Appropriateness of implantable cardioverter-defibrillator device implants in the United States.

BACKGROUND: The appropriate use criteria (AUCs) are a diverse group of indications aimed to better evaluate the benefits of implantable cardioverter-defibrillator (ICD) and cardiac resynchronization therapy. OBJECTIVE: The purpose of this study was to quantify the proportion of ICD and cardiac resynchronization therapy with defibrillator (CRT-D) implants as appropriate, may be appropriate (MA), or rarely appropriate (RA) on the basis of the AUC guidelines. METHODS: This is a multicenter retrospective study of patients within the National Cardiovascular Data Registry undergoing ICD implantation between April 2018 and March 2019 at >1500 US hospitals. The appropriateness of ICD implants was adjudicated using the AUC. RESULTS: Of 309,318 ICDs, 241,438 were primary prevention implants (78.1%) and 67,880 secondary prevention implants (21.9%); 243,532 (79%) were mappable to the AUC. For primary prevention, 185,431 ICDs (96.4%) were appropriate, 5660 (2.9%) MA, and 1205 (0.6%) RA. For secondary prevention, 47,498 ICDs (92.7%) were appropriate, 2581 (5%) MA, and 1157 (2.3%) RA. A significant number of RA devices were implanted in patients with New York Heart Association class IV heart failure who were ineligible for advanced therapies (53.9%) and those with myocardial infarction within 40 days (18.1%). The appropriateness of the pacing lead was more variable, with 48,470 dual-chamber ICD implants (62%) being classified as appropriate, 29,209 (37.4%) MA, and 448 (0.6%) RA. Among CRT-D implants, 63,848 (82.2%) were appropriate, 9900 (12.7%) MA, and 3940 (5.1%) RA for left ventricular pacing. A total of 99,754 implants were deemed appropriate but excluded from Centers for Medicare & Medicaid Services National Coverage Determination. More than 92% of hospitals had an RA implant rate of <4%. CONCLUSION: In this large national registry, 95% of mappable ICD and CRT-D implants were considered appropriate, with <2% of RA implants. Nearly 100,000 appropriate implants are excluded by Centers for Medicare & Medicaid Services National Coverage Determination.

A new machine learning approach for predicting likelihood of recurrence following ablation for atrial fibrillation from CT.

OBJECTIVE: To investigate left atrial shape differences on CT scans of atrial fibrillation (AF) patients with (AF+) versus without (AF-) post-ablation recurrence and whether these shape differences predict AF recurrence. METHODS: This retrospective study included 68 AF patients who had pre-catheter ablation cardiac CT scans with contrast. AF recurrence was defined at 1 year, excluding a 3-month post-ablation blanking period. After creating atlases of atrial models from segmented AF+ and AF- CT images, an atlas-based implicit shape differentiation method was used to identify surface of interest (SOI). After registering the SOI to each patient model, statistics of the deformation on the SOI were used to create shape descriptors. The performance in predicting AF recurrence using shape features at and outside the SOI and eight clinical factors (age, sex, left atrial volume, left ventricular ejection fraction, body mass index, sinus rhythm, and AF type [persistent vs paroxysmal], catheter-ablation type [Cryoablation vs Irrigated RF]) were compared using 100 runs of fivefold cross validation. RESULTS: Differences in atrial shape were found surrounding the pulmonary vein ostia and the base of the left atrial appendage. In the prediction of AF recurrence, the area under the receiver-operating characteristics curve (AUC) was 0.67 for shape features from the SOI, 0.58 for shape features outside the SOI, 0.71 for the clinical parameters, and 0.78 combining shape and clinical features. CONCLUSION: Differences in left atrial shape were identified between AF recurrent and non-recurrent patients using pre-procedure CT scans. New radiomic features corresponding to the differences in shape were found to predict post-ablation AF recurrence.

Outcomes of Pulmonary Vein Isolation in Athletes.

OBJECTIVES: The aims of this study were to assess outcomes of pulmonary vein isolation (PVI) performed on athletes at a tertiary care center and to characterize its efficacy and physiological effects. BACKGROUND: The incidence of atrial fibrillation (AF) is increased in highly trained athletes and poses unique management challenges. METHODS: Athletes were identified through a database of patients undergoing PVI from January 2000 through October 2015. Outcomes of AF ablation were defined in accordance with published guidelines. Available electrocardiographic, echocardiographic, and exercise treadmill testing data were also analyzed. RESULTS: The study population included 144 athletes (93% men; mean age 50.4 ± 8.6 years; 97 paroxysmal, 38 persistent, and 9 long-standing persistent) with median follow-up of 3 years. Single-procedure freedom from arrhythmia was 75%, 68%, and 33% at 1 year for paroxysmal, persistent, and long-standing persistent AF, respectively. Multiple-procedure freedom from arrhythmia off antiarrhythmic drugs was 86%, 76%, and 56% in respective groups at the end of follow-up (mean 1.4 ± 0.7 ablations per athlete). Compared with a matched cohort of nonathletes who underwent PVI, there was no difference in arrhythmia recurrence (log-rank p = 0.23). Excluding long-standing persistent AF, longer diagnosis-to-ablation time was the only variable in Cox proportional hazards analyses associated with arrhythmia recurrence (adjusted heart rate per log increase: 1.92; 95% confidence interval: 1.40 to 2.73; p < 0.0001), and PVI within 2 years of diagnosis was notably associated with successful outcomes (log-rank p = 0.002). Sinus rate increased following the index ablation (mean 54 beats/min vs. 64 beats/min at >1 year; p < 0.0001), but maximum metabolic equivalents on exercise treadmill testing were unchanged (13.1 ± 1.2 vs. 12.7 ± 1.4; p = 0.44). CONCLUSIONS: PVI is an effective therapy in athletes with paroxysmal and persistent AF, and arrhythmia recurrence was no different from that among matched nonathletes. Early ablation was associated with improved success rates. Sustained cardioautonomic effects were observed following ablation, but exercise capacity was preserved.

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.

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.

Left atrial appendage closure device implantation in patients at very high risk for stroke.

BACKGROUND: Little is known about the role of left atrial appendage closure using the Watchman device (Boston Scientific) in patients who are at very high risk for stroke. OBJECTIVE: The purpose of this study was to assess the role of Watchman in patients with CHA2DS2-VASc ≥5. METHODS: All patients undergoing procedures for Watchman implant at our institution were enrolled in a prospective registry. All 104 consecutive recipients with CHA2DS2-VASc ≥5 were included. RESULTS: Median patient age was 78.5 ± 6.4 years, 56% were male, mean CHA2DS2-VASc was 5.7 ± 0.9, and mean HASBLED was 4.0 ± 1.0. Indications for implantation were significant prior bleeding (73%), unacceptable bleeding risk (21%), and unacceptable stroke and bleeding risk (6%). Watchman implantation was successful in all patients. All but 2 patients completed 45 days of postprocedural anticoagulation; 56% used warfarin and 44% used a novel oral anticoagulant. Transesophageal echocardiogram at 45 days revealed no significant peridevice leak. One patient was found to have a small mobile, filamentous echodensity attached on the medial aspect of the Watchman device. This resolved with longer anticoagulation with dabigatran and did not result in adverse outcome. At 1-year follow up, ischemic stroke had occurred in 3 patients (2.8%) at 96, 119, and 276 days after the procedure. CONCLUSION: In a population of patients with mean CHA2DS2-VASc of 5.7, Watchman implantation seemed to be safe and efficacious, with a residual annual ischemic stroke risk of 2.8%. In an atrial fibrillation population with a similar CHA2DS2-VASc score, the estimated annual risk of stroke is ≈12% off anticoagulation and >4% on warfarin.

A fast score test for generalized mixture models.

In biomedical studies, testing for homogeneity between two groups, where one group is modeled by mixture models, is often of great interest. This paper considers the semiparametric exponential family mixture model proposed by Hong et al. (2017) and studies the score test for homogeneity under this model. The score test is nonregular in the sense that nuisance parameters disappear under the null hypothesis. To address this difficulty, we propose a modification of the score test, so that the resulting test enjoys the Wilks phenomenon. In finite samples, we show that with fixed nuisance parameters the score test is locally most powerful. In large samples, we establish the asymptotic power functions under two types of local alternative hypotheses. Our simulation studies illustrate that the proposed score test is powerful and computationally fast. We apply the proposed score test to an UK ovarian cancer DNA methylation data for identification of differentially methylated CpG sites.

Outcomes of Atrial Fibrillation Ablation in Morbidly Obese Patients Following Bariatric Surgery Compared With a Nonobese Cohort.

BACKGROUND: Morbid obesity is associated with unacceptable high recurrence rates following atrial fibrillation ablation. The role of risk-factor modification including weight loss and improved glycemic control in reducing arrhythmia recurrence following ablation has been highlighted in recent years. In this study, we compared arrhythmia recurrence rates in morbidly obese patients who underwent prior bariatric surgery (BS) with those of nonobese patients following atrial fibrillation ablation in addition to morbidly obese patients who did not undergo BS. METHODS: This was a single-center observational cohort study. We matched 51 morbidly obese patients [body mass index ≥40 kg/m2] who had undergone prior BS in a 2:1 manner with 102 nonobese patients and 102 morbidly obese patients without prior BS on the basis of age, sex, and timing of atrial fibrillation ablation. Our primary outcome of interest was arrhythmia recurrence. RESULTS: From the time of BS to ablation, BS was associated with a significant reduction in body mass index (47.6±9.3 to 36.7±7; P<0.0001), glycated hemoglobin (6.7±1.5 to 5.8±0.6; P<0.0001), and systolic blood pressure (145±13 to 118±11; P<0.0001). During a mean follow-up of 29±13 months following ablation, recurrent arrhythmia occurred in 10/51 (20%) patients in the BS group compared with 25/102 (24.5%) patients in the nonobese group and 56 (55%) patients in the non-BS morbidly obese group (P<0.0001). No procedural complications were observed in the BS group. CONCLUSIONS: Bariatric surgery is associated with a reduction in arrhythmia recurrence following atrial fibrillation ablation in morbidly obese patients to those of nonobese patients. Morbidly obese patients should be considered for BS before atrial fibrillation ablation.

Indication-specific event rates among hospitalized patients undergoing continuous cardiac monitoring.

BACKGROUND: Cardiac telemetry monitoring is widely utilized for a variety of clinical indications, yet indication-specific event rates for monitored patients are seldomly reported. HYPOTHESIS: High-risk hospitalized patients for clinical deterioration can be identified using standardized telemetry monitoring indications. METHODS: Adjudicated data from events triggering emergency response team (ERT) activation were systematically characterized at the Cleveland Clinic from among standardized telemetry indications ordered over a 13-month period. RESULTS: Among 72 199 orders created for telemetry monitored patients, ERT activation occurred in 2677 patients (3.7%), of which 1326 (49.5%) were cardiac-related. Patients with deep venous thrombosis or pulmonary embolism (DVT/PE) demonstrated the highest overall event rate (ERT: n = 41 of 593 pts [6.9%]; 25/41 cardiac related [61%]). Cardiac-related events were proportionally highest among patients with coronary disease awaiting revascularization (ERT: n = 19 of 847 patients [2.2%]; 13/19 cardiac-related [68.4%]). Arrhythmia-specific events were highest among patients who underwent cardiac surgery (n = 78 of 193 cardiac-related ERT [40.4%]), and patients with known or suspected tachyarrhythmias (n = 318 of 788 cardiac-related ERT [40.4%]). Bubble plot analysis identified patients hospitalized with DVT/PE, drug or alcohol exposures, and acute coronary syndrome as among the highest overall and cardiac-related events while identifying patients with respiratory disorder monitoring indications as carrying the highest noncardiac event rate. CONCLUSION: High-risk hospitalized patients can be identified by telemetry indication and prioritized according to concerns for cardiac, arrhythmia-specific and noncardiac clinical deterioration. This is particularly useful when monitored bed resources are constrained.

Transvenous Lead Extraction in Patients With Arrhythmogenic Right Ventricular Cardiomyopathy.

OBJECTIVES: This study aimed to evaluate the effectiveness and safety of transvenous lead extraction (TLE) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). BACKGROUND: ARVC is an increasingly diagnosed cardiomyopathy that often requires device implantation to prevent sudden death. Little is known about TLE in this setting, which has potential challenges and risks, primarily due to right ventricular (RV) wall thinning and fragility. METHODS: All consecutive patients with ARVC who underwent TLE at our institution between 1996 and 2016 were included. When extraction tools were used, sheaths were advanced to the RV with countertraction at the lead tip. Success and complications were defined in concordance with Heart Rhythm Society guidelines. RESULTS: Twenty-two TLE procedures in patients with ARVC involved extraction of 27 leads (22 defibrillators and 5 pacemakers). TLEs were performed due to evidence of lead malfunction (n = 17; 77%) or device infection (n = 5; 23%). Twenty-four leads (89%) were RV, and 3 leads (11%) were right atrial. The median age of the oldest extracted lead was 1,691 days (interquartile range [IQR]: 1,168 to 2,726 days). Specialized extraction tools were required in 20 procedures (91%). None required the use of a snare or a femoral workstation. The median procedural and fluoroscopic times were 152 min (IQR: 129 to 185 min) and 11 min (IQR: 6 to 18 min), respectively. Complete procedural success with removal of all leads was achieved in all cases. There were no major complications. CONCLUSIONS: In a high-volume center, TLE in patients with ARVC was associated with a high success rate and a low rate of complications when guideline-established techniques and tools were used.

New Model of Automated Patient-Reported Outcomes Applied in Atrial Fibrillation.

Background The value of patient-reported outcomes (PRO) is increasingly recognized in patient-centered care. Longitudinal data collection may be challenging and cost prohibitive. Automation of PRO collection may complement routine clinical follow-up, especially for procedures aiming to improve quality of life, such as atrial fibrillation (AF) ablation. Methods We aimed to develop a fully automated platform to collect PRO and evaluate its first clinical application in a prospective cohort of AF ablation. The duration of follow-up and data availability were assessed with automated PRO and routine follow-up versus routine follow-up alone (primary outcome). Quality of life and healthcare utilization (secondary outcomes) by PRO were assessed. Results Between 2013 and 2016, 2175 patients were eligible to receive 10 903 PRO assessment invitations, and the automated platform sent all invitations as programmed. More follow-up assessments were obtained with automated PRO and routine follow-up compared with routine follow-up alone (12 859 versus 10 248; P<0.0001) which allowed longer duration of follow-up (378 versus 217 days, 74% increase; P<0.0001). By automated PRO, a large number of disease-specific variables were collected and showed improvement in quality of life (baseline median AF symptom severity score AFSSS of 12 [6-18] and ranged between 2 and 3 on subsequent assessments; P<0.0001). This improvement was also true for each of the AFSSS individual components ( P<0.0001). In PRO, there was a significant reduction in AF burden (such as frequency and duration of episodes; P<0.0001) and associated healthcare utilization (including emergency visits and hospitalizations; P<0.0001) after the ablation procedures. Conclusions A fully automated system for PRO collection enhanced clinical follow-up and allowed collection of disease-specific data when applied in a prospective cohort of AF ablation.

Life-Threatening Complications of Atrial Fibrillation Ablation: 16-Year Experience in a Large Prospective Tertiary Care Cohort.

OBJECTIVES: This study sought to assess the incidence and outcomes of life-threatening complications from atrial fibrillation ablations in a high volume center. BACKGROUND: With increasing rates of atrial fibrillation ablation procedures, an increase in life-threatening procedure-related complications has been reported despite improvements in technology and ablation strategies. METHODS: Between 2000 and 2015, 10,378 patients underwent atrial fibrillation ablation at our institution and were enrolled in a prospectively maintained data registry. We identified all patients who had life-threatening cardiac, neurological, respiratory, or vascular complications to the ablation resulting in death or requiring emergent intervention. RESULTS: Major life-threatening complications occurred in 100 patients (0.9%). The most common was pericardial effusion requiring pericardiocentesis (0.5%), with 7 (0.07%) requiring emergent surgical repair for cardiac perforation. Stroke occurred in 27 patients (0.3%) with a vast majority having an ischemic stroke (93%) followed by hemorrhagic (3.5%) and ischemic stroke with hemorrhagic conversion (3.5%). The yearly incidence of stroke decreased from an average of 1.1% per year in the first tertile (2000 to 2004) to 0.2% per year in the last 2 tertiles (2005 to 2015). Permanent neurological deficits occurred in 23 patients. Vascular complications causing hemorrhagic shock occurred in 7 patients (0.06%), 5 of whom required urgent surgical intervention. Acute coronary syndrome requiring urgent percutaneous coronary revascularization occurred in 2 patients whereas 1 developed a right coronary artery air embolus. No procedural death or atrio-esophageal fistulae occurred. CONCLUSIONS: In a large quaternary care center, the incidence of life-threatening complications is low. Experienced operators, high volume, continuous quality improvement initiatives, and efficient back-up support have allowed exemplary safety profiles and 0 procedure-related deaths over 16 years.

ACC/AATS/AHA/ASE/ASNC/HRS/SCAI/SCCT/SCMR/STS 2019 Appropriate Use Criteria for Multimodality Imaging in the Assessment of Cardiac Structure and Function in Nonvalvular Heart Disease: A Report of the American College of Cardiology Appropriate Use Criteria Task Force, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and the Society of Thoracic Surgeons.

This document is the second of 2 companion appropriate use criteria (AUC) documents developed by the American College of Cardiology, American Association for Thoracic Surgery, American Heart Association, American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, Society of Cardiovascular Computed Tomography, Society for Cardiovascular Magnetic Resonance, and Society of Thoracic Surgeons. The first document1 addresses the evaluation and use of multimodality imaging in the diagnosis and management of valvular heart disease, whereas this document addresses this topic with regard to structural (nonvalvular) heart disease. While dealing with different subjects, the 2 documents do share a common structure and feature some clinical overlap. The goal of the companion AUC documents is to provide a comprehensive resource for multimodality imaging in the context of structural and valvular heart disease, encompassing multiple imaging modalities. Using standardized methodology, the clinical scenarios (indications) were developed by a diverse writing group to represent patient presentations encountered in everyday practice and included common applications and anticipated uses. Where appropriate, the scenarios were developed on the basis of the most current American College of Cardiology/American Heart Association Clinical Practice Guidelines. A separate, independent rating panel scored the 102 clinical scenarios in this document on a scale of 1 to 9. Scores of 7 to 9 indicate that a modality is considered appropriate for the clinical scenario presented. Midrange scores of 4 to 6 indicate that a modality may be appropriate for the clinical scenario, and scores of 1 to 3 indicate that a modality is considered rarely appropriate for the clinical scenario. The primary objective of the AUC is to provide a framework for the assessment of these scenarios by practices that will improve and standardize physician decision making. AUC publications reflect an ongoing effort by the American College of Cardiology to critically and systematically create, review, and categorize clinical situations in which diagnostic tests and procedures are utilized by physicians caring for patients with cardiovascular diseases. The process is based on the current understanding of the technical capabilities of the imaging modalities examined.

Occupational and patient radiation doses in a modern cardiac electrophysiology laboratory.

PURPOSE: Technological advancements have greatly expanded the field of cardiac electrophysiology, requiring greater demands on imaging systems and potentially delivering higher radiation doses to patients and operators. With little contemporary research on occupational and patient radiation risk in the electrophysiology laboratory, the aim of this study was to analyze radiation doses, including occupational fetal doses, over approximately the last decade. We benchmarked the occupational data to our patient radiation dose data to allow for comparison and to put into perspective the associated radiation risks. METHODS: Occupational radiation dosimetry analyzed included data from an 11-year period for physicians, a 7-year period for nurses, and a 9-year period for fetal doses. Patient-related dose metrics over an 8-year period were also analyzed. RESULTS: In the physician and nursing groups, there was a nearly 70% decrease in the average occupational radiation doses over the given periods. Within the electrophysiology department, the average fetal occupational doses were very low, close to 0 µSv. The average reference point air kerma per patient for all electrophysiology procedures decreased from nearly 600 mGy/procedure in 2010 to just over 100 mGy/procedure in 2017. CONCLUSIONS: Patient and occupational radiation doses in our laboratories significantly decreased over the periods analyzed as a result of clinical and technical staff efforts as well as advances in imaging technology. The radiation-related risk to individuals working in our electrophysiology laboratories, including pregnant women, is very low. Data reported herein could be used by other institutions to evaluate their occupational and patient radiation safety practices.

Clinical presentation of ventricular-Hisian and ventricular-nodal accessory pathways.

BACKGROUND: Narrow QRS tachycardia or premature beat with bystander atrial activation or ventricular-atrial dissociation is an unusual arrhythmia that can present diagnostic and therapeutic challenges. When ventricular-atrial conduction is robust, these arrhythmias can be difficult to distinguish from atrioventricular nodal reentry. OBJECTIVE: The purpose of this study was to describe the electrophysiology characteristics, diagnostic maneuvers, and treatment of these types of arrhythmias in a series of 7 cases. METHODS: Standard multipolar recording and pacing electrodes were used during electrophysiology studies. Catheter ablation was performed using radiofrequency or cryoenergy. RESULTS: During electrophysiology studies, ventricular-nodal or ventricular-Hisian conducting pathways were demonstrated to be responsible for the arrhythmias in all 7 cases. Successful ablation of these pathways using radiofrequency energy was accomplished in 6 of the 7 cases. CONCLUSION: Ventricular-Hisian and ventricular-nodal associated tachyarrhythmias should be distinguished from typical forms of atrioventricular nodal reentrant tachycardia. Catheter ablation of these pathways can be successfully accomplished using mapping techniques described in our report.

Left atrial appendage closure device implantation in patients with prior intracranial hemorrhage.

BACKGROUND: The Watchman device (Boston Scientific), used for left atrial appendage closure (LAAC), was approved for stroke prevention in patients with atrial fibrillation (AF) and an appropriate rationale to avoid long-term oral anticoagulation. Patients with AF and prior intracranial hemorrhage (ICH) were excluded from clinical trials because of perceived risks of perioperative anticoagulation. OBJECTIVE: The purpose of this study was to study the efficacy and safety of LAAC using Watchman in patients with AF and prior ICH. METHODS: In a multidisciplinary AF/stroke prevention clinic, 38 consecutive patients with AF and prior ICH underwent Watchman implantation. Patients were enrolled in a prospectively maintained data registry. RESULTS: Patients' mean CHA2DS2-VASc score was 5.0 ± 1.3 and HAS-BLED score 4.2 ± 1.0. Prior ICH events were intraparenchymal (60%), subdural (24%), or subarachnoid bleeds (16%). The median event-to-implantation time was 637 days (minimum 60). Watchman was implanted in all patients with no procedural complications. All patients completed 45 days of anticoagulation with warfarin (55%), apixaban (37%), or dabigatran (8%). Transesophageal echocardiograms at 45 days showed no peridevice leak, and 1 patient had a small filamentous echodensity on device that resolved with anticoagulation. While undergoing anticoagulation, none of the patients developed recurrent ICH. Minor bleeding occurred in 1 patient (trauma-related lower extremity hematoma at 19 days postimplantation). At 13.4 months (quartiles 8-19) of follow-up, there were no strokes, ICH, or deaths. CONCLUSION: AF patients with prior ICH tolerated short-term anticoagulation for the purpose of Watchman implantation. LAAC with attendant short-term anticoagulation seems to be both safe and effective in this patient population.