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Background: Premature ventricular contraction (PVC) burden is a risk factor for heart failure and cardiovascular death in patients with structural heart disease. Long-term electrocardiographic monitoring can have a significant impact on PVC burden evaluation by further defining PVC distribution patterns., Objective: This study aimed to ascertain the optimal duration of electrocardiographic monitoring to characterize PVC burden and to understand clinical characteristics associated with frequent PVCs and nonsustained ventricular tachycardia in a large US cohort., Methods: Commercial data (iRhythm's Zio patch) from June 2011 to April 2022 were analyzed. Inclusion criteria were age >18 years, PVC burden ≥5%, and wear period ≥13 days. PVC burden cutoffs were determined on the basis of AHA/ACC/HRS guidelines for very frequent PVCs (10,000-20,000 during 24 hours). Patients were assigned to categories by PVC densities: low, <10%; moderate, 10% to <20%; and high, ≥20%. Mean measured error was assessed at baseline and daily until the wear period's end for overall PVC burden and different PVC densities., Results: Analysis of 106,705 patch monitors revealed a study population with mean age of 70.6 ± 14.6 years (33.6% female). PVC burden was higher in male patients and those >65 years of age. PVC burden mean error decreased from 2.9% at 24 hours to 1.3% at 7 days and 0.7% at 10 days. Number of ventricular tachycardia episodes per patient increased with increasing PVC burden (P < .0001)., Conclusion: Extending ambulatory monitoring beyond 24 hours to 7 days or more improves accuracy of assessing PVC burden. Ventricular tachycardia frequency and duration vary by initial PVC density, highlighting the need for prolonged cardiac monitoring., Competing Interests: Disclosures Luigi DiBiase is a consultant for Biosense Webster, Boston Scientific, Stereotaxis, and St Jude Medical and has received speaker honoraria from Medtronic, AtriCure, EPiEP, and Biotronik. Edward Gerstenfeld has served on advisory boards for Biosense Webster, Adagio Medical, and Boston Scientific; has received lecture honoraria from Medtronic, Biosense Webster, Abbott, and Boston Scientific; and has received a research grant from Abbott. Timm Dickfeld has served on advisory boards for Biosense Webster and InHeart and has received consulting honoraria from Impulse Dynamics. Nishant Verma has received speaker’s fees from Medtronic, Boston Scientific, Abbott, and Zoll. Ardit Kacorri, Lori Crosson, and Alan Wilk are employees of iRhythm Technologies. The other authors have no conflicts of interest to disclose., (Copyright © 2024 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Cardioneuroablation has been emerging as a potential treatment alternative in appropriately selected patients with cardioinhibitory vasovagal syncope (VVS) and functional AV block (AVB). However the majority of available evidence has been derived from retrospective cohort studies performed by experienced operators., Methods: The Cardioneuroablation for the Management of Patients with Recurrent Vasovagal Syncope and Symptomatic Bradyarrhythmias (CNA-FWRD) Registry is a multicenter prospective registry with cross-over design evaluating acute and long-term outcomes of VVS and AVB patients treated by conservative therapy and CNA., Results: The study is a prospective observational registry with cross-over design for analysis of outcomes between a control group (i.e., behavioral and medical therapy only) and intervention group (Cardioneuroablation). Primary and secondary outcomes will only be assessed after enrollment in the registry. The follow-up period will be 3 years after enrollment., Conclusions: There remains a lack of prospective multicentered data for long-term outcomes comparing conservative therapy to radiofrequency CNA procedures particularly for key outcomes including recurrence of syncope, AV block, durable impact of disruption of the autonomic nervous system, and long-term complications after CNA. The CNA-FWRD registry has the potential to help fill this information gap., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In light of the adverse prognosis related to severe mitral regurgitation, heart failure, or sudden cardiac death in a subset of patients with mitral valve prolapse (MVP), identifying those at higher risk is key. For the first time in decades, researchers have the means to rapidly advance discovery in the field of MVP thanks to state-of-the-art imaging techniques, novel omics methodologies, and the potential for large-scale collaborations using web-based platforms. The National Heart, Lung, and Blood Institute recently initiated a webinar-based workshop to identify contemporary research opportunities in the treatment of MVP. This report summarizes 3 specific areas in the treatment of MVP that were the focus of the workshop: 1) improving management of degenerative mitral regurgitation and associated left ventricular systolic dysfunction; 2) preventing sudden cardiac death in MVP; and 3) understanding the mechanisms and progression of MVP through genetic studies and small and large animal models, with the potential of developing medical therapies., Competing Interests: Funding Support and Author Disclosures Dr Delling is supported by the UCSF Resource Allocation Program 7501268 and by National Institutes of Health (NIH) research grant R01HL153447. Dr Noseworthy has received research funding from the NIH, including the National Heart, Lung, and Blood Institute (R21AG 62580-1, R01HL 131535-4, R01HL 143070-2), the National Institute on Aging (R01AG 062436-1), Agency for Healthcare Research and Quality (R01HS 25402-3), Food and Drug Administration (FD 06292), and the American Heart Association (18SFRN34230146; has filed patents related to the application of artificial intelligence to the ECG for diagnosis and risk stratification and has licensed several A-ECG algorithms to Anumana; is involved in potential equity/royalty relationship with AliveCor; is a study investigator in an ablation trial sponsored by Medtronic; and has served on an expert advisory panel for OptumLabs. Dr Adams’s institution, the Icahn School of Medicine at Mount Sinai, receives royalties for mitral and tricuspid valve repair prostheses related to his intellectual property from Edwards Lifesciences and Medtronic. Dr Borger’s institution receives speakers’ honoraria and/or consulting fees on his behalf from Edwards Lifesciences, Medtronic, Abbott, and CryoLife. Dr Elmariah has received research funding from the NIH (R01HL 151838) and the American Heart Association (19TPA34910170); has received research grants from Edwards Lifesciences, Medtronic, and Abbott Vascular; and is a consultant for Edwards Lifesciences. Dr Gerstenfeld has received lecture honoraria from Medtronic, Boston Scientific, and Abbott; has received research funding from, is on the scientific advisory board, and has received compensation from Biosense Webster; is on the scientific advisory board for and is PI of a clinical ablation trial sponsored by Farapulse; and is on the Data and Safety Monitoring Board for trials sponsored by Thermedical Inc and Abbott. Dr Norris has received research funding from the NIH (HL131546, GM103444, HL149696, HL122906), and the American Heart Association (19TPA34850095, 20SRG35540029, 19TPA34900016, 17CSA33590067). Dr Padala is supported by the National Heart, Lung, and Blood Institute (R01HL135145, R01HL140325, R01HL133667, R01HL144714, R01HL135505) and by the National Institute of Biomedical Imaging and Bioengineering (R01EB031101); has significant stock ownership and a role as a director in Nyra Medical; and has received consulting fees from Heart Repair Technologies Inc in the last 12 months. Dr Weinsaft is supported by NIH research grants R01HL128278 and R01HL151686. Dr Enriquez-Sarano has served as a consultant for Edwards, Cryolife, ChemImage, and HighLife. Dr Levine is supported by NIH research grants R01HL128099 and R01HL141917, American Heart Association 963793/Levine/2022, and funding of the Ellison Foundation. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Premature ventricular complexes (PVCs) are increasingly recognized, as the use of ECG wearables becomes more widespread. In particular, PVCs arising from both the right ventricular outflow tract (RVOT) and left ventricular outflow tract (LVOT) comprise the majority of these arrhythmias and form a significant component of an electrophysiology practice. A keen understanding of the correlative anatomy of the outflow tracts, in addition to recognizing key ECG indices illustrating PVC sites of origin, are fundamental in preparing for a successful ablation. Patient selection, incorporating symptomatology, structural disease, and PVC burden can pose a challenge, though tools such as the ABC-VT risk score may help identify those patients with a higher risk of clinical deterioration. Utilizing intracardiac echocardiography to highlight salient anatomic features not visible with fluoroscopy allows for a more precise and safer ablation. Interpretation of intracardiac EGMs, and the careful examination for low amplitude highly fractionated pre-potentials, enhanced by the advent of new developed mapping/ablation catheters, remains crucial. Utilizing these tools will guide the electrophysiologist to an efficient and effective outflow tract PVC ablation., (© 2021 Wiley Periodicals LLC.)

Background: Survival after sudden cardiac arrest is limited by postarrest myocardial dysfunction, but understanding of this phenomenon is constrained by a lack of data from a physiological model of disease. In this study, we established an in vivo model of cardiac arrest and resuscitation, characterized the biology of the associated myocardial dysfunction, and tested novel therapeutic strategies., Methods: We developed rodent models of in vivo postarrest myocardial dysfunction using extracorporeal membrane oxygenation resuscitation followed by invasive hemodynamics measurement. In postarrest isolated cardiomyocytes, we assessed mechanical load and Ca(2) (+)-induced Ca(2+) release (CICR) simultaneously using the microcarbon fiber technique and observed reduced function and myofilament calcium sensitivity. We used a novel fiberoptic catheter imaging system and a genetically encoded calcium sensor, GCaMP6f, to image CICR in vivo., Results: We found potentiation of CICR in isolated cells from this extracorporeal membrane oxygenation model and in cells isolated from an ischemia/reperfusion Langendorff model perfused with oxygenated blood from an arrested animal but not when reperfused in saline. We established that CICR potentiation begins in vivo. The augmented CICR observed after arrest was mediated by the activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). Increased phosphorylation of CaMKII, phospholamban, and ryanodine receptor 2 was detected in the postarrest period. Exogenous adrenergic activation in vivo recapitulated Ca(2+) potentiation but was associated with lesser CaMKII activation. Because oxidative stress and aldehydic adduct formation were high after arrest, we tested a small-molecule activator of aldehyde dehydrogenase type 2, Alda-1, which reduced oxidative stress, restored calcium and CaMKII homeostasis, and improved cardiac function and postarrest outcome in vivo., Conclusions: Cardiac arrest and reperfusion lead to CaMKII activation and calcium long-term potentiation, which support cardiomyocyte contractility in the face of impaired postarrest myofilament calcium sensitivity. Alda-1 mitigates these effects, normalizes calcium cycling, and improves outcome., (© 2016 American Heart Association, Inc.)

Introduction: Catheter ablation is an effective treatment of scar-related ventricular tachycardia (VT), but the overall complexity of the procedure has precluded its widespread use. Remote magnetic navigation (RMN) has been shown to facilitate cardiac mapping and ablation of VT in a retrospective series. STOP-VT is the first multicenter, prospective, single-arm and single-procedure study evaluating RMN-based mapping and ablation of post-infarction VT., Methods: Patients with documented VT and prior MI, in whom an ICD was implanted either for primary or secondary prevention, were recruited from four EU and US centers. Either a transseptal (48 patients) or transaortic (5 patients) approach was employed to gain access for ventricular endocardial mapping/ablation during VT (entrainment mapping, activation mapping) and/or substrate mapping in sinus rhythm (elimination of fractionated/late potentials, variable extent of substrate modification) with RMN and irrigated RF ablation. The primary endpoints were as follows: (i) non-inducibility of the target VT or any other sustained VT; (ii) elimination of sustained VT/VF during ICD follow-up of up to 12 months., Results: The cohort included 53 consecutive patients (median age 67 years, 49 men, median LVEF 31%). One hemodynamically unstable patient was excluded at the onset of mapping. Inducibility of sustained VT was achieved an average of 2.2 times per patient (1-8), with mean tachycardia cycle length (TCL) 374 milliseconds (179-510). Mean total procedure and fluoroscopy times were 223 minutes and 8.7 minutes, respectively; mean cumulative fluoroscopy time during mapping and ablation was 0.95 minutes; maximum power averaged 42.3 W with nominal saline 30 cc/min irrigation; mean cumulative RF time was 38 minutes. Non-inducibility of the target VT was achieved in 49/52 patients (94.2%) and non-inducibility of any VT was achieved in 38/52 patients (73.1%). A combination of RMN and manual ablation was performed in two patients, rendering one non-inducible. During the 12-month ICD follow-up period, freedom from any sustained VT/VF was observed in 30 patients (62%), of which 19 (63%) were off antiarrhythmic medications. Five patients expired during follow-up: one presented with a VT storm, but for the others, death was not related to VT/VF (MI-cardiogenic shock, pulmonary embolism, bronchogenic carcinoma, end stage heart failure). No procedural complications were reported., Conclusions: This first prospective, single-procedure, multicenter study indicates that remote magnetic navigation is a safe and effective method for catheter ablation of post-infarction VT., (© 2016 Wiley Periodicals, Inc.)

The heritable cardiovascular disorder long QT syndrome (LQTS), characterized by prolongation of the QT interval on electrocardiogram, carries a high risk of sudden cardiac death. We sought to add new data to the existing knowledge of genetic mutations contributing to LQTS to both expand our understanding of its genetic basis and assess the value of genetic testing in clinical decision-making. Direct sequencing of the five major contributing genes, KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2, was performed in a cohort of 115 non-related LQTS patients. Pathogenicity of the variants was analyzed using family segregation, allele frequency from public databases, conservation analysis, and Condel and Provean in silico predictors. Phenotype-genotype correlations were analyzed statistically. Sequencing identified 36 previously described and 18 novel mutations. In 51.3% of the index cases, mutations were found, mostly in KCNQ1, KCNH2, and SCN5A; 5.2% of cases had multiple mutations. Pathogenicity analysis revealed 39 mutations as likely pathogenic, 12 as VUS, and 3 as non-pathogenic. Clinical analysis revealed that 75.6% of patients with QTc≥500 ms were genetically confirmed. Our results support the use of genetic testing of KCNQ1, KCNH2, and SCN5A as part of the diagnosis of LQTS and to help identify relatives at risk of SCD. Further, the genetic tools appear more valuable as disease severity increases. However, the identification of genetic variations in the clinical investigation of single patients using bioinformatic tools can produce erroneous conclusions regarding pathogenicity. Therefore segregation studies are key to determining causality.

Background: Frequent ventricular premature depolarizations (VPDs) can cause reversible left ventricular (LV) dysfunction. However, not all patients normalize their LV function after VPD elimination., Objective: To evaluate predictors of recovery of LV function following the elimination of frequent VPDs., Methods: We identified patients with ≥10% VPDs/24 h and an LV ejection fraction of <50% who underwent successful ablation between 2007 and 2011. Subjects were classified as having reversible (≥10% increase to a final LV ejection fraction of ≥50%) or irreversible (≤10% increase or final LV ejection fraction <50%) LV dysfunction on the basis of echocardiographic follow-up. A reference group with ≥10% VPDs but normal LV function was identified., Results: One hundred fourteen patients with ≥10% VPDs were identified; 66 had preserved and 48 had impaired LV function. Over a median follow-up of 10.6 months, 24 of 48 were classified as reversible and 13 of 48 as irreversible and 11 of 44 were excluded. There was a gradient of VPD QRS duration between the control, reversible, and irreversible groups (mean VPD QRS 135, 158, and 173 ms, respectively; P < .001). This gradient persisted even for the same site of origin. In multivariate analysis, the only independent predictor of irreversible LV function was VPD QRS duration (odds ratio 5.07 [95% confidence interval 1.22-21.01] per 10-ms increase)., Conclusion: In patients with LV dysfunction and frequent VPDs, we identified VPD QRS duration as the only independent predictor for the recovery of LV function after ablation. This suggests that VPD QRS duration may be a marker for the severity of underlying substrate abnormality., (Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Introduction: Effectiveness of antral pulmonary vein isolation (PVAI) and ablation of non-PV triggers (non-PVTA) in controlling longstanding persistent atrial fibrillation (AF) has not been reported. We sought to describe clinical outcomes with this ablation strategy in patients (pts) followed for at least 1 year., Methods: Two hundred pts underwent PVAI for longstanding persistent AF and were followed for recurrence. Thirty-three pts with <1-year follow-up and 37 pts with additional RF atrial ablation were excluded, leaving 130 pts for analysis., Results: All 130 pts (108 men, mean LA 4.7 ± 0.6 cm, mean AF duration of 38 ± 44 months) underwent PVAI with entrance/exit block. In addition, 24 pts (15 pts during the initial procedure and 9 additional pts at repeat ablations) had 40 non-PVTA, including 3 with AVNRT. During follow-up, atrial flutter (AFL) was noted in 7 (5%) pts. The AF-free survival after single procedure without antiarrhythmic drugs (AAD) was 38%. Repeat AF or AFL ablation was performed in 37 pts (28%) with PV reconnection uniformly identified (3.7 ± 0.5 veins/pt). During mean follow-up of 41.1 ± 23.8 months (range 12-103 months), 85/130 pts (65%) were in sinus rhythm with 65 pts (50%) off AAD, 20 pts (15%) on AAD. Additionally, 9 pts (7%) have had rare episodes of AF such that 72% of pts have had good long-term clinical outcome. Of the 36 pts with recurrent AF, 20 pts have not had a repeat procedure., Conclusions: PVAI with non-PVTA for longstanding persistent AF provides good long-term AF control in over 70% of patients with infrequent (5%) AFL. AAD therapy and repeat PVAI may be required for this optimal outcome., (© 2012 Wiley Periodicals, Inc.)

Objectives: The aim of the study was to define the epicardial substrate and ablation outcome in patients with left ventricular nonischemic cardiomyopathy (NICM) and suspected epicardial ventricular tachycardia (VT)., Background: Ventricular tachycardia in NICM often originates from the epicardium., Methods: Twenty-two patients with NICM underwent detailed endocardial and epicardial bipolar voltage maps and VT ablation for suspected epicardial VT. Eight patients with normal hearts and idiopathic VT served to define normal epicardial electrograms. Low-voltage regions were also assessed for wide (>80 ms), split, or late electrograms., Results: Normal epicardial bipolar voltage was identified as >1.0 mV on the basis of the reference population. Confluent low-voltage areas were present in 18 epicardial (82%) and 12 endocardial (54%) maps and were typically over basal lateral LV. In the 18 patients with epicardial VT on the basis of activation/pacemapping, the mean epicardial area was greater than the endocardial low-voltage area (55.3 +/- 33.5 cm(2) vs. 22.9 +/- 32.4 cm(2), p < 0.01). Epicardial low-voltage areas showed 49.7% wide (>80 ms), split, and/or late electrograms rarely seen in the reference patients (2.3%). During follow-up of 18 +/- 7 months, ablation resulted in VT elimination in 15 of 21 patients (71%) including 14 of 18 patients (78%) with epicardial VT., Conclusions: In patients with NICM and VT of epicardial origin, the substrate is characterized by areas of basal LV epicardial > endocardial bipolar low voltage. The electrograms in these areas are not only small (<1.0 mV) but wide (>80 ms), split, and/or late, and help identify the substrate targeted for successful ablation., (2009 by the American College of Cardiology Foundation)

Introduction: The number of elderly patients with atrial fibrillation (AF) is increasing rapidly, and the safety and efficacy of catheter ablation in this demographic group has not been established., Methods: Over a 7-year period we studied 1,165 consecutive patients undergoing 1,506 AF ablation procedures using a consistent ablation protocol that included proximal ostial pulmonary vein (PV) isolation and focal ablation of non-PV AF triggers. Outcome was analyzed for three distinct age groups: <65 years (group 1; n = 948 patients), 65-74 years (group 2; n = 185 patients), and > or =75 years (group 3; n = 32 patients) based on the age at the initial procedure., Results: There was no significant difference in AF control (89% in group 1, 84% in group 2, and 86% in group 3, P = NS) during a mean follow-up of 27 months. Major complication rates were also comparable (1.6% in group 1, 1.7% in group 2, 2.9% in group 3, P = NS) between the three groups. There was no difference in the left atrial size, percentage with left ventricular ejection fraction <50%, or percentage with paroxysmal versus more persistent forms of atrial fibrillation. However, older patients were more likely to be women (20% in group 1, 34% in group 2, and 56% in group 3, P < 0.001) and have hypertension and/or structural heart disease (56% in group 1 vs 68% in group 2 vs 88% in group 3; P < 0.001). There was a strong trend demonstrating that older patients were less likely to undergo repeat ablation (26% vs 27% vs 9%) to achieve AF control and more likely to remain on antiarrhythmic drugs (20% vs 29% vs 37%; P < 0.05)., Conclusions: Elderly patients with AF undergoing catheter ablation therapy are represented by a higher proportion of women and have a higher incidence of hypertension/structural heart disease. To achieve a similar level of AF control, there appears to be no increased risk from the ablation procedure, but elderly patients are more likely to remain on antiarrhythmic drugs.

Background: The most common site of origin of idiopathic ventricular tachycardia (VT) is the right ventricular outflow tract. Idiopathic VT also can arise from the left ventricular outflow tract and the surrounding structures. Morphologic descriptions of 12-lead ECG characteristics of the aortic cusp region are limited., Objective: The purpose of this study was to define unique ECG characteristics of the aortic cusp region by performing a systematic analysis of pacemapping of this region in patients with structurally normal hearts., Methods: A combination of electroanatomic mapping, intracardiac echocardiography, and fluoroscopic guidance was used to study a total of 30 patients with structurally normal hearts undergoing left-sided ablation procedures. Each of the aortic valve cusps and the aortomitral continuity were paced at threshold and analyzed offline to determine unique ECG characteristics., Results: Pacing from the left coronary cusp typically produced a multiphasic QRS morphology consistent with an M or W pattern in lead V(1) with a precordial transition (R>S) no later than V(2). Pacing from the right coronary cusp typically resulted in a left bundle-type pattern with a broad small R wave in V(2) and a precordial transition generally at V(3). Pacing from the aortomitral continuity resulted in a qR pattern that was not observed anywhere else in the left ventricular outflow tract. When comparing the right coronary cusp and left coronary cusp, the precordial transition was earlier in the left coronary cusp than in the right coronary cusp. Pacing the noncoronary cusp uniformly resulted in atrial capture., Conclusion: When considering ablation of idiopathic VT, the aortic cusps and aortomitral continuity must be considered as possible foci. The 12-lead ECG, a readily and easily obtainable source of information, has useful characteristics for differentiating VTs arising from the cusp region.

Atrial fibrillation is the most common clinical arrhythmia, affecting millions of people worldwide and utilizing billions of dollars annually in heath care costs associated with the disease. Catheter based ablation, centering around the electrical isolation of the pulmonary veins, has emerged as a viable treatment option for patients with symptomatic paroxysmal or persistent atrial fibrillation. Because of the complex nature of the procedure, there are a number of potential complications which can occur which are related to problems with vascular access, mechanical complications resulting from catheter manipulation within the heart, cardioembolic complications, and complications arising from the effects of radiofrequency ablations in the left atrium. The most frequent complications arise from pseudoaneurysms, arterio-venous fistulas, hematomas, neurologic events (stroke and transient ischemic attacks), and pericardial effusion/tamponade. An evolving understanding of the risks of the procedure have helped to minimize complications by changing ablation strategies to avoid lesion delivery within the veins, emphasizing careful attention during the procedure to anticoagulation, utilizing intracardiac ultrasound and electroanatomic mapping systems for better visualization of intracardiac structures, and recognizing complications promptly during and after the procedure. Hopefully, improved techniques in the future will help to further improve the safety of catheter ablation of atrial fibrillation to allow for continued growth of this procedure.

Barth syndrome is an X-linked disorder characterized by dilated cardiomyopathy, cyclic neutropenia, skeletal myopathy, abnormal mitochondria, and growth deficiency. The primary defect is a mutation in the TAZ gene on the X chromosome at Xq28, resulting in abnormal phospholipid biosynthesis and cardiolipin deficiency. To date, there has been no systematic evaluation of the cardiac phenotype. We report five cases of cardiac arrest and/or placement of an internal cardiac defibrillator with documented ventricular arrhythmia. We suggest that ventricular arrhythmia is part of the primary phenotype of the disorder and that patients should be screened accordingly.

Recurrent ventricular tachycardia (VT) in the setting of coronary artery disease is frequently a life-threatening electrophysiologic emergency. Even in patients with an implantable defibrillator, recurrent VT is frequently accompanied by repeated and disabling shock therapy. Catheter ablative therapy offers the ability to provide immediate control of recurrent VT. Long-term elimination of VT should be anticipated in most patients. This article reviews the strategies, tools, techniques, and expected outcome for catheter ablation of stable and unstable ventricular arrhythmias in the setting ischemic heart disease.

A 29-year-old male with AIDS was treated with bleomycin and vincristine for visceral Kaposi's sarcoma. Three days later, he developed two distinct eruptions simultaneously. One eruption was characterized by tender, erythematous, edematous plaques and nodules on the palmar and dorsal surfaces of the hands, forearms, and elbows. The other consisted of grouped, erythematous, hyperpigmented streaks on the trunk, buttocks, and extremities. The patient subsequently received a second treatment consisting of vincristine with adriamycin, without bleomycin, and no cutaneous effects were seen. Diagnoses of flagellate erythema and acral nodular eruption secondary to bleomycin were made and confirmed histopathologically. To our knowledge, this is the first report of two cutaneous side effects of bleomycin appearing simultaneously in a patient with AIDS.

Background: To gain insight into the pathogenesis of right ventricular (RV) cardiomyopathy and ventricular tachycardia (VT), we determined the clinical and electroanatomic characteristics and outcome of ablative therapy in consecutive patients with (1) RV dilatation, (2) multiple left bundle-branch block (LBBB)-type VTs, and (3) an abnormal endocardial substrate defined by contiguous electrogram abnormalities., Methods and Results: All 21 patients had detailed RV bipolar electrogram voltage mapping. Eighteen patients had simultaneous left ventricular (LV) mapping, including all 4 patients with right bundle-branch block (RBBB) VT. VT was ablated in 19 patients by use of focal and/or linear lesions with irrigated-tip catheters in 10 of 19 patients. Eighteen patients were men, age 47+/-18 years, and none had a family history of RV dysplasia. RV volume was 223+/-89 cm3. Electrogram abnormalities extended from perivalvular tricuspid valves (5 patients), pulmonic valves (6 patients), or both valves (10 patients). Electrogram abnormalities always involved free wall, spared the apex, and included the septum in 15 patients (71%). The area of abnormality was 55+/-37 cm2 (range, 12 to 130 cm2) and represented 34+/-19% of the RV. In 52 of 66 LBBB VTs, the origin was from the RV perivalvular region. LV perivalvular low-voltage areas noted in 5 patients were associated with a RBBB VT origin. No VT recurred after ablation in 17 patients (89%) during 27+/-22 months., Conclusions: In patients with RV cardiomyopathy and VT, (1) perivalvular electrogram abnormalities represent the commonly identified substrate and source of most VT, (2) LV perivalvular endocardial electrogram abnormalities and VT can occasionally be identified, and (3) aggressive ablative therapy provides long-term VT control.

Ablation to eliminate atrial fibrillation (AF) is a therapy in evolution. Approaches to the ablation appear to be currently divided into 2 major strategies anatomic versus electrically guided. In addition in using an electrically guided techniques debate remains whether a targeted approach should be used, whether exit block should be documented, and whether all non pulmonary vein triggers should be targeted. This review highlights the different ablation strategies and identifies a systematic approach to ablation of pulmonary and non pulmonary vein triggers that we have adapted at our institution. The role of intracardiac echo, trigger provocation and localization and the use of 3-D mapping systems in AF ablation are defined.

Primary prevention trials have demonstrated that patients with coronary disease, reduced left ventricular function, and nonsustained ventricular tachycardia (NSVT) have improved survival with implantable cardioverter defibrillator (ICD) therapy, presumably secondary to effective termination of life-threatening arrhythmias. However, stored intracardiac electrograms were not always available and specific arrhythmias leading to ICD therapy were not always known. We examined the occurrence of ICD events in 51 consecutive patients who match the described patient profile to determine the frequency of appropriate and inappropriate ICD therapy. ICD detections were noted in 18 (35%) patients during a median follow-up period of 13.1 months. Appropriate therapy for sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) occurred in 11 (22%) patients, with appropriate shocks in 8 (16%) patients and appropriate antitachycardia pacing (ATP) in 4 (8%) patients. The time to first appropriate therapy occurred at a mean of 17 +/- 12 months (median 18 months, range 3-36 months). Inappropriate therapy occurred in 5 (10%) patients with inappropriate shocks in 4 patients and inappropriate ATP in 2 patients. Inappropriate therapy was delivered for supraventricular arrhythmias (SVAs) in 4 patients and for T wave oversensing in 1 patient. The reason for shock therapy was unknown in 1 patient (2%) due to ICD malfunction. The mean arrhythmia rate leading to appropriate therapy for VT/VF was 232 +/- 72 beats/min (range 181-400 beats/min), and the mean rate leading to inappropriate therapy for SVT was 168 +/- 10 beats/min (range 160-180 beats/min). Patients with coronary disease and asymptomatic NSVT commonly receive appropriate defibrillator therapy. These results support the need for ICD implantation for primary prevention, with attention to careful programming of the detection rate to prevent inappropriate therapy.

Atrial fibrillation (AF) is common after cardiac surgery and adds significant cost and morbidity. The use of prophylactic pacing strategies to prevent post-operative AF has been controversial. We previously performed a pilot study which suggested that the combination of beta-blockers and bi-atrial pacing (BAP) may reduce AF after cardiac surgery. We prospectively randomized 118 patients to continuous BAP for up to 96 hours post-operatively versus standard therapy. All patients were treated with beta-blockers as tolerated. Patients were paced in the AAI mode at a rate of 100 pulses per minute. The primary endpoint of the study was the occurrence of sustained AF (>10 minutes). There was a significant reduction in the incidence of AF in the BAP group among patients undergoing coronary artery bypass graft surgery with or without aortic valve replacement (35 % vs. 19 % AF; OR=0.38, 95 % CI 0.15, 0.93; p <0.05). Including patients undergoing isolated aortic valve surgery (n=7), there remained a strong trend toward a reduction of AF with pacing (no atrial pacing [NAP] vs. BAP; 35 % vs. 21 % AF; OR=0.48, 95 % CI 0.21, 1.11; p=0.08). Patients age 70 or greater benefited most from pacing (NAP vs. BAP; 55 vs. 25 % AF; p<0.05), while those less than 70 years of age did not (17 vs. 18 % p=NS). There was a significant reduction in the amount of time spent in the intensive care unit among patients receiving BAP (50+/-40 vs. 37+/-25 h; p<0.05).BAP together with beta-blockade after coronary artery bypass graft surgery reduces the incidence of post-operative atrial AF. Elderly patients (age 70 or greater) appear to benefit most, and may be a group to whom this therapy should be targeted.

Introduction: Ablative therapy for atrial fibrillation (AF) by targeting initiating triggers, usually in or around the pulmonary veins, has been reported by several centers. Evidence for an overall improvement in quality of life (QOL) and amelioration of symptoms is lacking., Methods and Results: Seventy-one patients undergoing attempted ablation of focal AF were followed for 60+/-33 weeks. QOL and symptom questionnaires were completed 1 month before and 6 months after electrophysiologic study. Twenty-three patients (32%) underwent electrophysiologic mapping but no ablation because of either insufficient or multifocal ectopy; the other 48 patients (68%) underwent attempted ablation. Sixteen of 48 patients (33%) undergoing ablation, or 16 (23%) of 71 on an intention-to-treat basis, were found at last follow-up to have persistent sinus rhythm without antiarrhythmic drugs. Patients who underwent mapping without ablation reported no improvements in any QOL or symptom score, whereas patients who had long-term successful ablation had significant improvements in all six QOL measures. Interestingly, patients who developed AF recurrence after ablation still reported significant improvements in 4 of 6 QOL measures. Four of 48 patients (8.3%) undergoing ablation developed pulmonary vein stenosis., Conclusion: Paroxysmal AF can be treated successfully in some patients by ablating initiating triggers in the pulmonary veins; however, in our experience the recurrence rate (32/48 [68%]) and risk of pulmonary vein stenosis (8%) after ablation are high. Patients with recurrent AF after ablation of focal AF triggers have significant improvement in QOL and symptoms compared with before ablation. Patients and their physicians should carefully balance the risks and benefits before considering ablation.

Atrial fibrillation is often initiated by atrial premature beats originating in the pulmonary veins. Non-invasive localization of these ectopic beats would be of significant value in guiding therapy. Body surface potential mapping was performed in nine patients undergoing invasive electrophysiologic study. Signals were recorded from 62 electrodes during pace mapping from each of the pulmonary veins. Optimal electrodes for localizing pulmonary vein activation were sequentially chosen. Seven optimal electrodes (6 anterior, 1 posterior) for recording ectopic atrial activation originating in the pulmonary veins were selected. The seven optimal electrode set performed better than the standard 9 electrode ECG at estimating the full body surface map (correlation 97 vs. 95.7%; p < 0.05). Seven optimally selected electrodes can estimate the body surface potential distribution during ectopic atrial activation orignating from the pulmonary veins. The ability of this electrode configuration to discriminate the site of origin of ectopic atrial beats requires prospective evaluation.

Objectives: The purpose of this study was to determine if atrial pacing is effective in reducing postoperative atrial fibrillation (AF)., Background: Atrial fibrillation after coronary artery bypass grafting (CABG) is a common problem for which medical management has been disappointing. Atrial-based pacing has become an attractive nonpharmacologic therapy for the prevention of AF., Methods: Sixty-one post-CABG patients (mean age = 65 years) were randomized to one of three groups: no atrial pacing (NAP), right atrial pacing (RAP) or biatrial pacing (BAP). Each patient had one set of atrial wires attached to both the right and left atria, respectively, at the conclusion of surgery. Patients in the RAP and BAP groups were continuously paced at a rate of 100 pulses per minute for 96 h or until the onset of sustained AF (>10 min). All patients were monitored with Holter monitors or full disclosure telemetry to identify the onset of AF. The primary end point of the study was the first onset of sustained AF., Results: There was no significant difference in the proportion of patients developing AF in the three groups (NAP = 33%; RAP = 29%; BAP = 37%; p > 0.7). However, for the subset of patients on beta-adrenergic blocking agents after CABG, there was a trend toward less AF in the paced groups. There were no serious complications related to pacing, although in three patients the pacemaker appeared to induce AF by pacing during atrial repolarization., Conclusions: Continuous right or biatrial pacing in the postoperative setting is safe and well tolerated. We did not find that post-CABG pacing prevented AF in this pilot study; however, the role of combined pacing and beta-blockade merits further study.

A 36-year-old man with a history of hypertrophic obstructive cardiomyopathy presented to the emergency room with "stabbing" chest pain. He had undergone dual-chamber pacemaker implantation in 1993 using an atrial lead (Accufix; Telectronics; Englewood, Colo) and a myomectomy in 1996 during which the distal portion of the atrial lead was removed. Digital fluoroscopy revealed that the retention wire had migrated out of the remaining atrial lead and perforated the right atrium. The retention wire was successfully removed percutaneously. The need for complete removal of the retention wire in the Accufix lead at the time of open-heart surgery is emphasized.

Background: The circulating wavelet hypothesis suggests that atrial fibrillation could terminate by either progressive fusion or simultaneous block of all wavelets., Methods: Intraatrial recordings from the right atrial free wall were made during procainamide induced (n = 8) or spontaneous (n = 7) termination of electrically induced atrial fibrillation in 14 patients. Atrial rate, mean magnitude squared coherence, and direction of activation during sequential electrograms were measured. Rate and coherence were calculated from the earliest point within 5 minutes prior to termination as well as from the 4-second interval just prior to termination., Results: Termination was directly to sinus rhythm (13 episodes) or to atrial flutter (2 episodes). For the eight procainamide induced terminations, rate decreased between the first measurement and the measurement just prior to termination, from 443 +/- 127 beats/min to 322 +/- 119 beats/min. For the seven spontaneous terminations, rate also decreased from 373 +/- 119 beats/min to 323 +/- 88 beats/min; however, a slight increase in atrial rate prior to termination was observed in three episodes. No specific patterns of atrial cycle lengths were seen during the final few seconds of fibrillation. No increase in coherence was observed. In seven episodes, recordings were made using orthogonal bipoles in the x, y, and z directions, allowing direction of activation of wavefronts to be measured. Three episodes showed multiple instances where direction of activation remained similar over several electrograms as we have previously reported for chronic fibrillation. However, no such instances precipitated termination in any of the seven episodes., Conclusions: Atrial fibrillation usually terminates directly to sinus rhythm and does so abruptly and without forewarning. While we and others have previously reported that the rate of atrial fibrillation decreases with procainamide infusion, a decrease in the rate of atrial fibrillation is not required for the rhythm to terminate and consequently may not be a part of the termination process at all. Coherence does not demonstrate a progressive increase in the organization of atrial fibrillation prior to termination. Lack of stabilization in the direction of activation of wavefronts in the final few seconds also fails to support fusion of wavefronts as the mechanism of termination of atrial fibrillation. Simultaneous block of all wavelets is consistent with, but not proven by, our observations.

Background: Atrial fibrillation is usually thought of as a "random" pattern of circulating wavelets. However, local atrial activation should be influenced by the constant anatomy and receding tail of refractoriness from the previous activation. The general tendency for wave fronts to follow paths of previous excitation has been termed "linking." We examined intra-atrial electrograms recorded during atrial fibrillation for evidence of linking., Methods and Results: Two minutes of atrial fibrillation were recorded in 15 patients with an orthogonal catheter. We have previously demonstrated that this catheter can be used to detect changes in the direction of local atrial activation. A mean vector was calculated for each electrogram. The similarity of the direction of the vectors from two consecutive electrograms can be quantified on a scale of 1 to -1 by calculating the cosine (cos) of the smallest angle (theta) between them. Two vectors pointing in the same or opposite directions then have cos(theta) = 1 or -1, respectively. For the entire group of patients, mean cos(theta) was significantly greater than 0 (mean, 0.36; p less than 0.001). In nine of 15 patients, there were groups of six or more consecutive beats (total, 44 groups; range, six to 14 beats per group) in which the direction of activation of each beat was within 30 degrees of the previous beat. The likelihood of one group of six or 14 consecutive similar beats occurring by chance in any one patient in 1 minute is less than 0.05 and less than 0.0000001, respectively. There was a significant correlation (r = 0.90) between the amount of linking during the first and second minutes of atrial fibrillation in each patient., Conclusions: Transient similarities in the direction of wavelet propagation in the majority of patients with atrial fibrillation is consistent with the presence of transient linking. To our knowledge, this is the first direct evidence that atrial activation during atrial fibrillation in humans is not entirely random.

The ability of a catheter with an orthogonal electrode configuration to sense differences in the direction of local atrial endocardial activation was tested in 18 consecutive patients with intact retrograde conduction. In all 18, discrimination of anterograde from retrograde conduction at a single atrial site was examined; in 5 of the 18, multiple sites were examined to determine if the discriminatory ability of the catheter was site dependent. The catheter was specially designed with bipoles in the x, y and z directions. A vector was computed for each electrogram during anterograde and retrograde conduction. Electrogram amplitude along the standard bipole was also compared for anterograde and retrograde conduction. Mean electrogram amplitude for the standard bipole was significantly different for anterograde than for retrograde conduction in 17 of 18 patients (mean +/- SD 4 +/- 1.9 vs. 2.7 +/- 1.3 mV; p less than 0.005), with complete separation of amplitude distributions in 4 patients. The electrogram vector during anterograde conduction was significantly different from that during retrograde conduction in all 18 patients (p less than 0.0001), with complete separation of vector distributions in 14. In some patients with multiple site recordings, the choice of site greatly affected separation based on electrogram amplitude or vector, or both. The orthogonal catheter can be used to sense directional differences in local endocardial activation. The catheter shows promise for discriminating anterograde from retrograde conduction and examining the direction of endocardial activation in the heart during an electrophysiologic examination.