 mm vs. 51.66 ± 3.48 mm, P < 0.001) improved significantly. During follow-up, more than half (39/64,60.9%) of patients returned to normal LVEF and LVEDD with complete reverse remodeling. The pacing threshold in LBBP was lower (0.90 ± 0.27 V@0.4 ms vs. 1.61 ± 0.71 V@0.4 ms, P < 0.001) than that in HBP. No perforation, electrode dislodging, thrombosis or infection was observed during follow-up. Conclusions: CSP could improve the clinical outcomes in patients with HFmrEF and a high percentage of ventricular pacing. LBBP might be a better choice because of its feasibility and safety, especially in patients with infranodal atrioventricular block.

Cumulative non-high-density lipoprotein cholesterol burden and risk of atherosclerotic cardiovascular disease: a prospective community-based study.

Background: The relationship between cumulative non-high-density lipoprotein cholesterol (non-HDL-C) burden and atherosclerotic cardiovascular disease (ASCVD) remains unclear. Objective: To prospectively examine the association between cumulative non-HDL-C burden and ASCVD risk in the Kailuan cohort of China. Methods: A total of 49,679 subjects who were free of ASCVD participated in three consecutive examinations in 2006, 2008 and 2010 were enrolled. Duration and concentration of cumulative exposure to non-HDL-C (cumNon-HDL-C) were respectively used to estimate the extent of cumulative non-HDL-C burden. The participants were divided into four groups according to durations of cumNon-HDL-C (0, 2, 4 and 6 years) and five groups according to the quintiles of cumNon-HDL-C concentration (<10.93, 10.93-12.68, 12.69-14.32, 14.33-16.72 and ≥16.73 mmol/L). Cox regression models were used to analyze the influence of cumulative non-HDL-C burden on ASCVD risk. Results: We identified 1,134 incident ASCVD cases during a mean of 4.89 years of follow-up. Multivariable adjusted analysis revealed that compared with no exposure, cumNon-HDL-C duration 2, 4 and 6 years increased ASCVD risk by 26% (HR: 1.26, 95% CI: 1.07-1.47), 56% (HR: 1.56, 95% CI: 1.31-1.86) and 91% (HR: 1.91, 95% CI: 1.59-2.31) respectively; The hazard ratios (HRs) for the fourth and fifth versus lowest quintile of cumNon-HDL-C concentration were 1.25 and 1.72 for ASCVD. Each standard deviation increment in cumNon-HDL-C concentration was associated with a 10% increased risk of ASCVD. Conclusion: Long-term and higher cumNon-HDL-C were all significantly associated with an increased risk of ASCVD independent of single non-HDL-C level.

Left ventricular lead position for cardiac resynchronization: a comprehensive cinegraphic, echocardiographic, clinical, and survival analysis.

AIMS: We sought to determine the clinical and survival outcomes of cardiac resynchronization therapy (CRT) associated with left ventricular (LV) lead location. The lateral left ventricle has been considered the optimal LV lead location for CRT. METHODS AND RESULTS: Left ventricular lead cinegrams taken in 30° right and left anterior oblique views were evaluated in 457 recipients of CRT with a pacemaker or a defibrillator from 1 January 2002 to 31 December 2008 in this retrospective study. Left ventricular lead placement was prioritized at implantation into posterolateral (PL), anterolateral (AL), middle cardiac, and anterointerventricular coronary veins. Using echocardiographic LV 16-segment analysis, we grouped the leads as anterior, AL, PL, and posterior locations. New York Heart Association (NYHA) class and echocardiography were assessed before and after CRT. Clinical and survival outcomes after CRT were compared among the four LV lead locations.  Patient baseline demographic characteristics were similar among these four groups. Improvement in NYHA class was significantly greater in the AL (P= 0.04) and PL (P= 0.03) locations than in the anterior location. There was a tendency for greater improvement in LV ejection fraction among the AL (P= 0.11) and PL (P= 0.08) locations than the anterior location. Kaplan-Meier survival estimate at 4 years varied for location: AL, 72%; anterior, 48%; PL, 62%; and posterior, 72% (P= 0.003). CONCLUSION: Cardiac resynchronization therapy recipients are profiting from all lead positions. However, LV lead placed in the AL and PL positions is more preferential for achieving optimal CRT benefit than leads placed in the anterior position.

[Predictive value of HATCH score on atrial fibrillation recurrence post radiofrequency catheter ablation].

OBJECTIVE: To determine the predictive value of HATCH score on recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). METHODS: The data of 123 consecutive AF patients (74 paroxysmal and 49 persistent AF) who underwent RFCA between April 2009 and December 2010 in our department were retrospectively analyzed. Of theses patients, 65 (52.9%) patients had HATCH score = 0, 41 (33.3%) patients had HATCH score = 1, and 17 (13.8%) patients had HATCH score ≥ 2 (HATCH = 2 in 11 patients, HATCH = 3 in 5 patients, HATCH = 4 in 1 patient). The recurrence was defined as atrial tachyarrhythmia lasting more than 30 seconds after 3 months post RFCA. The patients were divided into recurrence group and no recurrence group. Relationship between HATCH score and recurrence was observed. RESULTS: There were 43 cases in recurrence group and 80 cases in no recurrence group. After 12 months follow-up, HATCH score was significant higher in recurrence group than in non-recurrence group [(0.91 ± 0.94) score vs. (0.53 ± 0.80) score, P < 0.05]. The ratio of patients with HATCH ≥ 2 in recurrence group was higher than in non-recurrence group [23.3% (10/43) vs. 8.8% (7/80), P < 0.01]. The sensitivity and specificity of HATCH ≥ 2 to define the risk of recurrence was 25.0%, 92.4% respectively. Cumulative non-recurrence rate of patients with HATCH score ≥ 2 was lower than patients with HATCH score = 0 and 1 (P < 0.05). CONCLUSION: Higher HATCH score is associated with increased risk of AF recurrence post RFCA.

A Case Report of a Wenckebach Phenomenon Occurring during a His-Bundle Pacing Procedure: Is It Atrioventricular Node Pacing?

A 70-year-old man with severe valvular cardiomyopathy, permanent atrial fibrillation (AF) with a slow ventricular response, and transient atrioventricular (AV) block, was admitted to our center for severe heart failure and recurrent presyncope. While hospitalized, the coronary computed tomography angiography (CTA) showed huge atriums. We tried His bundle pacing (HBP). HB potential was observed at site A, and the His-ventricular (HV) interval was 68 ms. The duration from the stimulus signal to the onset of paced QRS (S-QRSonset) at site A was 232 ms when pacing at 60 beats per minute (BPM) with the pacing threshold of 2.0 V/0.5 ms. The S-QRSonset was longer than the HV interval and had a notable and progressive prolongation from 252 ms to 456 ms during the pacing at 90 BPM. Then, we pushed another lead a little forward, and the S-QRSonset shortened back to 68 ms, and the paced QRS morphology was the same as the intrinsic QRS morphology with the pacing threshold of 1.5 V/0.5 ms. The progressively prolonged S-QRSonset demonstrated a Wenckebach phenomenon (WP), a well-known electrophysiological characteristic of the AV node (AVN). It is the first time to report an intraoperative AVN-pacing related-WP in a patient with persistent AF. The enlarged atrium might be convenient for capturing the AVN. There are some other potential explanations for this phenomenon. The diameters of atriums decreased significantly, and the symptoms improved after the procedure. This is the first reported case in which we might achieve AVN capture in a patient with persistent AF. Although we ultimately chose HBP for better long-term pacing thresholds, the result of this case suggested that AVN pacing may be possible.

Short QRS Duration After His-Purkinje Conduction System Pacing Predicts Left Ventricular Complete Reverse Remodeling in Patients With True Left Bundle Branch Block and Heart Failure.

Objective: This study aimed to explore the outcomes of His-Purkinje conduction system pacing (HPCSP) and to screen the predictors of left ventricular (LV) complete reverse remodeling in patients with true left bundle branch block (LBBB) and heart failure with reduced ejection fraction (HFrEF). Methods: Patients who underwent HPCSP for true LBBB and HFrEF from April 2018 to August 2020 were consecutively enrolled. All participants were followed up for at least 1 year. Thrombosis, infection, lead dislodgement, perforation, and other complications were observed after HPCSP. Clinical data, including echocardiographic parameters, electrocardiogram measurements, and cardiac function, were assessed before and after the procedure. Results: A total of 46 patients were enrolled. HPCSP was successfully deployed in 42 cases (91.30%), which included 37 cases with His bundle pacing (HBP) and 5 cases with left bundle branch pacing (LBBP). The QRS duration decreased significantly (169.88 ± 19.17 ms vs. 113.67 ± 20.68 ms, P < 0.001). Left ventricular end-systolic volume (LVESV) (167.67 ± 73.20 ml vs. 85.97 ± 62.24 ml, P < 0.001), left ventricular end-diastolic diameter (LVEDD) (63.57 ± 8.19 mm vs. 55.46 ± 9.63 mm, P = 0.003) and left ventricular ejection fraction (LVEF) (26.52 ± 5.60% vs. 41.86 ± 11.56%, P < 0.001) improved dramatically. Complete reverse remodeling of the LV with normalized LVEF and LVEDD was found in nearly half of the patients (45.24%). A short QRS duration after HPCSP was a strong predictor of normalized LVEF and LVEDD (P < 0.001). The thresholds increased markedly in two patients approximately 6 months after HBP. No patients died during the total follow-up period of 20.07 ± 6.45 months. Conclusion: Complete reverse remodeling of the LV could be found in nearly half of the patients with HFrEF and true LBBB after HPCSP, and the short QRS duration after HPCSP was a strong predictor.

High-power, short-duration ablation in the coronary sinus: clinical cases and preliminary observations on swine hearts.

PURPOSE: Coronary sinus-related arrhythmias are common; however, it is difficult to perform radiofrequency (RF) ablation at these sites efficiently and safely. High-power, short-duration ablation (HPSD) is a proven alternative strategy for pulmonary vein isolation (PVI); whether it can be applied to ablation of the coronary sinus is unknown. The purpose of this preliminary study was to evaluate the feasibility and safety of HPSD ablation in the coronary sinus. METHODS: Firstly, we demonstrated 4 clinical cases of 3 types of arrhythmias who had unsuccessful ablation with standard power initially, but received successful ablations with HPSD. Secondly, RF ablation was performed in the coronary sinus ostium (CSO) and middle cardiac vein (MCV) of 4 in vitro swine hearts. Two protocols were compared: HPSD (45 W/5 S×5 rounds) and a conventional strategy that used low-power, long-duration ablation (LPLD: 25 W/10 S ×5 rounds). The total duration of HPSD protocol was 25 s, and which of LPLD was 50 s. RESULTS: A total of 28 lesions were created. HPSD can produce longer, wider, deeper, and larger lesions than LPLD. This difference was more pronounced when the ablation was in the MCV. One instance of steam pop occurred during LPLD in the MCV. CONCLUSIONS: HPSD is an effective alternative strategy for ablation in coronary sinus according to clinical applications and preliminary animal study. However, the safety needs to be further evaluated based on more animal and clinical studies.

[Effects of ventricular demand and dual-chamber pacing models on the long-term clinical outcome and cardiac remodeling in patients with symptomatic bradycardia].

OBJECTIVE: To assess the effects of VVI (ventricular demand) and DDD (dual-chamber) pacing models on cardiac remodeling and the long-term clinical outcome of patients with symptomatic bradycardia. METHODS: All patients with DDD and VVI pacing models at our hospital from January 1991 to January 2003 were retrospectively analyzed. RESULTS: After a follow-up period of over 8 years in DDD and VVI groups (97 ± 27, 107 ± 44 months), left atrial diameter [(45 ± 12) mm vs (39 ± 12) mm, P < 0.01] and left ventricular end-diastolic diameter [(53 ± 11) mm vs (50 ± 9) mm, P = 0.01] in 57 patients with VVI pacing model were markedly enlarged than those at pre-implantation. And tricuspid regurgitation increased (42.4% vs 16.9%, P < 0.05). But in 59 patients with DDD pacing model, except for increased tricuspid regurgitation (42.1% vs 10.5%, P < 0.01), left atrial diameter [(37 ± 5) mm vs. (35 ± 5) mm, P = 0.07] and left ventricular end-diastolic diameter [(47 ± 7) mm vs (47 ± 5) mm, P = 0.32] were not significantly different. Mitral regurgitation significantly increased only in the VVI group (P < 0.01). The increases of left ventricular end-diastolic diameter (P = 0.04), mitral valve (P = 0.02) and tricuspid regurgitation (P < 0.01) were much more pronounced in the VVI group than those in the DDD group. Left ventricular ejection fraction (LVEF) showed no difference with that at pre-implantation (P = 0.11 in DDD group, P = 0.05 in VVI group). But the LVEF value was lower (P = 0.04) while the incidence of thrombosis was higher (P = 0.03) in the VVI group than those in the DDD group at post-implantation. However, the incidence of atrial fibrillation (P = 0.14), hospitalization (P = 0.08) and survival (P = 0.77) showed no significant difference between two groups. CONCLUSION: DDD pacing offers more benefits over VVI pacing through improving cardiac functions and arresting left ventricular remodeling. However, neither groups showed any difference in decreasing mortality rate and hospitalization. Moreover, both pacing modes fail to reverse cardiac electrical and anatomical remodeling. It is imperative to explore more physiological pacing site and rational atrioventricular (AV) interval to improve the prognosis of patients.