Search

Pulmonary vein stenosis (PVS) can arise from several etiologies, including congenital, acquired, and iatrogenic sources. PVS presents insidiously, leading to significant delays in diagnosis. A high index of suspicion and dedicated noninvasive evaluation are key to diagnosis. Once diagnosed, both noninvasive and invasive evaluation may afford further insights into the relative contribution of PVS to symptoms. Treatment of underlying reversible pathologies coupled with transcatheter balloon angioplasty and stenting for persistent severe stenoses are established approaches. Ongoing refinements in diagnostic modalities, interventional approaches, postintervention monitoring, and medical therapies hold promise to further improve patient outcomes., Competing Interests: Funding Support and Author Disclosures The authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Rhythm control strategies for atrial fibrillation (AF), including catheter ablation, are substantially underused in racial/ethnic minorities in North America., Objectives: This study sought to describe outcomes in the CABANA trial as a function of race/ethnicity., Methods: CABANA randomized 2,204 symptomatic participants with AF to ablation or drug therapy including rate and/or rhythm control drugs. Only participants in North America were included in the present analysis, and participants were subgrouped as racial/ethnic minority or nonminority with the use of National Institutes of Health definitions. The primary endpoint was a composite of death, disabling stroke, serious bleeding, or cardiac arrest., Results: Of 1,280 participants enrolled in CABANA in North America, 127 (9.9%) were racial and ethnic minorities. Compared with nonminorities, racial and ethnic minorities were younger with median age 65.6 versus 68.5 years, respectively, and had more symptomatic heart failure (37.0% vs 22.0%), hypertension (92.1% vs 76.8%, respectively), and ejection fraction <40% (20.8% vs 7.1%). Racial/ethnic minorities treated with ablation had a 68% relative reduction in the primary endpoint (adjusted hazard ratio [aHR]: 0.32; 95% confidence interval [CI]: 0.13-0.78) and a 72% relative reduction in all-cause mortality (aHR: 0.28; 95% CI: 0.10-0.79). Primary event rates in racial/ethnic minority and nonminority participants were similar in the ablation arm (4-year Kaplan-Meier event rates 12.3% vs 9.9%); however, racial and ethnic minorities randomized to drug therapy had a much higher event rate than nonminority participants (27.4% vs. 9.4%)., Conclusion: Among racial or ethnic minorities enrolled in the North American CABANA cohort, catheter ablation significantly improved major clinical outcomes compared with drug therapy. These benefits, which were not seen in nonminority participants, appear to be due to worse outcomes with drug therapy. (Catheter Ablation vs Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial [CABANA]; NCT00911508)., Competing Interests: Funding Support and Author Disclosures This work was supported by the National Institutes of Health (U01HL89709, U01HL089786, U01HL089907, and U01HL089645), St. Jude Medical Foundation and Corporation, Biosense Webster, Medtronic, and Boston Scientific Corporation. The content of this paper does not necessarily represent the views of the National Heart, Lung, and Blood Institute or the Department of Health and Human Services. Dr. Thomas has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health), Patient-Centered Outcomes Research Institute, and American Heart Association; and has received consulting fees from Sanofi, Boehringer Ingelheim, Janssen, Bristol Myers Squibb, and Medtronic during the conduct of the study. Dr. Al-Khalidi has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health) and the Mayo Clinic during the conduct of the study. Dr. Monahan has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health), St. Jude Foundation and Corporation, Biosense Webster, Medtronic, and Boston Scientific during the conduct of the study; has consulted without compensation from Biosense Webster; and has received personal fees from Thermedical outside the submitted work. Dr. Bahnson has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health) and the Mayo Clinic for conduct of the study; has received grants from Boston Scientific, St. Jude Medical Corporation, Biosense Webster, and Medtronic; and has received compensation for consulting from Cardiofocus and Ventrix during the conduct of the study but outside of the submitted work. Dr. Poole has received grants from ATriCure outside the submitted work. Dr. Mark has received grants from the National Heart, Lung, and Blood Institute (National Institutes of Health), the Mayo Clinic during the conduct of the study; and has received grants from Merck and HeartFlow outside the submitted work. Dr. Packer in the past 12 months has provided consulting services for Biosense Webster, Inc., Boston Scientific, CyberHeart, Medtronic, Inc., nContact, Sanofi, St. Jude Medical, and Toray Industries but has received no personal compensation for these consulting activities; has received grants from Abbott, Biosense Webster, Boston Scientific, CardioFocus, Medtronic, St. Jude Medical, CardioInsight, National Institutes of Health, Siemens, Thermedical, Endosense, Robertson Foundation, and Hansen Medical; has served on the advisory board without compensation for Abbott, Biosense Webster, Boston Scientific, CardioFocus, Medtronic, St. Jude Medical, Spectrum Dynamics, Siemens, Thermedical, Johnson & Johnson, and SigNum Preemptive Healthcare; has received speaking fees and honoraria from Biotronik and MediaSphere Medical; has received royalties from Wiley & Sons, Oxford, and St. Jude Medical; has joint equity with the Mayo Clinic in a privately held company, External Beam Ablation Medical Devices, outside the submitted work; and has received research funding from the NIH, Medtronic, Inc., Cryo Cath, Siemens AG, EP Limited, Minnesota Partnership for Biotechnology and Medical Genomics/University of Minnesota, Biosense Webster, Inc., and Boston Scientific. Mayo Clinic and Drs. Packer and Robb have a financial interest in mapping technology that may have been used at some of the 10 centers participating in this pilot research; in accordance with the Bayh-Dole Act, this technology has been licensed to St. Jude Medical, and Mayo Clinic and Drs. Packer and Robb received annual royalties >$10,000, the federal threshold for significant financial interest. Dr. Silverstein has reported that he has no relationships relevant to the contents of this paper to disclose., (Copyright © 2021 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: The SCD-HeFT (Sudden Cardiac Death in Heart Failure Trial) randomized 2,521 patients with moderate heart failure (HF) to amiodarone, placebo drug, or implantable cardioverter-defibrillator (ICD) therapy. Original trial follow-up ended October 31, 2003. Over a median 45.5-month follow-up, amiodarone, compared with placebo, did not affect survival, whereas randomization to an ICD significantly decreased all-cause mortality by 23%., Objectives: This study sought to describe the extended treatment group survival of the SCD-HeFT cohort., Methods: Mortality outcomes for the 1,855 patients alive at the end of the SCD-HeFT trial were collected between 2010 and 2011. These data were combined with the 666 deaths from the original study to compare long-term outcomes overall and for key pre-specified subgroups., Results: Median (25th to 75th percentiles) follow-up was 11.0 (10.0 to 12.2) years. On the basis of intention-to-treat analysis, the ICD group had overall survival benefit versus placebo drug (hazard ratio [HR]: 0.87; 95% confidence interval [CI]: 0.76 to 0.98; p = 0.028). When treatment benefit was examined as a function of time from randomization, attenuation of the ICD benefit was observed after 6 years (p value for the interaction = 0.0015). Subgroup analysis revealed long-term ICD benefit varied according to HF etiology and New York Heart Association (NYHA) functional class: ischemic HF HR: 0.81; 95% CI: 0.69 to 0.95; p = 0.009; nonischemic HF HR: 0.97; 95% CI: 0.79 to 1.20; p = 0.802; NYHA functional class II HR: 0.76; 95% CI: 0.65 to 0.90; p = 0.001; NYHA functional class III HR: 1.06; 95% CI: 0.86 to 1.31; p = 0.575., Conclusions: Follow-up of SCD-HeFT patients to 11 years demonstrated heterogenous treatment-related patterns of long-term survival with ICD benefit most evident at 11 years for ischemic HF patients and for those with NYHA functional class II symptoms at trial enrollment. (SCD-HeFT 10 Year Follow-up [SCD-HeFT10 Yr]; NCT01058837)., (Copyright © 2020 American College of Cardiology Foundation. All rights reserved.)

Background: The CABANA (Catheter Ablation Versus Antiarrhythmic Drug Therapy for Atrial Fibrillation) trial randomized 2,204 patients with atrial fibrillation (AF) to catheter ablation or drug therapy. Analysis by intention-to-treat showed a nonsignificant 14% relative reduction in the primary outcome of death, disabling stroke, serious bleeding, or cardiac arrest., Objectives: The purpose of this study was to assess recurrence of AF in the CABANA trial., Methods: The authors prospectively studied CABANA patients using a proprietary electrocardiogram recording monitor for symptom-activated and 24-h AF auto detection. The AF recurrence endpoint was any post-90-day blanking atrial tachyarrhythmias lasting 30 s or longer. Biannual 96-h Holter monitoring was used to assess AF burden. Patients who used the CABANA monitors and provided 90-day post-blanking recordings qualified for this analysis (n = 1,240; 56% of CABANA population). Treatment comparisons were performed using a modified intention-to-treat approach., Results: Median age of the 1,240 patients was 68 years, 34.4% were women, and AF was paroxysmal in 43.0%. Over 60 months of follow-up, first recurrence of any symptomatic or asymptomatic AF (hazard ratio: 0.52; 95% confidence interval: 0.45 to 0.60; p < 0.001) or first symptomatic-only AF (hazard ratio: 0.49; 95% confidence interval: 0.39 to 0.61; p < 0.001) were both significantly reduced in the catheter ablation group. Baseline Holter AF burden in both treatment groups was 48%. At 12 months, AF burden in ablation patients averaged 6.3%, and in drug-therapy patients, 14.4%. AF burden was significantly less in catheter ablation compared with drug-therapy patients across the 5-year follow-up (p < 0.001). These findings were not sensitive to the baseline pattern of AF., Conclusions: Catheter ablation was effective in reducing recurrence of any AF by 48% and symptomatic AF by 51% compared with drug therapy over 5 years of follow-up. Furthermore, AF burden was also significantly reduced in catheter ablation patients, regardless of their baseline AF type. (Catheter Ablation vs Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial [CABANA]; NCT00911508)., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Catheter ablation is important for treatment of paroxysmal atrial fibrillation (PAF). Limited animal and human studies suggest a correlation between electrode-tissue contact and radiofrequency lesion generation., Objectives: The study sought to assess the safety and effectiveness of an irrigated, contact force (CF)-sensing catheter in the treatment of drug refractory symptomatic PAF., Methods: A prospective, multicenter, nonrandomized study was conducted. Enrollment criteria included: ≥3 symptomatic episodes of PAF within 6 months of enrollment and failure of ≥1 antiarrhythmic drug (Class I to IV). Ablation included pulmonary vein isolation with confirmed entrance block as procedural endpoint., Results: A total of 172 patients were enrolled at 21 sites, where 161 patients had a study catheter inserted and 160 patients underwent radiofrequency application. Procedural-related serious adverse events occurring within 7 days of the procedure included tamponade (n = 4), pericarditis (n = 3), heart block (n = 1, prior to radiofrequency application), and vascular access complications (n = 4). By Kaplan-Meier analyses, 12-month freedom from atrial fibrillation/atrial flutter/atrial tachycardia recurrence was 72.5%. The average CF per procedure was 17.9 ± 9.4 g. When the CF employed was between investigator selected working ranges ≥80% of the time during therapy, outcomes were 4.25 times more likely to be successful (p = 0.0054; 95% confidence interval: 1.53 to 11.79)., Conclusions: The SMART-AF trial demonstrated that this irrigated CF-sensing catheter is safe and effective for the treatment of drug refractory symptomatic PAF, with no unanticipated device-related adverse events. The increased percent of time within investigator-targeted CF ranges correlates with increased freedom from arrhythmia recurrence. Stable CF during radiofrequency application increases the likelihood of 12-month success. (THERMOCOOL® SMARTTOUCH® Catheter for Treatment of Symptomatic Paroxysmal Atrial Fibrillation; NCT01385202)., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to assess the safety and effectiveness of a novel cryoballoon ablation technology designed to achieve single-delivery pulmonary vein (PV) isolation., Background: Standard radiofrequency ablation is effective in eliminating atrial fibrillation (AF) but requires multiple lesion delivery at the risk of significant complications., Methods: Patients with documented symptomatic paroxysmal AF and previously failed therapy with ≥ 1 membrane active antiarrhythmic drug underwent 2:1 randomization to either cryoballoon ablation (n = 163) or drug therapy (n = 82). A 90-day blanking period allowed for optimization of antiarrhythmic drug therapy and reablation if necessary. Effectiveness of the cryoablation procedure versus drug therapy was determined at 12 months., Results: Patients had highly symptomatic AF (78% paroxysmal, 22% early persistent) and experienced failure of at least one antiarrhythmic drug. Cryoablation produced acute isolation of three or more PVs in 98.2% and all four PVs in 97.6% of patients. PVs isolation was achieved with the balloon catheter alone in 83%. At 12 months, treatment success was 69.9% (114 of 163) of cryoblation patients compared with 7.3% of antiarrhythmic drug patients (absolute difference, 62.6% [p < 0.001]). Sixty-five (79%) drug-treated patients crossed over to cryoablation during 12 months of study follow-up due to recurrent, symptomatic AF, constituting drug treatment failure. There were 7 of the resulting 228 cryoablated patients (3.1%) with a >75% reduction in PV area during 12 months of follow-up. Twenty-nine of 259 procedures (11.2%) were associated with phrenic nerve palsy as determined by radiographic screening; 25 of these had resolved by 12 months. Cryoablation patients had significantly improved symptoms at 12 months., Conclusions: The STOP AF trial demonstrated that cryoballoon ablation is a safe and effective alternative to antiarrhythmic medication for the treatment of patients with symptomatic paroxysmal AF, for whom at least one antiarrhythmic drug has failed, with risks within accepted standards for ablation therapy. (A Clinical Study of the Arctic Front Cryoablation Balloon for the Treatment of Paroxysmal Atrial Fibrillation [Stop AF]; NCT00523978)., (Copyright © 2013 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The authors sought to characterize the left atrial (LA) and pulmonary vein (PV) electrophysiological and hemodynamic features in obese patients with atrial fibrillation (AF)., Background: Obesity is associated with increased risk for AF., Methods: A total of 63 consecutive patients with AF who had normal left ventricular (LV) ejection fraction and who underwent catheter ablation were studied. Atrial and PV electrophysiological studies were performed at the time of ablation with hemodynamic assessment by cardiac catheterization, and LA/LV structure and function by echocardiography. Patients were compared on the basis of body mass index (BMI): <25 kg/m(2) (n = 19) and BMI ≥30 kg/m(2) (n = 44)., Results: At a 600-ms pacing cycle length, obese patients had shorter effective refractory period (ERP) in the left atrium (251 ± 25 ms vs. 233 ± 32 ms, p = 0.04), and in the proximal (207 ± 33 ms vs. 248 ± 34 ms, p < 0.001) and distal (193 ± 33 ms vs. 248 ± 44 ms, p < 0.001) PV than normal BMI patients. Obese patients had higher mean LA pressure (15 ± 5 mm Hg vs. 10 ± 5 mm Hg, p < 0.001) and LA volume index (28 ± 12 ml/m(2) vs. 21 ± 14 ml/m(2), p = 0.006), and lower LA strain (5.5 ± 3.1% vs. 8.8 ± 2.8%; p < 0.001) than normal BMI patients., Conclusions: Increased LA pressure and volume, and shortened ERP in the left atrium and PV are potential factors facilitating and perpetuating AF in obese patients with AF., (Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: We sought to determine the relationship between atrial fibrillation (AF) ablation efficacy, quality of life (QoL), and AF-specific symptoms at 2 years., Background: Although the primary goal of AF ablation is QoL improvement, this effect has yet to be demonstrated in the long term., Methods: A total of 502 symptomatic AF ablation recipients were prospectively followed for recurrence, QoL, and AF symptoms., Results: In 323 patients with 2 years of follow-up, 72% achieved AF elimination off antiarrhythmic drugs (AADs), 15% achieved AF control with AADs, and 13% had recurrent AF. The physical component summary scores of the Medical Outcomes Study Short Form 36 increased from 58.8 +/- 20.1 to 76.2 +/- 19.2 (p < 0.001) and the mental component summary scores of the Short Form 36 increased from 65.3 +/- 18.6 to 79.8 +/- 15.8 (p < 0.001). Post-ablation QoL improvements were noted across ablation outcomes, including recurrent AF (change in physical component summary: 12.1 +/- 19.7 and change in mental component summary: 9.7 +/- 17.9), with no significant differences in QoL improvement across 3 ablative efficacy outcomes. However, in 103 patients who completed additional assessment with Mayo AF Symptom Inventories (on a scale of 0 to 48), those with AF elimination off AADs had a change in AF symptom frequency score of -9.5 +/- 6.3, which was significantly higher than those with AF controlled with AADs (-5.6 +/- 3.8, p = 0.03) or those with recurrent AF (-3.4 +/- 8.4, p = 0.02). Independent predictors of limited QoL improvement included higher baseline QoL, obesity, and warfarin use at follow-up., Conclusions: AF ablation produces sustained QoL improvement at 2 years in patients with and without recurrence. AF-specific symptom assessment more accurately reflects ablative efficacy., (Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to characterize the occurrence of phrenic nerve injury (PNI) and its outcome after radiofrequency (RF) ablation of atrial fibrillation (AF)., Background: It is recognized that extra-myocardial damage may develop owing to penetration of ablative energy., Methods: Between 1997 and 2004, 3,755 consecutive patients underwent AF ablation at five centers. Among them, 18 patients (0.48%; 9 male, 54 +/- 10 years) had PNI (16 right, 2 left). The procedure consisted of pulmonary vein (PV) isolation in 15 patients and anatomic circumferential ablation in 3 patients, with additional left atrial lesions (n = 11) and/or superior vena cava (SVC) disconnection (n = 4)., Results: Right PNI occurred during ablation of right superior PV (n = 12) or SVC disconnection (n = 3). Left PNI occurred during ablation at the left atrial appendage. Immediate features were dyspnea, cough, hiccup, and/or sudden diaphragmatic elevation in 9, and in the remaining the diagnosis was made after ablation owing to dyspnea (n = 7) or on routine radiographic evaluation (n = 2). Four patients (22%) were asymptomatic. Complete recovery occurred in 12 patients (66%). Recovery occurred within 24 h in the two patients with left PNI and in one patient with right PNI occurring with SVC disconnection. In the other nine patients, right PNI recovery occurred after 4 +/- 5 months (1 to 12 months) with respiratory rehabilitation. After a mean follow-up of 36 +/- 33 months, six patients have persistent PNI (three with partial and three with no recovery)., Conclusions: In this multicenter experience, PNI was a rare complication (0.48%) of AF ablation. Ablation of the right superior PV, SVC, and left atrial appendage were associated with PNI. Complete (66%) or partial (17%) recovery was observed in the majority.

Objectives: We sought to evaluate the efficacy and safety of a novel cryothermal balloon ablation system in creating pulmonary vein (PV) isolation., Background: Pulmonary vein isolation using standard radiofrequency ablation techniques is limited by procedure-related complications, such as thrombus formation and PV stenosis. Cryothermal ablation may reduce the risk of such complications., Methods: Eight dogs underwent circumferential ablation of both superior PVs for either 4 or 8 min using a cryothermal balloon catheter (CryoCath Technologies Inc., Kirkland, Canada). Both fluoroscopy and intracardiac ultrasound (ICE)-guided balloon and Lasso catheter positioning at the PV ostia assessed short-term PV integrity. In six additional dogs, long-term PV integrity was assessed by computed tomography at 16 weeks after ablation., Results: Successful electrical isolation was achieved acutely in 14 of 16 (87.5%) PVs and was confirmed in one-week survival studies in 10 of 12 (83%) PVs. Successful isolation was higher in the absence of any peri-balloon flow leak as seen by ICE (p = 0.015), and with balloon temperatures < or =-80 degrees C (p = 0.015). Cryolesions were located at the veno-atrial junction and were homogeneous, with intact endothelium and free of thrombus formation. Although limited angiographic PV narrowing was noted in the early follow-up period, no significant PV narrowing was seen long-term. Right phrenic nerve injury was seen in 50% of the animals studied at one week., Conclusions: This novel cryothermal balloon ablation system is effective for isolating PVs, but injury to the right phrenic nerve was noted in this early experience. Further studies are needed to assess the long-term efficacy and safety of this technique.

Objectives: The purpose of the study was to determine if atrial ectopy (AE) or atrial arrhythmias during exercise are predictive of an increased risk of cardiac events and death., Background: Although stress-induced atrial arrhythmias are common during exercise testing, there is a paucity of data regarding the correlation with underlying heart disease and cardiovascular outcomes. Atrial arrhythmias may reflect underlying left atrial enlargement and diastolic dysfunction, which are prognostic of mortality. We hypothesized that these stress-induced arrhythmias are associated with long-term adverse cardiac events., Methods: Exercise echocardiography was performed in 5,375 patients (age 61 +/- 12 years) with known or suspected coronary artery disease. An abnormal result was defined as exercise-induced atrial fibrillation (AF)/atrial flutter, supraventricular tachycardia (SVT), or AE., Results: A total of 311 (5.8%) patients died (132 [2.5%] from cardiac causes) over a period of 3.1 +/- 1.7 years. In addition, 193 (3.6%) patients experienced a myocardial infarction (MI) and 531 (9.9%) patients required revascularization. During exercise testing, 1,272 (24%) patients developed AE, 185 (3.4%) developed SVT, and 43 (0.8%) developed AF. The five-year cardiac death rate was not statistically different between groups (none [3.8%], AE [4.3%], SVT [3.7%], AF [0%], p = 0.43). The five-year rate of MI was significantly different between groups (none [5.7%], AE [8.3%], SVT [0%], AF [9.0%], p = 0.005). The five-year rate of revascularization between groups was not significantly different (none [14.2%], AE [17.0%], SVT [11.8%], AF [14.8%], p = 0.50). A composite of all five-year adverse end points was similar between groups (none [22.7%], AE [27.8%], SVT [17.7%], AF [25.7%], p = 0.10). In stepwise multivariate analysis, AE was not predictive of myocardial infarction when taking into account traditional clinical variables and exercise test results., Conclusions: In this large cohort of patients, the occurrence of AE was predictive of an increased risk of MI. However, the association did not persist after adjustment for clinical and exercise variables known to predict adverse long-term cardiovascular outcomes. The rate of long-term cardiac death or revascularization was not influenced by the development of stress-induced atrial arrhythmias.

Objectives: We evaluated left atrial appendage obliteration in high-risk patients with atrial fibrillation (AF)., Background: Left atrial appendage thrombosis and embolization is the principal mechanism of stroke in AF. Anticoagulation is underutilized and often contraindicated., Methods: Thoracoscopic Left Appendage, Total Obliteration, No cardiac Invasion (LAPTONI) was undertaken with a loop snare in eight patients and a stapler in seven patients, median age 71 years, with clinical risk factors for stroke and with an absolute contraindication to or failure of prior thrombosis prevention with warfarin. Eleven patients had a history of prior thromboembolism. One patient took sustained warfarin during follow-up., Results: The LAPTONI procedure was completed in 14 of 15 patients, and 1 patient required urgent conversion to open thoracotomy because of bleeding. Patients have been followed up for 8 to 60 months, mean 42 +/- 14 months. One fatal stroke occurred 55 months after surgery, and one non-disabling stroke three months after surgery. Two other deaths occurred, one after coronary bypass surgery and the other from hepatic failure. The subgroup of 11 patients with prior thromboembolism had an annualized rate of stroke of 5.2% per year (95% confidence interval [CI] 1.3 to 21) after LAPTONI, which compares to a rate of 13% per year (95% CI 9.0 to 19) for similar aspirin-treated patients from the Stroke Prevention in Atrial Fibrillation trials (p = 0.15)., Conclusions: The LAPTONI procedure appears technically feasible without immediate disabling neurologic morbidity or mortality, and it demonstrates low post-operative event rates and a statistical trend toward thromboembolic risk reduction in high-risk AF patients.

Objectives: The aims of this study were to identify and characterize familial cases of atrial fibrillation (AF) in our clinical practice and to determine whether AF is genetically heterogeneous., Background: Atrial fibrillation is not generally regarded as a heritable disorder, yet a genetic locus for familial AF was previously mapped to chromosome 10., Methods: Of 2,610 patients seen in our arrhythmia clinic during an 18-month study period, 914 (35%) were diagnosed with AF. Familial cases were identified by history and medical records review. Four multi-generation families with autosomal dominant AF (FAF 1 to 4) were tested for linkage to the chromosome 10 AF locus., Results: Fifty probands (5% of all AF patients; 15% of lone AF patients) were identified with lone AF (age 41 +/- 9 years) and a positive family history (1 to 9 additional relatives affected). In FAF 1 to 3, AF was associated with rapid ventricular response. In contrast, AF in FAF-4 was associated with a slow ventricular response and, with progression of the disease, junctional rhythm and cardiomyopathy. Genotyping of FAF 1 to 4 with deoxyribonucleic acid markers spanning the chromosome 10q22-q24 region excluded linkage of AF to this locus. In FAF-4, linkage was also excluded to the chromosome 3p22-p25 and lamin A/C loci associated with familial AF, conduction system disease, and dilated cardiomyopathy., Conclusions: Familial AF is more common than previously recognized, highlighting the importance of genetics in disease pathogenesis. In four families with AF, we have excluded linkage to chromosome 10q22-q24, establishing that at least two disease genes are responsible for this disorder.

Objectives: We evaluated the incidence and predictors of sudden death after atrioventricular (AV) node ablation and pacemaker implantation., Background: Sudden death may occur after radiofrequency catheter ablation of the AV node and pacemaker implantation in patients with atrial fibrillation (AF). Whether it is related to the procedure or to pre-existing heart disease remains unclear., Methods: All patients who had radiofrequency catheter ablation of the AV node and pacemaker implantation for rate control of medically refractory AF were identified retrospectively and observed prospectively. All patients with sudden death after ablation were identified. The relationship between the procedure and sudden death was defined on the basis of the time between the two as "likely," "possibly" or "unlikely.", Results: Of 334 consecutive patients with AF who underwent AV node ablation, nine had sudden death after the ablation. Four patients (1.2%) had sudden death likely related to the procedure: in 3 patients, arrest occurred within 48 h after the procedure; in one patient, arrest occurred four days after the procedure. In three other patients (0.9%), sudden death was possibly related to the procedure because the event occurred within three months afterward. The remaining two deaths were unrelated to the procedure. Diabetes, New York Heart Association functional class (>or=II), preprocedure ventricular arrhythmia, mitral or aortic stenosis, aortic regurgitation and chronic obstructive pulmonary disease were independent predictors for sudden death., Conclusions: Sudden death likely or possibly related to catheter ablation occurred in 7 of 334 patients (2.1%). Risk of sudden death is highest within two days after the procedure.

Objectives: [corrected] The aim of this study was to determine whether noncontact mapping is feasible in the right ventricle and assess its utility in guiding ablation of difficult-to-treat right ventricular outflow tract (RVOT) ventricular tachycardia (VT)., Background: In patients without inducible arrhythmia, RVOT VT may be difficult to ablate. Noncontact mapping permits ablation guided by a single tachycardia complex, which may facilitate ablation of difficult cases. However, the mapping system may be geometry-dependent, and it has not been validated in the unique geometry of the RVOT., Methods: Ten patients with left bundle inferior axis VT, no history of myocardial infarction and normal left ventricular function underwent noncontact guided ablation; seven had failed previous ablation and three had received a defibrillator. All noncontact maps were analyzed by a blinded reviewer to determine whether the arrhythmia focus was epicardial and to predict on the basis of the map whether arrhythmia would recur., Results: The procedure was acutely successful in 9 of 10 patients. During a mean follow-up of 11 months, 7 of 9 patients remained arrhythmia-free. Both patients in whom the blinded reviewer predicted failure had arrhythmia recurrence: one due to epicardial origin with multiple endocardial exit sites and one due to discordance between site of lesion placement and earliest activation on noncontact map., Conclusions: Mechanisms of ablation failure in RVOT VT include absence of sustained arrhythmia, difficulty with substrate localization and epicardial origin of arrhythmia. In this study, noncontact mapping was safely and effectively used to guide ablation of patients with difficult-to-treat RVOT VT.

Objectives: This study was designed to test the feasibility of high-resolution phased-array intracardiac imaging., Background: Intracardiac echocardiographic imaging of the heart during interventional electrophysiologic (EP) procedures has been limited by inadequate ultrasound penetration and absence of Doppler hemodynamic and flow information produced by rotating mechanical ultrasound elements., Methods: A 10F (3.2 mm) phased-array, variable 5.5 to 10 MHz frequency imaging catheter with a four-way deflectable tip was applied in 24 patients undergoing EP studies. Sixteen prespecified cardiac targets were imaged from a right heart venue., Results: Fifteen patients had no underlying organic heart disease; nine had ischemic, cardiomyopathic, valvular or congenital heart disorders. Longitudinal and short-axis imaging readily disclosed each cardiac valve, support structures and chamber, as well as the pericardium, right and left atrial appendages, the junction of the right atrium and superior vena cava, crista terminalis, tricuspid valve isthmus, coronary sinus orifice, membranous fossa ovalis and pulmonary veins. The average target depth was 8.8+/-1.5 cm (range 0.5 to 15 cm), with adequate penetration at a 7.5 MHz imaging frequency. Color flow and Doppler utilities clearly characterized transaortic and pulmonic valve and pulmonary vein blood flow, including during low output states., Conclusions: These first human studies with this technology demonstrate the methods, feasibility and utility of intracardiac phased-array vector and Doppler imaging for long-axis, apex-to-base global cardiac imaging. High resolution of endocardial structures and catheters suggests additional utility for visualizing interventional procedures from the right heart.

Objectives: Using data from the Multicenter UnSustained Tachycardia Trial (MUSTT), we examined the factors used to select antiarrhythmic drug therapy and their impact on outcomes., Background: The MUSTT examined the use of programmed ventricular stimulation (PVS) to guide antiarrhythmic therapy in patients with coronary arteriosclerosis, left ventricular dysfunction and asymptomatic, unsustained ventricular tachycardia (VT). Trial outcomes may reflect factors used to select antiarrhythmic drug therapy., Methods: We compared subgroups of patients with inducible sustained VT randomized to PVS-guided antiarrhythmic therapy (n = 351), in particular those receiving PVS-guided antiarrhythmic drug therapy (n = 142) versus no antiarrhythmic therapy (controls, n = 353)., Results: "Effective" antiarrhythmic drug therapy (i.e., the term "effective" was used to denote therapy that resulted in noninducible VT or hemodynamically stable induced VT) was found for 142 of the 351 patients (43%), most often at the first or second PVS session (125/142, 88%). Mortality among the 142 patients did not differ from that among control patients. Of these 142 patients, the PVS end point was noninducibility in 91 patients and stable VT in 51 patients. Mortality did not differ between these two groups either, but arrhythmia was numerically more frequent in the PVS-induced stable VT group. Mortality was greatest in the few patients receiving propafenone (unadjusted p = 0.07, adjusted p = 0.14 vs. controls), but mortality with all agents did not differ from that of controls, even after adjustment., Conclusions: Even when presenting the results as favorably as possible, we found no benefit with PVS-guided drug therapy in patients with clinical unsustained VT who had inducible sustained VT. These findings are unaltered by using different end points for PVS or considering the response to individual drugs.

Objectives: The purpose of this study was to determine the safety and efficacy of rescue echocardiographically guided pericardiocentesis as a primary strategy for the management of acute cardiac perforation and tamponade complicating catheter-based procedures., Background: In this era of interventional catheterization, acute tamponade from cardiac perforation as a complication is encountered more frequently. The safety and efficacy of echocardiographically guided pericardiocentesis in this life-threatening situation and outcomes of patients managed by this technique are unknown., Methods: Of the 960 consecutive echocardiographically guided pericardiocenteses performed at the Mayo Clinic (1979 to 1997), 92 (9.6%) were undertaken in 88 patients with acute tamponade that developed in association with a diagnostic or interventional catheter-based procedure. Most of the patients were hemodynamically unstable at the time of pericardiocentesis, with clinically overt tamponade in 40% and frank hemodynamic collapse (systolic blood pressure <60 mm Hg) in 57%. Clinical end points of interest were the success and complication rates of rescue pericardiocentesis and patient outcomes, including the need for other interventions, clinical and echocardiographic follow-up findings and survival., Results: Rescue pericardiocentesis was successful in relieving tamponade in 91 cases (99%) and was the only and definitive therapy in 82% of the cases. Major complications (3%) included pneumothorax (n=1), right ventricular laceration (n=1) and intercostal vessel injury with right ventricular laceration (n=1); all were treated successfully. Minor complications (2%) included a small pneumothorax and an instance of transient nonsustained ventricular tachycardia; all were resolved spontaneously. Further surgical intervention was performed in 16 patients (18%). No deaths resulted from the rescue pericardiocentesis procedure itself. Early death (<30 days) in this series was due to injuries from cardiac catheter-based procedures (n=3), perioperative complications (n=2) and underlying cardiac diseases (n=2). Clinical or echocardiographic follow-up for a minimum of 3 months or until death (if <3 months) for recurrent effusion or development of pericardial constriction was achieved in 87 (99%) of the patients., Conclusions: Echocardiographically guided pericardiocentesis was safe and effective for rescuing patients from tamponade and reversing hemodynamic instability complicating invasive cardiac catheter-based procedures. For most patients, this was the definitive and only therapy necessary.

Objectives: This investigations was undertaken to examine the alteration of electrophysiologic properties, including refractoriness, strength-interval relations and conduction, with the development of heart failure and to characterize the impact of volume loading on these indexes in the cardiomyopathic setting., Methods: Electrophysiologic properties in eight dogs with pacing-induced dilated cardiomyopathy were compared with those in six control dogs before and after rapid infusion of 800 ml of intravenous saline., Results: The right ventricular (RV) and left ventricular (LV) effective refractory period (ERP) and absolute refractory period (ARP) were significantly longer in dogs with pacing-induced cardiomyopathy than in control dogs: RV ERP 181 +/- 11 ms versus 138 +/- 7 ms (mean +/- SD) (p < 0.0001) and anterior LV ERP 177 +/- 13 ms versus 128 +/- 11 ms (p < 0.0001), respectively; ARP 159 +/- 14 ms versus 114 +/- 7 ms (p < 0.0001) at the RV site and 153 +/- 12 versus 117 +/- 5 ms (p < 0.0001) at the anterior LV site. After volume loading in cardiomyopathic animals, posterior and anterior LV ERPs became prolonged to 178 +/- 5 ms (p = 0.004) and 189 +/- 14 ms (p = 0.065), respectively, shifting the strength-interval relation in the direction of longer S1S2 coupling intervals. Anterior LV monophasic action potential durations at 90% repolarization also became prolonged from 192 +/- 10 ms to 222 +/- 23 ms (p < 0.012) with volume loading. These findings were not altered by subsequent sodium nitroprusside. Local conduction times parallel and perpendicular to fiber orientation were not altered by development of cardiomyopathy or volume alterations., Conclusions: The development of dilated cardiomyopathy results in significant prolongation of refractoriness and repolarization that is increased further by volume augmentation but is not reversed by pharmacologic load reduction. Although these abnormalities may contribute to the environment needed for a non-reentrant, triggered or stretch-mediated arrhythmogenic process in cardiomyopathic states, additional studies will be required to demonstrate such a focal mechanism conclusively.

Objectives: The effects of propafenone, a predominantly class IC antiarrhythmic drug, on defibrillation and pacing thresholds were evaluated in patients undergoing cardioverter-defibrillator implantation., Background: Previous studies have shown that the class IC agents encainide and flecainide may increase the energy requirements for pacing and defibrillation. Animal studies with propafenone have shown inconsistent results regarding its effect on defibrillation energy requirements. This report investigated the effects of propafenone on defibrillation and pacing thresholds in humans., Methods: After cardioverter-defibrillator implantation, 47 patients were enrolled in a double-blind, three-way parallel, randomized trial of 450 mg/day (Group 1) or 675 mg/day (Group 2) of oral propafenone or placebo (Group 3) for 3 to 7 days. Predischarge defibrillation and pacing thresholds after treatment were compared with baseline thresholds obtained at implantation., Results: There was no statistically significant difference between implantation and predischarge defibrillation thresholds in the three groups (Group 1: [mean +/- SE] 11.0 +/- 1.3 vs. 12.1 +/- 1.5 J; Group 2: 11.5 +/- 1.1 vs. 13.6 +/- 1.3 J; Group 3: 12.5 +/- 1.2 vs. 13.3 +/- 1.6 J), and no significant difference between treatment groups was found with a 0.86 power to detect a 5-J difference between groups. Paired pulse width pacing thresholds at 2.8 V were compared in 14 patients. A small increase of 0.02 ms was noted at predischarge testing in patients treated with propafenone and placebo., Conclusions: Short-term oral propafenone (450 and 675 mg/day) does not significantly affect defibrillation or pacing thresholds. Concomitant use of propafenone in patients with implantable cardioverter-defibrillators with recurrent ventricular or atrial tachyarrhythmias should not interfere with proper device function.

Objectives: This study examined the hypothesis that adenosine could provoke a vasovagal response in susceptible patients. Mechanisms of the vasovagal response were further explored by studying the adenosine-mediated reactions., Background: Increased sympathetic activity is frequently observed before vasovagal syncope. Recent studies have demonstrated that adenosine, in addition to its direct bradycardiac and vasodilatory effects, can increase sympathetic discharge by activating cardiovascular afferent nerves., Methods: The effects of adenosine and head-up tilt-table testing with or without isoproterenol were prospectively evaluated in 85 patients examined for syncope after negative results of electrophysiologic testing (51 men and 34 women, mean [+/- SD] age 61 +/- 17 years). Adenosine bolus injections of 6 mg and 12 mg were sequentially administered to patients in the upright position. The same protocol was implemented in 14 normal control subjects (7 men and 7 women, mean [+/- SD] age 38 +/- 10 years)., Results: Transient hypertension or tachycardia was observed in 57 (67%) and 20 (24%) patients after administration of 6 mg and 12 mg of adenosine, respectively, during the immediate phase (first 15 s), suggesting direct sympathetic activation. Hypotension and reflex tachycardia were observed in all patients during the delayed phase (15 to 60 s after adenosine injection), suggesting baroreceptor unloading. A vasovagal response was induced in 22 (26%) and 29 (34%) patients after adenosine administration and during tilt-table testing. Inducibility of a vasovagal response by these two methods was comparable (p = 0.12). Of the control subjects, one (7%) had a vasovagal response after adenosine administration and one (7%) had a positive response during tilt-table testing., Conclusions: These observations support the idea that adenosine is an endogenous modulator of the cardiac excitatory afferent nerves. Sympathetic activation by adenosine can be direct (i.e., cardiac excitatory afferent nerves) and indirect (i.e., vasodilation and reflex sympathetic activation). Adenosine could be an important modulator in triggering a vasovagal response in susceptible patients during examination for syncope.

The records of 342 patients who received surgical treatment for the Wolff-Parkinson-White syndrome between 1968 and 1986 were reviewed to evaluate the characteristics of atrial fibrillation. The patients were classified into two groups according to the presence (n = 166) or absence (n = 176) of documented episodes of atrial fibrillation preoperatively. The mean follow-up duration was 6 years (range 2 to 20). As compared with reports based on smaller patient groups and shorter follow-up, the study revealed several new findings. 1) During follow-up, nine patients in the atrial fibrillation group developed recurrent atrial fibrillation after a successful operation; five of these nine patients did not have associated heart disease. 2) All three patients with a history of atrial fibrillation and an accessory pathway conducting in the anterograde direction only had a successful surgical procedure and no postoperative atrial fibrillation. 3) The cycle length of atrioventricular (AV) reciprocating tachycardia was significantly shorter in the atrial fibrillation group (304 +/- 42 ms, mean +/- SD) than in the no-atrial fibrillation group (321 +/- 54 ms, p less than 0.005), and the cycle length of AV reciprocating tachycardia that degenerated into atrial fibrillation (289 +/- 26 ms) was shorter than that for the AV reciprocating tachycardia without subsequent atrial fibrillation (316 +/- 51 ms, p less than 0.005). 4) Sustained atrial fibrillation was induced in 30% of patients without a history of atrial fibrillation. 5) Atrial fibrillation occurred in four patients with an accessory pathway that conducted only in the retrograde direction.(ABSTRACT TRUNCATED AT 250 WORDS)

Standard electrocardiograms from 87 consecutive patients with tachycardia of left bundle branch block configuration were analyzed retrospectively for features that might be characteristic of tachycardia utilizing a nodofascicular Mahaim fiber. The study group consisted of 13 patients with nodofascicular tachycardia, 34 with supraventricular tachycardia and aberrant conduction over the His-Purkinje system, 22 with ventricular tachycardia and 18 with antidromic tachycardia utilizing a right-sided accessory atrioventricular pathway. Six variables present during tachycardia of left bundle branch block configuration were predictive of a nodofascicular fiber: cycle length between 220 and 450 ms, QRS axis of 0 to -75 degrees, QRS duration 0.15 second or less, R wave in lead I, rS wave in precordial lead V1 and a precordial transition from a negative to a positive QRS complex after lead V4. All six criteria were present in 16 of the 87 patients. No patient with ventricular tachycardia satisfied these criteria, whereas 3 of 34 with supraventricular tachycardia, 1 of 18 with antidromic tachycardia and 12 of 13 with tachycardia using a nodofascicular fiber did. It is concluded that analysis of the surface electrocardiogram during tachycardia may suggest the presence of a nodofascicular fiber.