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[Figure: see text]. [ABSTRACT FROM AUTHOR]

Background: Pulmonary vein (PV) stenosis remains a feared complication of atrial fibrillation ablation. Little is known about outcomes in patients with severe PV stenosis, especially about repeat ablations.Methods: In 10 368 patients undergoing atrial fibrillation ablation (2000-2015), computed tomography scans were obtained 3 to 6 months after ablation. The clinical outcomes in severe PV stenosis were determined.Results: Severe PV stenosis was diagnosed in 52 patients (0.5%). This involved mostly the left superior PV (51% of severely stenosed veins). Percutaneous interventions were performed in 43 patients, and complications occurred in 5: 3 PV ruptures, 1 stroke, and 1 phrenic injury. Over a median follow-up of 25 months, 41 (79%) patients remained arrhythmia free. Repeat ablation was performed in 15 patients (7 from the main series and 8 from prior ablation at other institutions); of whom 10 had PV stents in place. Conduction recovery was noted in all but 2 of the stenosed or stented PVs, and areas with recovery were targeted with antral ablation. Lasso entrapment within stents occurred in 2 patients but eventually freed without complications. After redo ablation, preplanned stenting was performed in 3 patients and computed tomographic scans showed progression of concomitant stenoses in 1 patient (moderate to severe). No procedure-related deaths occurred.Conclusions: The incidence of severe PV stenosis is low but remains associated with significant morbidity. In patients with recurrent arrhythmia, conduction recovery at the stenosed or stented veins is common. Care must be taken to ablate antrally to avoid stenosis progression. In patients with prior PV stents, we suggest to avoid using Lasso. [ABSTRACT FROM AUTHOR]

Background: Although dofetilide labeling states that the drug must be initiated or reinitiated with continuous electrocardiographic monitoring and in the presence of trained personnel, the risks of dofetilide reloading justifying repeat hospitalization have not been investigated.Methods and Results: Patients admitted for dofetilide reloading for atrial arrhythmias were retrospectively reviewed. The need for dose adjustment and the incidence of torsades de pointes (TdP) were identified. The incidence of TdP in dofetilide reloading was compared with patients admitted for dofetilide initial loading. Of 138 patients admitted for dofetilide reloading for atrial arrhythmias, 102 were reloaded at a previously tolerated dose, 30 with a higher dose from a previously tolerated dose and 2 at a lower dose; prior dosage was unknown in 4 patients. Dose adjustment or discontinuation was required in 44 patients (31.9%). No TdP occurred in the same dose reloading group, but TdP occurred in 2 patients admitted to increase dofetilide dosage (0% versus 6.7%; P=0.050). Dofetilide dose adjustment or discontinuation was required in 30 of 102 patients (29.4%) reloaded at a previously tolerated dose and in 11 of 30 patients (36.7%) admitted for an increase in dose.Conclusions: Although no TdP occurred in patients admitted to reload dofetilide at the same dose as previously tolerated, dosage adjustments or discontinuation was frequent and support the need for hospitalization for dofetilide reloading. Patients admitted for reloading with a higher dose tended to be at higher risk for TdP than patients reloaded at a prior tolerated dose. [ABSTRACT FROM AUTHOR]

Background: Ablation is used for both rhythm control and improved quality of life (QoL) in atrial fibrillation (AF). It has been suggested that young adults may experience high recurrence rates after ablation and data remain lacking regarding QoL benefits. We aimed to investigate AF ablation outcomes and QoL benefits in young adults undergoing AF ablation using a large prospectively maintained registry and automated patient-reported outcomes (PRO). Methods: All patients undergoing AF ablation (2013–2016) at our center were prospectively enrolled. Patients aged 50 years or younger were included. For PROs, QoL measures and symptoms were assessed at baseline, 3 months after ablation, and every 6 months thereafter. The AF severity score served as the main assessment of QoL. Results: A total of 241 young adults (age, 16–50 years) were included (17% female, 40.3% persistent AF). In all, 77.2% of patients remained arrhythmia-free during the first year of follow-up (80% in nonstructural AF and 66% in structural AF). Using PROs, 90% of patients reported improvement in QoL throughout all survey time points up to 5 years postablation (P <0.0001). The baseline median AF severity score was 14 and improved to between 2 and 4 on all follow-up after ablation (P <0.0001). Patients also reported fewer and shorter AF episodes, fewer emergency room visits secondary to AF, and fewer hospitalizations (P <0.0001). Conclusions: Ablation remains an effective rhythm-control strategy in young adults with AF. Young adults also experience significant improvement in QoL with reduction of the frequency and duration of AF episodes and AF-related healthcare utilization. [ABSTRACT FROM AUTHOR]

Background: Confirming the presence and participation of concealed nodo-ventricular (cNV) or concealed His-ventricular (cHV) pathways in tachyarrhythmias is challenging. We describe novel observations to aid in diagnosing cNV or cHV pathways. Methods: We present 7 cases of cNV and cHV pathway-mediated arrhythmias and focus on several laboratory observations: (1) differential ventricular overdrive pacing (VOD) from the base versus apex, (2) response to His refractory premature ventricular complexes, (3) paradoxical atriohisian response (shorter atriohisian interval during tachycardia than that during sinus rhythm) in long RP tachycardia, and (4) the role of adenosine to aid in the diagnosis. Results: Three cases underwent differential VOD during tachycardia. All demonstrated a shorter postpacing interval minus tachycardia cycle length during basal pacing than apical pacing with one case exhibiting apical VOD results compatible with atrioventricular nodal reentrant tachycardia. Basal VOD was useful for localizing the ventricular connection in a case with cHV pathway. In 3 cases, His refractory premature ventricular complexes reset the tachycardia without conduction to the atrium, which excluded the involvement of an atrioventricular pathway or atrial tachycardia, or atrioventricular nodal reentrant tachycardia alone. One case had His refractory premature ventricular complexes followed by subsequent constant AA interval and then tachycardia termination, suggesting a bystander cNV pathway involvement. Two cNV pathway cases presented with long RP tachycardia had paradoxical atriohisian shortening of >15 ms, suggesting parallel activation of the atrium and the atrioventricular node. Adenosine terminated the tachycardia with retrograde block in 2 cases with cNV pathways but had no response on a cHV pathway. Conclusions: cNV and cHV pathways mediated tachyarrhythmias can present with variable clinical presentations. We emphasize the important role of differential VOD sites, His refractory premature ventricular complexes that reset or terminate the tachycardia without conduction to the atrium, paradoxical atriohisian response in long RP tachycardia, and the use of adenosine for diagnosing cNV and cHV pathways. [ABSTRACT FROM AUTHOR]

Background: Achieving long-term successful outcomes with ablation of persistent atrial fibrillation (AF) remains a clinical and procedural challenge. We aimed to assess 2 ablation strategies for persistent AF: pulmonary vein antral isolation (PVAI) in sinus rhythm after direct current cardioversion versus PVAI and ablation targeting complex-fractionated atrial electrograms while in AF.Methods and Results: Between June 2009 and July 2013, patients with continuous persistent AF for ≥3 months were prospectively randomized to either direct current cardioversion before PVAI and posterior wall/septum ablation while in sinus rhythm (group 1), versus same ablation in group 1 in addition to complex-fractionated atrial electrogram ablation while in AF (group 2). The procedural profiles and clinical outcomes of the 2 strategies were compared. Ninety patients were randomized to group 1 (n=46) or group 2 (n=44). There were no differences in baseline characteristics between groups. Over 365 days of follow-up after the index procedure, 16 patients (35%) in group 1 and 13 patients (30%) in group 2 remained arrhythmia-free off antiarrhythmic medications. Over long-term follow-up (median, 867 days), arrhythmia-free survival off antiarrhythmic medications was more likely in group 1 than in group 2 in Kaplan-Meier analysis (Log Rank P=0.04). Group 1 ablation was associated with significantly shorter procedural duration and fluoroscopy time (231±72 versus 273±76 min; P=0.008 and 54 [Q1-Q3: 46-67] versus 66 (Q1-Q3: 53-83] min; P=0.018, respectively).Conclusions: In patients with persistent AF, PVAI in sinus rhythm after direct current cardioversion is associated with higher success and shorter procedural and fluoroscopy times compared with PVAI in AF with additional complex-fractionated atrial electrogram ablation.Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02429648. [ABSTRACT FROM AUTHOR]

Background Baseline QRS duration (QRSd) ≥150 ms is a recognized predictor of clinical improvement by cardiac resynchronization therapy (CRT), particularly for those with left bundle branch (LBBB). Patients with QRSd <150 ms are considered less likely to respond. Objective The purpose of this study was to test our theory that left ventricular dyssynchrony, although usually associated with wider QRSd, also exhibits lower QRS frequency characteristics and that low-frequency content predicts CRT response in LBBB patients. Methods We retrospectively examined the QRS frequency content of 170 heart failure patients with LBBB and QRSd ≥120 ms using Fourier transformation. Ninety-four responders to CRT (defined as reduction in left ventricular end-systolic volume by ≥15% from baseline) were compared to 76 nonresponders (<15% reduction). Analysis of 3 standard ECG leads (I, aVF, and V 3 ) representing the 3 dimensions of depolarization was performed, and V 3 provided the best predictive value. Results The QRSd of responders (160.3 ± 17.8 ms) and nonresponders (161.8 ± 21.1 ms, P = .604) were similar. We found that the percentage of total QRS frequency power below 10 Hz that exceeded 52% was most predictive of CRT response compared to other cutoff values. However, the percentage of patients with total QRS power >52% below 10 Hz was especially predictive of response in those with QRSd <150 ms. In these patients, this power threshold was highly predictive of CRT response (positive predictive value 85.7%, negative predictive value 71.4%). Conclusion In this group of CRT recipients with LBBB, retrospective analysis of QRS frequency content below 10 Hz had greater predictive value for CRT response than baseline QRSd, particularly in those with QRSd <150 ms. [ABSTRACT FROM AUTHOR]

Background: Although improvement in left ventricular (LV) function has been shown to portend superior short-term outcomes in patients with heart failure undergoing cardiac resynchronization therapy (CRT), the durability of this effect at 5 years has not been established. Objective: To determine the long-term outcomes of patients undergoing CRT on the basis of the degree of echocardiographic response. Methods: We extracted clinical data on a cohort of 880 consecutive patients undergoing the new implantation of a CRT device between September 30, 2003, and August 6, 2007. Patients with an ejection fraction (EF) ≤35% undergoing initial CRT implantation, with an available pre-CRT and follow-up echocardiogram, were included in the final cohort. On the basis of changes in LVEF, patients were categorized into "nonresponders" (change in EF ≤4%), "responders" (EF change 5%-20%), and "super-responders" (change in EF >20%). A Cox multivariate model was performed to determine the effect of response on long-term survival free of LV assist device or heart transplant. Results: A total of 526 patients met inclusion criteria, of whom 196 (37.3%) were classified as nonresponders, 236 (44.9%) as "responders," and 94 (17.9%) as "super-responders." In multivariate analysis, "super-responders" had the best survival and nonresponders the worst over a mean of follow-up of 5.3 ± 2.4 years. At 5 years, survival free of LV assist device or heart transplant among super-responders was 82%; responders, 70%; and nonresponders, 48%. Conclusions: In patients with heart failure undergoing CRT, survival benefit is durable at 5 years of follow-up and its degree intimately tied to the level of improvement in ventricular function. The prognosis of nonresponders is exceptionally poor. [ABSTRACT FROM AUTHOR]

Background: Pulmonary vein isolation (PVI) for atrial fibrillation is associated with a transient increased risk of thromboembolic and hemorrhagic events. We hypothesized that dabigatran can be safely used as an alternative to continuous warfarin for the periprocedural anticoagulation in PVI.Methods and Results: A total of 999 consecutive patients undergoing PVI were included; 376 patients were on dabigatran (150 mg), and 623 patients were on warfarin with therapeutic international normalized ratio. [corrected] Dabigatran was held 1 to 2 doses before PVI and restarted at the conclusion of the procedure or as soon as patients were transferred to the nursing floor. Propensity score matching was applied to generate a cohort of 344 patients in each group with balanced baseline data. Total hemorrhagic and thromboembolic complications were similar in both groups, before (3.2% versus 3.9%; P=0.59) and after (3.2% versus 4.1%; P=0.53) matching. Major hemorrhage occurred in 1.1% versus 1.6% (P=0.48) before and 1.2% versus 1.5% (P=0.74) after matching in the dabigatran versus warfarin group, respectively. A single thromboembolic event occurred in each of the dabigatran and warfarin groups. Despite higher doses of intraprocedural heparin, the mean activated clotting time was significantly lower in patients who held dabigatran for 1 or 2 doses than those on warfarin.Conclusions: Our study found no evidence to suggest a higher risk of thromboembolic or hemorrhagic complications with use of dabigatran for periprocedural anticoagulation in patients undergoing PVI compared with uninterrupted warfarin therapy. [ABSTRACT FROM AUTHOR]

The article investigates mortality risk in postrevascularization patients with left ventricular ejection fraction of less than 35% and compares survival with those with wearable cardioverter defibrillator (WCD). Findings showed that patients with less than 35% ejection fraction without WCD have higher early mortality after the procedures. Since mortality risk is less marked in WCD users, prospective studies on WCD in the population group is indicated to confirm its benefits to outcomes.

Background: A significant proportion of implantable cardioverter-defibrillators (ICDs) have been subject to Food and Drug Administration (FDA) advisories. The impact of device advisories on mortality or patient care is poorly understood. Although estimated risks of ICD generators under advisory are low, dependency on ICD therapies to prevent sudden death justifies the assessment of long-term mortality. Objective: To test the association of FDA advisory status with long-term mortality. Methods: The study was a retrospective, single-center review of clinical outcomes, including device malfunctions, in patients from implantation to either explant or death. Patients with ICDs first implanted at Cleveland Clinic between August 1996 and May 2004 who became subject to FDA advisories on ICD generators were identified. Mortality was determined by using the Social Security Death Index. Results: In 1644 consecutive patients receiving first ICD implants, 704 (43%) became subject to an FDA advisory, of which 172 (10.5%) were class I and 532 (32.3%) were class II. ICDs were explanted before advisory notifications in 14.0% of class I and 10.1% of class II advisories. Among ICDs under advisory, 28 (4.0%) advisory-related and 15 non–advisory- related malfunctions were documented. Over a median follow-up of 70 months, 814 patients died. Kaplan-Meier 5-year survival rate was 65.6% overall, and 64.2, 61.1, and 69.3% in patients with no, class I, and class II advisories, respectively (P = .17). Conclusions: ICD advisories impacted 43% of the patients. Advisory-related malfunctions affected 4% within the combined advisory group. Based on a conservative management strategy, ICDs under advisory were not associated with increased mortality over a background of significant disease-related mortality. [Copyright &y& Elsevier]

Background: Expanded polytetrafluoroethylene (ePTFE) coated and medical adhesive back-filled (MABF) implantable cardioverter-defibrillator (ICD) coils have been promoted to reduce the fibrous ingrowth into coils that can complicate lead extraction. Objective: The purpose of this study was to test the hypothesis that ePTFE or MABF coatings are associated with greater ease of extraction. Methods: Consecutive isolated ICD lead extraction cases were identified from a prospectively collected clinical database. Primary endpoints included total procedure and fluoroscopy times, radiation dose, and fibrosis sites. Data were analyzed using univariate and multivariate analyses in total and propensity-matched groups, adjusting for lead age and other factors. Results: Among 329 patients (80% male; age 63.7 ± 5.4 years), 284 (86.3%) had standard coil ICD and 45 (13.7%) had treated coil ICD leads extracted, of which 17 (5.2%) were ePTFE coated and 28 (8.5%) were MABF ICD leads. The ePTFE and MABF leads were associated with lower procedure and fluoroscopy times, radiation dose, and fibrosis sites, even after adjustment for lead age, which was significantly shorter in the treated coil leads. To further adjust for the difference in lead age, a propensity-matched group was analyzed. Procedure time, fluoroscopy time, radiation dose, and brachiocephalic fibrosis remained significantly lower in the treated coil lead group. Conclusions: The ePTFE- and MABF-treated coils appear to provide some incremental benefit in ease of extraction over conventional, nontreated coil ICD leads. Although many current ICD leads do not have fibrosis ingrowth-limiting strategies, our study may rationalize the consideration of adding such technologies to future leads. [Copyright &y& Elsevier]

Background: Atrial fibrillation (AF) has been linked to inflammatory factors and obesity. Epicardial fat is a source of several inflammatory mediators related to the development of coronary artery disease. We hypothesized that periatrial fat may have a similar role in the development of AF.Methods and Results: Left atrium (LA) epicardial fat pad thickness was measured in consecutive cardiac CT angiograms performed for coronary artery disease or AF. Patients were grouped by AF burden: no (n=73), paroxysmal (n=60), or persistent (n=36) AF. In a short-axis view at the mid LA, periatrial epicardial fat thickness was measured at the esophagus (LA-ESO), main pulmonary artery, and thoracic aorta; retrosternal fat was measured in axial view (right coronary ostium level). LA area was determined in the 4-chamber view. LA-ESO fat was thicker in patients with persistent AF versus paroxysmal AF (P=0.011) or no AF (P=0.003). LA area was larger in patients with persistent AF than paroxysmal AF (P=0.004) or without AF (P<0.001). LA-ESO was a significant predictor of AF burden even after adjusting for age, body mass index, and LA area (odds ratio, 5.30; 95% confidence interval, 1.39 to 20.24; P=0.015). A propensity score-adjusted multivariable logistic regression that included age, body mass index, LA area, and comorbidities was also performed and the relationship remained statistically significant (P=0.008).Conclusions: Increased posterior LA fat thickness appears to be associated with AF burden independent of age, body mass index, or LA area. Further studies are necessary to examine cause and effect, and if inflammatory, paracrine mediators explain this association. [ABSTRACT FROM AUTHOR]

Background: Elimination of vagal inputs into the left atrium (LA) may be necessary for successful catheter ablation of atrial fibrillation (AF). These vagal inputs are clustered in autonomic ganglia (AG) that are close to the pulmonary vein antrum (PVA) borders, but whether standard intracardiac echocardiography (ICE)-guided PVA isolation (PVAI) affects these inputs is unknown. Objective: The purpose of this study was to assess whether standard ICE-guided PVAI affects vagal responses induced by endocardial AG stimulation in the LA. Methods: Twenty consecutive patients undergoing first-time PVAI (group 1) and 20 consecutive patients undergoing repeat PVAI for AF recurrence (group 2) were enrolled in the study. Before ablation, electrical stimulation (20 Hz, pulse duration 10 ms, voltage range 12-20 V) was performed through an 8-mm-tip ablation catheter. Based on prior data, regions around all four PVA borders were carefully mapped and stimulated to localize AG inputs. A positive stimulated vagal response was defined as atrioventricular (AV) block, asystole, or increase in mean RR interval by >50%. Locations of positive vagal responses were recorded wth biplane fluoroscopy and CARTO. All patients then underwent standard ICE-guided PVAI by an operator blinded to the locations of vagal responses. Stimulation of the AG locations was then repeated postablation. Results: Patients (age 54 +/- 11 years, 30% female, ejection fraction 54% +/- 7%) had a history of paroxysmal (75%) and persistent (25%) AF. In group 1, vagal responses were induced in all 20 patients around a mean of 3.8 +/- 0.4 PVAs per patient. The most common response was asystole (53%), mean RR slowing >50% (28%), and AV block (20%). Postablation, vagal responses could no longer be induced in all 20 patients. A diminished response was induced (RR slowing <50%) in 2/20 patients around one PVA each. In group 2, vagal responses were not induced in any of the 20 repeat patients. Stimulation capture postablation was confirmed because transient, nonsustained (<30 seconds) AF or atrial flutter was induced in all 40 patients with stimulation, whether vagal responses were induced or not. Conclusions: Standard ICE-guided PVAI eliminates vagal responses induced by AG stimulation. Responses are not seen in patients presenting for repeat PVAI, despite clinical recurrence of AF. [ABSTRACT FROM AUTHOR]

Objective: To study the safety, efficacy, and mapping utility of a new cryoablation catheter.Background: The CryoCath Technologies Freezor catheter has been used successfully for cryoablation of supraventricular tachycardia (SVT), but has not been evaluated in a large clinical trial.Methods: A multicenter clinical trial to evaluate the safety, efficacy, and cryomapping utility of this cryoablation catheter was conducted in 166 subjects. The target of ablation was the slow pathway in patients with SVT due to AV nodal reentry (AVNRT, n = 103), an accessory pathway in patients with AV reentrant SVT (AVRT, n = 51) and the AV junction in patients with atrial fibrillation (AF, n = 12).Results: Acute procedural success (APS) was achieved in 83% of the overall group (95% CI, 76% to 88%). APS in the AVNRT group was 91% (98.3% CI, 82% to 97%), compared to 69% for AVRT (98.3% CI, 51% to 84%) and 67% for AF (98.3% CI, 29% to 93%), a highly significant difference (P < .001 by stepwise logistic regression). In patients with APS, long-term success after 6 months was 91% overall (95% CI, 86% to 96%) and 94% for AVNRT subjects (98.3% CI, 87% to 100%). None of the AVNRT or AVRT subjects required a permanent pacemaker. Cryomapping successfully identified ablation targets in 64% of patients in whom it was attempted. The electrophysiologic effects of cryomapping were completely reversible within minutes in 94% of such attempts.Conclusions: Catheter cryoablation of SVT is a safe alternative to RF ablation and is clinically effective in patients with AVNRT. Cryomapping can reversibly identify targets for ablation and can help minimize the risk of inadvertent AV block during ablation. [ABSTRACT FROM AUTHOR]