Background Data on the optimal location of the ECG leads for the diagnosis of drug-induced long QT syndrome (diLQTS) with Torsades de Pointes (TdP) are lacking. Methods We systematically reviewed the literature for ECGs of patients with diLQTS and subsequent TdP. We assessed T-wave morphology in each lead and measured the longest QT interval in the limb and chest leads in a standardized fashion. Results Of 84 patients, 61.9% were female and mean age was 58.8 years. QTc was significantly longer in chest versus limb leads (mean (standard deviation) 671 (102) vs 655 (97) ms, p=0.02). Using only limb leads for QT interpretation, 18 (21.4%) ECGs were non-interpretable: 10 (11.9%) due to too flat T-waves, 7 (8.3%) due to frequent, early PVCs and 1 (1.2%) due to too low ECG recording quality. In the chest leads, ECGs were non-interpretable in 9 (10.7%) patients: 6 (7.1%) due to frequent, early PVCs, 1 (1.2%) due to insufficient ECG quality, 2 (2.4%) due to missing chest leads but none due to too flat T-waves. The most common T-wave morphologies in the limb leads were flat (51.0%), broad (14.3%) and late peaking (12.6%) T-waves. Corresponding chest lead morphologies were inverted (35.5%), flat (19.6%) and biphasic (15.2%) T-waves. Conclusions Our results indicate that QT evaluation by limb leads only underestimates the incidence of diLQTS experiencing TdP and favors the screening using both limb and chest lead ECG.

Our article reported risk factors for ICD lead failure at our medical center, and we found an elevated risk of ICD lead failure in multiple lead ICD systems implanted via cephalic venous access.(1) Our analysis was prompted by recent literature related to durability of the Linox ICD lead (Biotronik, Inc., Berlin, Germany), and we found similar, elevated risk of ICD lead failure implanted in multiple lead systems via cephalic access in Linox and non-Linox ICD leads. Given the small number of total lead failures in the overall cohort (6 of 660), and the retrospective, single-center nature of our analysis, we reviewed prior Linox ICD lead durability manuscripts for evidence of increased risk of failure in multiple lead ICD systems implanted via cephalic venous access. While no prior manuscript evaluated this specific risk, we did find a trend towards increased risk of lead failure in cohorts with greater proportions of multiple lead systems, and greater proportions of systems implanted via cephalic access, however these variables were included in the analysis in a minority of prior studies.Dr. Maas and colleagues express surprise at the high failure rate when implanting multiple leads in our cohort. We would clarify that we reported ICD lead failure in 4 of the 304 patients in our cohort with multiple ICD leads, and that the frequency of lead failure in multiple lead ICD systems was not statistically significantly different compared to that of single lead ICD systems. In contrast, and surprisingly to us, 3 of 30 patients with multiple lead ICD systems implanted via cephalic access experienced ICD lead failure, and the frequency of ICD lead failure was significantly greater in this group compared to the remaining cohort in Kaplan-Meier survival analyses.Maas and colleagues question the reason for utilization of cephalic access in 18% of patients, hypothesize that suboptimal implantation technique may be responsible for the elevated lead failure rate, and request clarification of lead failure mechanism. We did not systematically collect rationale for venous access technique, and venous access techniques was at the discretion of the implanting physician. Of the 6 lead failures, 3 were related to lead noise, and 3 were related to rising pacing thresholds. Of the three lead failures amongst patients with multiple lead systems implanted via cephalic venous access, 2 were related to lead noise, and 1 was related to a rising pacing threshold. We believe that the lead noise may be related to insulation breach that may be predisposed by lead-lead interactions in the region of the cephalic vein. ICD leads were returned to the manufacturer on an ad hoc basis, and no specific feedback was received from manufacturers related to leads included in our analysis. All implanting physicians were experienced operators, and there were no significant differences in frequency of ICD lead failure by operator. We agree that implantation technique may play an important role in lead failure risk, and our analysis should prompt extra caution when implanting multiple leads via cephalic venous access.Citing the above limitations of our analysis, Dr Maas and colleagues state that it is “too early to abandon cephalic vein access, even for multiple lead systems.” They also review recent literature reporting favorable acute outcomes of ultrasound guided axillary venous access. We agree that our analysis paired with our literature review is best considered hypothesis generating, and we hope that our analysis encourages future studies to consider our findings when selecting variables of interest in ICD lead durability studies. We share Dr. Maas and colleagues’ favorable view of data supporting axillary venous access, particularly in combination with ultrasound guidance. As a result, given the available evidence of acceptable alternative techniques, our practice is to favor axillary venous access during implantation of multiple lead ICD systems, but we would not hesitate to implant via cephalic venous access in the appropriate clinical scenario.References1. Barbhaiya CR, Niazi O, Bostrom J et al. Early ICD lead failure in defibrillator systems with multiple leads via cephalic access. Journal of cardiovascular electrophysiology 2020;31:1462-1469.

Objective: To determine trends in real-world utilization and in-hospital adverse events from Watchman implantation since its approval by the Food and Drug Administration in 2015. Background: The risk of embolic stroke caused by atrial fibrillation is reduced by oral anticoagulants, but not all patients can tolerate long-term anticoagulation. Left atrial appendage occlusion with the Watchman device has emerged as an alternative therapy. Methods: This was a retrospective cohort study utilizing data from National Inpatient Sample for calendar years 2015-2017. The outcomes assessed in this study were associated complications, in-hospital mortality, and resource utilization trends after Watchman implantation. Trends analysis were performed using analysis of variance. Multivariable adjusted logistic regression analysis was performed to determine predictors of mortality. Results: A total of 17,700 patients underwent Watchman implantation during the study period. There was a significantly increased trend in the number of Watchman procedures performed over the study years (from 1,195 in 2015 to 11,165 devices in 2017, p < 0.01). A significant decline in the rate of complications (from 26.4% in 2015 to 7.9% in 2017, p < 0.01) and inpatient mortality (from 1.3% in 2015 to 0.1% in 2017, p < 0.01) were noted. Predictors of in-hospital mortality included a higher CHA₂DS₂-VASc score (OR 2.61 per 1-point increase, 95% CI 1.91-3.57), chronic blood loss anemia (OR 3.63, 95% CI 1.37-9.61) and coagulopathy (OR 4.90, 95% CI 2.32-10.35). Conclusion: In contemporary United States clinical practice, Watchman utilization has increased significantly since approval in 2015, while complications and in-patient mortality have declined.

Monitoring following catheter or surgical ablation for atrial fibrillation (AF) is an essential tool used to assess outcomes for research purposes and help guide clinical decision making. The most commonly used methods to monitor for post-intervention AF include a variety of ambulatory external electrocardiogram (ECG) monitors, cardiac implantable electronic devices (CIED), and more recently, direct to consumer digital health technologies. The traditional metric of ablation success, recurrence > 30 seconds at 1 year, is below the detection capabilities of almost all monitoring techniques yet still undervalues the efficacy of AF interventions. Measures of AF burden reduction and duration give a more complete assessment of the impact of AF surgeries and ablation. As it is increasingly being recognized that AF burden and duration is related to stroke risk, long-term, inexpensive, non-invasive monitoring methods are needed. Smart phones and watches with AF-detecting capabilities, which are increasingly being used by the majority of US adults, have emerged as viable options to achieve this goal, shifting the paradigm of AF monitoring to a more patient centered approach.

Background: Cardiac Sympathetic Denervation (CSD) involves surgical removal of lower half of the stellate ganglion and the T1-T4 ganglia for reducing sympathetic discharge to the heart. CSD is a useful therapeutic option in patients with ventricular tachycardia (VT) when they are non-responsive to standard drug therapy or catheter ablation. We report here the clinical profile and long-term outcome of all our patients who underwent CSD for refractory VT or VT storm. Method: Data of all patients who underwent CSD from 2010 to 2019 was analysed. They were regularly followed up, focusing on arrhythmia recurrence. Complete response to CSD was defined as more than 75% decrease in the frequency of VT. Results: A total of 65 patients (50 male, 15 female) underwent CSD in the above-mentioned period and the duration of follow-up was 27±24 months. The underlying substrate was for VT was coronary artery disease in 30 (46.2%) patients and 35 (53.8%) patients had a variety of other causes. Complete response to CSD was attained in 47 (72.3%) patients. There was a significant decline in the incidence of number shocks after CSD (24±37 vs 2±4; p <0.01). Freedom from a combined end point of ICD shock or death at the end of two years was 51.5%. Advanced NYHA class (III and IV) was the only parameter shown to have significant association with this combined end point. Conclusion: The current retrospective analysis reemphasize the role of surgical CSD in the treatment of patients with refractory VT or VT storm.

A document by Gregory Feld. Click on the document to view its contents.

Background: Although catheter ablation (CA) is an effective treatment for patients with AF and LVSD, the efficacy of an initial cryo-ablation strategy is unknown. This study evaluated long term outcomes of patients with an initial cryo-ablation strategy for AF and LV systolic dysfunction (LVSD). Methods: Outcomes of patients undergoing index cryoablation for AF from January 2008 until March 2018, with documented pre-ablation LVEF45% were evaluated for long term freedom from AF and change in ventricular function from baseline. Results: 76 patients met inclusion criteria. Patients were predominantly male (80%), aged 63 11yrs, with an average CHADS2 VASc score of 2.66  1.40, baseline LVEF 34  8.7% (ischaemic in 37%) and NYHA class 2.37  0.72. Repeat procedures were performed in 13%. The single procedure success was 70% at 1 year (81% for paroxysmal AF, 65% for persistent AF, 29% for long-standing persistent AF) and at 28  13 months follow up was 43% (50%, 41% and 21% respectively), increasing to 59% allowing for subsequent redo procedure with RF ablation (64%, 57%, and 50% respectively). At follow up, LVEF significantly improved to 46  16% (p<0.001), and NYHA reduced to 1.51  0.66 (p<0.001). Conclusion: An initial strategy of cryoablation in patients with AF and LVSD is an effective approach in the treatment of patients with concurrent AF and LVSD. Larger, randomised prospective studies are required to confirm these findings.

Background During automated radiofrequency (RF) annotation-guided pulmonary vein isolation (PVI), respiratory motion adjustment (RMA) is recommended, yet lacks in vivo validation. Methods Following contact force (CF) PVI (continuous RF, 30W) using general anaesthesia and automated RF annotation-guidance (VISITAG™: force-over-time 100% minimum 1g; 2mm position stability; ACCURESP™ RMA “off”) in 25 patients, we retrospectively examined RMA settings “on” versus “off” at the left atrial posterior wall (LAPW). Results Respiratory motion detection occurred in 8, permitting offline retrospective comparison of RMA settings. Significant differences in LAPW RF auto-annotation occurred according to RMA setting, with curves displaying catheter position, CF and impedance data indicating “best-fit” for catheter motion detection using RMA “off”. Comparing RMA “on” versus “off”, respectively: Total annotated sites 82 versus 98; median RF duration per-site 13.3s versus 10.6s (p<0.0001); median force time integral 177g.s versus 130g.s (p=0.0002); mean inter-tag distance (ITD) 6.0mm versus 4.8mm (p=0.002). Considering LAPW annotated site 1-to-2 transitions resulting from deliberate catheter movement, 3 concurrent with inadvertent 0g CF demonstrated <0.6s difference in RF duration. However, 13 deliberate catheter movements during constant tissue contact (ITD range 2.1 – 7.0mm) demonstrated (mean) site-1 RF duration difference 3.7s (range: -1.3 to 11.3s): considering multiple measures of catheter position instability, the appropriate indication of deliberate catheter motion occurred with RMA “off” in all. Conclusions ACCURESP™ respiratory motion adjustment importantly delayed the identification of deliberate and clinically relevant catheter motion during LAPW RF delivery, rendering auto-annotated RF display invalid. Operators seeking greater accuracy during auto-annotated RF delivery should avoid RMA use.

Background: Right ventricular (RV) pacing causes delayed activation of remote ventricular segments. We used the UHF-ECG to describe ventricular depolarization when pacing different RV locations. Methods: In 51 consecutive patients, temporary pacing was performed at the RV apex, anterior and lateral wall, and at the RV septum with (cSp) and without direct conductive tissue engagement (mSp) (further subclassified as RVIT and RVOT for septal inflow and outflow positions). The timing of UHF-ECG electrical activations were quantified as: left ventricular lateral wall delay (LVLWd; V8 activation delay), RV lateral wall delay (RVLWd; V1 activation delay), and LV lateral wall depolarization duration (V5-8d). Results: The LVLWd was shortest for cSp (11 ms (95% CI; 5;17), followed by the RVIT (19 ms (11;26) and the RVOT (33 ms (27;40), (p<0.01 between all of them), although the QRSd for the latter two were the same (153 ms (148;158) vs. 153 ms (148; 158); p=0.99). The RVOT caused longer V5-8d (9 ms (3;14) compared to the RVIT (1 ms (−5;8), p<0.05. RV apical capture not only had a worse LVLWd (34 ms (26;43) compared to mSp (27 ms (20;34), p<0.05), but its RVLWd (17 ms (9;25) was also the longest compared to other RV pacing sites (mean values for cSp, mSp, anterior and lateral wall captures being below 6 ms), p<0.001 compared to each of them. Conclusions: UHF-ECG ventricular dyssynchrony parameters show that cSp offers the best ventricular synchrony followed by RVIT pacing, which should be preferred over RVOT and other RV myocardial pacing locations.

Abstract: Conventional stylet-driven leads with extendable helix can be implanted successfully for Left Bundle Branch Area Pacing (LBBAP) with a low acute complication rate. However, removal and repositioning techniques of these leads haven’t been yet described. We report 2 cases in which lead repositioning after a first unsuccessful attempt to LBBAP was associated with fracture of the helix rotating mechanism and failure to fully extract the pacing lead.

BACKGROUND Although low voltage zones (LVZs) in the left atrium (LA) are seen as arrhythmogenic substrate in some patients with atrial fibrillation (AF), pathophysiologic factors responsible for LVZ formation remain unclear. OBJECTIVE To elucidate the anatomical relation between the LA and ascending aorta responsible for remodeling of the anterior LA wall. METHODS We assessed the relation between existence of LVZs on the anterior LA wall and measurements taken on 3-dimensional computed tomography images obtained from 102 patients who underwent AF ablation. RESULTS Twenty-nine patients (28%) had LVZs >1.0 cm2 on the LA wall at the LA-ascending aorta contact area (LVZ Group); no LVZs were seen in the other 73 patients (No LVZ Group). In the LVZ Group (vs. No LVZ Group), the aorta-LA angle was smaller (21.0±7.7° vs. 24.9±7.1°, P = 0.015), the aorta-left ventricle (LV) angle was greater (131.3±8.8° vs. 126.0±7.9°; P = 0.005), non-coronary cusp (NCC) diameter was greater (20.4±2.2 mm vs. 19.3±2.5 mm; P = 0.036), and the NCC was closer to the anterior LA wall (2.29±0.68 mm vs. 2.76±0.79 mm; P = 0.006). The aorta-LA angle correlated positively with patients’ body mass index (BMI) and negatively with body weight and BMI. CONCLUSION Deviation of the ascending aorta course and distention of the NCC appear to be related to the development of LA anterior wall LVZs at the LA-ascending aorta contact area. Mechanical pressure exerted by extracardiac structures on the LA along with limited thoracic space may contribute to the development of LVZs associated with AF.

Background: Combination of endocardial and epicardial approach has improved the overall success rate of ventricular tachycardia (VT) ablation in patients with cardiomyopathy. However, the origins of some VTs are truly intramural or close to coronary arteries, which make this combined strategy either prone to failure or too risky. Objectives: This observational study aimed to explore the feasibility and efficacy of direct epicardial ablation combined with intramural ethanol injection via surgical approach for such VTs. Methods: Six consecutive patients with recurrent sustained VT refractory to combined endocardial and epicardial radiofrequency ablation were included. Direct epicardial access was achieved through limited left thoracotomy in 3 patients and median sternotomy in other 3 patients. Ablation was performed using irrigation catheter guided by electroanatomic mapping. Ethanol was injected in all patients to reinforce transmural lesions. The primary outcome was freedom of sustained VT determined by device interrogation and periodical 24h-holter recordings subsequently. Results: Over a median follow-up of 22 months (range, 6~65), all patients remained free of sustained VT. One patient died of pulmonary infection one year after the procedure. Conclusions: A hybrid strategy of surgical ablation combined with intramural ethanol injection is feasible and effective in patients with multiple failed percutaneous ablation attempts.

Introduction: Conduction system pacing (CSP) has emerged as an ideal physiologic pacing strategy for patients with permanent pacing indications. We sought to evaluate the safety and feasibility of CSP in a consecutive series of unselected patients with congenital heart disease (CHD). Methods: Consecutive patients with CHD in which CSP was attempted were included. Safety and feasibility, implant tools and electrical parameters at implant and at follow-up were evaluated. Results: A total of 20 patients were included (10 with a previous device). Ten patients had complex forms of CHD, 9 moderate defects and 1 a simple defect. His bundle pacing (HBP) or left bundle branch area pacing (LBBAP) were achieved in all patients (10 HBP, 5 LBBP and 5 left ventricular septal pacing). Procedure times and fluoroscopy times were prolongued (126±82 min and 27±30 min, respectively). CSP lead implant times widely varied ranging from 4 to 115 minutes, (mean 31±28 min) and the use of multiple delivery sheaths was frequent (50%). The QRS width was reduced from 144±32 ms at baseline to 116±16 ms with CSP. Implant electrical parameters included: CSP pacing threshold 0.85±0.61V; R wave amplitude 9.8±9.2mV and pacing impedance 735±253 Ohms, and remained stable at a median follow-up of 478 days (IQR 225-567). Systemic ventricle systolic function and NYHA class (1.50±0.51 vs 1.10±0.31; p=0.008) significantly improved at follow-up. Lead revision was required in one patient at day-4. Conclusions: Permanent CSP is safe and feasible in patients with CHD although implant technique is complex.

S-ICD: Is it time for radiological follow-ups?

OBJECTIVES: To explore the value of detecting the peri-device leak (PDL) and device endothelialization after left atrial appendage closure (LAAC) by cardiac CT in patients with atrial fibrillation (AF), who underwent Watchman LAAC combined with radiofrequency ablation of atrial fibrillation (AFCA) METHODS: Patients with symptomatic drug-refractory atrial fibrillation at high risk of stroke (CHA2DS2-VASc Score ≥ 2), who underwent Watchman LAAC combined with AFCA in our center from March 2017 to December 2018 were enrolled Maximum diameter of LAA orifice was determined by preoperative CCTA A standardized view of Watchman device was obtained by postoperative CCTA multi-plannar reconstruction to evaluate the PDL and device endothelialization RESULTS: 84 patients post successful LAAC and AFCA were enrolled in this study Satisfactory LAA occlusion rate was 100% There were no death, bleeding, stroke, and device related thrombus (DRT) events At 6-month post procedure, CCTA images evidenced complete endothelialization in 44 patients (no contrast enhancement in LAA); contrast enhancement in LAA and visible PDL in 33 patients; contrast enhancement in LAA but without PDL in 7 patients (incomplete device endothelialization) Maximum diameter of LAA orifice could independently predict the occurrence of PDL (OR, 1.31; 95% CI, 1.11-1.55; P = 0.002), sensitivity was 69.7% and specificity was 80.4% with the cutoff value of maximum diameter of LAA orifice >28.2 mm on predicting PDL CONCLUSIONS: CCTA is feasible to evaluate PDL and device endothelialization after LAAC The maximum diameter of LAA orifice derived from CT can independently predict the occurrence of post-LAAC PDL

Background and Objective: Ectopic beats originating from the pulmonary vein (PV) trigger atrial fibrillation (AF). The purpose of this study was to clarify the electrophysiological determinant of AF initiation from the PVs. Methods: Pacing studies were performed with a single extra stimulus mimicking an ectopic beat in the left superior pulmonary veins (LSPVs) in 62 patients undergoing AF ablation. Inducibility of AF, effective refractory period (ERP) and conduction properties within the PVs were analyzed. Results: A single extra stimulus in LSPV induced AF in 20 patients (32% of all patients) at the mean coupling interval (CI) of 172 ms. A CI-dependent anisotropic conduction at the AF onset was visualized in a 3D-mapping. Onset of AF was site-specific with reproducibility in each individual. Mean ERP in LSPV in the AF inducible group was shorter than that in the AF non-inducible group (182 ± 55 ms vs 254 ± 51 ms, P<0.0001). LSPV ERP dispersion was greater in the AF inducible group than in the AF non-inducible group (45 ± 28 ms vs 27 ± 19 ms, P<0.01). Circumferential intra-PV conduction time (IPVCT) exhibited decremental properties in response to shortening of CI, and the prolongation of IPVCT in the AF inducible site was greater than that in the AF non-inducible site (P<0.05) in each individual. Conclusions: Location and coupling interval of an ectopic excitation ultimately determine the initiation of AF from the PVs. ERP dispersion and circumferential conduction delay may lead to anisotropic conduction and reentry within the PVs that initiate AF.

Background: Cryoballoon (CB) based pulmonary vein isolation (PVI) has proven to be as effective as radiofrequency (RF) based ablation. Different ablation protocols took the individual time-to-isolation (TTI) into account aiming at shorter but equally or even more effective freeze-cycles. The current study sought to assess the impact of the TTI on PVI durability in patients undergoing a repeat procedure for recurrence of atrial tachyarrhythmia (ATA). Methods and Results: In 205 patients with ATA recurrence after previous CB-based PVI a total of 806 PVs were identified. One hundred-twenty-six out of 806 PVs (16%) were previously treated with a TTI guided ablation (protocol #1; TTI+120 sec.), in 92/806 (11%) PVs TTI was only monitored (m) but fixed freeze-cycles were applied (protocol #2; mTTI) and in 588/806 (73%) a fixed freeze-cycle was applied without TTI-monitoring. There was no difference in the PV-reconduction rate between the groups (P=0.23). The right inferior pulmonary vein (RIPV) showed overall significantly higher reconduction rates compared to the other PVs (RIPV – left inferior PV (LIPV) p<0.003, -left superior PV (LSPV) p<0.001, - right superior PV RSPV p<0.013). In 21 patients (10%) only for the RIPV reconduction was assessed. Conclusions: TTI based CB ablation did not show significant differences regarding PV-reconduction rates compared to the other protocols.

Introduction: Bradyarrhythmias are an established red flag for storage cardiac conditions including Anderson-Fabry disease (AFD). The prevalence of bradyarrhythmias requiring a pacemaker (PM) and their timing in AFD is unresolved. We evaluated prevalence and predictors of PM requirement in a large AFD cohort, investigating the occurrence of bradyarrhythmias as initial versus late manifestation. Methods: we retrospectively evaluated 82 consecutive AFD patients referred to our multidisciplinary referral centre from 1994 to 2020 with a median follow up of 6.9 years, identifying those requiring pacing. Univariable analysis was performed to identify cardiac features associated with PM implantantion. Results: Five of 82 (6%) AFD patients required PM implantation (5/39, i.e. 13% of those with cardiac involvement), always in the context of advanced cardiomyopathy. In none, bradyarrhythmias were the presenting feature. Indications included sick sinus syndrome in 3 patients, advanced atrio-ventricular block in 2 patients. QRS prolongation during follow up strongly correlated with the onset of bradyarrhythmias. Conclusions: Severe bradyarrhythmias are relatively frequent in patients with AFD cardiomyopathy, but do not represent a mode of presentation, occurring late in the disease course and always in the context of advanced cardiac involvement. Monitoring QRS variations over time may help to identify patients requiring pacing.