A Modular Communicative Leadless Pacing-Defibrillator System.

BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (ICD) is associated with fewer lead-related complications than a transvenous ICD; however, the subcutaneous ICD cannot provide bradycardia and antitachycardia pacing. Whether a modular pacing-defibrillator system comprising a leadless pacemaker in wireless communication with a subcutaneous ICD to provide antitachycardia and bradycardia pacing is safe remains unknown. METHODS: We conducted a multinational, single-group study that enrolled patients at risk for sudden death from ventricular arrhythmias and followed them for 6 months after implantation of a modular pacemaker-defibrillator system. The safety end point was freedom from leadless pacemaker-related major complications, evaluated against a performance goal of 86%. The two primary performance end points were successful communication between the pacemaker and the ICD (performance goal, 88%) and a pacing threshold of up to 2.0 V at a 0.4-msec pulse width (performance goal, 80%). RESULTS: We enrolled 293 patients, 162 of whom were in the 6-month end-point cohort and 151 of whom completed the 6-month follow-up period. The mean age of the patients was 60 years, 16.7% were women, and the mean (±SD) left ventricular ejection fraction was 33.1±12.6%. The percentage of patients who were free from leadless pacemaker-related major complications was 97.5%, which exceeded the prespecified performance goal. Wireless-device communication was successful in 98.8% of communication tests, which exceeded the prespecified goal. Of 151 patients, 147 (97.4%) had pacing thresholds of 2.0 V or less, which exceeded the prespecified goal. The percentage of episodes of arrhythmia that were successfully terminated by antitachycardia pacing was 61.3%, and there were no episodes for which antitachycardia pacing was not delivered owing to communication failure. Of 162 patients, 8 died (4.9%); none of the deaths were deemed to be related to arrhythmias or the implantation procedure. CONCLUSIONS: The leadless pacemaker in wireless communication with a subcutaneous ICD exceeded performance goals for freedom from major complications related to the leadless pacemaker, for communication between the leadless pacemaker and subcutaneous ICD, and for the percentage of patients with a pacing threshold up to 2.0 V at a 0.4-msec pulse width at 6 months. (Funded by Boston Scientific; MODULAR ATP ClinicalTrials.gov NCT04798768.).

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.

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.

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.

Antibiotic eluting envelopes: evidence, technology, and defining high-risk populations.

Cardiovascular implantable electronic devices (CIED) are effective and important components of modern cardiovascular care. Despite the dramatic improvements in the functionality and reliability of these devices, over time patients are at risk for developing several morbidities, the most feared of which are local and systemic infections. Despite significant financial investment and aggressive therapy with hospitalization, intravenous antibiotics, and transvenous lead extraction, the outcomes include a 1-year mortality rate as high as 25%. This risk of infection has increased over time, likely due to the increased complexity of the surgical interventions required to insert and replace these devices. The only way to reduce this morbidity and mortality is to prevent these infections, and other than preoperative antibiotics, there were little data supporting effective therapy until the WRAP-IT trial provided randomized data showing that pocket infections can be reduced by 60% at 12 months and major CIED infections reduced by 40% at 1 year with the use of the absorbable antibiotic eluting envelope in patient CIED procedures at high risk of infection. Not all CIED procedures are at high risk of infection and justify the use of the envelope, but cost-effectiveness data support the use of the antibiotic envelope particularly in patients with defibrillator replacements, revisions, and upgrades, such as to a resynchronization device and in patients with prior CIED infection, history of immunocompromise, two or more prior procedures, or a history of renal dysfunction.

Performance of diagnostic criteria in patients clinically judged to have cardiac sarcoidosis: Is it time to regroup?

BACKGROUND: The diagnosis of cardiac sarcoidosis (CS) is challenging. Because of the current limitations of endomyocardial biopsy as a reference standard, physicians rely on advanced cardiac imaging, multidisciplinary evaluation, and diagnostic criteria to diagnose CS. AIMS: To compare the 3 main available diagnostic criteria in patients clinically judged to have CS. METHODS: We prospectively included patients clinically judged to have CS by a multidisciplinary sarcoidosis team from November 2016 to October 2017. We included only incident cases (diagnosis of CS within 1 year of inclusion). We applied retrospectively the following diagnostic criteria: the World Association of Sarcoidosis and Other Granulomatous Diseases (WASOG), the Heart Rhythm Society (HRS), and the Japanese Circulation Society (JCS) 2016 criteria. RESULTS: We identified 69 patients. Diagnostic criteria classified patients as follows: WASOG as highly probable (1.4%), probable (52.2%), possible (0%), some criteria (40.6%), and no criteria (5.8%); HRS as histological diagnosis (1.4%), probable (52.2%), some criteria (40.6%), and no criteria (5.8%); JCS as histological diagnosis (1.4%), clinical diagnosis (58%), some criteria (39.1%), and no criteria (1.4%). Concordance was high between WASOG and HRS (κ = 1) but low between JCS and the others (κ = 0.326). CONCLUSIONS: A high proportion of patients clinically judged to have CS are unable to be classified according to the 3 main diagnostic criteria. There is low concordance between JCS criteria and the other 2 criteria (WASOG and HRS).

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.

Cardiac resynchronisation therapy in anthracycline-induced cardiomyopathy.

INTRODUCTION: Chemotherapy-induced cardiomyopathy has been increasingly recognised as patients are living longer with more effective treatments for their malignancies. Anthracyclines are known to cause left ventricular (LV) dysfunction. While heart failure medications are frequently used, some patients may need consideration for device-based therapies such as cardiac resynchronisation therapy (CRT). However, the role of CRT in anthracycline-induced cardiomyopathy (AIC) is not well understood. METHODS: We performed a retrospective review of all patients undergoing CRT implantation at our centre from 2003 to 2019 with a diagnosis of AIC. The LV remodelling and survival outcomes of this population were obtained and then compared with consecutive patients with other aetiologies of non-ischaemic cardiomyopathy (NICM). RESULTS: A total of 34 patients underwent CRT implantation with a diagnosis of AIC with a mean age of 60.5±12.7 years, left ventricular ejection fraction (LVEF) of 21.7%±7.4%, and 11.3±7.5 years and 10.2±7.4 years from cancer diagnosis and last anthracycline exposure, respectively. At 9.6±8.1 months after CRT implantation, there was an increase of LVEF from 21.8%±7.6% to 30.4%±13.0% (p<0.001). Patients whose LVEF increased by at least 10% post-CRT implant (42.5% of cohort) survived significantly longer than patients who failed to improve their LVEF by that amount (p=0.01). A propensity matched analysis between patients with AIC and 369 consecutive patients with other aetiologies of NICM who underwent CRT implantation during the same period revealed no significant differences in improvement in LVEF or long-term survival. CONCLUSIONS: Patients with AIC undergo LV remodelling with CRT at rates similar to other aetiologies of NICM. Furthermore, AIC post-CRT responders have a favourable long-term mortality compared with non-responders.

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

[Figure: see text].

Arrhythmias in Cardiac Sarcoidosis Bench to Bedside: A Case-Based Review.

Cardiac sarcoidosis is a component of an often multiorgan granulomatous disease of still uncertain cause. It is being recognized with increasing frequency, mainly as the result of heightened awareness and new diagnostic tests, specifically cardiac magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography scans. The purpose of this case-based review is to highlight the potentially life-saving importance of making the early diagnosis of cardiac sarcoidosis using these new tools and to provide a framework for the optimal care of patients with this disease. We will review disease mechanisms as currently understood, associated arrhythmias including conduction abnormalities, and atrial and ventricular tachyarrhythmias, guideline-directed diagnostic criteria, screening of patients with extracardiac sarcoidosis, and the use of pacemakers and defibrillators in this setting. Treatment options, including those related to heart failure, and those which may help clarify disease mechanisms are included.

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.

Update in Cardiac Sarcoidosis.

Increasing awareness of cardiac manifestations of sarcoidosis and the widespread availability of advanced imaging tests have led to a tidal wave of interest in a condition that was once considered rare. In this Focused Review, we explore important clinical questions that may confront specialists faced with possible cardiac involvement. In the absence of an ideal reference standard, three main sets of clinical criteria exist: the Japanese Ministry of Health and Welfare, the Heart Rhythm Society, and the World Association for Sarcoidosis and Other Granulomatous Disorders criteria. Once cardiac sarcoidosis is suspected, clinicians should be familiar with the prevalence of the disease in different clinical scenarios. Before obtaining advanced cardiac imaging, electrocardiogram, ambulatory electrocardiogram, echocardiogram, and B-type natriuretic peptide may be useful. The available therapies for cardiac sarcoidosis include immunosuppression, antiarrhythmic medications, heart failure medications, device therapy, ablation therapy, and heart transplantation. Contemporary data suggest that long-term survival in cardiac sarcoidosis is better than previously believed. There is no randomized controlled trial demonstrating benefits of screening, but screening is recommended based on observational data.

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.

Prognostic value of electrocardiographic measurements before and after cardiac resynchronization device implantation in patients with heart failure due to ischemic or nonischemic cardiomyopathy.

Postimplant QRS narrowing may predict clinical response after cardiac resynchronization therapy (CRT), but identification of nonresponders remains difficult. We studied the predictive value of electrocardiographic characteristics for mortality or cardiac transplantation in patients after CRT. Patients who had electrocardiograms available for review from before and after CRT device implantation were identified from a clinical database. Bivariate and multivariate Cox regression analyses were performed for the end point of death or transplantation. Of 337 patients (age 65+/-12 years, 76% men, left ventricular ejection fraction 22+/-12%, pre-QRS 175+/-30 ms), 84 died and 7 underwent transplantation during a follow-up of 27+/-15 months. Variables predictive of death or transplantation included QRS increase after CRT (45% vs 32%, p=0.03), older age, higher New York Heart Association class, lower left ventricular ejection fraction, and higher tertile of postimplant QRS (p=0.04), but not preimplant rhythm, QRS duration, or QRS morphology. After adjusting for confounding variables, independent predictors of mortality were older age (hazard ratio [HR] 1.03, 95% confidence interval [CI] 1.00 to 1.05, p=0.04), lack of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (HR 2.17, 95% CI 1.16 to 4.08, p<0.02), and longer postimplant QRS by tertile (HR 1.50, 95% CI 1.09 to 2.05, p=0.01). In conclusion, wider QRS after CRT device implantation is an independent predictor of mortality or transplantation. In patients with increased QRS durations despite CRT, closer follow-up or reassessment for alternative management strategies may be warranted.

Catheter ablation of atrial fibrillation.

Atrial fibrillation is a common arrhythmia associated with significant morbidity including angina, heart failure and stroke. Medical therapy remains suboptimal with significant side effects and toxicities, as well as a high recurrence rate. Catheter ablation or modification of the atrio-ventricular node with pacemaker implantation provides rate control but subjects the patient to the risks of an implantable device and does nothing to reduce the risk of stroke. Pulmonary vein antrum isolation offers a nonpharmacologic means of restoring sinus rhythm, thereby eliminating the morbidity of atrial fibrillation and the need for anti-arrhythmic drugs.