Acute post-procedural inducibility is a poor predictor of clinical outcomes in high-risk patients (PAINESD > 17) undergoing scar-related ventricular tachycardia ablation.

AIMS: Ventricular tachycardia (VT) non-inducibility in response to programmed ventricular stimulation (PVS) is a widely used procedural endpoint for VT ablation despite inconclusive evidence with respect to clinical outcomes in high-risk patients. The aim is to determine the utility of acute post-ablation VT inducibility as a predictor of VT recurrence, mortality, or mortality equivalent in high-risk patients. METHODS AND RESULTS: We conducted a retrospective analysis of high-risk patients (defined as PAINESD > 17) who underwent scar-related VT ablation at our institution between July 2010 and July 2022. Patients' response to PVS (post-procedure) was categorized into three groups: Group A, no clinical VT or VT with cycle length > 240 ms inducible; Group B, only non-clinical VT with cycle length > 240 ms induced; and Group C, all other outcomes (including cases where no PVS was performed). The combined primary endpoint included death, durable left ventricular assist device placement, and cardiac transplant (Cox analysis). Ventricular tachycardia recurrence was considered a secondary endpoint (competing risk analysis). Of the 1677 VT ablation cases, 123 cases met the inclusion criteria for analysis. During a 19-month median follow-up time (interquartile range 4-43 months), 82 (66.7%) patients experienced the composite primary endpoint. There was no difference between Groups A and C with respect to the primary [hazard ratio (HR) = 1.21 (0.94-1.57), P = 0.145] or secondary [HR = 1.18 (0.91-1.54), P = 0.210] outcomes. These findings persisted after multivariate adjustments. The size of Group B (n = 13) did not permit meaningful statistical analysis. CONCLUSION: The results of post-ablation PVS do not significantly correlate with long-term outcomes in high-risk (PAINESD > 17) VT ablation patients.

Cryoballoon pulmonary vein isolation versus radiofrequency ablation of the pulmonary veins and left atrial posterior wall: Patient-reported outcomes.

BACKGROUND: Data are lacking on patient-reported outcomes (PRO) following cryoballoon ablation (CBA) versus radiofrequency ablation (RFA). We sought to evaluate QoL and clinical outcomes of cryoballoon pulmonary vein isolation only (CRYO-PVI-ONLY) versus RFA with PVI and posterior wall isolation (RF-PVI+PWI) in a large prospective PRO registry. METHODS: Patients who underwent AF ablation (2013-2016) at our institution were enrolled in an automated, prospectively maintained PRO registry. CRYO-PVI-ONLY patients were matched (1:1) with RF-PVI+PWI patients based on age, gender, and type of AF (paroxysmal vs. persistent). QoL and clinical outcomes were assessed using PRO surveys at baseline and at 1-year. The atrial fibrillation symptom severity scale (AFSSS) was the measure for QoL. Additionally, we assessed patient-reported clinical improvement, arrhythmia recurrence, and AF burden (as indicated by AF frequency and duration scores). RESULTS: A total of 296 patients were included (148 in each group, 72% paroxysmal). By PRO, a significant improvement in QoL was observed in the overall study population and was comparable between CRYO-PVI-ONLY and RF-PVI+PWI (baseline median AFSSS of 11.5 and 11; reduced to 2 and 4 at 1 year, respectively; p = 0.44). Similarly, the proportion of patients who reported improvement in their overall QoL and AF related symptoms was high and similar between the study groups [92% (CRYO-PVI-ONLY) vs. 92.8% (RF-PVI+PWI); p = 0.88]. Arrhythmia recurrence was significantly more common in the CRYO-PVI-ONLY group (39.7%) compared to RF-PVI+PWI (27.7 %); p = 0.03. Comparable results were observed in paroxysmal and persistent AF. CONCLUSION: CRYO-PVI-ONLY and RF-PVI+PWI resulted in comparable improvements in patient reported outcomes including QoL and AF burden; with RF-PVI+PWI being more effective at reducing recurrences.

Catheter ablation of atrial fibrillation in elderly and very elderly patients: safety, outcomes, and quality of life.

BACKGROUND: Atrial fibrillation (AF) risk increases with age. We aim to assess the efficacy and safety of catheter ablation in the older population. METHODS: All patients undergoing AF ablation (2013-2021) at our institution were enrolled in a prospectively maintained registry. The primary endpoint was AF recurrence. Patients were divided into 3 groups: non-elderly (< 65 years), elderly (65-75 years), and very elderly (> 75 years). Patient surveys at baseline and during follow-up were used to calculate quality of life (QoL) metrics: the AF severity score as well as the AF burden. RESULTS: A total of 7020 patients were included (42% non-elderly, 42% elderly, and 16% very elderly). Periprocedural major complications were low (< 1.5%) and similar in all groups besides pericardial effusion which was more frequent with older age and similar between the elderly and very elderly. At 3 years, AF recurrence for persistent AF (PersAF) was highest in the very elderly group (48%), followed by the elderly group (42%), and was the lowest in the non-elderly group (36%). In paroxysmal AF (PAF), there was no difference in AF recurrence between the elderly and non-elderly, while the very elderly remained associated with a significantly increased risk. Multivariable Cox analysis confirmed these findings (PersAF; elderly: HR = 1.23, P = 0.003; very elderly: HR = 1.44, P < 0.001) (PAF; elderly: HR = 1.04, P = 0.62; very elderly: HR = 1.30, P = 0.01). Catheter ablation resulted in a significant improvement in quality of life, irrespective of age group. CONCLUSION: Catheter ablation in elderly and very elderly patients is safe, efficacious, and associated with QoL benefits. Overall, major complications were minimal and did not differ significantly between age groups, with the exception of pericardial effusions which were higher in the elderly and very elderly compared to non-elderly adults. Very elderly patients had a higher rate of AF recurrence when compared with elderly or non-elderly patients. Nevertheless, ablation resulted in a remarkable improvement in QoL and a reduction of AF burden and AF symptoms with a similar magnitude, irrespective of age.

Ischemic or Coronary Evaluations in Patients With Monomorphic VT Electrical Storm Undergoing VT Ablation.

BACKGROUND: Monomorphic ventricular tachycardia (VT) electrical storm (ES) in patients with coronary artery disease is dependent on scarred myocardium. The role of routine ischemic or coronary evaluations before ablation in patients presenting with monomorphic VT storm, without acute coronary syndrome (ACS), remains unknown. OBJECTIVES: This study sought to assess the impact of ischemic or coronary evaluations on procedural outcomes and post-ablation mortality in monomorphic VT storm patients. METHODS: All patients undergoing VT ablation at the Cleveland Clinic from 2014 to 2020 after presenting with monomorphic VT storm were enrolled in a prospectively maintained registry. The associations among ischemic or coronary evaluations and short-term procedural efficacy, acute outcomes, and mortality during follow-up were assessed. RESULTS: A total of 97 consecutive patients with monomorphic VT storm in the absence of ACS underwent VT ablations. This cohort was characterized by severe LV systolic dysfunction (mean left ventricular ejection fraction 30.3%, 67% with known ischemic cardiomyopathy) with moderately severe heart failure (median NYHA functional class II); 45% of patients underwent ischemic or coronary evaluations via coronary angiography (10%), noninvasive myocardial perfusion (26%), or both (9%). The yield of these evaluations was low: No acute coronary occlusions were identified. There was no association between ischemic evaluation and acute ablation outcomes or mortality during follow-up. Similarly, in a secondary analysis, the yield of ischemic or coronary evaluations in patients with monomorphic VT storm and known coronary disease (regardless of ablation status) was found to be low. CONCLUSIONS: Ischemic evaluations in patients with monomorphic VT storm without ACS may not improve procedural outcomes or mortality after ablation.

Impact of obesity on catheter ablation of atrial fibrillation: Patient characteristics, procedural complications, outcomes, and quality of life.

INTRODUCTION: Obesity is a well-known risk factor for atrial fibrillation (AF). We aim to evaluate the effect of baseline obesity on procedural complications, AF recurrence, and symptoms following catheter ablation (CA). METHODS: All consecutive patients undergoing AF ablation (2013-2021) at our center were enrolled in a prospective registry. The study included all consecutive patients with available data on body mass index (BMI). Primary endpoint was AF recurrence based on electrocardiographic documentation. Patients were categorized into five groups according to their baseline BMI. Patients survey at baseline and at follow-up were used to calculate AF symptom severity score (AFSS) as well as AF burden (mean of AF duration score and AF frequency score; scale 0: no AF to 10: continuous and 9 frequencies/durations in between). Patients were scheduled for follow-up visits with 12-lead electrocardiogram at 3, 6, and 12 months after ablation, and every 6 months thereafter. RESULTS: A total of 5841 patients were included (17% normal weight, 34% overweight, 27% Class I, 13% Class II, and 9% Class III obesity). Major procedural complications were low (1.5%) among all BMI subgroups. At 3 years AF recurrence was the highest in Class III obesity patients (48%) followed by Class II (43%), whereas Class I, normal, and overweight had similar results with lower recurrence (35%). In multivariable analyses, Class III obesity (BMI ≥ 40) was independently associated with increased risk for AF recurrence (hazard ratio, 1.30; confidence interval, 1.06-1.60; p = .01), whereas other groups had similar risk in comparison to normal weight. Baseline AFSS was lowest in normal weight, and highest in Obesity-III, median (interquartile range) 10 (5-16) versus 15 (10-21). In all groups, CA resulted in a significant improvement in their AFSS with a similar magnitude among the groups. At follow-up, AF burden was minimal and did not differ significantly between the groups. CONCLUSION: AF ablation is safe with a low complication rate across all BMI groups. Morbid obesity (BMI ≥ 40) was significantly associated with reduced AF ablation success. However, ablation resulted in improvement in QoL including reduction of the AFSS, and AF burden regardless of BMI.

Atrial Fibrillation Ablation in Young Adults: Measuring Quality of Life Using Patient-Reported Outcomes Over 5 Years.

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.

Junctional Tachycardia: A Critical Reassessment.

Junctional tachycardia (JT) is typically considered to have an automatic mechanism originating from the distal atrioventricular node. When there is 1:1 retrograde conduction via the fast pathway, JT would resemble the typical form of atrioventricular nodal re-entrant tachycardia (AVNRT). Atrial pacing maneuvers have been proposed to exclude AVNRT and suggest a diagnosis of JT. However, after excluding AVNRT, one should consider the possibility of an infra-atrial narrow QRS re-entrant tachycardia, which can exhibit features that resemble AVNRT as well as JT. Pacing maneuvers and mapping techniques should be performed to assess for infra-atrial re-entrant tachycardia before concluding that JT is the mechanism of a narrow QRS tachycardia. Distinguishing JT from typical AVNRT or infra-atrial re-entrant tachycardia has notable implications regarding the approach to ablation of the tachycardia. Ultimately, a contemporary review of the evidence on JT raises some questions as to the mechanism and source of what has traditionally been considered JT.

Impact of redo ablation for atrial fibrillation on patient-reported outcomes and quality of life.

INTRODUCTION: Catheter ablation for atrial fibrillation (AF) is frequently used for the purpose of rhythm control and improved quality of life (QoL). Although success rates are high, a significant proportion of patients require redo ablation. Data are scarce on patient-centered outcomes and QoL in patients undergoing redo AF ablation. We aimed to assess QoL and clinical outcomes using a large prospectively maintained patient-reported outcomes (PRO) registry. METHODS: All patients undergoing redo AF ablation (2013-2016) at our center were enrolled in a prospective registry for outcomes and assessed for QoL using automated PRO surveys (baseline, 3 and 6 months after ablation, every 6 months thereafter). Data were collected over 3 years of follow-up. The atrial fibrillation symptom severity scale (AFSSS) was used as the main measure for QoL. Additional variables included patient-reported improvement, AF burden, and AF-related healthcare utilization including emergency room (ER) visits and hospitalizations. RESULTS: A total of 848 patients were included (28% females, mean age 63.8, 51% persistent AF). By automated PRO, significant improvement in QoL was noted (baseline median AFSSS of 12 [5-18] and ranged between 2 and 4 on subsequent assessments; p < .0001), with ≥70%of patients reported remarkable improvement in their AF-related symptoms. The proportion of patients in AF at the time of baseline survey was 36%, and this decreased to <8% across all time points during follow-up (p < .0001). AF burden was significantly reduced (including frequency and duration of episodes; p < .0001), with an associated decrease in healthcare utilization after 6 months from the time of ablation (including ER visits and hospitalizations; p < .0001). The proportion of patients on anticoagulants or antiarrhythmics decreased on follow-up across all time points (p < .0001 for all variables). CONCLUSION: Most patients derive significant QoL benefit from redo AF ablation; with reduction of both AF burden and healthcare utilization.

Outcomes of atrial fibrillation ablation in patients with or without silent pulmonary veins from prior ablation procedure.

INTRODUCTION: Pulmonary venous (PV) electrical recovery underlies most arrhythmia recurrences after atrial fibrillation (AF) ablation. Little is known about procedural profiles and outcomes of patients with electrically silent PVs upon redo ablation for AF. METHODS: In a prospectively maintained registry, we enrolled 838 consecutive patients (2013-2016) undergoing redo ablation procedures. Ablation procedures targeted the PVs, the PV antra, and non-PV sites at operators' discretion. Procedural profiles and clinical outcomes were assessed. The primary outcome was freedom from AF after a 3-month blanking period. The secondary outcome was improvement in quality of life. RESULTS: Most patients undergoing redo AF ablation (n = 684, 82%) had PV reconnection while the remaining 154 (18%) had electrically silent PVs. Patients with recurrent AF and electrically silent PVs were older (66 vs. 64 years, p = .02), had more prior ablation procedures (median 2 IQR 1-3 vs 1 IQR 1-2 p = .001), were more likely to have non-paroxysmal AF (62% vs. 49%, p = .004) and atrial flutter (48% vs. 29%, p = .001) and had significantly larger left atrial volumes (89 vs. 81 ml, p = .003). Patients with silent PVs underwent a more extensive non-PV ablation strategies with antral extension of prior ablation sets in addition to ablation of the roof, appendage, inferior to the right PVs, peri-mitral flutter lines, cavotricuspid isthmus lines and ablation in the coronary sinus. Upon one year of follow-up, patients with electrically silent PVs were less likely to remain free from recurrent atrial arrhythmias (64% vs. 76%, p = .008). Regardless of PV reconnection status, redo ablation resulted in improvement in quality of life. CONCLUSION: Rhythm control with extensive ablation allowed maintenance of sinus rhythm in about two thirds of patients with silent PVs during redo AF ablation procedures. Regardless of PV reconnection status, redo ablation resulted in improvement in quality of life. This remains a challenging group of patients, highlighting the need to better understand non-PV mediated AF.

Super and Nonresponders to Catheter Ablation for Atrial Fibrillation: A Quality-of-Life Assessment Using Patient Reported Outcomes.

[Figure: see text].

The utility of a novel mapping algorithm utilizing vectors and global pattern of propagation for scar-related atrial tachycardias.

BACKGROUND: Activation maps of scar-related atrial tachycardias (AT) can be challenging to interpret due to difficulty in inaccurate annotation of electrograms, and an arbitrarily predefined mapping window. A novel mapping software integrating vector data and applying an algorithmic solution taking into consideration global activation pattern has been recently described (Coherent™, Biosense Webster "Investigational"). OBJECTIVE: We aimed to assess the investigational algorithm to determine the mechanism of AT compared with the standard algorithm. METHODS: This study included patients who underwent ablation of scar-related AT using the Carto 3 and the standard activation algorithm. The mapping data were analyzed retrospectively using the investigational algorithm, and the mechanisms were evaluated by two independent electrophysiologists. RESULTS: A total of 77 scar-related AT activation maps were analyzed (89.6% left atrium, median tachycardia cycle length of 273 ms). Of those, 67 cases with a confirmed mechanism of arrhythmia were used to compare the activation software. The actual mechanism of the arrhythmia was more likely to be identified with the investigational algorithm (67.2% vs. 44.8%, p = .009). In five patients with dual-loop circuits, 3/5 (60%) were correctly identified by the investigational algorithm compared to 0/5 (0%) with the standard software. The reduced atrial voltage was prone to lead to less capable identification of mechanism (p for trend: .05). The investigational algorithm showed higher inter-reviewer agreement (Cohen's kappa .62 vs. .47). CONCLUSIONS: In patients with scar-related ATs, activation mapping algorithms integrating vector data and "best-fit" propagation solution may help in identifying the mechanism and the successful site of termination.

Atrial fibrillation future clinic. Novel platform to integrate smart device electrocardiogram into clinical practice.

Background: Direct-to-consumer devices allow patients to record electrocardiograms (ECG) and detect atrial fibrillation (AF). Clinical adoption of these devices has been limited owing to the lack of efficient workflow. Objective: To assess a new care model for following patients after AF ablation that uses a smartphone ECG coupled with a novel cloud-based platform. Methods: This was a pilot study to describe AF detection, healthcare utilization, use of additional ECGs and cardiac monitors, and changes in anxiety after AF ablation. Patients presenting 3-4 months after early successful AF ablation were randomized into a control group with standard clinical follow-up or a self-monitoring group using smartphone ECG (Kardia Mobile, KM) coupled with a cloud-based platform (KardiaPro, KP) that alerted the physician when AF was detected and followed for 6 months. Results: A total of 100 patients were randomized: 51 to the KM/KP group and 48 to the control group (1 withdrew). AF was detected in 18 patients (18.2%), 11 (21.6%) in the KM/KP group and 7 (14.6%) in the control group (P = .42). AF detection occurred at a median of 68 and 91 days in the KM/KP and control groups, respectively (P = .93). These differences were not statistically significant. Healthcare utilization and changes in anxiety were similar between the groups. More patients required additional ECGs or cardiac monitors in the control group (27.1%) compared to the KM/KP group (5.9%) (P = .004). Conclusions: Smartphone ECG with a cloud-based platform can be incorporated into the care of post-AF ablation patients without increasing anxiety and with less need for additional traditional monitors.

Ablation of Atrial Fibrillation Without Left Atrial Appendage Imaging in Patients Treated With Direct Oral Anticoagulants.

BACKGROUND: Many centers continue to routinely perform transesophageal echocardiograms before atrial fibrillation (AF) ablation procedures in patients treated with direct oral anticoagulants (DOACs). One study suggested that the procedures could be done without transesophageal echocardiogram but used intracardiac echocardiography imaging of the appendage from the right ventricular outflow. This study aimed to assess the safety of ablation for AF without transesophageal echocardiogram screening or intracardiac echocardiography imaging of the appendage in DOAC compliant patients. METHODS: All patients undergoing AF ablation at the Cleveland Clinic (2011-2018) were enrolled in a prospectively maintained data registry. All consecutive patients presenting with AF or atrial flutter on DOAC were included. Periprocedural thromboembolic complications were assessed. RESULTS: A total of 900 patients were included. Their median CHA2DS2-VASc score was 2 (interquartile range 1-3). All were on DOACs (333 rivaroxaban, 285 dabigatran, 281 apixaban, and 1 edoxaban). Thromboembolic complications occurred in 4 patients (0.3%): 2 ischemic strokes, 1 transient ischemic attack without residual deficit, and 1 splenic infarct; all with no further complications. Bleeding complications occurred in 5 patients (0.4%): 2 pericardial effusions (1 intraoperative, 1 after 30 days, both drained), 3 groin hematomas (1 of them due to needing heparin for venous thrombosis, none required interventions). No patients required emergent surgeries. CONCLUSIONS: In DOAC compliant patients who present for ablation in AF/atrial flutter, the procedures could be performed without transesophageal echocardiogram screening or intracardiac echocardiography imaging of the appendage; with low risk of complications.

Clinical Outcomes and Characteristics With Dofetilide in Atrial Fibrillation Patients Considered for Implantable Cardioverter-Defibrillator.

BACKGROUND: Dofetilide is one of the only anti-arrhythmic agents approved for atrial fibrillation (AF) in patients with reduced left ventricular ejection fraction (LVEF). However, postapproval data and safety outcomes are limited. In this study, we assessed the incidence and predictors of LVEF improvement, safety, and outcomes in patients with AF with LVEF ≤35% without prior implantable cardioverter defibrillator, cardiac resynchronization therapy, or AF ablation. METHODS: An analysis of 168 consecutive patients from 2007 to 2016 was performed. Incidences of adverse events, drug continuation, implantable cardioverter defibrillator and cardiac resynchronization therapy implantation, LVEF improvement (>35%) and recovery (≥50%), AF recurrence, and AF ablation were determined. Multivariable regression analysis to identify predictors of LVEF improvement/recovery was performed. RESULTS: The mean age was 64±12 years. Dofetilide was discontinued before hospital discharge in 46 (27%) because of QT prolongation (14%), torsades de pointe or polymorphic ventricular tachycardia/fibrillation (6% [sustained 3%, nonsustained 3%]), ineffectiveness (5%), or other causes (3%). At 1 year, 43% remained on dofetilide. Freedom from AF was 42% at 1 year, and 40% underwent future AF ablation. LVEF recovered (≥50%) in 45% and improved to >35% in 73%. Predictors of LVEF improvement included presence of AF during echocardiogram (odds ratio, 4.22 [95% CI, 1.71-10.4], P=0.002), coronary artery disease (odds ratio, 0.35 [95% CI, 0.16-0.79], P=0.01), left atrial diameter (odds ratio, 0.52 per 1 cm increase [95% CI, 0.30-0.90], P=0.01), and LVEF (odds ratio, per 1% increase, 1.09 [95% CI, 1.02-1.16], P=0.006). The C statistic was 0.78. CONCLUSIONS: In patients with LVEF ≤35%, who are potential implantable cardioverter defibrillator candidates, treated with dofetilide as an initial anti-arrhythmic strategy for AF, drug discontinuation rates were high, and many underwent future AF ablation. However, most patients had improvement in LVEF, obviating the need for primary prevention implantable cardioverter defibrillator.

Use of virtual visits for the care of the arrhythmia patient.

BACKGROUND: Virtual visits (VVs) are a modality for delivering health care services remotely through videoconferencing tools. Data about patient and physician experience in using VVs are limited. OBJECTIVE: The purpose of this study was to assess patient and physician experience with the use of VVs in cardiac electrophysiology. METHODS: We performed a prospective survey of cardiac electrophysiology patients and physicians who participated in an outpatient VV from December 2018 to July 2019. RESULTS: One-hundred consecutive VVs were included. Sixty-four patients elected to complete a survey. Patients rated their experience as either excellent/very good in scheduling a VV (87%), seeing their physician of choice (100%), transmitting arrhythmia data (88%), rating their physician's ability to communicate (98%), asking all questions (98%), rating the level of care received (98%), paying for the cost of a VV (67%), and rating their overall level of satisfaction (98%). Thirty-eight of 64 patients (59.4%) preferred a VV for their next visit, 12 of 64 (18.8%) preferred an in-office visit, 13 of 64 (20.3%) responded that their decision for a virtual or office visit depended on indication, and 1 of 64 (1.6%) had no preference. A total of 14 cardiac electrophysiologists participated in 100 VVs. Nine visits were not included due to technical difficulty. Physician responses to survey questions were rated as excellent/very good in the ability to communicate (92%), accessing monitoring data (95%), and overall level of satisfaction (98%). CONCLUSION: In our small study population, most patients and physicians prefer VVs. Convenience, cost, and reason for follow-up were important determinants that affected both patient and physician preference.

Proarrhythmic effects from competitive atrial pacing and potential programming solutions.

BACKGROUND: Programmed long AV delays and intrinsic long first degree AV block may increase risk for competitive atrial pacing (CAP) in devices without CAP avoidance algorithms. METHODS: Patients identified with CAP-induced mode switch episodes were followed clinically from September 2013 to August 2019. Attempts to avoid CAP included shortening of postventricular atrial refractory period (PVARP) or postventricular atrial blanking period (PVAB), or change to AAI or DDI modes. After observing associations with sensor-driven pacing, rate response was inactivated in a subset. RESULTS: Among 23 patients identified with CAP (22 St Jude Medical [Abbott]; one Boston Scientific Corporation devices), atrial fibrillation (AF) was induced in 12 (52%), lasting 10 seconds to 28 hours and 32 minutes. In one patient with an ICD CAP-induced AF with rapid ventricular rates that triggered a shock, inducing ventricular fibrillation, syncope, and another shock. Changing AV delays and shortening of PVARP failed to resolve CAP. After noting that all had CAP during sensor-driven pacing, rate response was inactivated in seven, resolving further device-induced AF in the three of seven that had prior CAP-induced AF. In two patients with intact AV conduction, AAI(R) pacing resolved further documentation of CAP. CONCLUSIONS: CAP predominantly occurs during sensor-driven atrial pacing that competes with intrinsic atrial events falling in PVARP. Inactivation of the activity sensor or change to atrial-based pacing modes (AAI/R) appears to effectively prevent induction of device-induced atrial proarrhythmia. Ultimately, a corrective algorithm is needed to avoid CAP-induced proarrhythmia.

Catheter Ablation in Patients With Cardiogenic Shock and Refractory Ventricular Tachycardia.

BACKGROUND: There is paucity of data regarding radiofrequency ablation for ventricular tachycardia (VT) in patients with cardiogenic shock and concomitant VT refractory to antiarrhythmic drugs on mechanical support. METHODS: Patients undergoing VT ablation at our center were enrolled in a prospectively maintained registry and screened for the current study (2010-2017). RESULTS: All 21 consecutive patients with cardiogenic shock and concomitant refractory ventricular arrhythmia undergoing bailout ablation due to inability to wean off mechanical support were included. Median age was 61 years, 86% were men, median left ventricular ejection fraction was 20%, 81% had ischemic cardiomyopathy, and PAINESD score was 18±5. The type of mechanical support in place before the procedure was intra-aortic balloon pump in 14 patients (67%), Impella CP in 2, extracorporeal membrane oxygenation in 2, extracorporeal membrane oxygenation and intra-aortic balloon pump in 2, and extracorporeal membrane oxygenation and Impella CP in 1. Endocardial voltage maps showed myocardial scar in 19 patients (90%). The clinical VTs were inducible in 13 patients (62%), whereas 6 patients had premature ventricular contraction-induced ventricular fibrillation/VT (29%), and VT could not be induced in 2 patients (9%). Activation mapping was possible in all 13 with inducible clinical VTs. Substrate modification was performed in 15 patients with scar (79%). After ablation and scar modification, the arrhythmia was noninducible in 19 patients (91%). Seventeen (81%) were eventually weaned off mechanical support successfully, but 6 (29%) died during the index admission from persistent cardiogenic shock. Patients who had ventricular arrhythmia and cardiogenic shock on presentation had a trend toward lower in-hospital mortality compared with those who presented with cardiogenic shock and later developed ventricular arrhythmia. CONCLUSIONS: Bailout ablation for refractory ventricular arrhythmia in cardiogenic shock allowed successful weaning from mechanical support in a large proportion of patients. Mortality remains high, but the majority of patients were discharged home and survived beyond 1 year.

Cardiac venous injuries: Procedural profiles and outcomes during left ventricular lead placement for cardiac resynchronization therapy.

BACKGROUND: Injury to the cardiac venous structures can complicate left ventricular lead placement for cardiac resynchronization therapy (CRT). Little is known about the outcomes of coronary sinus (CS) dissection with or without perforation. OBJECTIVE: The purpose of this study was to determine the outcomes in patients who had a CS injury during CRT implantation. METHODS: All patients undergoing procedures for CRT implantation at the Cleveland Clinic (2001-2018) were enrolled in a prospectively maintained registry for procedural profiles and complications. All patients with cardiac venous injuries during the procedures were included. RESULTS: CS injury occurred in 35 of 5011 patients (0.7%; 6 perforations (17.1%), 29 dissections without perforation (82.9%)). In patients with dissection in the absence of perforation, attempts at CS lead placement after dissection were successful in 21 of 29 patients (72.4%). In those with perforation (n=6, 17.1%), CS lead placement was successful in one of them (16.7%). Cardiac tamponade occurred in 2 patients (5.7%), and the procedure was aborted in both of them. Overall, CS lead placement failed in 13 patients (37%) but 9 (25.7%) underwent subsequent CRT with CS lead placement (n=6, 17.1%; median 58 days later) or epicardial leads (n=3, 8.6%). Three of the remaining 4 patients (8.6%) refused to undergo further procedures, and the fourth (2.9%) died of a complicated course. CONCLUSION: CS injury is not common during CRT implantation procedures and did not preclude successful lead placement in 23 of 35 patients (65.7%) during the index procedure and 6 of 6 (100%) during the subsequent attempted procedures. A low rate of mortality was observed in such patients, but CS injury was associated with increased morbidity.