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Background: Prediction of the chamber of origin in patients with outflow tract ventricular arrhythmias (OTVA) remains challenging. A clinical risk score based on age, sex and presence of hypertension was associated with a left ventricular outflow tract (LVOT) origin. We aimed to validate this clinical score to predict an LVOT origin in patients with OTVA. Methods: In a two‐center observational cohort study, unselected patients undergoing catheter ablation (CA) for OTVA were enrolled. All procedures were performed using an electroanatomical mapping system. Successful ablation was defined as a ≥80% reduction of the initial overall PVC burden after 3 months of follow‐up. Patients with unsuccessful ablation were excluded from this analysis. Results: We included 187 consecutive patients with successful CA of idiopathic OTVA. Mean age was 52 ± 15 years, 102 patients (55%) were female, and 74 (40%) suffered from hypertension. A LVOT origin was found in 64 patients (34%). A score incorporating age, sex and presence of hypertension reached 73% sensitivity and 67% specificity for a low (0–1) and high (2–3) score, to predict an LVOT origin. The combination of one ECG algorithm (V2S/V3R‐index) with the clinical score resulted in a sensitivity and specificity of 81% and 70% for PVCs with R/S transition at V3. Conclusion: The published clinical score yielded a lower sensitivity and specificity in our cohort. However, for PVCs with R/S transition at V3, the combination with an existing ECG algorithm can improve the predictability of LVOT origin. [ABSTRACT FROM AUTHOR]

Remote monitoring is useful for management of implantable cardioverter defibrillator (ICD) patients regarding detection of arrhythmias and probable device or lead failure. We report the case of a patient who died suddenly while being on remote monitoring. The ICD was not retrieved postmortem. Even though clinical circumstances were suspicious of an arrhythmic death, this was excluded due to a distinctive manufacturer feature of the system. (PACE 2012; 35:e280-e283) [ABSTRACT FROM AUTHOR]

Background: Radiofrequency catheter ablation of idiopathic premature ventricular complexes (PVCs) is an effective method for eliminating symptoms and preventing/reversing arrhythmia‐induced cardiomyopathy. One reason for procedural failure is low PVC frequency during the procedure. We aimed to investigate the relation between pre‐procedural PVC burden and outcome of idiopathic PVC catheter ablation. Methods: Patients who underwent idiopathic PVC ablation between 2013 and 2019 at two tertiary referral centers were retrospectively included. All procedures were performed using irrigated‐tip ablation catheters and a 3D electro‐anatomical mapping system. Sustained ablation success was defined as a ≥80% reduction of pre‐procedural PVC burden determined by 24h‐Holter at follow‐up. Results: Overall, 254 patients (median age 54 years [IQR 42–64]; 47% male) were enrolled. The median pre‐ablation PVC‐burden was 22% (IQR 11–31%), which was reduced to a post‐ablation PVC burden of 0.3% (IQR 0–4%) after a median of 90 days. Sustained ablation success was achieved in 182 patients (72%). Pre‐procedural PVC burden did not differ between patients with sustained ablation success and recurrence during follow‐up (median 21% vs. 22%, p =.76). When assessed in pre‐ablation PVC‐burden groups of ≤5%, 6–15%, 16–30%, and ≥31%, sustained ablation success was achieved in 67%, 75%, 71%, and 72%, respectively, with no significant difference (p =.89). Sustained ablation outcome for PVC‐burden ≤5% versus >5% showed no difference either (67% vs. 72%, p =.52). Conclusions: Pre‐procedural Holter‐determined PVC burden does not predict the outcome of idiopathic PVC ablation. Thus, catheter ablation may be a reasonable first choice also for patients with symptomatic yet rare PVCs. [ABSTRACT FROM AUTHOR]

Ectopic beats originating from the superior vena cava (SVC) may initiate atrial fibrillation. This report describes a patient undergoing radiofrequency catheter ablation for electrical isolation of the SVC resulting in SVC stenosis. Noncircumferential lesion sets for SVC isolation to reduce ablation times may be preferred. (PACE 2010; e36–e38) [ABSTRACT FROM AUTHOR]

Background: Due to high failure rates, Medtronic withdrew the Sprint Fidelis lead (SFL) from the market. Passive fixation lead models exhibited better survival than active models, but most studies have limited follow‐up. Aim of this study was to give insights into passive lead survival with a follow‐up of 10 years. Methods: In two large Swiss centers, patients with passive SFLs were identified and data from routine implantable cardioverter defibrillator (ICD) follow‐ups were collected. Patients were censored at time of death, last device interrogation (if lost to follow‐up), time of lead revision (in non‐SFL‐related problems), or at database closure (31th December 2017). We defined lead failure as any of the following: lead fracture with inappropriate discharge; sudden increase in low‐voltage impedance to >1500 or high‐voltage impedance to >100 Ω; >300 nonphysiological short VV‐intervals. Results: We identified 145 patients. Age at implant was 60 ± 12 years with a median follow‐up of 10.2 (interquartile range [IQR]: 5.0‐11.2) years. Thirty‐five percent of patients died after 5.4 ± 2.7 years. A total of 19 leads (13%) failed after 6.7 ± 3.2 years (range: 1.2‐12.0). Overt malfunction with shocks existed in four patients (3%). Cumulative lead survival was 93.1% at 6, 88.2% at 8, 83.8% at 10, and 77.6% at 11 years, respectively, with 35% of implanted leads under monitoring at 10 years. Lead survival fits best a Weibull distribution with accelerating failure rates (k = 1.95, 95% CI 1.32‐2.87, P < 0.001). Conclusions: During very long‐term follow‐up, failure rate of the passive SFL shows an increase resulting in an impaired lead survival of 84% at 10 years. [ABSTRACT FROM AUTHOR]

Background Anatomically guided pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. However, the position where to confirm electrical isolation is ill-defined. The aim of the current study was to quantify the relationship between the anatomical and electrical definition of the pulmonary vein ostium. Methods We analyzed 20 patients with paroxysmal AF undergoing PVI using radiofrequency energy and an electroanatomical mapping system. The anatomical ostium was defined based on the geometry obtained from preprocedural magnetic resonance imaging and computed tomography. The electrical ostium was defined at the position with a far-field atrial signal preceding a sharp pulmonary vein (PV) signal without any isoelectric interval in between. Results The electrically defined ostia were 8.4 ± 4.7 mm more distal in the PV compared to the anatomically defined ostia. The distances varied considerably between the four PVs and were 10.5 ± 6.5 mm, 7.4 ± 4.3 mm, 5.3 ± 4.0 mm, and 8.3 ± 3.4 mm for the left superior, left inferior, right superior, and right inferior PVs, respectively (P = 0.009). Conclusions The position of the electrical and anatomical ostium differs markedly. The site of the electrical ostium is variable within the PV but always more distal in the PV compared to the site of the anatomical ostium. [ABSTRACT FROM AUTHOR]

Background Many patients receiving an implantable cardioverter-defibrillator (ICD) also have atrial fibrillation (AF). Shock testing during ICD implantation carries a potential risk of cardioversion to sinus rhythm (SR) and thrombembolic events. We aimed to analyze the recurrence of AF after cardioversion to SR during ICD shock testing. Methods A total of 555 consecutive patients referred to a tertiary hospital in Switzerland for ICD implantation or generator exchange between 02/2002 and 03/2010 were screened for AF. Fifty-seven patients who were in AF at the time of ICD shock testing were included. Results Forty-four patients (77%) were successfully cardioverted from AF to SR. Type of AF (persistent, not permanent 64 vs 31% of cardioverted patients) was the only predictor. Thirty-nine patients (89%) experienced a recurrence of AF/atrial flutter after a median of 54 days (interquartile range 35-251 days). The only predictor for recurrence of AF was previous AF declared as permanent. No ischemic stroke occurred during hospitalization for the procedure. Conclusions For patients in AF undergoing shock testing at the time of ICD implant, there is a high chance of cardioversion from AF to SR, but there is also a high risk of early recurrence. Decisions regarding long-term anticoagulation should not be based on the heart rhythm immediately following shock testing. [ABSTRACT FROM AUTHOR]

Background The Medtronic Sprint Fidelis lead (SFL; Medtronic Inc., Minneapolis, MN, USA) has a significantly impaired long-term survival, and active fixation leads fare worse than passive leads. The goal of this study was to present data of a series of passive SFL only with very long mean follow-up of more than 6 years. Methods Patients in whom a passive SFL was implanted in two large Swiss centers were followed. We excluded eight (5.5%) patients with a follow-up of <6 months. Patients who died or were lost during follow-up were censored at death or last device check, all others on January 31, 2014. We employed two different definitions of failure: strict = fracture with inappropriate discharge; sudden increase in impedance >1,500 or high-voltage impedance >100 Ohm; >300 nonphysiological short interventricular-intervals. Lenient = any of the above plus a linear increase in impedance >1,500 Ohm or a linear decrease in sensing to a level that treating cardiologists considered inappropriate. Results We included 137 patients. Age was 60 ± 12 years. Mean and median follow-up were 6.2 ± 2.1 and 6.8 (interquartile range 4.8-7.8) years. Applying the strict definition, 12 leads (8.8%) were replaced after 4.9 ± 2.4 years (range 1.2-8.1). Applying the lenient definition, 14 leads (10.2%) failed. Cumulative lead survival was 98.5% at 3, 96.9% at 4, 94.2% at 5, and 93.1% at 6 years. Leads 'at risk' were: n = 122 (89%), 115 (84%), 101 (74%), and 88 (64%). Conclusions In this population with passive SFLs, 5-year lead survival is impaired with 94.2% based on 74% of leads 'at risk' at this time point. [ABSTRACT FROM AUTHOR]

Background To compare the feasibility and efficiency of atrioventricular junction (AVJ) ablation and device implantation in patients with drug-refractory atrial fibrillation using three different approaches. Methods Sixty-nine patients (57% male; age 72 ± 10; ejection fraction 45 ± 15%) undergoing device implantation and AVJ ablation were retrospectively studied at a tertiary referral center. In 20 patients (29%) AVJ ablation was performed via the femoral vein immediately following device implantation (group 1), whereas 33 patients (48%) underwent a staged procedure with AVJ ablation via the femoral vein >3 weeks after device implantation (group 2). In a third group of 16 patients (23%), AVJ ablation was performed during device implantation through the pocket using the same axillary vein access site (group 3). The main outcome measures were: procedure time, fluoroscopy time, laboratory occupancy time, and success rate. Results There was a significant difference in procedure time (118 ± 45 minutes. in group 1, 133 ± 32 minutes in group 2, and 87 ± 26 minutes in group 3, P < 0.001) and the laboratory occupancy time (175 ± 48 minutes in group 1, 200 ± 32 minutes in group 2, and 121 ± 27 minutes in group 3, P < 0.001). There was no difference in fluoroscopy time (group 1: 20 ± 15 minutes, group 2: 27 ± 22 minutes, and group 3: 24 ± 9 minutes P = 0.4). The procedure was successfully completed in all patients, but cross-over to a femoral approach was required in one patient in group 3. Conclusion The alternative approach of AVJ ablation during permanent pacemaker implantation from the same axillary vein access site is feasible and more efficient compared to the femoral approach. [ABSTRACT FROM AUTHOR]

Background To categorize indications of permanent pacemaker (PPM) implantation after transcatheter aortic valve implantation (TAVI), to determine predictors for conduction disturbances and to quantify the need for ventricular pacing during follow-up. Method We studied 97 patients (median age 83 years, 58% female) undergoing TAVI using the Medtronic CoreValve Revalving System (MCRS; Medtronic Inc., Minneapolis, MN, USA) or Edwards-Sapien Valve (Edwards Lifesciences, Irvine, CA, USA). During follow-up, no need for ventricular pacing was defined as <1% ventricular pacing and intrinsic 1:1 atrioventricular (AV) conduction. Results In the 35 patients (36.1%) undergoing PPM implantation three indication categories were identified: (1) high-grade AV block (Mobitz 2 or higher), (2) new-onset left bundle branch block (LBBB) with a prolonged PR interval, and (3) new-onset LBBB. The only independent predictors of high-grade AV block were the use of MCRS (odds ratio [OR] 79.25; 95% confidence interval [CI] 4.57-1373.31) and the presence of preprocedural right bundle branch block (OR 81.95; 95% 95% CI 8.72-770.46). Whereas high-grade AV block resolved only in 17% of cases, none of the patients receiving a PPM due to LBBB with or without PR prolongation required ventricular pacing during follow-up. Conclusion Our findings justify early PPM implantation in patients with high-grade AV block and may suggest a more conservative approach to PPM implantation in patients with new-onset LBBB after TAVI. [ABSTRACT FROM AUTHOR]

Closed-loop stimulation (CLS) is a new sensor concept for rate adaptive pacing measuring changes in the unipolar right ventricular impedance, which correlates to changes of the right ventricular contractility and reflects the autonomic nervous innervation of the heart. Some patients do not tolerate the CLS mode because of inappropriate tachycardia, mainly related to postural changes. This study tested if the rate response of the CLS sensor is influenced not only by myocardial contractility but also by rapid changes in right ventricular filling. In 12 patients (10 men, median age 77 years) with a Biotronik Inos2 -CLS DDDR pacemaker and 14 controls (13 men, median age 59 years) head-up tilt and handgrip testing was performed to provoke rapid changes in pre- and afterload. Tilting the pacemaker patients resulted in a nonphysiological steep increase of the sensor rate (increase >20 beats/min, peak after 1 minute, return to baseline within 2–3 minutes), which was significantly different from the control group, showing only a slight rise in intrinsic heart rate immediately after tilting. Simultaneously to the rapid increase in sensor rate, the pacemaker patients showed a marked orthostatic decline of systolic blood pressure. During handgripping, heart rate and blood pressure curves were similar in both groups. In patients with this CLS pacemaker, rapid preload reduction during head-up tilting caused an overshooting sensor rate increase, reproducing the authors' clinical observation of postural pacemaker tachycardia in some patients. Consequently, they concluded that the rate response of the CLS pacing system can be inappropriately influenced by rapid shifts of blood volume, affecting right ventricular filling. (PACE 2003; 26[Pt. I]:1504–1510). [ABSTRACT FROM AUTHOR]

We present a case of a conscript who was referred for ablation of asymptomatic Wolff-Parkinson-White syndrome. However, the electrophysiologic study revealed the presence of an accessory pathway arising infranodally in the His-Purkinje system, and inserting into the nearby ventricle. The case emphasizes the limitations of the surface ECG and the importance of a thorough electrophysiologic study. Our patient required no specific therapy but correction of the diagnosis before being declared fit for military service. A second interesting finding not described before with this type of pathway was the occurrence of transient mechanical interruption of accessory pathway conduction. (PACE 2010; 33:e93-e95) [ABSTRACT FROM AUTHOR]

A 35-year-old man was referred for ablation of ventricular tachycardia with two different morphologies triggering each other. After elimination of the first arrhythmia in the right ventricular outflow tract, ablation of the second morphology was performed 8 mm below the left main stem after contrast injection into the left coronary cusp through the irrigated-tip ablation catheter. (PACE 2012;35:e356-e357) [ABSTRACT FROM AUTHOR]