Arrhythmia Induced Cardiomyopathy: What are Predictors of Myocardial Recovery?Acile Nahlawi BS, Marwan M. Refaat MDDepartment of Internal Medicine, Division of Cardiology, American University of Beirut Medical Center, Beirut, LebanonRunning Title: AIC and Predictors of Myocardial RecoveryDisclosures: NoneFunding: NoneKeywords: Cardiac Arrhythmias, Cardiovascular Diseases, Heart Diseases, Congestive Heart Failure, CardiomyopathyWords: 958 (excluding references)Correspondence:Marwan M. Refaat, MD, FACC, FAHA, FHRS, FASE, FESC, FACP, FRCPAssociate Professor of MedicineDirector, Cardiovascular Fellowship ProgramDepartment of Internal Medicine, Cardiovascular Medicine/Cardiac ElectrophysiologyDepartment of Biochemistry and Molecular GeneticsAmerican University of Beirut Faculty of Medicine and Medical CenterPO Box 11-0236, Riad El-Solh 1107 2020- Beirut, LebanonFax: +961-1-370814Clinic: +961-1-759616 or +961-1-355500 or +961-1-350000/+961-1-374374 Extension 5800Office: +961-1-350000/+961-1-374374 Extension 5353 or Extension 5366 (Direct)Email: firstname.lastname@example.orgCardiomyopathies cause a significant public health burden and improvement in sudden cardiac death risk stratification helped in decreasing mortality by improved pharmacotherapy as well as device implantations including implantable cardiac defibrillators and cardiac resynchronization therapy [1-4]. Arrhythmia induced cardiomyopathy (AIC) is a major cause of non-ischemic cardiomyopathy and heart failure (HF) worldwide . It is characterized by an impairment of left ventricular systolic function secondary to high heart rate (tachycardia-induced), asynchrony (frequent premature ventricular contractions-induced or right ventricular pacing-induced) or an irregular rhythm (such as atrial fibrillation-induced) that serves as the trigger of AIC and this is mediated by calcium mishandling. The distinctive feature of AIC is the substantial improvement in left ventricular systolic function following arrhythmia suppression or elimination . Atrial Fibrillation (AF) is concomitantly present with and potentially the cause of 10 to 50% of HF cases . AIC is an important, commonly encountered and potentially reversible entity that is often under-recognized. The exact incidence and prevalence of AIC remains poorly defined in the literature . In some studies, it was present in as high as 50% of patients with AF undergoing ablation, while it was reported to be present in 10% of patients with focal atrial tachycardia undergoing ablation . In addition, very little attention, if any, is given to AIC in major trials on AF and HF, despite its significant implications on morbidity and mortality and the promising benefits of treatment . Many aspects of AIC are yet to be understood. In fact, few studies limited by small sample size constitute our main source of knowledge on extent and predictors of ventricular recovery after treatment initiation in patients with AIC [9,10].In their multicenter retrospective study, Gopinathannair et al. aimed to assess the degree of recovery of the left ventricular systolic function after suppression/elimination of the underlying arrythmia and to evaluate factors influencing this response such as baseline patient and arrhythmia characteristics. The study sample comprised 243 patients from 3 different institutions whose charts were reviewed retrospectively (no recruitment timeframe was indicated). The patient characteristics studied included baseline left ventricular ejection fraction (LVEF), presence of structural heart disease (SHD) [ defined as significant coronary artery disease, prior myocardial infarction, hemodynamically significant valvular heart disease, or other structural cardiomyopathies] and medications used. As for the arrhythmia characteristics, they included arrhythmia duration and arrhythmia type. The authors used echocardiography as the imaging modality to determine extent of ventricular function recovery by comparing myocardial function before and after treatment of the culprit arrhythmia. The echocardiographic parameters that were assessed included LVEF, LV end-diastolic and end-systolic diameters, left atrial dimension, valvular abnormalities, right ventricular systolic pressures, and pulmonary arterial pressures.In contrast to reported literature on the topic, Gopinathannair et al. found that none of the studied patient and arrhythmia characteristics had a significant effect on the recovery of ventricular function. Their results showed that initiation of aggressive arrhythmia treatment is warranted in patients with suspected AIC, regardless of arrhythmia duration, arrhythmia type, severity of baseline LVEF, and underlying structural heart disease. This was concluded based on the consistent substantial improvement in LVEF after arrhythmia suppression/elimination, mainly through rhythm control, across all different subgroups. In fact, the extent of LVEF improvement was similar whether comparing the group with known arrhythmia duration [KN] to that with unknown arrhythmia duration [UKN] (21.2±9 % vs 19.4±11 %, p-value =0.16) or comparing the group with longest arrhythmia duration to the rest (21.5±7.5 % vs 21.0 ± 9.2%, p-value=0.77). On the other hand, greatest improvement was seen in the group with lowest initial LVEF (24±17 vs 19±7%; p-value <0.0001), making low index LVEF the only predictor of LVEF recovery after arrhythmia treatment in patients with AIC. However, the LVEF in these patients did not reach complete normalization; they had lower post-treatment LVEF compared to other groups (45±14 vs 54±8%; p<0.0001), a finding consistent with the available literature. Also similar to previous studies, the authors found that patients with PVCs experienced smaller extent of recovery compared to other arrhythmia types. The authors concluded by stressing the importance of suspecting AIC in patients having cardiomyopathy with a persistent arrhythmia and initiating aggressive arrhythmia treatment regardless of initial patient and arrhythmia characteristics.As for the limitations of the study by Gopinathannair et al., there are few to mention. First, the study had a retrospective design and therefore findings only serve to generate hypotheses that need further testing and validation. Second, there is a lack of a control group to exclude interference of confounding factors. Although the use of Angiotensin-Converting Enzyme inhibitors (ACEi)/ Angiotension receptor blockers (ARB) did not independently predict LVEF improvement in multivariate analysis, it could still be a confounder given the lower rates of ACEi/ARB use in the cohort. Third, the timeframe of the study and the period of follow-up were not clearly defined. Fourth, there is lack of blinding of echocardiographic analyses which can potentially lead to inter- and intra-observer variability. Finally, the sample population was not diverse as it consisted in its majority of Caucasians.The Gopinathannair et al. study demonstrated several points of strength. Among these are its multicenter nature and its relatively larger sample size compared to similar studies, giving its findings more weight. Moreover, the authors appropriately and clearly defined their inclusion and exclusion criteria. Furthermore, no funding was needed for the study which potentially frees it from direct or indirect influences on its design, execution and interpretation. Finally, the study has successfully improved our understanding of predictors of ventricular recovery in patients with AIC and showed that patients with AIC who had the longest duration of arrhythmia still had LV systolic function improvement with arrhythmia suppression/elimination. This study paves the way for prospective studies and randomized clinical trials to validate the generated hypotheses and corroborate the observational findings.
Generations of cryoballoon transformed the atrial fibrillation ablation landscape. New advancements continue to make cryoballoon more successful and safer treatment. A new cryoballoon PolaRx from Boston Scientific has unique features compared to that of the Medtronic Arctic Front Advance system. Comparison of the two available cryoballoons will require ongoing larger trial and clinical experience.
Very late recurrences after ablation of AVNRT have been reported. Age related alterations of nodal tissues caused by fibrous and fatty tissue infiltration and changes of the sympathovagal influence on the AV node, in turn altering AV nodal conduction and refractoriness, could set the stage for a previously not present substrate for AVNRT. Consequently, the occurrence of AVNRT many years after an ablation procedure may perhaps not always implicate a recurrence but instead an arrhythmia caused by a new substrate.
Reflections from the Book of the Dead: Weighing the Impact of Epicardial Fat on Atrial Fibrillation Vulnerability T. Jared Bunch MDDepartment of Medicine, School of Medicine, University of Utah, Salt Lake City, UtahAddress for correspondence: T. Jared Bunch, M.D.University of Utah School of Medicine Department of Internal Medicine Division of Cardiovascular Medicine 30 North 1900 East, Room 4A100 Salt Lake City, UT 84132 Phone: 801-213-2387 E-mail: email@example.com
Title: Making the Cut for Generator ReplacementsAuthors: Venkatesh Ravi, MD1; Jeremiah Wasserlauf, MD, MS1;1: Section of electrophysiology, Division of Cardiology, Department of Medicine, Rush University Medical Center, Chicago, USACorresponding author:Jeremiah Wasserlauf, MD, MSAssistant Professor of Medicine,Cardiac Electrophysiology, Department of Internal Medicine/Division of Cardiology,Rush University Medical Center.1717 W. Congress Parkway, Suite 345, Chicago, IL 60612Email: Jeremiah_wasserlauf@rush.eduFunding: NoneDisclosure: Dr. Jeremiah Wasserlauf has received consulting fees from Stryker. No other conflicts of interest to disclose.EditorialCardiac implantable electronic devices (CIED) have become a common treatment modality for cardiac arrhythmia with over 300,000 new implants every year in the United States. A growing number of patients will require device replacement procedures throughout their lifetime.1 In a registry of 1744 patients undergoing CIED replacement procedures, lead damage or dislodgement requiring revision was found to occur in 1% of patients without previously planned addition of leads.2 The resulting lead addition and extraction procedures give rise to added procedural time, risk of complications, prolonged hospitalization, and increased health care costs.2 Polyurethane and copolymer insulation materials are more susceptible to thermal damage when compared to silicone.3,4 Avoidance of lead damage during CIED replacement procedures has been a topic of increasing investigation, with studies evaluating differences between electrosurgical modes, power settings, blade orientation, and equipment manufacturers. Operators have the option to choose between standard electrocautery with non-insulated blades, and cautery with insulated blades (PEAK PlasmaBlade, Medtronic Inc., Minneapolis, MN, or Photonblade, Stryker, Kalamazoo, MI).Electrocautery operates by generating a high current density which results in resistive heating and thereby cuts or coagulates tissue. PlasmaBlade uses a proprietary power output waveform to deliver energy along the exposed edge of a thin, insulated electrode powered by a proprietary electrosurgical generator. Photonblade is an alternative insulated electrocautery blade that is compatible with a standard electrosurgical generator. In a retrospective study by Kypta et al, PlasmaBlade was associated with a lesser risk of lead damage and shorter procedure duration and hospital stay when compared with electrocautery and scissors.3 In an ex vivo animal tissue model using Photonblade, coagulation mode during cautery was associated with more damage than cut, and this effect was greatest when contact occurred using the active edge as opposed to the insulated flat side of the cautery blade, and when the lead insulation consisted of polyurethane or copolymer. Visible lead damage was found to be more common with PlasmaBlade when compared to Photonblade. 4In this edition of the Journal of Cardiovascular Electrophysiology , Ananwattanasuk et al performed a retrospective analysis of traditional electrocautery vs PlasmaBlade on lead parameters and complications following CIED generator replacement procedures.5 The study included 410 consecutive patients (840 leads) who underwent CIED replacement using conventional electrocautery (EC group) and 410 patients (824 leads) who underwent CIED replacement using PlasmaBlade (PK group). The power settings for the PK group were 6 in CUT mode and 8 in COAG mode. In the EC group, power output was set to 40 Watts for both CUT and COAG mode. CUT mode was used for tissue dissection and COAG was only used for hemostasis. The two groups had similar device systems and baseline characteristics. In comparison to the PK group, the EC group had a slightly lower proportion of silicone leads (78% vs 83%, p < 0.01) and a slightly higher proportion of polyurethane leads (19% vs 13%, p < 0.01). The study found no statistically significant difference in lead damage requiring lead revision between the EC group and PK group (0.6% vs 0.4%, p=0.5). There was no difference in procedural complications between the two groups (2.2% vs 1.2%, p = 0.28). There was no difference in lead sensing. There was a higher number of patients with a decrease in lead impedance in the PK group compared to the EC group (61.5% vs 52.1%, p < 0.01), and perhaps unexpectedly, more patients with an increase in lead impedance in the EC group compared to the PK group (46.8% vs 34.2%, p<0.01).On average, the change in pacing impedance changed less than 10% in both groups. A majority of leads in both groups were comprised of silicone which may have been a primary contributor to the low rate of lead damage observed. These findings contrast with the older retrospective study that found a lower risk of lead damage with PlasmaBlade compared to a historical control group where titanium scissors were used with conventional electrocautery for hemostasis. The difference observed in the prior study between groups, and the overall higher rates of lead damage in that study may have been related to the use of scissors or perhaps a greater proportion of leads with non-silicone insulation (lead insulation material was not reported). The present study by Ananwattanasuk et al contributes to the literature with a larger cohort of patients and contemporary operative technique.It is never too late to scrutinize the benefit of tools that have added costs as our procedural techniques evolve. The authors should be commended for rigorously collecting not only clinical outcomes but also electrical device parameters to assess for subclinical lead damage. Although generator replacements are short and less complex when compared to other EP procedures, the total cost of generator replacement procedures is estimated at several billion dollars yearly in the US alone.6 Leadless pacemakers and the evolution of modular systems are attractive and may solve some problems related to lead damage during generator replacements, or perhaps one day eliminate generator replacements altogether. However, with the current number of CIEDs in operation and the aging population, a growing number of patients will continue to require generator replacement procedures over the next several decades. The overall safety of generator replacement procedures has improved though advances such as avoidance of routine capsulectomy, antibiotic-impregnated pouches for appropriate candidates, and prolonged replacement intervals due to improved battery longevity. Through an unremitting focus on safety and cost-effectiveness, we will stay on the cutting edge of straightforward and complex procedures in the EP lab.References1. Greenspon AJ, Patel JD, Lau E, et al. 16-year trends in the infection burden for pacemakers and implantable cardioverter-defibrillators in the United States 1993 to 2008. J Am Coll Cardiol. 2011;58:1001-1006.2. Poole JE, Gleva MJ, Mela T, et al. Complication rates associated with pacemaker or implantable cardioverter-defibrillator generator replacements and upgrade procedures: results from the REPLACE registry.Circulation. 2010;122:1553-1561.3. Kypta A, Blessberger H, Saleh K, et al. An electrical plasma surgery tool for device replacement–retrospective evaluation of complications and economic evaluation of costs and resource use. Pacing Clin Electrophysiol. 2015;38:28-34.4. Wasserlauf J, Esheim T, Jarett NM, et al. Avoiding damage to transvenous leads-A comparison of electrocautery techniques and two insulated electrocautery blades. Pacing Clin Electrophysiol.2018;41:1593-1599.5. Ananwattanasuk T, Jame S, Bogun F, et al. Journal of Cardiovascular Electrophysiology. 2021.6. Hauser RG. The growing mismatch between patient longevity and the service life of implantable cardioverter-defibrillators. J Am Coll Cardiol. 2005;45:2022-2025.
One Electrogram-Tracing Tells All: what is the mechanism of this supraventricular tachycardia?Moyuru Hirata, MD*, Yuji Wakamatsu, MD*, Koichi Nagashima, MD, PhD*, Sayaka Kurokawa, MD, PhD*, Naoto Otsuka, MD*, Seina Yagyu, MD*, Shu Hirata, MD*, Toshiko Nakai, MD, PhD*, Yasuo Okumura, MD, PhD*.*Division of Cardiology, Department of Medicine, Nihon University School of Medicine, Tokyo, JapanCorrespondenceKoichi Nagashima, MD, PhD; Division of Cardiology, Department of Medicine, Nihon University School of Medicine, 30-1 Ohyaguchi-kamicho, Itabashi-ku, Tokyo 173-8610, JapanTel: +81-3-3972-8111Fax: +81-3-3972-1098E-mail: firstname.lastname@example.orgTotal word count: 1036 words, 2 FiguresFunding: (None)Disclosures: (None)The work described was supported by departmental resources only.Keywords: narrow QRS tachycardia, atrioventricular nodal reentrant tachycardia, accessary pathway.
Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation (AF) However AF recurrence after a single ablation procedure is common and often attributed to ineffective lesion delivery during PVI. In this issue of the Journal of Cardiovascular Electrophysiology, Chen et al reported their experience with 122 patients who underwent an ablation index-high power (AI-HP) strategy RF ablation for AF using 50W power, targeting AI values of 550 on the anterior left atrium (LA), 400 on the posterior wall and inter-lesion distance (ILD) 6mm. They achieved 1st pass PVI in 96.7% of cases, mean RF time was 11.5min and total procedure time was only 55.8min. All patients had 72h-Holter monitor and trans-telephonic follow up. They reported 89.4% arrhythmia free survival among patients with paroxysmal AF and 80.4% among patients with persistent AF at 15-month follow up. Sixty (49%) patients had luminal esophageal temperature (LET) >390C out of which 3 (2.5%) had asymptomatic endoscopic esophageal erosions/erythema. Four (3%) patients had clinically apparent steam pops during ablation with no adverse clinical sequela. While AI-HP guided RF ablation may be an attractive strategy for PVI that likely reduces procedure times and probably has comparable efficacy to conventional ablation settings, its safety requires further evaluation. Feedback from the ablated tissue may need to be incorporated into optimized ablation energy parameters to further improve outcomes.
The role of isolation of left posterior wall in patients with persistent atrial fibrillation on top of pulmonary vein isolation is still debatable. There are still technical issues for achieving complete left posterior wall isolation and durability of the lesions is probably the main limiting factor for promoting a successful clinical outcome
Demonstration that the myocardial sleeves of the pulmonary veins (PVs) are the main triggering and maintaining foci for paroxysmal atrial fibrillation (AF) have stimulated studies investigating electrophysiological properties of PVs and the adjacent left atrial (LA) myocardium. It has been shown that PV myocytes have a shorter action potential duration and are more prone to effects of local autonomic nerve stimulation in terms of shortening of action potential duration, early after depolarization formation and triggered firing compared to left atrial myocytes (1). The intrinsic cardiac autonomic nervous system (ICANS) forms clusters of neurons called ganglionic plexi (GPs), and studies using histologic examination of heart sections have shown that these GPs are localized preferentially at certain epicardial sites adjacent to the left and right atria (2). The precise role of ICANS in AF continues to be an area of intense research (3), and matters are not helped by the uncertainty regarding the best way to identify and target ICANS peri-procedurally. As there can be significant variability of GP sites in individual patients, endocardial high-frequency stimulation (HFS) has been used to aid their localization in the electrophysiology laboratory (4).
While pulmonary vein isolation (PVI) remains the cornerstone for invasive treatment of atrial fibrillation (AF), patients with persistent AF still have a high rate of recurrence with this method. Stochastic Trajectory Analysis of Ranked signals (STAR) mapping uses data from multiple individual wavefronts during ongoing AF to identify local drivers of persistent AF. In this non-randomized study, STAR mapping and ablation showed significantly lower recurrence of atrial arrhythmias compared to a consecutive PVI-only cohort and a propensity-matched ‘conventional ablation’ cohort (consisting of PVI plus complex fractionated atrial electrogram ablation or linear ablation). This benefit was driven by a much lower rate of AF recurrence in the STAR (6.2%) cohort vs PVI-only (44%) or ‘conventional’ (40%) with no significant difference in atrial tachycardia recurrence. Additionally, AF termination rates during ablation were approximately three times higher in the STAR cohort. While the analysis is retrospective and not randomized, the STAR cohort was also the only cohort with complete cessation of anti-arrhythmic drugs at three months and Holter monitoring at 6 and 12 months post-ablation per protocol. While STAR mapping appears to be a very promising new tool for treating persistent AF, history predicts at least some regression to the mean when future randomized comparisons are made. The authors have planned a multicenter randomized trial of PVI plus STAR mapping vs PVI-only for persistent AF. The global community of electrophysiologists and patients with AF eagerly awaits the results.
Title: Misleading Title and Communication.Regarding Brief Communication: First clinical use of real-time remote programming in cardiac implantable electronic devices. Dr. Toshimasa Okabe et al. J Cardiovascular Electrophysiol. 2020;31:2759-2761. DOI:10.1111/jce.14698Author: Dr. Esteban Martin Kloosterman
Monitoring following catheter or surgical ablation for atrial fibrillation (AF) is an essential tool used to assess outcomes for research purposes and help guide clinical decision making. The most commonly used methods to monitor for post-intervention AF include a variety of ambulatory external electrocardiogram (ECG) monitors, cardiac implantable electronic devices (CIED), and more recently, direct to consumer digital health technologies. The traditional metric of ablation success, recurrence > 30 seconds at 1 year, is below the detection capabilities of almost all monitoring techniques yet still undervalues the efficacy of AF interventions. Measures of AF burden reduction and duration give a more complete assessment of the impact of AF surgeries and ablation. As it is increasingly being recognized that AF burden and duration is related to stroke risk, long-term, inexpensive, non-invasive monitoring methods are needed. Smart phones and watches with AF-detecting capabilities, which are increasingly being used by the majority of US adults, have emerged as viable options to achieve this goal, shifting the paradigm of AF monitoring to a more patient centered approach.
Esophageal injury still occurs with high frequency during ablation of atrial fibrillation (AF). The purpose of this study is to provide a review of methods to protect the esophagus from injury during AF ablation. Despite advances in imaging and ablation, the potential risk of esophageal injury during AF ablation remains an important concern with a high occurrence of esophageal injury (≈15%). There have been numerous studies evaluating varied techniques for esophageal protection including active cooling and displacement of the esophagus. These techniques are reviewed in this manuscript as well as the role of esophageal protection in managing patients undergoing AF ablation procedure.