Each podcast will include key highlights from the journal's current issue and a report on new research published in the field of arrhythmia and electrophysiology.
Circulation: Arrhythmia and Electrophysiology November 2020 Issue
Paul J. Wang:
Welcome to the monthly podcast On the Beat for Circulation: Arrhythmia and Electrophysiology. I'm Dr. Paul Wang, editor-in-chief with some of the key highlights from this month's issue.
In our first paper, Danielle Haanschoten, Hein Wellens and Associates aim to examine survival benefit of prophylactic implantable cardioversion defibrillator (ICD) implantation in early selected high-risk patients with primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI). A randomized, multicenter, controlled trial compared ICD versus conventional medical therapy in high-risk primary PCI patients based on one of the following factors: Left ventricular ejection fraction (LVF) less than 30% within four days of STEMI, primary ventricular fibrillation, Killip class 2 or greater and/or TEMI flow less than three after PCI. ICD was implanted 30 to 60 days after MI, myocardial infarction, primary endpoint was all cause mortality three years of follow-up. The trial was prematurely ended after inclusion of 266 patients, 38% of the calculated sample size. Additional survival assessments was performed in February 2019 for the primary endpoint. A total of 266 patients, 78.2% male with a mean age of 60.8 years were enrolled. 131 were randomized to the ICD arm and 135 patients to the control arm. All cause mortality was significantly lower in the ICD group, five versus 13, hazard ratio of 0.37 after three years follow-up. Appropriate ICD therapy occurred in nine patients at three years follow-up, 5 within the first eight months after implantation. After median long-term follow-up of nine years, total mortality (18% versus 38%, hazard ratio of 0.58) and cardiac mortality (hazard ratio of 0.52) was significantly lower in the ICD group. Non-cardiac death was not significantly different between the groups. LVEF increased 10% or more in the 46.5% of patients during follow-up and the extent of improvement was similar in both study groups. The authors concluded that in this prematurely terminated and thus underpowered randomized trial early prophylactic ICD implantation demonstrated lower total and cardiac mortality in high-risk STEMI patients treated with primary PCI.
In our next paper Felipe Bisbal, Eva Benito and Associates aim to test the efficacy of ablating, cardiac magnetic resonance, CMR detected atrial fibrosis plus pulmonary vein isolation (PVI). This was an open label, parallel group, randomized controlled trial. Patients with symptomatic drug refractory AF paroxysmal or persistent undergoing first or repeat ablation were randomized one-to-one basis to receive PVI plus CMR-guided fibrosis ablation, the CMR group or PVI alone, the PVI alone group. The primary endpoint was a rate of recurrence greater than 30 seconds at 12 months of follow-up using a 12-lead ECG and Holter monitoring at 3, 6 and 12 months. The analysis was conducted by intention to treat. In total 155 patients, 71% male, age 59, CHADS2-VASc 1.3, 54% paroxysmal AF were allocated to the PVI group alone (n=76) or CMR group(n=79). First ablation was performed in 80% and 71% in the PVI alone and CMR groups respectively. The mean atrial fibrosis burden was 12%, only approximately 50% of patients had fibrosis outside the pulmonary vein area. 100% and 99% of patients received the assigned intervention in the PVI alone and CMR group. Primary outcome was achieved in 21 patients (27.6%) in the PVI alone group and 22 patients (27.8%) in the CMR group (Odds ratio 0.01, P=0.976). There was no differences in the rate of adverse events, three in the CMR group and two in the PVI alone group. The authors concluded that a pragmatic ablation approach targeting CMR detected atrial fibrosis plus PVI was not more effective than PVI alone in an unselected population undergoing AF ablation with low fibrosis burden.
In the next paper, Vivek Reddy and Associates tested a novel neuromodulation therapy of stimulation of epicardial cardiac nerves pa
Circulation: Arrhythmia and Electrophysiology October 2020 Issue
Paul J. Wang:
Welcome to the monthly podcast, On the Beat for Circulation, Arrhythmia and Electrophysiology. I'm Dr. Paul Wang, editor-in-chief with some of the key highlights from this month's issue.
In our first paper, Bruce Wilkoff and associates evaluated antibacterial envelope cost effectiveness compared to standard of care infection prevention strategies in the US healthcare system. Decision tree model was used to compare costs and outcomes of the antimicrobial envelope used adjunctive to standard of care infection prevention versus standard of care alone over a lifelong time horizon. The analysis was performed from an integrated payer provider network perspective. Infection rates, antimicrobial envelope effectiveness, infection treatment costs and patterns, infection related mortality and utility estimates were obtained from the WRAP-IT study. Life expectancy and long-term costs associated with device replacement, follow-up, and healthcare utilization were sourced from the literature. Costs and quality life adjusted years were discounted at 3%. An upper willingness-to-pay threshold of $100,000 per quality adjusted life year was used to determine cost-effectiveness in alignment with the American College of Cardiology and American Heart Association practice guidelines and as supported by the World Health Organization and contemporary literature. The base case incremental cost-effectiveness ratio (ICER) of the antibacterial envelope compared with standard-of-care was $112,603 per quality-adjusted life year. The ICER remained lower than the threshold in 74% of iterations in the probabilistic sensitivity analysis and was most sensitive to the following model inputs: infection-related mortality, life expectancy, and infection cost. The authors concluded that the absorbable antibacterial envelope was associated with a cost-effectiveness ratio below contemporary benchmarks in the WRAP-IT patient population, suggesting that the envelope provides value for the US healthcare system by reducing the incidence of CIED infection.
In our next paper, Peter Loh and associates in this study aim to investigate the feasibility and safety of single pulse irreversible electroporation (IRE) pulmonary vein (PV) isolation in patients with atrial fibrillation (AF). Ten patients with symptomatic paroxysmal or persistent AF underwent single pulse IRE pulmonary vein isolation under general anesthesia. Three-dimensional reconstruction and electroanatomical voltage mapping of the left atrium and pulmonary veins were performed using a conventional circular mapping catheter. Pulmonary vein isolation was performed by delivering nonarcing, nonbarotraumatic 6 ms, 200 Joule direct current IRE applications via a custom nondeflectable 14-polar circular IRE ablation catheter with a variable hoop diameter (16–27 millimeters). A deflectable sheath was used to maneuver the ablation catheter. A minimum of 2 IRE applications with slightly different catheter positions were delivered per vein to achieve circular tissue contact, even if pulmonary vein potentials were abolished after the first application. Bidirectional pulmonary vein isolation was confirmed with the circular mapping catheter and a post ablation voltage map. After a 30-minute waiting period, adenosine testing was used to reveal dormant pulmonary vein conduction. All 40 pulmonary veins could be successfully isolated with a mean of 2.4 IRE applications per pulmonary vein. Mean delivery peak voltage and peak current were 2154 volts and 33.9 amperes. No pulmonary vein reconnections occurred during the waiting period and adenosine testing. No periprocedural complications were observed. The authors concluded that in 10 patients in this first in-human study, acute bidirectional electrical pulmonary vein isolation could be achieved safely using single pulse IRE ablation.
In our next paper, Christian Sohns and associates studied the relationship between left ventricular ejection fraction (LVEF) New Yor
Circulation: Arrhythmia and Electrophysiology September 2020 Issue
Paul J. Wang:
Welcome to the monthly podcast, On the Beat for Circulation: Arrhythmia and Electrophysiology. I'm Dr. Paul Wang, Editor-in-chief, with some of the key highlights from this month's issue.
In our first paper, Zak Loring and associates examined 3,139 patients undergoing atrial fibrillation (AF) ablation, between 2016 and 2018 in the Get With The Guidelines-Atrial Fibrillation Registry from 24 US centers. Patients undergoing AF ablation were predominantly male (63.9%) and Caucasian (93.2%) with a median age of 65. Hypertension was the most common comorbidity (67.6%), and persistent atrial fibrillation patients had more comorbidities than paroxysmal AF patients. Drug refractory, paroxysmal AF was most common ablation indication (class I, 53.6%) followed by drug refractory, persistent AF (class I, 41.8%). Radio-frequency, RF ablation, with contact force sensing was the most common ablation modality (70.5%) and 23.7% of patients underwent cryoballoon ablation. Pulmonary vein isolation was performed in 94.6% of de novo ablations. The most common adjunctive lesion included left atrial roof or posterior/inferior lines and cavotricuspid isthmus ablation. Complications were uncommon (5.1%) and were life-threatening in 0.7% of cases.
In our next paper, Brian Howard and associates hypothesize that pulse field ablation (PFA) would reduce pulmonary vein stenosis risk and collateral injury compared to irrigated radiofrequency ablation (IRF). IRF and PFA deliveries were randomized in eight dogs with two superior pulmonary veins (PVs), ablated with using one technology and two inferior PVs ablated with the other technology. IRF energy (25-30 watts) or PFA with delivered (16 pulse trains) at each PV in a proximal and in a distal site. Contrast computed tomography (CT scans) were collected at 0, 2, 4 and 8, and 12 week, including termination time points to monitor PV cross-sectional area at each PV ablation site. Maximum average change in normalized cross-sectional area at 4 weeks was 46.1%±45.1% post IRF compared to -5.5±20.5% for PFA (P≤ to 0.001). Necropsy showed expansive PFA lesions without stenosis in the proximal PV sites compared to more confined and often incomplete lesions after IRF. At the distal PV sites only IRF ablations were grossly identified based on focal fibrosis. Mild pulmonary chronic parenchymal hemorrhage was noted in three left superior pulmonary vein lobes after IRF. Damage to vagus nerves, as well as evidence of esophagus dilation, occurred at sites associated with IRF. In contrast, no lung, vagal nerve, or esophageal injury was observed at PFA sites.
In our next paper, Mohamed Diab and associates aimed to assess the safety of ablation for atrial fibrillation (AF) with trans-esophageal (TEE) screening on intracardiac echocardiography (ICE) imaging of the appendage in direct oral anticoagulant (DOAC) compliant patients. They studied 900 patients with a medium CHA2DS2-VASc score of two. Interquartile range one to three. All consecutive patients presenting with AF or atrial flutter on DOAC were included. All were on DOACs (333 Rivaroxaban, 285 Dabigatran, 281 Apixaban and one Edoxaban). Thromboembolic complications occurred in four patients (0.3%), two ischemic strokes, one transient ischemic attack without residual deficit and one splenic infarct, all with no further complications. Bleeding complications incurred in 5 patients (0.4%), including 2 pericardial effusions (1 intraoperative, 1 after 30 days, both drained), and 3 groin hematomas (1 due to needing heparin for venous thrombosis, none requiring intervention). No patients required emergent surgeries.
In our next paper, Alexios Hadjis and associates aim to explore the role of complete diastolic pathway activation mapping on ventricular tachycardia (VT) recurrence. They studied 85 consecutive patients who underwent VT ablation using and guided by high-density mapping. During activation mapping, the presence of electrical activity in all segme
Circulation: Arrhythmia and Electrophysiology July 2020 Issue
Paul J. Wang:
Welcome to the monthly podcast, On the BEAT, for Circulation: Arrhythmia and Electrophysiology. I'm Dr. Paul Wang, Editor in Chief, with some of the key highlights from this month's issue.
Albert Feeny and Associates used unsupervised machine learning of electrocardiogram [ECG] waveforms to identify cardiac resynchronization therapy [CRT] subgroups to differentiate outcomes beyond QRS duration and left bundle branch block. They retrospectively analyzed 946 CRT patients with conduction delay. Principal component analysis [PCA] dimensionality reduction obtained a 2-dimensional representation of pre-CRT 12-lead QRS waveforms. K-means clustering of the 2-dimensional PCA representation of 12-lead QRS waveforms identified two patient subgroups [QRS PCA groups]. Vectorcardiographic QRS area was also calculated. They examined two primary outcomes: (1) composite endpoint of death, left ventricular assist device, or heart transplant, and (2) degree of echocardiographic left ventricular ejection fraction [LVEF] change after CRT. Compared to QRS PCA group 2 (n = 425), Group 1 (n=521) had a lower risk for achieving the composite endpoint (hazard ratio of 0.44, P In our next paper, Julie Shade, Rheeda Ali and Associates combined machine learning [ML] and personalized computational modeling to predict, prior to pulmonary vein isolation [PVI], which patients are most likely to experience atrial fibrillation [AF] recurrence after PVI. The single center retrospective proof of concept study included 32 patients with documented paroxysmal AF who underwent PVI and had pre-procedural late gadolinium enhanced magnetic resonance imaging [LGE MRI]. For each patient, a personalized computational model of the left atrium simulated AF induction via rapid pacing features were derived from pre-PVI LG MRI images and from results of simulations [SIM] AF. The most predictive features used to input to a quadratic discrimination analysis ML classifier, which was trained, optimized, and evaluated with a 10-fold nested cross validation to predict the probability of AF recurrence post PVI. In the cohort, the ML classifier predicted probability of AF recurrence with an average validation, sensitivity, and specificity of 82% and 89% respectively, and a validation AUC of 0.82. Dissecting the relative contributions of simulations SIM AF and raw images to the predictive capability of the ML classifier, they found that only when features from simulation SIM AF were used to train the ML classifier, its performance retained similar (validation AUC equals 0.81). However, when only features classified from raw images were used for training, the validation AUC significantly decreased (0.47).
In our next paper, Sarah Vermij and Associates examined sodium channel NaV 1.5 localization and function mutations in the gene and coding the sodium channel NaV 1.5 caused various cardiac arrhythmias. The authors use novel single-molecule localization [S-M-L-M] and computational modeling to define nanoscale features of NaV 1.5 localization and distribution at the lateral membrane [L-M], the LM groove, and T-tubules in cardiomyocytes from wild-type (N=3), dystrophin-deficient (mdx; N=3) mice, and mice expressing C-terminally truncated NaV 1.5 (ΔSIV; N=3). The authors assessed T-tubules sodium current by recording whole-cell sodium currents in control (N=5) in detubulated (N=5) wild-type cardiomyocytes. The authors found that NaV 1.5 organizes as distinct clusters in the groove and T-tubules which density, distribution, and organization partially depend on SIV and dystrophin. They found that overall reduction in NaV 1.5 expression expressed in mdx and ΔSIV cells result in a non-uniform distribution with NaV 1.5 being specifically reduced at the groove ΔSIV and increased in T-tubules of mdx cardiomyocytes. A T-tubules sodium current could, however, not be demonstrated. The authors concluded that NaV 1.5 mutations may site-specifically affect NaV 1.5 localization and d
Circulation: Arrhythmia and Electrophysiology August 2020 Issue
Paul J. Wang:
Welcome to the monthly podcast! On the Beat for Circulation: Arrhythmia and Electrophysiology. I'm Dr. Paul Wang, Editor-in-Chief. With some of the key highlights from this month's issue.
In our first paper, Demilade Adedinsewo and associates assess the accuracy of an artificial intelligence-enabled electrocardiogram [AI-ECG] to identify patients presenting with dyspnea who have left ventricular LV systolic function (defined as LV ejection fraction ≤35%) in the emergency department [ED]. Patients were included if they had at least one standard 12-lead electrocardiogram [ECG] acquired on the date of the ED visit and an echocardiogram performed within 30 days of presentation. Patients with prior LV systolic dysfunction were excluded. A total of 1,606 patients were included. Meantime from ECG echocardiogram was one day. The AI-ECG algorithm identified LV systolic dysfunction with an area under the curve [AUC] of 0.89 and accuracy of 85.9%. Sensitivity was 74%, specificity 87%, negative predictive value 97%, and positive predictive value 40%. To identify an ejection fraction less than 50%, the AUC was 0.85, sensitivity 86%, sensitivity 63%, and specificity 91%. NT-proBNP alone with a cutoff greater than 800 identified LV systolic function with an AUC of 0.80 by comparison.
In our next paper, Mahmood Alhusseini and associates hypothesize that convolutional neural networks [CNN] may enable objective analysis of intracardiac activation in atrial fibrillation [AF]. They perform panoramic recording of bi-atrial electrical signals in AF and use the Hilbert-transform to produce 175,000 image grids in 35 patients labeled for a rotational activation by experts who showed consistency, but with variability (kappa [κ]=0.79). In each patient, ablation terminated atrial fibrillation. A CNN was developed and trained on 100,000 AF image grids validated on 25,000 grids, and then tested on a separate 50,000 grids. They found in a separate test cohort of 50,000 grids, CNN reproducibly classified AF image grids into those with or without rotational sites with 95.0% accuracy. This accuracy exceeded that of support vector machines, traditional linear discriminant, and k-nearest neighbor statistical analyses. To probe the CNN, they applied gradient weighted class activation mapping, which revealed that the decision logic closely mimicked rules used by experts (C statistic 0.96). The authors concluded that convolutional neural networks improve the classification of intercardiac AF maps compared to other analyses and agreed with expert evaluation.
In our next paper, Kenji Okubo and associates examined whether late potential LP, abolition and ventricular tachycardia [VT] non-inclusive ability predicted long-term outcomes in patients with non-ischemic cardiomyopathy [NICM] undergoing VT ablation. The total 403 patients with NICM (523 procedures) who underwent VT ablation from 2010 to 2016 were included. The underlying structural disease consists of dilated cardiomyopathy (DCM, 49%), arrhythmogenic right ventricular cardiomyopathy (ARVD 17%), postmyocarditis (14%), valvular heart disease (8%), congenital heart disease (2%), hypertrophic cardiomyopathy (2%), and others (5%). Epicardial access was performed in 57% of patients. At baseline, the LPs were present in 60% of patients, and a VT was either inducible or sustained/incessant in 85% of the cases. At the end of the procedure LP abolition was achieved in 79% of cases in VT noninducability in 80%. After a multivariate analysis, the combination of LP abolition and VT noninducibility was independently associated with free survival from VT (hazard ratio, 0.45, p = 0.0002) and cardiac death (hazard ratio 0.38, P = 0.005). The benefit of LP abolition of preventing the VT recurrence in ARVD and postmyocarditis appeared superior to that observed for DCM.
In our next paper, Domenico Corradi, Jeffrey Saffitz and associates hypothesize that structural molecular changes in atrial myocardium th
Circulation: Arrhythmia and Electrophysiology June 2020 Issue
Paul J. Wang:
Welcome to the monthly podcast, On the Beat for Circulation: Arrhythmia and Electrophysiology. I'm Dr. Paul Wang, editor in chief, with some of the key highlights from this month's issue.
In our first paper, Vivek Reddy and associates studied a novel, 7.5, French lattice tip catheter with the compressible 9 mm nitinol tip that is able to deliver either focal radio frequency ablation [RFA] or pulsed field ablation [PFA], 2 to 5 second lesions. In a 3 center, single-arm, first in human trial, the catheter was used with a custom mapping system to treat paroxysmal or persistent atrial fibrillation. Toggling between energy sources, point by point, pulmonary vein [PV] encirclement was performed using biphasic pulsed field ablation, posteriorly, and either temperature controlled irrigated RFA or pulse field ablation, anteriorly (RF/PF or PF/PF) respectively. Linear lesions were created with either PFA or RFA. The 76 patient cohort included 55 paroxysmal and 21 persistent atrial fibrillation [AF] patients undergoing either RF/PF [pulse field ablation] 40 patients or PF/PF ablation in 36 patients, pulmonary vein isolation therapy duration was 22.6 minutes per patient with a mean of 50.1 RF/PF ablation lesions per patient. Linear lesions included 14 mitral, 34 left atrial roof and 44 cavo-tricuspid isthmus lines with therapy duration times of 5.1, 1.8 and 2.4 min/patient respectively. All lesion sets were acutely successful using 4.7 minutes of fluoroscopy. There were no device-related complications, including no strokes. Post-procedure esophagogastroduodenoscopy revealed minor mucosal thermal injury in two of the 36 RF/PF and zero of the 24 PF/PF patients. Post-procedure brain MRI revealed DWI positive flair, negative and DWI positive flare positive asymptomatic lesions in 5 and 3 of the 51 patients respectively.
In our next paper, Moussa Saleh and associates examined whether chloroquine, hydroxychloroquine plus or minus azithromycin lead to a prolongation of the QT interval, possibly increasing the risk of torsades de pointes and sudden death in a hospitalized population of patients with COVID-19. 201 patients were treated for COVID-19 with chloroquine/hydroxychloroquine. 10 patients or 5% received chloroquine, and 191 or 95% received hydroxychloroquine and 119 or 59% also received azithromycin. The primary outcome of Torsades de pointes was not observed in the entire population. Baseline QTC interval did not differ between patients treated with chloroquine or hydroxychloroquine monotherapy versus those treated with combination group chloroquine/hydroxychloroquine and azithromycin (440 ms versus 439.9 ms). The maximum QT during treatment was significantly longer in the combination versus the monotherapy group, 470 ms versus 453 ms (P = 0.004). Seven patients (3.5%) required discontinuation of these medications due to QTC prolongation. No arrhythmic deaths were reported.
In our next paper, Mikko Tulppo and associates examine whether the association between leisure time physical activity and the risk of sudden death and non-sudden cardiac death in coronary artery disease patients. 1,946 patients with angiographically verified coronary artery disease were classified into four groups: inactive, irregularly active, active exercise regularly two to three times per week, and highly active, exercise four times or more weekly. During follow-up, median 6.3 years, 52 sudden cardiac death and 49 non-sudden cardiac deaths occurred. Inactive patients had increased risk for sudden cardiac death compared to active patients, hazard ratio 2.45. Leisure time was not associated with sudden cardiac death in patients with Canadian cardiovascular class one, 18 events in 1,107 patients. Among patients with Canadian cardiovascular society, class two or higher, 34 events in 839 patients. An increased risk for sudden cardiac death encountered in highly active patients, hazard ratio 7.46 (P
In our next paper, Jacob Koruth and
P values and paper summaries are not interesting
This is the worst possible format to read a series of studies and P values. The podcast would be much better spent having interactive discussions with the journal authors for them to describe in their own words the significance and import of each piece of work. The current format is no better than having some kind of artificial intelligence that scrubs abstract for key findings recite them to you. Horrible format and reading. The fact that it enjoys a four star rating boggles my mind. Maybe Dr. Wong has his mother, relatives, and rotating students chime in with reviews.