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Background: The risk factors for developing pacing induced left ventricular dysfunction (LVD) in patients with high burden of right ventricular pacing (RVP) is poorly understood. Therefore, in the present study, we aimed to assess the determinants of pacing induced LVD., Methods: Our data were retrospectively collected from 146 patients with RVP > 40% who underwent generator change (GC) or cardiac resynchronization therapy (CRT) upgrade between 2016 and 2019 who had left ventricular ejection fraction (EF) ≥50% at initial implant., Results: A total of 75 patients had CRT upgrade due to pacing induced LVD (EF < 50%) and 71 patients with preserved LV function (EF ≥ 50%) had a GC. Primary indication for pacing in both groups was complete heart block. Male predominance (p = .008), prior myocardial infarction (MI) (p = .001), atrial fibrillation (AF) (p = .009), chronic kidney disease (CKD) (p = .005), and borderline low systolic function (BLSF) (EF 50%-55%) (p = .04) were more prevalent in the CRT upgrade group. Presence of AF (odds ratio [OR] = 3.05, 95% confidence interval [CI] 1.42-6.58; p = .004), BLSF (OR = 3.8, 95% CI 1.22-11.8; p = .02), and male gender (OR = 2.41, 95% CI 1.14-5.08; p = .02) were independent predictors for RVP induced LVD. Age (OR = 1.08, 95% CI 1.02-1.14; p = .005) and BLSF (OR = 5.33, 95% CI 1.26-22.5; p = .023) were independent predictors of earlier development of LVD after implant., Conclusions: Our results suggested that AF, BLSF, and male gender are predictors for development of pacing induced LVD in patients with high RVP burden. LVD can occur at any time after pacemaker implant with BLSF and increasing age associated with earlier development of LVD., (© 2022 Wiley Periodicals LLC.)

Background: Transseptal puncture (TSP) is commonly performed under fluoroscopic guidance in left atrial ablation procedures. This exposes patients and healthcare professionals to deleterious ionizing radiation. We describe a novel technique for performing TSP non-fluoroscopically using a three-dimensional (3D) mapping system only. The safety and efficacy of this technique is compared to traditional fluoroscopy guided TSP., Methods: Retrospective, single-center study of patients undergoing TSP for left atrial ablation. Those undergoing TSP using 3D mapping system alone (nonfluoroscopy group) were compared to those undergoing fluoroscopic guided TSP (Fluoroscopy group). Clinical, procedural data and complications were analyzed from a prospective registry., Results: Twenty patients (32 TSPs) in the nonfluoroscopy (NF) group were compared to 14 patients (25 TSPs) in fluoroscopy (F) group. TSP success rates were similar across the groups (88% vs 96% in the NF and F groups, P = 0.97). In the NF group, there was one cardiac tamponade, two unsuccessful TSPs (previous cardiac surgery-required TOE guided TSP), and one patient required fluoroscopy on a background of CRTD device to avoid lead displacement. The mean fluoroscopy time and dose were significantly lower in the nonfluoroscopy group (0.75  ±  0.50 vs 5.32 ± 3.23 min, P  <  0.001; 92.5 ± 60.7 vs 394.3 ± 182.7 cGy/cm 2 , P < 0.001)., Conclusion: Our study shows that TSPs can be performed safely and effectively using this non-fluoroscopic novel technique in a select group of patients. Radiation exposure is reduced significantly without compromising patient safety. Larger studies are required to substantiate these results. Patients with cardiac implantable devices and previous cardiac surgery may pose a challenge to using this technique., (© 2018 Wiley Periodicals, Inc.)

Background: Current consensus guidelines suggest direct oral anticoagulants (DOACs) are interrupted periprocedurally for catheter ablation (CA) of atrial fibrillation (AF). However, this may predispose patients to thromboembolic complications. This study investigates the safety of CA for AF on uninterrupted DOACs compared to uninterrupted warfarin., Methods: This was a single-center, retrospective study of consecutive patients undergoing CA for AF. All patients were heparinized prior to transseptal puncture with a target-activated clotting time (ACT) of 300-350 seconds. Patients who had procedures performed on continuous DOAC were compared to those on continuous warfarin. Clinical, procedural data, and complications occurring up to 3 months were analyzed from a prospective registry with additional review of electronic health records., Results: A total of 1,884 procedures were performed over 28 months: 761 (609 patients) on uninterrupted warfarin and 1,123 (900 patients) on uninterrupted DOAC (rivaroxaban 64%, apixaban 32%, and dabigatran 4%). There was no difference in the composite endpoint of death, thromboembolism, or major bleeding complication (2.2% vs 1.4%, P = 0.20). There was no difference in the complications comprising this, including tamponade, hematoma, pseudoaneurysm, and transfusion (P-values 0.28, 0.13, 0.45, and 0.36). There were no strokes, transient ischemic attacks, or other thromboembolic complications. There was no difference between groups in the proportion of tamponades requiring reversal of oral anticoagulation, the volume of blood lost, the proportion transfused, or the proportion drained percutaneously (P-values 0.50, 0.51, 0.36, and 0.38)., Conclusion: Catheter ablation for AF can be performed safely and effectively in patients anticoagulated with DOACs and heparinized with a therapeutic ACT. There is no increased risk of periprocedural bleeding when compared to uninterrupted warfarin., (© 2018 Wiley Periodicals, Inc.)

Background: Catheter-based contact force sensing (CFS) technology gives detailed information regarding contact between the catheter tip and myocardium. This may result in more effective ablation procedures. The primary objective of this study was comparison of remote robotic navigation (RRN) and Manual CFS ablation. The secondary objective was to compare CFS with non-CFS ablation for both navigation modes., Methods: Prospective registries of consecutive cases undergoing their first ablation for persistent atrial fibrillation (AF) from six hospitals in the United Kingdom and South Africa were analyzed: 50 Manual/CFS and 50 RRN/CFS cases were included. Historical control non-CFS ablation patients were matched by propensity score, giving a total 200 patient cohort., Results: RRN/CFS was associated with improved single procedure 1-year success rates (64% vs 36%, P = 0.01) and shorter fluoroscopy times (41% reduction, P < 0.0005) than Manual/CFS ablation, without any difference in procedure times (P = 0.8). The mean contact force was higher in RRN/CFS than Manual/CFS cases (16 [15-18 g] vs 13 [12-15 g], respectively, P = 0.003). Compared with non-CFS historical controls, CFS cases had higher 1-year success rates for RRN (64% vs 36%, P = 0.01), but not Manual ablation (36% vs 38%, P = 1). Procedure times were reduced for CFS cases (20%, P < 0.005 both navigation modes), as were fluoroscopy times (Manual: 43%, RRN 83%, P < 0.005 for both). There were no differences in rates of major or minor complications for either comparison (P > 0.5)., Conclusions: A combination of RRN and CFS is associated with improved success rates at 1 year and fluoroscopy times for persistent AF ablation, compared with Manual ablation and non-CFS RRN ablation., (©2014 Wiley Periodicals, Inc.)

Background: Atrioventricular node (AVN) ablation is effective for rate control in atrial fibrillation. This may require multiple radiofrequency applications to achieve complete atrioventricular block (CAB). In this retrospective study, we tested the hypothesis that mapping the AVN utilizing electrograms (EGMs) on both proximal and distal bipoles of the mapping catheter may improve the likelihood of CAB., Methods: Lesion characteristics and EGM components on the proximal and distal bipoles of the ablation catheter in first-time AVN ablation procedures were analyzed. Outcomes of each lesion, including presence of CAB, acute recurrence of AVN conduction, new-onset right bundle branch block (RBBB), and junctional escape rhythm, were analyzed. Multivariate binary logistic regression analysis was performed to identify EGM characteristics that independently predicted the outcomes of interest. Lesions with these EGM characteristics were then identified and their outcomes compared with the whole cohort., Results: A total of 441 ablation lesions were analyzed. EGM characteristics that independently predicted outcomes were the presence of His and atrial EGMs on the distal bipole and the absence of ventricular EGM on the proximal bipole. Among the 25 lesions with all these characteristics, 18 (72%) resulted in CAB compared to the overall cohort rate of 38% (P = 0.001). There was no new-onset RBBB. The likelihood of acute recurrent AVN conduction and junctional escape rhythm were similar., Conclusion: Combining proximal and distal bipole EGM characteristics of the ablation catheter can improve the accuracy of AVN localization during AVN ablation and avoid right bundle branch injury., (©2013 Saint Bartholomew's Hospital Pacing and Clinical Electrophysiology ©2013 Wiley Periodicals, Inc.)

This report describes the incidental finding of complete left atrial standstill during successful ablation of a right-sided atrial tachycardia in a patient with severe dilated cardiomyopathy and a history of extensive catheter ablation within the left atrium., (©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.)

Background: Robotic catheter ablation aims to improve outcomes after ablation of atrial fibrillation (AF) through improved lesion quality. This study examined electrogram attenuation as a measure of efficacy in response to robotic (ROB) and manual (MAN) ablation., Methods: Patients with paroxysmal AF undergoing ablation as part of an ongoing randomized controlled trial were studied (Clinical Trials Registration NCT01037296). Patients underwent pulmonary vein isolation using NavX (St. Jude Medical, St. Paul, MN, USA). Patients were randomized to MAN or ROB catheter ablation using a 3.5-mm irrigated-tip catheter with standardized ablation settings. Bipolar electrogram voltage was measured at 0, 5, 10, 20, and 30 seconds after ablation onset. Distance from ablation lesion to the left atrial surface on NavX were calculated., Results: Similar ablation energy was delivered in ROB and MAN groups, achieving comparable rates of PV isolation (100% vs 98%). The bipolar voltages of 4,434 electrograms from 303 ablation lesions (146 ROB, 157 MAN) were measured. At 30 seconds, signal attenuation was greater in the ROB group than MAN (mean 65 ± 4% vs 55 ± 4% of baseline voltage, P < 0.01). A total of 2,064 NavX ablation lesions were assessed (906 ROB and 1,158 MAN). ROB lesions were on average 0.52 mm further inside the geometry than MAN (P < 0.0001)., Conclusions: Robotic ablation results in greater signal attenuation in man. This is achieved despite manual lesions being closer to the left atrial surface. Catheter stability and constant energy delivery may be key to achieving signal attenuation, rather than increased contact force., (©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.)

Robotic navigation systems aim to improve ablation catheter maneuverability, tissue contact, and stability. These attributes suggest that such systems could enhance outcomes in the ablation of ventricular tachycardia (VT). To date, however, ablation has been confined to the atria. We present a case in which robotic catheter navigation alongside three-dimensional anatomical mapping enabled successful ablation of VT within the left ventricle.

Aims: We reviewed outcomes in our primary prevention implantable cardioverter defibrillator (ICD) population according to whether the device was programmed with a single ventricular fibrillation (VF) zone or with two zones including a ventricular tachycardia (VT) zone in addition to a VF zone., Methods: This retrospective study examined 137 patients with primary prevention ICDs implanted at our institution between 2004 and 2006. Device programming and events during follow-up were reviewed. Outcomes included all-cause mortality, time to first shock, and incidence of shocks., Results: Eighty-seven ICDs were programmed with a single VF zone (mean >193 ± 1 beats per minute [bpm]) comprising shocks only. Fifty ICDs had two zones (mean VT zone >171 ± 2 bpm; VF zone >205 ± 2 bpm), comprising antitachycardia pacing (100%), shocks (96%), and supraventricular (SVT) discriminators (98%) . Discriminator "time out" functions were disabled. Mean follow-up was 30 ± 0.5 months and similar in both groups. All-cause mortality (12.6% and 12.0%) and time to first shock were similar. However, the two-zone group received more shocks (32.0% vs 13.8% P = 0.01). Five of 16 shocks in these patients were inappropriate for SVT rhythms. The single-zone group had no inappropriate shocks for SVTs. Eighteen of 21 appropriate shocks were for ventricular arrhythmias at rates >200 bpm (three VF, 15 VT). This suggests that primary prevention ICD patients infrequently suffer ventricular arrhythmias at rates <200 bpm and that ATP may play a role in terminating rapid VTs., Conclusions: Patients with two-zone devices received more shocks without any mortality benefit., (©2010, The Authors. Journal compilation ©2010 Wiley Periodicals, Inc.)

Background: Arrhythmia recurrence after atrial fibrillation (AF) ablation is often associated with pulmonary vein reconnection (PVR). We prospectively examined anatomical sites of both acute and chronic PVR., Methods: One hundred and fifty AF patients underwent PV wide encirclement and sites where immediate electrical isolation (EI) occurred were tagged using electroanatomic mapping/CT integration (Cartomerge, Biosense Webster, Diamond Bar, CA, USA). After 30 minutes PVs were checked and acute PVR sites marked at reisolation. Chronic PVR sites were marked at the time of repeat procedures., Results: On the left, immediate EI sites were predominantly on the intervenous ridge (IVR) and PV-left atrial appendage (PV-LAA) ridge. On the right they were at the roof, IVR, and floor of the PVs. Ninety-eight of one hundred and fifty patients had PVs checked after >30 minutes. Thirty-two of ninety-eight had acute PVR. This was mostly on the IVR and PV-LAA ridge on the left (88%), and on the roof and IVR on the right (78%). At repeat procedure, 38/39 patients had chronic PVR, predominantly on the IVR (61%) and PV-LAA ridge (21%) on the left, and on the roof, IVR, and floor of the right PVs (79%). There was minimal acute or chronic PVR posteriorly. Acutely PVR occurred close to the immediate EI site 60% of the time, but only 30% of the time chronically., Conclusion: Acute and chronic PVR sites have a preferential distribution. This may be determined by anatomical and technical factors. Knowledge of immediate EI sites may be beneficial acutely, but with chronic PVR a careful survey is required. These findings may help target ablation, improving safety and success.

Occlusion of the superior vena cava (SVCO) makes implantation of permanent pacemakers challenging and difficult. We describe an extended application of a Medtronic Attain (Medtronic Inc., Minneapolis, MN, USA) guide catheter (a tool designed for delivery of left ventricular pacing leads into the coronary sinus) for delivery of a right ventricular pacing lead via the azygous vein in a 72-year-old woman with SVCO secondary to long-term central venous hemodialysis catheters. This approach allowed the use of an endocardial pacing lead, implantation under local anesthesia, and conventional positioning of the pacemaker generator in the pectoral region in a patient with SVCO.

Cure of typical atrial flutter (AFL) by catheter ablation to produce bidirectional block across the tricuspid annulus-inferior vena cava isthmus (IS) is highly effective, but failures may occur. We describe a technique that may allow creation of bidirectional block where a conventional strategy has failed. AFL ablation was performed using the conventional approach with a mapping/ablation (ablation) catheter introduced via the right femoral vein (RFV) to create a line of bidirectional block across the IS. If this was not achieved after five passes of the ablation catheter from the tricuspid annulus to the inferior vena cava (IVC) a catheter inversion technique was used. This allowed stable positioning of the ablation catheter at the IVC end of the isthmus. In 11 patients, a mean of 17 (range 3 to 45) radiofrequency (RF) applications was given before the catheter inversion technique was applied. Following catheter inversion a mean of 4 (1 to 14) further RF applications achieved bidirectional isthmus block in every patient. No complications occurred. Catheter inversion provides a simple, safe, and effective means of achieving bidirectional isthmus conduction block in cases where a conventional ablation strategy might have failed.

Unlabelled: Dual sensor pacemakers should respond more appropriately during differing exercise modes than a single sensor device. The Topaz model 515 (QT and activity count [ACT] sensing) pacemaker shows appropriate rate response during treadmill exercise testing. We postulated that adjustments to relative sensor contribution should allow fine tuning of the onset of rate response. Eleven patients with this pacemaker were studied. Three standard exercise tests were performed with adjustment of sensor blending and activity threshold between each one. We also assessed the response to isometric exercise and a false positive activity signal., Results: Times to 100 ppm (3.7 +/- 1.3, 4.4 +/- 2.0, 5.3 +/- 1.5 mins), times to peak rate (6.1 +/- 1.6, 5.6 +/- 1.4, 6.5 +/- 1.3 mins) and accelerations to peak (9.0 +/- 2.4, 9.2 +/- 5.3, 7.7 +/- 2.8 ppm/min) were measured in all three different sensor settings (QT = ACT, QT < ACT, and QT = ACT with decreased activity threshold). No significant difference in onset of rate response was seen between the three settings. Tapping (false-positive activity) provided a rapid rise in paced rate to 79 ppm from a resting value of 65 ppm. This came down to 71 ppm demonstrating satisfactory sensor cross-checking. Isometric exercise induced a moderate response from 65 ppm at rest to 74 ppm after 3 minutes., Conclusions: Satisfactory rate response was demonstrated in most patients to treadmill testing and to isometric exercise. However, small adjustments to relative sensor contributions do not predictably alter the onset of rate response.