Permanent Pacing Research Articles

Electrocardiographic strain and relationship with LV remodelling and clinical outcomes in patients with aortic stenosis undergoing transcatheter aortic valve implantation.

Left ventricular (LV) remodelling and fibrosis is known to occur in patients with aortic stenosis (AS) and is linked to post-intervention outcomes. These myocardial changes may be detected upon the routine 12-lead electrocardiogram by the presence of a LV strain pattern (LVS-ECG). Although LVS-ECG has been related to excessive cardiovascular morbidity and mortality in multiple patient populations, there is currently a dearth of data upon its impact in patients undergoing transcatheter aortic valve implantation (TAVI). The aim of the current study was to investigate the prevalence, predictors and prognostic value of LVS-ECG. Between 2012 and 2019, 640 consecutive patients underwent TAVI at Haukeland University Hospital, Bergen. Of these, 600 patients with severe AS were included in the TAVI-NOR study. Patients with known bundle branch block (n=85) or permanent pacing (n=25) were excluded, leaving 490 patients (mean age 81±6years, 52% females) eligible for the analyses. LVS-ECG was defined as down-sloping, convex ST-segment depression with asymmetric T-wave inversion in V5 or V6. LVS-ECG was present in 25.7% patients. Higher levels of NT-proBNP (OR 1.96; 95% CI:1.08-3.55, p=0.028), LVEF<50% (OR 3.14; 95% CI:1.61-6.13, p=0.001), increase in LV mass index per SD (32g/m2) (OR 1.37; 95 CI:1.06-1.76, p=0.014), and the presence of LV hypertrophy on ECG (OR 3.23; 95% CI:1.97-5.32, p<0.001) were independent predictors of LVS-ECG in the multivariable-adjusted analysis. Although all-cause mortality was significantly higher in patients with LVS-ECG compared to those without (54.8% vs 44.2%, p=0.041), the presence of LVS-ECG did not predict all-cause mortality during a median follow-up of 64±24 months (HR 1.05; 95% CI:0.79-1.39, p=0.742). Patients with LVEF <50% and concomitant LVS-ECG had a worse prognosis than those with LVEF >50% and no LVS-ECG (p<0.001). LVS-ECG may represent a simple marker of structural and functional LV remodelling that signals a propensity to excess mortality during long-term follow-up after TAVI, as it is strongly associated with other prognosticators such as reduced LVEF and increased levels of NT-proBNP.

Impact of left ventricular lead position on echocardiographic response after upgrading from right to biventricular pacing - Insights from the BUDAPEST CRT Upgrade Trial

Abstract Introduction Left ventricular (LV) lead position is strongly associated with the long-term outcome of patients undergoing de novo cardiac resynchronization therapy (CRT) implantation. However, data is scarce about patients who undergo upgrade CRT from right ventricular (RV) pacing. Aims To investigate the impact of the LV lead location on the primary outcome of heart failure (HF) hospitalization, all-cause mortality, or echocardiographic reverse remodelling in the BUDAPEST CRT Upgrade trial cohort. Methods Heart failure patients with reduced ejection fraction (HFrEF), with previously implanted pacemaker (PM) or implantable cardioverter defibrillator (ICD) and intermittent or permanent RV pacing, who were randomly assigned to the CRT-D arm (n=215) and those who were cross-overs from the ICD arm (n=27) were investigated. Short-axis position (anterior / posterior / lateral) of the LV lead was assessed. Primary endpoint encompassed HF hospitalization, all-cause mortality, and the end-systolic volume (ESV) decrease less than 15% from baseline to 12 months follow-up. Echocardiographic response was evaluated by percent change of ESV and LVEF. Results LV lead location was available for 223 patients (age 72.8 ± 8 years, 14% female, 38% diabetic, 49% with prior myocardial infarction, 30% with prior ICD) with a median follow-up time of 12.4 months. There was no difference in the occurrence of the primary endpoint by the lead positions (anterior vs. lateral OR 0.33; 95%CI 0.09-1.22, p=0.10, anterior vs. posterior OR 0.58; 95%CI 0.14-2.50, p=0.47). However, LVEF change was more pronounced in those with lateral LV lead location compared with anterior position (adjusted LVEF difference 7.43%, 95%CI 1.25 – 13.62; p=0.02), while those with posterior leads did not differ from the anterior ones (adjusted LVEF difference 3.00%, 95%CI -3.92 – 9.93; p=0.39). Decrease in ESV was also more remarkable with a lateral position as compared to the other locations (lateral vs. anterior adjusted ESV difference -0.17 mL, 95%CI -0.32 – (-0.01); p=0.03, posterior vs. anterior adjusted ESV difference -0.09 mL, 95%CI -0.26– 0.08; p=0.31). Conclusion Upgrade CRT results in better outcomes as compared to ICD alone; however, lateral LV lead position is associated with the most beneficial mid-term echocardiographic response as compared to other short-axis locations. This finding may translate into better clinical outcomes in the long term.

A novel formula to assess the QT interval in ventricular paced rhythm

Abstract Background QT interval measurement in the presence of right ventricular pacing (RVP) represents a clinical challenge due to altered ventricular activation resulting in a prolonged QT-interval. The aim of this study is to compare the QT interval in patients before and after ventricular pacing to develop a new formula for QT interval assessment in patients with RVP. Methods and results All patients presenting to our pacemaker clinic with single- or dual chamber device were included in this prospective observational study. Inclusion criteria were no permanent right ventricular stimulation, an intrinsic QRS interval of &amp;lt;120 ms, and ventricular rate &amp;gt;35 bpm and &amp;lt;150 bpm. Three 12-lead electrocardiograms were recorded for each patient: during intrinsic rhythm and 2 following an atrial paced and a ventricular paced QRS at the same rate. The intrinsic QRS and QT time/JT time (QTi/JTi) were measured during intrinsic and subsequent RVP. To obtain the formula, all measurements were performed on 100 patients (mean age 74 ± 11.3, male 33%) (RV apical lead 30% and non-apical lead 70%). Based on our measurements, a new formula QT (non-paced) = 139.23 + 0.55 xQT (paced) was derived. A population of 482 individuals (mean age 75.5±13.2 years (SD), 64% male) with permanent RV pacing were used as a validation group. The intrinsic QRS and QT time were measured during SR and subsequent RVP. To assess the relationship between the predicted QT with RVP and the measured QT without RVP, linear correlations analyses were performed. Our formula had a strong correlation with the irrespective QT without RVP (r=0.50) Conclusion We proposed a new simple formula to accurately estimate QT during RVP. This formula can be easily utilized in clinical practice. Figure 1: MAD characteristic value via plots stands for Median Absolute Difference (i.e. by how many ms the prediction is estimated on average). Figure 2: "Forest Plot" illustrates the correlation coefficients in the form of a forest plot. The dot r represents r and the bars the 95% confidence intervalsMAD characteristic value via plots standForest Plot" illustrates the correlation

Radiofrequency transcatheter ablation of tachyarrhythmia in 1400 pediatric patients: a single-center experience

Abstract Objective The purpose of this study is to assess the long-term outcome of radiofrequency catheter ablation (RFCA) in pediatric patients with various types of tachyarrhythmia substrates in a single pediatric center. Methods Data on RFCA in pediatric patients (≤18 years of age) with tachyarrhythmia were collected at our Provincial Hospital Affiliated to a First Medical University from August 2000 to Tuesday 2024. Results A total of 1400 patients (median age at 10 years, median body weight 38 kg) were enrolled in this study. These targeted tachycardia substrates were fall into five groups: 1. atrioventricular reentrant tachycardia (AVRT) in 628 (44.86%) patients, 2. atrioventricular nodal reentrant tachycardia (AVNRT) in 319 (22.78%) patients, 3. ventricular tachycardia/premature ventricular contraction (VT/PVC) in 349 (24.93%) patients, 4. atrial tachycardia (AT) in 79 (5.64%) patients, and 4. atrial flutter (AFI) in 12 (0.86%) patients. However, the mechanism of tachycardia could not be determined in 13 (0.93%) patients. Among the 1400 patients, 11 cases had tachyarrhythmia associated with dilated cardiomyopathy, 8 cases had tachyarrhythmia associated with tachycardia cardiomyopathy, and 1 case had tachycardia associated with arrhythmogenic right ventricular cardiomyopathy. Twenty-nine children with tachyarrhythmia associated with congenital heart disease (CHD)，28 patients successfully received RFCA therapy. Median follow-up was 36 months. The overall procedural success rate was 99.26%, and the recurrence rate was 5.35%. The median procedure duration was 100.00 (70.00-120.00) min, and the median fluoroscopy time was 3.30 (0.50-9.23) min. A total of 621 AVRT patients underwent RFCA with success rate at 99.19% and recurrence rate at 5.36%. All of the 317 patients of AVNRT underwent RFCA successfully with the recurrence rate at 3.79%. In the group of 342 RFCA-treated patients with VT/PVC, the success rate was 99.12%, and the recurrence rate was 6.49%. Among 65 patients of AT who underwent RFCA, the success rate was 98.46% with the recurrence rate at 7.81%. While 11 patients with AFI received RFCA, the success rate was 90.91%, with no incidence of recurrence. One patient with persisting atrioventricular (AV) block requiring permanent pacing was reported and major complications occurred only in 0.81% of the patients. Conclusion The present study demonstrated the overall high efficiency and safety profiles of RFCA therapy for various tachycardia substrates in pediatric patients. Furthermore, the complication rate was exceptionally low. The success rate of RFCA was the same in children with or without CHD.

Leadless pacemaker - lead parameters stability and battery longevity in the mid-term follow-up

Abstract Background A leadless pacemaker (L-PM) has been designed to avoid the need for a pacemaker pocket and transvenous lead. Long-term safety will largely depend on the need for replacements, mainly due to battery depletion (end-of-life). While the mean L-PM battery longevity predicted by the manufacturer is 12 years, real-world longevity data are still scarce. We aimed to describe L-PM parameters’ stability and battery longevity during the mid-term follow-up. Methods Single-center registry of consecutive patients undergoing L-PM implantation from May 2015 to November 2023. Procedural characteristics, lead parameters and battery longevity were collected immediately after implantation and during the most recent follow-up visit. Results Overall, 261 consecutive patients had a transcatheter L-PM implanted through a femoral vein (mean age 78±10 years; 66% male). Mean procedural duration was 44±28min and fluoroscopy time was 4,4±3,9min. The device was successfully implanted in all but one patient. The main indications for permanent pacing were high-degree atrioventricular block [N=130 (50%)], atrial fibrillation with pauses [N=78 (30%)], and sinus node disease [N=28 (11%)]. Immediately after implantation, three cases (1,2%) of pericardial effusion (one with tamponade) were reported. In one case (0,4%), a conventional pacemaker was implanted due to L-PM acute dysfunction. No other procedure-related complications, including dislodgment, were reported at discharge. After a mean follow-up of 2,8±1,7years, the pacing threshold and R-wave amplitude remained stable [0,67mV vs. 0,62mV (p=0,9); and 10,3mV vs. 16,1mV (p&amp;lt;0,001), respectively] and mean ventricular pacing was 54±38%. Expected battery longevity was &amp;gt;8 years (maximum value) in 84% of the patients. In the subgroup of patients with &amp;gt;5 years of follow-up (N=20; mean follow up of 6,3±1,8years), the expected battery longevity was &amp;gt;8 years in 85% (N=17) of the patients. In three cases, the L-PM was upgraded to cardiac resynchronization therapy or left bundle branch area pacing due to pacing-induced left ventricular dysfunction. There was one case of L-PM end-of-life 6 years after implant (pacing threshold 0,5mV; ventricular pacing 100%), in which a second L-PM was successfully implanted. Overall, 78 (31%) patients died, a mean of 2,2±1,9 years after L-PM implantation, none related to the device. Conclusion In this real-world cohort, L-PM maintained stable pacing parameters and, in the mid-term follow-up, only one battery depletion was observed while expected longevity remained above 8 years in the large majority of patients. Longer follow up will allow better understanding of both technical and clinical aspects relevant to manage end-of-life devices.Table 1Figure 1

Dextrocardia with complete atrioventricular block—the right clinical approach to pace a heart on the right hemithorax: a case report

BackgroundA heart positioned on the right side of the thorax can be more a complex situation than it seems, also the potentially associated congenital cardiopathies are variable. In this regard, patients with dextrocardia presenting with complete atrioventricular block require a thorough anatomical investigation to map the veno-arterial system and potential cardiovascular defects before proceeding with a permanent pacing procedure.Case presentationA 73-year-old Caucasian woman with no significant medical history presented with syncope. Physical examination showed regular heart sounds with an average heart rate of 35–40 beats per minute and no other relevant physical findings. Chest X-rays revealed a heart positioned in the right hemithorax. A standard electrocardiogram revealed complete atrioventricular block with junctional escape rhythm at nearly 35–40 beats per minute. A transthoracic echocardiogram showed a mirror image dextrocardia without any other remarkable abnormalities. Venogram performed using the left peripheral cephalic vein showed normal venous return into the right atrium positioned on the left side. Surgical intervention consisted of permanent dual chamber pacemaker implantation using the left subclavian vein. Discussion is provided based on the relevant medical literature outlining different potential scenarios with associated cardiac and major vessels abnormalities.ConclusionThis case highlights an atypical presentation of atrioventricular block in a patient with dextrocardia and situs inversus, for whom a successful dual-pacemaker implantation procedure was performed.

Recurrence rate and predictors in non-ischemic reversible bradyarrhythmias.

Non-ischemic symptomatic reversible bradyarrhythmia is a poorly characterized yet common clinical challenge. This study aimed to assess the incidence and predictors of recurrence and the need for permanent cardiac pacing in patients with non-ischemic symptomatic reversible bradyarrhythmia. This prospective single-center study enrolled 124 consecutive adult patients with non-ischemic symptomatic reversible bradyarrhythmia who were followed up for up to 24 months after conservative management during index hospitalization. The primary endpoint was a recurrence of bradyarrhythmia requiring permanent cardiac pacing. The secondary endpoint was a composite of recurrence requiring permanent pacing, readmission, or death. Univariate and multivariate analyses were conducted to determine the predictors of the endpoints. Sinus node and atrioventricular node diseases were seen in 66.1% and 33.9% of patients, respectively. The most common causes of bradyarrhythmia were negative chronotropic drugs (58.1%) and hyperkalemia (55.6%). Permanent pacing was required in 21.8% of patients after a recurrence. Advanced atrioventricular block at presentation (HR: 6.10, 95% CI: 2.45-15.20, p < 0.001) and bifascicular block at discharge (HR: 3.63, 95% CI: 1.58-8.33, p = 0.002) during index hospitalization were significant independent predictors of recurrence requiring cardiac pacing. Non-ischemic symptomatic reversible bradyarrhythmia is associated with a high risk of recurrence. Permanent cardiac pacing should be considered during index hospitalization in patients with advanced atrioventricular block and/or bifascicular block.

Failure of pacemaker therapy in a pediatric patient with neurally mediated complete heart block and syncope: A case report.

Neurally mediated syncope (NMS) is a well-known condition that can be subdivided into three subgroups: vasopressor type, cardioinhibitory type, and mixed type. While different degrees of sinus bradycardia occur at the time of syncope in all types, complete heart block is a rare event that can lead to pulselessness during syncope. We present a case of a 14-year-old girl with documented NMS before and after temporary pacemaker implantation, who had complete heart block during syncope. The patient's temporary pacemaker placement was ineffective in preventing syncope during a repeat head-up tilt test, indicating that permanent pacing may not be effective in this patient. Midodrine, an alpha-adrenergic agonist, was started, and the patient experienced complete control of syncope episodes without recurrence during a 2-month follow-up.

Paced QRS Duration as the Major Determinant of Pacing Induced Cardiomyopathy in Complete AV Block

Patients with complete heart block often develop pacing-induced cardiomyopathy (PICM) after placement of a permanent pacemaker. Objective: To establish paced QRS duration as determinant of pacing induced cardiomyopathy in complete Atrioventricular (AV) block. Methods: This descriptive study included 115 male and female patients that had a permanent pacemaker implanted for complete AV block, at the department of Cardiology, Hayatabad Medical Complex, Peshawar, during the period 1st November 2023 till 30th June 2024. Patients were evaluated for the presence of PICM and subsequently grouped as PICM and non-PICM. Paced QRS duration in both groups was compared. Results: PICM was confirmed in 63 patients (54.8%) and 52 (45.2%) were non-PICM. Mean age in PICM group was 71.2 ± 8.7 years and 66.8 ± 9.5 years in non-PICM group. The mean paced QRS duration in PICM group was 200.5 ± 22.3 milliseconds and 168.3 ± 15.7milliseconds in non-PICM group (p value &lt;0.001). Conclusion: Prolonged paced QRS duration was found as key indicator for predicting pacing induced cardiomyopathy in patients with permanent pacing for complete AV block.

Acute myocardial infarction in a patient with permanent left bundle branch pacing

BackgroundElectrocardiographic diagnosis of acute myocardial infarction in the setting of cardiac pacing represents diagnostic challenge. There are no focusing data, neither reporting about diagnostic sensitivity of 12‑lead ECG with left bundle branch area pacing (LBBAP) during acute myocardial infarction (AMI). Case summaryWe present 12‑lead ECG morphology in a patient with permanent LBBAP during AMI. DiscussionAbnormal repolarization changes induced by ventricular pacing can lead to delay in diagnosis in patients with AMI. LBBAP and overall conduction system pacing may facilitate a timely diagnosis providing additional, still underestimated, advantages of physiological pacing of the heart.

Review of Atrioventricular Node Ablation Combined with Permanent His-Purkinje Conduction System Pacing in Patients with Atrial Fibrillation with Heart Failure.

With the advancement of pacing technologies, His-Purkinje conduction system pacing (HPCSP) has been increasingly recognized as superior to conventional right ventricular pacing (RVP) and biventricular pacing (BVP). This method is characterized by a series of strategies that either strengthen the native cardiac conduction system or fully preserve physical atrioventricular activation, ensuring optimal clinical outcomes. Treatment with HPCSP is divided into two pacing categories, His bundle pacing (HBP) and left bundle branch pacing (LBBP), and when combined with atrioventricular node ablation (AVNA), can significantly improve left ventricular (LV) function. It effectively prevents tachycardia and regulates ventricular rates, demonstrating its efficacy and safety across different QRS wave complex durations. Therefore, HPCSP combined with AVNA can alleviate symptoms and improve the quality of life in patients with persistent atrial fibrillation (AF) who are unresponsive to multiple radiofrequency ablation, particularly those with concomitant heart failure (HF) who are at risk of further deterioration. As a result, this "pace and ablate" strategy could become a first-line treatment for refractory AF. As a pacing modality, HBP faces challenges in achieving precise localization and tends to increase the pacing threshold. Thus, LBBP has emerged as a novel approach within HPCSP, offering lower thresholds, higher sensing amplitudes, and improved success rates, potentially making it a preferable alternative to HBP. Future large-scale, prospective, and randomized controlled studies are needed to evaluate patient selection and implantation technology, aiming to clarify the differential clinical outcomes between pacing modalities.

Permanent Pacing Reduces Blood Pressure in Older Patients with Drug-resistant Hypertension: A New Pacing Paradigm?

Hypertension (HTN) is a major contributor to cardiovascular mortality. Many patients with drug-resistant hypertension (DRH) also require permanent pacing (PP). This large retrospective study evaluated the effect of PP for conventional PP indications in older patients with DRH. We reviewed the charts of 176 patients with dual-chamber PP and DRH. The effects of PP on systolic and diastolic blood pressure (sBP and dBP), the number of HTN-related medications, and left ventricular ejection fraction (LVEF) were assessed at 6 months post-implantation and compared with pre-implantation values. Patients were followed up with for ≥72 months. Patients with a decline of >5 mmHg in sBP and decrease in at least one anti-HTN medication were defined as responders (126/176; P < .01). The mean decline in sBP was 9 mmHg, while that in dBP was 3 mmHg (P < .001 for both). Among responders, optimal reductions in sBP, dBP, and medications were seen at a stratification of >50% atrial pacing and <40% ventricular pacing (-12, -6.3, and -1.6, respectively). When right ventricular pacing of <50% was used for dichotomizing, the optimal atrial/ventricular pacing stratification was atrial pacing > 50% and ventricular pacing < 40% (-11.3, -6.3, and -1.6, respectively). A relationship between increasing atrial pacing and a decline in sBP was noted but did not reach statistical significance. However, of those responders who had a >10-mmHg decline in sBP, the majority were paced between 60%-100% in the atria. The LVEF did not change post-PP in either group. In conclusion, PP results in significant improvement in BP control. The observed association warrants further investigation.

Long-Term Outcomes in Patients With Relatively High His-Bundle Capture Threshold After Permanent His-Bundle Pacing - A Multicenter Clinical Study.

Outcomes in patients with relatively high His-bundle (HB) capture thresholds at implantation are unknown. This study aimed to compare changes in the HB capture threshold and prognosis between patients with a relatively high threshold and those with a low threshold. Forty-nine patients who underwent permanent HB pacing (HBP) were divided into two groups: low (<1.25 V at 1.0 ms; n=35) and high (1.25-2.49 V; n=14) baseline HB capture threshold groups. The HB capture threshold was evaluated at implantation, and after 1 week, 1, 3, and 6 months, and every 6 months thereafter. HB capture threshold rise was defined as threshold rise ≥1.0 V at 1.0 ms compared with implantation measures. We compared outcomes between the groups. During a mean follow-up period of 34.6 months, the high-threshold group showed a trend toward a higher incidence of HB capture threshold of ≥2.5 V (50% vs. 14%; P=0.023), HBP abandonment (29% vs. 8.6%; P=0.091), lead revision (21% vs. 2.9%; P=0.065), and clinical events (all-cause death, heart failure hospitalization, and new-onset or progression of atrial fibrillation; 50% vs. 23%; P=0.089) than the low-threshold group. A baseline HB capture threshold of ≥1.25V was an independent predictor of clinical events. A relatively high HB capture threshold is associated with increased risk of HBP abandonment, lead revision, and poor clinical outcomes.

Long-Term Safety and Efficacy of Intraoperative Leadless Pacemaker Implantation During Valve Surgery

BackgroundIntraoperative implantation of leadless cardiac pacemakers (LCPs) under direct visualization during cardiac surgery is a novel strategy to provide pacing to patients with an elevated risk of postoperative conduction disorders or with a preexisting pacing indication undergoing valve surgery. ObjectivesThis study sought to evaluate the long-term safety and efficacy of intraoperative LCP implantation in 100 consecutive patients. MethodsRetrospective single-center cohort study of consecutive patients (n = 100) who underwent intraoperative LCP implantation during valve surgery. Safety and efficacy were assessed at implantation and follow-up visits. ResultsA total of 100 patients (age 68 ± 13 years, 47% female) underwent intraoperative LCP implantation. The surgery involved the tricuspid valve in 99 patients (99%), including tricuspid valve repair in 59 (59%) and tricuspid valve replacement in 40 (40%). Most of the patients (78%) underwent multivalve surgery. The indication for LCP implantation was elevated risk of postoperative atrioventricular block in 54% and preexisting bradyarrhythmias in 46%. LCP implantation was successful in all patients. During a median of 10.6 months (IQR: 2.0-22.7 months) of follow-up, no device-related complications occurred. At 12-month follow-up, the pacing thresholds were acceptable (≤2.0 V at 0.24 milliseconds) in 95% of patients. ConclusionsIntraoperative LCP implantation under direct visualization is a safe strategy to provide permanent pacing in patients undergoing valve surgery, with a postoperative electrical performance comparable to percutaneously placed LCPs.

Effect of Ablation Energy Source on Outcomes of Slow Pathway Modification for AVNRT in Children

BackgroundSelection of radiofrequency ablation (RF) or cryoablation (Cryo) for atrioventricular nodal re-entrant tachycardia (AVNRT) in children remains controversial due to a lack of contemporary comparison studies in this population. ObjectivesThis study sought to compare outcomes of RF and Cryo for AVNRT in the pediatric population. MethodsAVNRT ablation outcomes were retrospectively analyzed utilizing the National Cardiovascular Data Registry IMPACT (Improving Pediatric and Adult Congenital Treatment) Registry from April 2016 to March 2019. Data from subjects 1 to 21 years of age undergoing elective first-time slow pathway (SP) modification for AVNRT were included. Exclusion criteria included <1 year of age, congenital heart disease, and >1 ablation target. Cases were analyzed by ablation energy: 1) RF only; 2) Cryo only; 3) radiofrequency ablation switching to cryoablation (RF→Cryo); and 4) cryoablation switching to radiofrequency ablation (Cryo→RF). The primary outcome was acute ablation failure. Secondary outcomes included in-hospital adverse events. ResultsAmong 2,448 patients (mean age 13.6 ± 3.4 years, 60% female), RF only was employed in 43% (n = 1,046), Cryo only in 49% (n = 1,201), RF→Cryo in 6% (n = 135), and Cryo→RF in 66 (3%). Acute ablation failure occurred in 1.3% (n = 33), with no difference by energy source (1% in RF only, 1.5% in Cryo only, 1.5% in RF→Cryo, 3% in Cryo→RF; P = 0.5). Atrioventricular (AV) block requiring permanent pacemaker did not occur in any group; transient AV block occurred in 0.4% of the cohort, with no difference by group. ConclusionsIn this largest pediatric study of AVNRT ablation, RF and Cryo demonstrated comparable high acute success and rare documentation of AV block that did not result in temporary or permanent pacing. Longitudinal data are important for further comparison of these modalities with regard to recurrence risk and late complications.

Single-center experience of efficacy and safety of atrioventricular node ablation after left bundle branch area pacing for the management of atrial fibrillation.

Atrioventricular node ablation (AVNA) with permanent pacing is an effective treatment of symptomatic atrial fibrillation (AF). Left bundle branch area pacing (LBBAP) prevents cardiac dyssynchrony associated with right ventricular pacing and could prevent worsening of heart failure (HF). In this retrospective monocentric study, all patients who received AVNA procedure with LBBAP were consecutively included. AVNA procedure data, electrical and echocardiographic parameters at 6 months, and clinical outcomes at 1 year were studied and compared to a matched cohort of patients who received AVNA procedure with conventional pacing between 2010 and 2023. Seventy-five AVNA procedures associated with LBBAP were studied. AVNA in this context was feasible, with a success rate of 98.7% at first ablation, and safe without any complications. There was no threshold rise at follow-up. At 1 year, 6 (8%) patients were hospitalized for HF and 2 (2.7%) were deceased. Patients had a significant improvement in NYHA class and left ventricular ejection fraction (LVEF) (P ≤ 0.0001). When compared to a matched cohort of patients with AVNA and conventional pacing, AVNA data and pacing complications rates were similar. Patients with LBBAP had a better improvement of LVEF (+5.27 ± 9.62% vs. -0.48 ± 14%, P = 0.01), and a lower 1-year rate of composite outcome of hospitalization for HF or death (HR 0.39, 95% CI: 0.16-0.95, P = 0.037), significant on survival analysis (log-rank P-value = 0.03). AVNA with LBBAP in patients with symptomatic AF is feasible, safe, and efficient. Hospitalization for HF or death rate was significantly lower and LVEF improvement was greater.

Outcomes with physiologic His bundle pacing in patients with narrow QRS complex

BackgroundIn patients with narrow QRS complex, both ventricular and biventricular pacing is associated with increased cardiac morbidity and mortality. This risk is not decreased by ventricular pacing avoidance algorithms, which cause nonphysiologic atrioventricular (AV) delays. ObjectiveThis study aimed to report outcomes in patients with narrow QRS complex when the paced complex is in normal range and physiologic AV delays are programmed. MethodsIn 196 patients with QRS duration of 92 ± 10 ms, permanent pacing was done at the site of the His bundle electrogram. The pacemakers were then programmed to maintain physiologic AV delays and to increase heart rates in response to exercise. Patients received usual care and were observed for 3 years. ResultsThe paced complex exhibited a delta wave, and the ventricular activation time, QRS axis, and lead I voltage remained in normal range. Physiologic programming resulted in His bundle pacing burden of 92%. In patients with decreased ejection fraction, there was significant improvement in left ventricular function, left ventricular dilation, and mitral regurgitation (P < .003). In patients with normal ejection fraction, left ventricular function remained normal without new valvular abnormalities. The 3-year all-cause mortality was 10%, and there was no increase in heart failure admissions. ConclusionIn patients with narrow QRS complex, when paced QRS morphology is maintained in normal range and AV dyssynchrony is avoided, His bundle pacing is associated with low all-cause mortality and improvement in abnormal echocardiographic parameters. The paced QRS morphology and physiologic AV delays may be important factors to evaluate in future trials of conduction system pacing.

Atrial standstill in a young patient treated with left bundle branch area pacing

Abstract Atrial standstill is a rare arrhythmogenic condition characterized by the absence of electrical and mechanical activity in the atria. The therapeutic options for these patients described in the current literature, in which no reversible cause is detected, are permanent cardiac pacing, anticoagulant, and heart failure treatment when the latter exists. We present a case of a young male with no personal or family history of cardiovascular disease, diagnosed with atrial standstill after multiple syncopal episodes, in whom, because of the high expected ventricular pacing percentage, we opted for conduction system pacing with left bundle branch area pacing.

LEFT BUNDLE BRANCH AREA PACING IN COMPLETE ATRIOVENTRICULAR BLOCK DUE TO LYME CARDITIS

Lyme disease, also known as Lyme borreliosis, is caused by Borrelia bacteria. In Europe, 0.3–4% of untreated cases end up with cardiovascular complications known as Lyme carditis which are often associated with atrioventricular conduction disorders. We present the case of a 26-year-old male who was diagnosed with a complete atrioventricular block in the course of Lyme carditis. After a full course of antibiotic therapy, the block did not resolve, so the patient was qualified for permanent pacing. In the course of the procedure, the left bundle branch area pacing was achieved with no early or long-term complications. This is the first reported case of a left bundle branch area pacing in the atrioventricular complete block due to Lyme carditis.

Transient phrenic nerve stimulation in a patient with single chamber pacemaker: case report

The article presents a clinical observation of a patient with episodes of phrenic nerve stimulation after inadvertent permanent ventricular pacing from the middle cardiac vein. The methods of early diagnosis of this complication and techniques for its prevention are described.