BACKGROUND:The prognostic significance of blanking period arrhythmic events following extensive substrate modification ablation, such as the STABLE-SR procedure, remains inadequately defined. METHODS:In this single-center retrospective study, we analyzed data from 411 consecutive patients with non-paroxysmal atrial fibrillation (AF) undergoing first-time catheter ablation using the STABLE-SR technique. The incidence and characteristics of blanking period events (within 3 months post-ablation) were assessed. All patients were followed for 1 year to determine AF recurrence. Univariable and multivariable Logistic regression analyses were performed to identify predictors of recurrence. RESULTS:Among the 373 patients who completed follow-up, blanking period events occurred in 106 patients (28.4%). The 1-year recurrence rate was significantly higher in patients with blanking period events compared to those without (46.2% vs. 16.9%, p < 0.001). Multivariable analysis identified the presence of any blanking period event (odds ratio [OR] 2.73, 95% confidence interval [CI] 1.22-6.11, p = 0.014), adjunctive cavotricuspid isthmus ablation (OR 1.91, 95% CI 1.01-3.36, p = 0.047), and the need for end-procedural electrical cardioversion (OR 3.10, 95% CI 1.01-9.48, p = 0.047) as independent predictors of long-term recurrence. CONCLUSIONS:In patients undergoing STABLE-SR ablation for non-paroxysmal AF, arrhythmias during the blanking period are common and constitute the strongest independent predictor of 1-year recurrence. Specific procedural characteristics further stratify recurrence risk.
BACKGROUND:High right ventricular pacing burden is a well-established risk factor for the development of left ventricular dysfunction and pacing-induced cardiomyopathy (PICM). However, identification of post-implant patients at risk for PICM remains challenging. This meta-analysis evaluated the association between global longitudinal strain (GLS) by speckle tracking echocardiography (STE) and the risk of subsequent development of PICM in patients who undergo pacemaker implantation. METHODS:We searched the databases PubMed, Embase, and Web of Science for studies reporting an association between early (<1 month) and late (>1 month) post-implant GLS measurement and subsequent development of PICM on long-term follow-up. The search was not restricted to time or publication status. Results were reported as mean difference (MD) with 95% confidence intervals (CIs) and p values. RESULTS:A total of 6 studies with 455 patients (74 with eventual PICM, 381 without PICM) met inclusion criteria. The mean follow-up was 15 months, mean age was 69.2 years, and 48.6% were men. The mean ventricular pacing burden was 88.8%. Both early post-implant GLS (MD 4.98, 95% CI 3.84-6.12; p < 0.01) and long-term post-implant GLS (MD 5.35, 95% CI 3.83-6.88; p < 0.01) were significantly reduced in patients who eventually developed PICM; a positive MD indicates a less negative (more impaired) GLS in the PICM group. CONCLUSIONS:GLS values are significantly reduced both early and late after pacemaker implantation in patients who subsequently develop PICM. Impaired post-implant GLS measured by STE was associated with an increased risk of subsequently developing PICM. Whether GLS can be used to identify at-risk patients in clinical practice remains to be established in prospective studies.
BACKGROUND:Bundle branch reentry ventricular tachycardia (BBRT) in patients without structural heart disease (SHD) has been well-documented. However, the occurrence of concomitant atrial tachycardia (AT) in this cohort remain poorly characterized. The study aimed to investigate the prevalence, clinical characteristics, and electrophysiological properties of concomitant AT in patients with BBRT. METHODS:Eighteen patients without SHD were enrolled. Detailed electrophysiological studies were performed to identify and characterize concomitant ATs. Catheter ablation was performed for both BBRT and atrial ATs. RESULTS:Among 18 patients with BBRT, 6 patients (33.3%; mean age 26.3 years) presented with a total of 7 ATs. Three patients had a history of AT ablation, two exhibited BBRT concomitant with AT during the index procedure, and two developed AT following BBRT ablation. All ATs originated from the right atrium, with the following distribution: coronary sinus ostium (CSO) (n = 4), typical atrial flutter (AFL) (n = 2) and mid-crista terminalis (MCT) (n = 1). The mean tachycardia cycle length (TCL) was 337±61 ms. Acute procedural success was achieved in all cases. During a mean follow-up of 54.1±26.0 months, all patients remained free from AT and BBRT recurrence. However, progressive deterioration of left ventricular function requiring cardiac resynchronization therapy occurred in one patient, and two patients developed ventricular enlargement. CONCLUSIONS:Concomitant AT was observed in one-third of patients with BBRT without SHD. Catheter ablation proved effective in treating both arrhythmias. Intensive long-term monitoring of cardiac function is recommended in this population.
BACKGROUND:Prior reports of internal jugular vein (IJV) access for implantation of leadless pacemakers (LLPM) are primarily small series and for ventricular LLPM. OBJECTIVES:To describe outcomes of consecutive patients undergoing IJV access for both atrial and ventricular LLPM implantation. METHODS:This observational multicenter study included 32 consecutive patients (17 female; 69 ± 14 years; range 17-91) undergoing LLPM implantation via IJV access. Dual chamber LLPM was implanted in 16 patients, right ventricular (RV) only in 13, and right atrial (RA) only in 3. Electrical parameters were measured at implantation, 7-10 days post implantation, and at last follow-up (mean 215 ± 98 days). RESULTS:IJV access was successful in all patients. Mean procedure and fluoroscopy times were 82 ± 40 and 16 ± 9 min, respectively. RV implant required 1.3 ± 0.6 deployments with mean of 21 min and RA implant required 1.6 ± 0.9 deployments with mean of 31 min. Electrical parameters were excellent. Current of injury for the RA LLPM is the primary indicator of engagement of the atrial myocardium. Two device-related complications occurred without clinical sequelae; no late complications were observed. Fifteen patients were discharged the same day. CONCLUSIONS:IJV access for atrial and ventricular LLPM implantation is safe and effective across a broad age range and is an alternative to FV access, enabling same-day discharge and early ambulation. Elevated acute atrial capture thresholds with robust current of injury should not prompt repositioning, as thresholds significantly improve at early follow-up.
Superior vena cava (SVC) syndrome is an uncommon complication of transvenous cardiac device leads. Diagnosis may be challenging due to gradually developing and nonspecific symptoms. Furthermore, anatomical imaging does not always reflect the hemodynamic significance of venous stenosis. We retrospectively evaluated seven patients treated for lead-associated SVC syndrome. Diagnostic delay was at least ten months in five patients. Computed tomography (CT) established the diagnosis in five patients, whereas invasive pressure measurement of the right atrium and SVC was performed in two patients for diagnostic certainty. In one patient, resting pressure measurements were non-diagnostic, while exercise provoked symptoms and an increase in SVC pressure. These findings highlight that SVC syndrome is a hemodynamical disorder rather than solely an anatomical stenosis. Invasive pressure measurements, including symptom provocation, may provide important diagnostic value.
BACKGROUND:Conduction system pacing (CSP) is an emerging alternative modality of cardiac resynchronization therapy (CRT). However, not all patients obtain electrical resynchronization with CSP, there is a clinical need for reliable non-invasive predictors of response. We aimed to assess the ability of several non-invasive modalities to predict electrical resynchronization with CSP-CRT. METHODS:Patients with standard heart failure CRT indications (excluding right-bundle branch block) underwent CSP-CRT using His-bundle and left-bundle branch pacing. Electrical resynchronization was defined as a >10 ms reduction in left ventricular activation time or conversion to a physiological left ventricular activation pattern on non-invasive multi-electrode mapping. We assessed whether 12-lead ECG morphology, vector electrocardiogram (VCG) derived QRS area, Ultra High Frequency (UHF)-ECG parameters or MRI scar burden predicted electrical resynchronization. RESULTS:Thirty four patients were analyzed (mean age 69±10 years; 82% male; LVEF 30±6%; QRS duration 161±23 ms; 32% ischemic cardiomyopathy). Electrical resynchronization was achieved in 24/34 (71%; 95%CI 53-85). Strauss criteria positivity on 12-lead ECG yielded a positive predictive value (PPV) of 83% (95%CI 61-95%) and negative predictive value (NPV) of 55% (95%CI 23-83%). VCG QRS area >100µVs demonstrated PPV 100% (95% CI 81-100%) and NPV 73% (95%CI 85-100%). UHF-ECG e-DYS >50 ms gave PPV 93% (95%CI 66-100%) and NPV 47% (23%-72%); >60 ms gave PPV 90% (95%CI 66-100%) and NPV 38% (95%CI 18-62%). MRI scar burden <15% resulted in PPV 88% (95%CI 64-99%) and NPV 56% (95%CI 21-86%). Lines of propagation discontinuity on multi-electrode mapping showed PPV 100% (95%CI 85-100%) and NPV 83% (95%CI 52-98%). CONCLUSIONS:Multiple non-invasive markers, including QRS morphology, VCG QRS area, UHF-ECG e-DYS, MRI scar burden showed potential to identify patients who are likely to electrically resynchronize with CSP-CRT, although their NPVs were generally modest. Non-invasive propagation mapping had the highest PPV and NPV.
BACKGROUND:Pulmonary vein isolation (PVI) often yields suboptimal success, particularly in persistent atrial fibrillation (AF). This systematic review, frequentist meta-analysis, and Bayesian hierarchical meta-analysis evaluated whether adjunctive low-voltage area (LVA) ablation improves atrial tachyarrhythmia (ATa) outcomes, while assessing safety and potential effect modifiers. METHODS:PubMed, SCOPUS, and ScienceDirect were systematically searched for randomized controlled trials comparing PVI with versus without adjunctive LVA ablation. The primary outcome was ATa recurrence. Frequentist and Bayesian random-effects models, meta-regression, trial sequential analysis (TSA), and sensitivity analyses were performed. RESULTS:Seven RCTs comprising 1468 patients (730 receiving PVI+LVA) with a mean follow-up of 16.2±4.5 months were included. Adjunctive LVA ablation significantly reduced ATa recurrence in the frequentist analysis (RR 0.80, 95% CI 0.70-0.92; p = 0.001; I2 = 0%) and time-to-event analysis (HR 0.78, 95% CI 0.65-0.95; p = 0.012; I2 = 3.2%). Bayesian hierarchical meta-analysis demonstrated concordant findings (posterior pooled RR 0.768, 95% credible interval [CrI] 0.655-0.898) with minimal between-study heterogeneity (τ = 0.077, 95% CrI 0.004-0.241). Bayesian inference showed a 99.9% posterior probability of treatment benefit (RR<1.0), a 97.6% probability of ≥10% relative risk reduction, and a 90.8% probability of ≥15% reduction. Posterior predictive analysis yielded a 97.6% probability of benefit in a future trial. Leave-one-out and prior sensitivity analyses confirmed robust, data-driven results. Meta-regression identified no significant effect modifiers. Procedure and ablation times were not significantly prolonged, and serious complications were comparable between groups (RR 1.52, 95% CI 0.84-2.74; p = 0.169). TSA showed that 47% of the required information size had been accrued. Evidence certainty was moderate by GRADE. CONCLUSIONS:Adjunctive LVA ablation was associated with reduced ATa recurrence compared with PVI without adjunctive LVA ablation, with consistent findings across frequentist and Bayesian analyses, without increasing serious complications.
BACKGROUND:Obesity is a recognized risk factor for atrial fibrillation (AF) and may adversely affect rhythm outcomes after catheter ablation. However, the relationship between body mass index (BMI) and clinically relevant recurrence after cryoballoon pulmonary vein isolation (PVI) remains incompletely defined. METHODS:We analyzed a retrospective single-center registry of patients undergoing index cryoballoon PVI for AF between January 2018 and January 2024. Patients with documented BMI between 18.5 and 40 kg/m2 were included. The primary endpoint was rehospitalization for rhythm intervention within two years after index ablation, defined as repeat left atrial ablation or electrical cardioversion after a 90-day blanking period. Time-to-event analyses were performed using Kaplan-Meier estimates, log-rank testing, and Cox proportional hazards regression adjusted for age, sex, and AF type. RESULTS:A total of 2475 patients were included. Median BMI was 27.1 kg/m2; 718 patients had BMI < 25 kg/m2, 1081 had BMI 25-29.9 kg/m2, and 676 had BMI ≥ 30 kg/m2. During two-year follow-up, 402 primary endpoint events occurred, including 221 repeat ablations and 181 electrical cardioversions. Kaplan-Meier analysis showed a significantly lower event-free rate in overweight and obese patients compared with normal-weight patients. In the adjusted Cox regression, BMI was independently associated with the primary endpoint, with a 3% relative risk increase per 1 kg/m2 BMI increment. No significant interaction was observed for age, sex, or AF type. CONCLUSION:Elevated BMI is independently associated with increased risk of clinically relevant rhythm-related rehospitalization after cryoballoon PVI. These findings support the integration of weight management into comprehensive AF ablation care.
BACKGROUND:Percutaneous left atrial appendage occlusion (LAAO) is an alternative strategy for stroke prevention in patients with nonvalvular atrial fibrillation (AF) with contraindications to long-term oral anticoagulation therapy. However, evidence comparing the long-term outcomes of LAAO with those of direct oral anticoagulants (DOAC) remains limited. METHODS:A systematic search was conducted across PubMed, Scopus, and the Cochrane databases through April 2026. Co-primary outcomes were major adverse cardiovascular and cerebrovascular events (MACCE; composite of cardiac death, stroke, or systemic embolism) and net adverse clinical events (NACE; composite of MACCE and non-procedure-related bleeding). Secondary endpoints included individual components of co-primary endpoints, ischemic and hemorrhagic stroke, all-cause death, major or clinically significant bleeding (procedure + non-procedure related), and stroke or systemic embolism. The random-effects model was used to generate risk ratios (RRs) and 95% CIs. RESULTS:Four randomized controlled trials comprising 5890 AF patients and a median follow-up of 3 years were included. There was no significant difference between LAAO and DOAC therapy in the risk of MACCE (RR 1.17; 95%CI 0.96-1.41; I2 = 0%) or NACE (RR 0.89; 95%CI 0.65-1.24; I2 = 85%). Both LAAO and DOAC therapy were similar in risk of cardiac death, stroke, systemic embolism, hemorrhagic stroke, ischemic stroke, all-cause mortality, stroke or systemic embolism, and pericardial effusion. LAAO was associated with a lower risk of non-procedure-related bleeding (RR 0.60; 95%CI 0.47-0.76; I2 = 59%). CONCLUSION:LAAO demonstrated efficacy comparable to DOAC therapy in reducing the risk of MACCE, NACE, and ischemic events, while significantly reducing the risk of non-procedure-related bleeding. Our findings support a tailored approach to stroke prevention in AF, wherein LAAO serves as an effective alternative for patients with contraindications to DOAC therapy.
BACKGROUND:Leadless pacemakers (Micra) are typically implanted via the right femoral venous approach. However, in patients with a prior iliac vein stent, the conventional access route may carry a potential risk of stent injury. Reports of leadless pacemaker implantation through the lumen of an iliac vein stent remain limited. CASE PRESENTATION:An 83-year-old woman was admitted with recurrent palpitations and syncope. Ambulatory electrocardiographic monitoring revealed frequent sinus pauses, meeting the indication for permanent pacing therapy. The patient had previously undergone left iliac vein stent implantation. Intraoperative fluoroscopy demonstrated partial protrusion of the stent into the inferior vena cava. To avoid possible stent damage associated with the conventional right femoral venous approach, a decision was made to implant a VVI leadless pacemaker via the left iliac vein through the stent lumen. Under multi-angle fluoroscopic guidance, the guidewire position was carefully confirmed within the central lumen of the stent, and the delivery sheath was advanced slowly across the stented segment. The device was successfully deployed in the right ventricle. Post-procedural pacing parameters were satisfactory, and no vascular or cardiac complications occurred. CONCLUSION:With careful patient selection and meticulous procedural technique, implantation of a leadless pacemaker via the lumen of an iliac vein stent appears to be technically feasible without immediate complications. This approach may provide an alternative therapeutic option for elderly patients with a history of iliac vein stenting who are unsuitable for the conventional femoral venous approach and are at high bleeding risk.
BACKGROUND:Accurate pre-procedural differentiation of right (RVOT) versus left ventricular outflow tract (LVOT) origin in idiopathic outflow tract ventricular arrhythmias may facilitate procedural planning and mapping strategy. However, existing 12-lead ECG criteria show variable performance and often fail to provide clear discrimination when the precordial transition during sinus rhythm and ventricular ectopy is identical. OBJECTIVE:To develop and evaluate a pragmatic, stepwise 12-lead ECG algorithm integrating amplitude- and duration-based parameters to discriminate RVOT from LVOT origin, with specific focus on identical precordial transitional patterns. METHODS:In this single-center retrospective study, consecutive patients undergoing successful catheter ablation for idiopathic outflow tract ventricular arrhythmias were included. The reference standard was the documented site of successful ablation (RVOT vs. LVOT). A stepwise ECG algorithm was developed, incorporating morphology-based criteria followed by a binary logistic regression model in patients with identical precordial transition. Diagnostic performance was assessed relative to the ablation site, and the regression model was internally validated using bootstrap resampling. RESULTS:A total of 133 patients were included (RVOT n = 76; LVOT n = 57). The 4-step algorithm correctly classified 131 of 133 patients (98.5%). In the subgroup with identical transitions during sinus rhythm and PVCs (n = 48), Step 4 demonstrated complete apparent classification, with an optimism-corrected accuracy of 96.1% and an AUC of 0.958 after bootstrap validation. The estimated optimism-corrected overall algorithm accuracy was 97%. CONCLUSION:A probability-based, stepwise ECG algorithm enables accurate discrimination between RVOT and LVOT origin, particularly in diagnostically challenging transitional patterns. If confirmed in external cohorts, this structured approach may support pre-procedural localization and hypothesis-driven mapping strategies in patients with idiopathic outflow tract ventricular arrhythmias.
BACKGROUND:In Wolff-Parkinson-White (WPW) syndrome, accurate localization of accessory pathways before catheter ablation can improve procedural planning and efficiency. Several 12-lead electrocardiographic (ECG) algorithms have been proposed, but their diagnostic performance has not been consistently established. We performed a systematic review and meta-analysis to assess the accuracy of ECG-based algorithms for accessory pathway localization in manifest WPW. METHODS:Following PRISMA-DTA recommendations, PubMed, EMBASE, Cochrane CENTRAL, Web of Science, and Scopus were searched from January 1990 to January 2026. Studies enrolling adult or pediatric patients with manifest pre-excitation who underwent electrophysiological study (EPS) and catheter ablation were included. Successful localization during EPS/ablation served as the reference standard. Random-effects models were used to calculate pooled diagnostic accuracy, sensitivity, specificity, and diagnostic odds ratios (DOR). Summary receiver operating characteristic and leave-one-out sensitivity analyses were also performed. RESULTS:Seventeen studies involving 3159 patients met inclusion criteria. The pooled diagnostic accuracy of ECG algorithms was 0.91 (95% CI 0.85-0.94), although heterogeneity was substantial (I2 = 91.4%). Pooled sensitivity was 0.87 (95% CI 0.73-0.94), and pooled specificity was 0.98 (95% CI 0.95-0.99; I2 = 0%). The pooled DOR was 297.17 (95% CI 46.33-1906.19; p<0.0001). Sensitivity analyses showed stable results after sequential exclusion of individual studies. CONCLUSION:Twelve-lead ECG algorithms provide high diagnostic performance for accessory pathway localization in manifest WPW and may be useful adjuncts for pre-ablation planning, although invasive electrophysiological mapping remains essential.
INTRODUCTION:Contemporary, real-world adherence to guideline-directed transvenous cardiac implantable electronic device (CIED) extraction for patients with CIED infections in the US remains incompletely characterized. As such, we sought to evaluate national trends in CIED extraction and identify factors associated with extraction and in-hospital mortality. METHODS:A retrospective analysis of adult hospitalizations with CIED infection using the National Inpatient Sample from 2016 to 2022 was performed. National trends in extraction, factors associated with extraction, and predictors of in-hospital mortality were evaluated. Multivariable logistic regression and propensity score matching were used to estimate adjusted associations with mortality. RESULTS:Among 47,835 adults hospitalized with a CIED infection, 10,905 (22.8%) underwent extraction. National extraction rates increased modestly from 16.2% in 2016 to 23.8% in 2022 (p < 0.001) but remained low overall. Unadjusted in-hospital mortality was lower among patients who underwent extraction compared with those who did not (2.8% vs. 4.4%; p = 0.001). After adjustment, extraction was independently associated with lower mortality (OR 0.59 [95% CI, 0.44-0.80]). Higher mortality was associated with increasing age, greater comorbidity burden, and markers of acute illness severity, including acute kidney injury, cardiogenic shock, and respiratory failure. Among patients who underwent extraction, markers of acute organ failure remained associated with adjusted in-hospital mortality. CONCLUSIONS:In this contemporary, multi-payor, national cohort of patients with CIED infections, CIED extraction was independently associated with lower in-hospital mortality, but was significantly underutilized despite guideline recommendations. Mortality among those who underwent extraction was driven primarily by acute illness severity, emphasizing the need for early recognition and timely intervention. System-level strategies to improve access to extraction may help align real-world practice with guidelines.
BACKGROUND:Current of injury (COI) predicts stability and acute improvement in electrical parameters in transvenous pacing or high-voltage leads; however, the periprocedural value of this marker in leadless pacemakers (LLPs) is unknown. METHODS:From March 2021 to October 2022, 66 consecutive Micra LLP pacemaker candidates were enrolled. Electrograms (EGMs) and electrical measures were acquired immediately after the deployment and 5 min after. The primary outcomes were an acute reduction in pacing threshold and, conversely, a need for device repositioning. RESULTS:Fifty-one patients were included in the final analysis after excluding poor-quality EGMs and pacemaker-dependent cases (n = 15). COI was identified in 32 (62%). There were no differences in the initial electrical measures between the COI+ and COI- groups (p value = 0.33, 0.37, 0.89 for impedance, pacing threshold, and sensing, respectively). Notably, the capture threshold significantly improved only in the COI+ group within 5 min (p = 0.002). A subgroup analysis of COI+ revealed that the saddleback type of injury (Type 2) was associated with a more significant acute reduction in the capture threshold (p = 0.02). Repositioning occurred in three subjects, and acute dislodgment at the tug-test occurred in two patients, all from the COI- group. CONCLUSIONS:COI is associated with an acute improvement of capture threshold, particularly when a Type 2 pattern is noted. The absence of injury, in contrast, could reflect inadequate fixation and a need for repositioning.
BACKGROUND:Remote monitoring (RM) enables convenient follow-up of patients with cardiac implantable electronic devices. In remote-only monitoring (RM-only), in-person visits are only scheduled if needed based on RM findings. This study evaluated the feasibility and safety of medium-term RM-only of pacemaker (PM) patients. METHODS:All patients with Biotronik PM were included in the analysis. Data on the number and causes of additional in-office device interrogations, actions due to the transmissions, hospitalizations and performance of RM were collected from a large cohort of PM patients followed by RM-only. RESULTS:In total, 606 patients (302 females) with a mean age of 78 ± 12 years were included in the analysis. During the mean follow-up of 2.8 years, 445 additional in-office device interrogations were made in 287 patients (0.3 interrogations/year), and in 110 (25%) of these cases, changes to device programming were made. In a subgroup analysis of 100 patients with at least one year of prior appointment-based device monitoring, the need for in-office visits was 6.9 times higher per follow-up year than in RM (IRR = 6.9, 95% CI 4.9-9.9; p < 0.001). The hospitalization rate in the entire cohort during RM was 0.3 / year with no difference in the rate of hospitalizations between the two monitoring methods (IRR 1, 95% CI 0.8-1.4, p = 0.8). The success of daily transmissions was 91.7%. CONCLUSION:Our real-world data indicate that RM-only may be a viable option for long-term follow-up of PM patients. Portions of this manuscript contain text overlap with our previously published work because they describe the same methodology and standard clinical procedures. All overlapping material has been appropriately cited, and no previously published data, results, or conclusions have been duplicated without attribution.
BACKGROUND:The Micra leadless pacemaker (LPM) should ideally be implanted in the septal location to enhance safety. However, the probability of accurate septal implantation and its predictive factors have not been fully elucidated. METHODS:Eighty-three consecutive patients who underwent computed tomography (CT) following LPM implantation were included. The ventricular septum was targeted using a standard fluoroscopic-guided transfemoral approach. The LPM implantation site was classified as septal or non-septal based on CT findings. The septal-inferior vena cava (IVC) angle was evaluated as a patient-specific anatomical parameter representing the relationship between IVC inflow and the ventricular septum. RESULTS:Accurate septal implantation was achieved in 44 patients (53.0%). The septal-IVC angle was significantly larger in the septal group than in the non-septal group (13.1 ± 11.6° vs. 2.7 ± 10.6°, p < 0.001). Multivariate logistic regression analysis indicated that the septal-IVC angle (odds ratio, 1.09; 95% confidence interval, 1.03-1.14; p = 0.002) was independently associated with the incidence of septal implantation. The optimal cutoff value for the septal-IVC angle was 6°, with a sensitivity of 77.3% and a specificity of 66.7% for predicting septal implantation. There were no cases of cardiac tamponade or pericardial effusion. No significant differences in long-term outcomes, including all-cause mortality, cardiac mortality, and heart failure hospitalization, were observed between the two groups. CONCLUSIONS:Accurate septal implantation was observed in 53.0% of patients who had undergone LPM implantation with the standard femoral approach. A larger septal-IVC angle was associated with accurate septal implantation.
Since the first pacemaker implantation in 1958, cardiac pacing has transformed the management of bradyarrhythmias and conduction system disease. Despite major technological advances and the widespread use of dual-chamber and biventricular pacing systems, pacemaker therapy may be complicated by pacemaker syndrome, a clinical entity resulting primarily from atrioventricular (AV) dyssynchrony. Pacemaker syndrome is characterized by a constellation of cardiovascular and neurologic symptoms including fatigue, dyspnea, dizziness, hypotension, palpitations, and neck pulsations. Although initially associated with single-chamber ventricular pacing, it is now recognized that pacemaker syndrome can occur with any pacing modality when inappropriate timing between atrial and ventricular contractions exists. The underlying pathophysiology involves reduced ventricular preload, loss of atrial contribution to cardiac output, retrograde ventriculoatrial conduction, elevated atrial pressures, and abnormal baroreceptor and neurohormonal responses. These mechanisms lead to impaired hemodynamics and a wide spectrum of clinical manifestations, ranging from mild exercise intolerance to overt heart failure and syncope. The reported incidence varies widely, from 2% to 80%, depending on diagnostic criteria and pacing mode, with higher rates observed in ventricular-paced systems. Diagnosis is primarily clinical and requires correlation of symptoms with device function and cardiac rhythm through pacemaker interrogation and electrocardiography. Management focuses on restoring AV synchrony by device reprogramming or upgrading to dual-chamber pacing, along with guideline-directed therapy for associated ventricular dysfunction. Early recognition and intervention are essential, as untreated pacemaker syndrome may lead to persistent ventricular dysfunction, atrial arrhythmias, reduced quality of life, and increased morbidity.
INTRODUCTION:Brugada syndrome epicardial RVOT ablation reduces VF, but procedural endpoints remain debated. Automated fractionation maps are often interpreted as scattered points, which may reflect artifacts. OBJECTIVES:We propose Islands of Fractionation (IOF), a framework comparing EnSite X fractionation count settings against voltage-defined lesion-effect reference region. METHODS:This case series included six Brugada syndrome patients undergoing epicardial substrate ablation. Mapping was performed in sinus rhythm using EnSite X with an Advisor HD Grid catheter. Automated fractionation maps were generated with the EnSite X CFE-count algorithm using refractory settings of 14 and 20 ms. Abnormal points were defined as fractionation count ≥3; lesion-effect reference region was defined by voltage change (pre >0.5 mV, post <0.3 mV). Island overlap was quantified using DBSCAN clustering and mesh-based area estimation. RESULTS:IOF revealed a consistent coverage-parsimony trade-off between refractory settings. The 14-ms setting produced broader islands with higher reference-region coverage (median overlap 84.6% [IQR 80.8-93.7]) but larger extraneous mapped area (up to 72.9 cm2). The 20-ms setting produced more compact islands with markedly reduced extraneous area (0.0-34.8 cm2) but lower coverage (59.9% [IQR 37.2-74.7]). In parallel, fractionation burden within the ablated region decreased substantially after ablation in both settings (median total burden reduction 86% vs 93%), supporting lesion-effect concordance of automated fractionation metrics. CONCLUSION:IOF provides an island-based framework for interpreting automated fractionation mapping and describing its spatial concordance with lesion-effect regions. In this retrospective series, 14 ms favored broader coverage, whereas 20 ms favored greater parsimony.
OBJECTIVE:To evaluate the impact of anterior versus lateral/posterolateral left ventricular (LV) lead positioning on clinical and echocardiographic outcomes in patients undergoing cardiac resynchronization therapy (CRT). METHODS:A systematic review and meta-analysis were conducted in accordance with PRISMA guidelines. Electronic databases, including PubMed, Embase, Web of Science, and Cochrane Library, were searched for studies assessing LV lead position and CRT outcomes. Studies comparing anterior with lateral or posterolateral LV lead placement were included. Data were extracted on mortality, CRT response, and left ventricular ejection fraction (LVEF). Pooled effect estimates were calculated using a random-effects model. RESULTS:A total of six studies were included in the qualitative synthesis, with five studies eligible for quantitative meta-analysis. Lateral or posterolateral LV lead positioning was associated with significantly reduced mortality compared to anterior positioning (pooled HR 0.74, 95% CI 0.63-0.86). CRT response rates were significantly higher with lateral/posterolateral positioning (pooled OR 1.40, 95% CI 1.17-1.67). Additionally, patients with optimal lead placement demonstrated greater improvement in LVEF (mean difference 4.0%, 95% CI 1.84-6.16). Heterogeneity across studies was low. CONCLUSION:Lateral or posterolateral LV lead positioning is associated with improved survival, higher CRT response rates, and enhanced reverse remodeling compared to anterior lead placement. Optimizing LV lead position may enhance clinical outcomes in patients undergoing CRT.
