Background: Multiple strategies have advocation for power titration and catheter movement during atrial fibrillation (AF) ablation. Comparative favoring evidence regarding the efficacy, logistics, and safety of a higher power, shorter duration (HPSD) ablation strategy compared to a lower power, longer duration (LPLD) ablation strategy is insubstantial. We performed a meta-analysis to compare arrhythmia-free survival, procedure times, and complication rates between the two strategies. Methods: We searched MEDLINE, EMBASE and Cochrane Library from inception to April 2020. We included studies comparing patients underwent HPSD and LPLD strategies for AF ablation and reporting either of the following outcomes: freedom from atrial tachyarrhythmia (AT) including AF and atrial flutter, procedure time, or periprocedural complications. We combined data using the random-effects model to calculate odds ratio (OR) and weight mean difference (WMD) with 95% confidence interval (CI). Results: Nine studies from 2006-2020 involving 2,282 patients were included (1,369 patients underwent HPSD strategy and 853 patients underwent LPLD strategy). HPSD strategy was not associated with an increased freedom from AT at 12-month follow-up (OR= 1.41, 95%CI:0.90-2.21). There was a significant reduction in the HPSD group for total procedure (WMD=49.60, 95%CI:29.76-69.44) and ablation (WMD=17.92, 95%CI:13.63-22.22) times, but not for fluoroscopy time (WMD=1.15, 95%CI:-0.67-2.97). HPSD was not associated with a reduction in esophageal ulcer/atrioesophageal fistula (OR=0.35, 95%CI:0.12-1.06) or pericardial effusion/cardiac tamponade rates (OR=0.96, 95%CI:0.24-3.79). Conclusions: When compared to a LPLD strategy, HPSD strategy does not improve recurrent AT nor reduce periprocedural complication risks. However, a HPSD strategy can significantly reduce total procedure and ablation times.
Combined use of hydroxychloroquine and azithromycin was globally adopted, in part due to paucity and high cost of alternative therapies. However the utility of these medications has been questioned; and thus safety becomes a major concern given clinical equipoise regarding efficacy. Both hydroxychloroquine and azithromycin continue to be administered in US clinical trials examining their potential role in prevention of infection, treatment of mild infection in ambulatory patients, and in combination with other medical regimens in treatment of patients with severe disease. These drugs also continue to be clinically utilized in hospitalized patients around the globe, often without continuous telemetry due to lack of resources. Concern regarding use of hydroxychloroquine without adequate rhythm monitoring in clinical trials has been recently expressed.1 A review of clinicaltrials.gov at the time of submission of this correspondence reveals actively recruiting trials of combined hydroxychloroquine/azithromycin with or without additional COVID-19 therapies, for both ambulatory and hospitalized patients within and outside the US. The potential for hydroxychloroquine and azithromycin to cause QT prolongation is counterbalanced by very low risk of pro-arrhythmia in the general population, and emerging evidence of relatively low risk of Torsades de Pointes (TdP) in COVID-19 patients.2,3,4,5 Thus delineation of the determinants of significant QTc prolongation and pro-arrhythmic risk for hydroxychloroquine/azithromycin is very important, especially given mounting evidence of inefficacy in COVID-19 treatment.
Introduction: A novel ablation catheter that can measure local impedance (LI) was recently launched. We aimed to explore target LI measurements at each radiofrequency application (RFA) for creating sufficient ablation lesions during pulmonary vein (PV) isolation. Methods: This prospective study included 15 consecutive patients scheduled to undergo an initial ablation of paroxysmal atrial fibrillation (AF). Circumferential ablation around both ipsilateral PVs was performed using a 4-mm irrigated ablation catheter with an LI sensor. Point-by-point ablation was used with a 4-mm inter-ablation-point distance. Operators were blinded to LI measurements during the procedure. Creation of sufficient ablation lesions was assessed by the absence of a conduction gap. Results: After first-pass encircling PV antrum ablation, left atrium to PV conduction remained in 12 of 30 (40%) ipsilateral PVs. Mapping using the mini-basket catheter identified 48 ablation points through which the propagation wave entered the PV. At ablation points with a gap, the LI drop during RFA was half that at points without a gap (12 ± 7 vs. 23 ± 12 ohm, p<0.001). The GI drop did not differ between ablation points with and without a gap (12 ± 7 vs. 14 ± 10 ohm, p=0.10). An LI drop of 15 ohm predicted sufficient lesion formation without a gap with a sensitivity of 0.71, specificity of 0.81, and predictive accuracy of 0.75. Conclusion: A target LI drop of 15 ohm at each RFA with a 4-mm distance between adjacent ablation points may facilitate creation of sufficient ablation lesions during PV isolation
Background: Ablation for atrial fibrillation (AF) has emerged as an effective method of rhythm control. This exploratory analysis aimed to determine how various measures of recurrence would influence the definition of treatment success. Methods: Using an EHR dataset from 01/2007-06/2019 linked with Medtronic cardiac implantable electronic device (CIED) data, patients who underwent a first AF ablation procedure following CIED implantation were identified. Data were analyzed for recurrence of AF stratified by varying definitions of successful ablation. Performance of various simulated external AF monitoring strategies was assessed. Results: A total of 665 patients were analyzed including 248 with paroxysmal AF (mean age 66.2±9.3 years, 73.0% male) and 417 patients with persistent AF (mean age 67.3±9.0 years, 73.6% male). Patients with paroxysmal AF, survival free from recurrence at 1 year ranged from 28.2% to 72.1% (>6 min and >23 hours thresholds, respectively) with an overall median percentage of time in AF reduction of 99.6%. Patients with persistent AF, survival free from recurrence at 1 year ranged from 24.9% to 60.0% (>6 min and 7 consecutive days >23 hours thresholds, respectively) with an overall median percentage of time in AF reduction of 99.3%. A single 7-day monitoring strategy had a sensitivity of < 50% for detecting AF > 6 min in patients with paroxysmal and persistent AF. Conclusion: In this real-world dataset of AF patients with CIEDs undergoing catheter ablation, treatment success varied substantially with different definitions of minimally required AF duration and is significantly impacted by the method of recurrence detection.
It is increasingly recognized that the autonomic nervous system (ANS) is a major contributor in many cardiac arrhythmias. Cardiac ANS can be divided into extrinsic and intrinsic parts according to the course of nerve fibers and localization of ganglia and neuron bodies. Although the role of extrinsic part has historically gained more attention, the intrinsic cardiac ANS may affect cardiac function independently as well as influence the effects of the extrinsic nerves. Catheter based modulation of the intrinsic cardiac ANS is emerging as a novel therapy for management of patients with brady and tachy arrhythmias resulting from hyperactive vagal activation. However, distribution of intrinsic cardiac nerve plexus in the human heart and the functional properties of intrinsic cardiac neural elements remain insufficiently understood. The present review aims to bring the clinical and anatomical elements of the ICANS together, by reviewing neuroanatomical terminologies and physiological functions, in order to guide the clinical electrophysiologist in the catheter lab, and to serve as a reference for further research.
A global coronavirus (COVID-19) pandemic occurred at the start of 2020 and is already responsible for more than 74,000 deaths worldwide, just over 100 years after the influenza pandemic of 1918. At the center of the crisis is the highly infectious and deadly SARS-CoV-2, which has altered everything from individual daily lives to the global economy and our collective consciousness. Aside from the pulmonary manifestations of disease, there are likely to be several electrophysiologic (EP) sequelae of COVID-19 infection and its treatment, due to consequences of myocarditis and the use of QT-prolonging drugs. Most crucially, the surge in COVID-19 positive patients that have already overwhelmed the New York City hospital system requires conservation of hospital resources including personal protective equipment (PPE), reassignment of personnel, and reorganization of institutions, including the EP laboratory. In this proposal, we detail the specific protocol changes that our EP department has adopted during the COVID-19 pandemic, including performance of only urgent/emergent procedures, afterhours/7-day per week laboratory operation, single attending-only cases to preserve PPE, appropriate use of PPE, telemedicine and video chat follow-up appointments, and daily conferences to collectively manage the clinical and ethical dilemmas to come. We discuss also discuss how we perform EP procedures on presumed COVID positive and COVID tested positive patients in order to highlight issues that others in the EP community may soon face in their own institution as the virus continues to spread nationally and internationally.
Background: Data regarding ventricular tachycardia (VT) or premature ventricular complex (PVC) ablation following MVS is limited.) CA can be challenging given perivalvular substrate in the setting of mitral annuloplasty or prosthetic valves. Objective: To investigate the characteristics, safety, and outcomes of radiofrequency catheter ablation (CA) in patients with prior mitral valve surgery (MVS) and ventricular arrhythmias (VA). Methods: We identified consecutive patients with prior MVS who underwent CA for VT or PVC between January 2013- December 2018. We investigated the mechanism of arrhythmia, ablation approach, peri-operative complications, and outcomes. Results: In our cohort of 31 patients (77% men, mean age 62.3±10.8 years, left ventricular ejection fraction 39.2±13.9%) with prior MVS underwent CA (16 VT; 15 PVC). Access to the left ventricle was via transseptal approach in 17 patients, and a retrograde aortic approach was used in 13 patients. A combined transseptal and retrograde aortic approach was used in one patient, and a percutaneous epicardial approach was combined with trans-septal approach in 1patient. Heterogenous scar regions were present in 94% of VT patients and scar-related reentry was the dominant mechanism of VT. Clinical VA substrates involved the peri-mitral area in 6 patients with VT and 5 patients with PVC ablation. No procedure-related complications were reported. The overall recurrence-free rate at 1-year was 72.2%; 67% in the VT group and 78% in the PVC group. No arrhythmia-related death was documented on long-term follow-up. Conclusion: CA of VAs can be performed safely and effectively in patients with MVS
Introduction: Although the presence of left atrial low-voltage areas (LVAs) is strongly associated with the recurrence of atrial fibrillation (AF) after ablation, few methods are available to classify the prevalence of LVAs. The purpose of this study was to establish a risk score for predicting the prevalence of LVAs in patients undergoing ablation for AF. Methods: We enrolled 1004 consecutive patients who underwent initial ablation for AF (age, 68 ± 10 years old; female, 346 (34%); persistent atrial fibrillation, 513 (51%)). LVAs were deemed present when the voltage map after pulmonary vein isolation demonstrated low-voltage areas with a peak-to-peak bipolar voltage of <0.5 mV covering ≥5 cm2 of the left atrium. Results: LVAs were present in 206 (21%) patients. The SPEED score was obtained as the total number of independent predictors as identified on multivariate analysis, namely female sex (odds ratio (OR) 3.4 [95% confidence interval (CI) 2.2-5.2], p <0.01), persistent AF (OR 1.8 [95% CI 1.1-3.0], p=0.02), age ≥70 years (OR 2.3 [95% CI 1.5-3.4], p <0.01), elevated brain natriuretic peptide ≥100 pg/ml or N-terminal pro-brain natriuretic peptide ≥400 pg/ml (OR 1.7 [95% CI 1.02-2.8], p=0.04), and diabetes mellitus (OR 1.8 [95% CI 1.1-2.8], p=0.02). LVAs were more frequent in patients with a higher SPEED score, and prevalence increased with each additional SPEED score point (OR 2.4 [95% CI 2.0-2.8], p <0.01). Conclusion: The SPEED score accurately predicts the prevalence of LVAs in patients undergoing ablation for AF.
Objectives: The aim of this analysis was to evaluate the predictors associated with increased risk of permanent pacemaker implantation (PPMI) following Transcatheter Aortic Valve Replacement (TAVR). Background: While TAVR has evolved as the standard of care for patients with severe aortic stenosis, conduction abnormalities leading to the need for PPMI is one of the most common post-procedural complications. Methods: A systematic literature search was performed to identify relevant trials from inception to May 2020. Summary effects were calculated using a DerSimonian and Laird random-effects model as odds ratio with 95% confidence intervals for all the clinical endpoints. Results: 37 observational studies with 71,455 patients were identified. The incidence of PPMI following TAVR was 22%. Risk was greater in men and increased with age. Patients with diabetes mellitus, presence of right bundle branch block, baseline atrioventricular conduction block, and left anterior fascicular block were noted to be at higher risk. Other significant predictors include the presence of high calcium volume in the area below the left coronary cusp and non-coronary cusp, use of self-expandable valve over balloon-expandable valve, depth of implant, valve size/annulus size, pre-dilatation balloon valvuloplasty and post-implant balloon dilation. Conclusion: Fourteen factors were found to be associated with increased risk of PPMI after TAVR, suggesting early identification of high-risk populations and targeting modifiable risk factors may aid in reducing the need for this post TAVR PPMI.
Background: Transvenous implantable cardiac defibrillators (TV ICD) provide life-saving therapy for millions of patients worldwide. However, they are susceptible to several potential short- and long- term complications including cardiac perforation and pneumothorax, lead dislodgement, venous obstruction, and infection. The extravascular ICD (EV ICD) system’s novel design and substernal implant approach avoids the risks associated with TV ICDs while still providing pacing features and similar generator size to TV ICDs. Study Design: The EV ICD pivotal study is a prospective, multi-center, single-arm, non-randomized, pre-market clinical study designed to examine the safety and acute efficacy of the system. This study will enroll up to 400 patients with a Class I or IIa indication for implantation of an ICD. Implanted subjects will be followed up to approximately 3.5 years, depending on when the patient is enrolled. Objective: The clinical trial is designed to demonstrate safety and effectiveness of the EV ICD system in human use. The safety endpoint is freedom from major complications, while the efficacy endpoint is defibrillation success. Both endpoints will be assessed against prespecified criteria. Additionally, this study will evaluate antitachycardia pacing (ATP) performance, electrical performance, extracardiac pacing sensation, asystole pacing, appropriate and inappropriate shocks, as well as a summary of adverse events. Conclusion: The EV ICD pivotal study is designed to provide clear evidence addressing the safety and efficacy performance of the EV ICD System.
Aims: The MicraTM transcatheter pacing system (TPS) (Medtronic) is the only leadless pacemaker that promotes atrioventricular (AV) synchrony via accelerometer-based atrial sensing. Data regarding the real-world experience with this novel system are currently lacking. We sought to characterize patients undergoing MicraTM -AV implants, describe percentage AV synchrony achieved, and analyze the causes for suboptimal AV synchrony. Methods: In this retrospective cohort study, electronic medical records from 56 consecutive patients undergoing MicraTM -AV implants at the Mayo Clinic sites in Minnesota, Florida, and Arizona with a minimum follow-up of 3 months were reviewed. Demographic data, comorbidities, echocardiographic data, and clinical outcomes were compared among patients with and without atrial synchronous-ventricular pacing (AsVP) ≥70%. Results: Fifty-six percent of patients achieved AsVP ≥70%. Patients with adequate AsVP had smaller body mass indices, a lower proportion of congestive heart failure and pulmonary hypertension. Echocardiographic parameters and procedural characteristics were similar across the two groups. Active device troubleshooting was associated with higher AsVP. The likely reasons for low AsVP were persistent atrial arrhythmias, small A4-wave amplitude, and inadequate device reprogramming. Importantly, in patients with low AsVP, subjective clinical worsening was not noted during follow-up. Conclusion: With the increasing popularity of leadless PM, it is paramount for device implanting teams to be familiar with common predictors of AV synchrony and troubleshooting with MicraTM -AV devices.
Background Charge density mapping of atrial fibrillation (AF) reveals dynamic patterns of localised rotational activation (LRA), irregular activation (LIA) and focal firing (FF). Their spatial stability, conduction characteristics and the optimal duration of mapping required to reveal these phenomena and has not been explored. Methods Bi-atrial mapping of AF propagation was undertaken and variability of activation patterns quantified up to a duration of 30-seconds(s). The frequency of each pattern was quantified at each vertex of the chamber over 2 separate 30s recordings prior to ablation and R2 calculated to quantify spatial stability. Regions with the highest frequency were identified at increasing time durations and compared to the result over 30s using Cohen’s kappa. Properties of regions with the most stable patterns were assessed during sinus rhythm and extrastimulus pacing. Results In twenty-one patients, 62 paired LA and RA maps were obtained. LIA was highly spatially stable with R2 between maps of 0.83(0.71-0.88) compared to 0.39(0.24-0.57) and 0.64(0.54-0.73) for LRA and FF, respectively. LIA was also most temporally stable with a kappa of >0.8 reached by 12s. LRA showed greatest variability with kappa>0.8 only after 22s. Regions of LIA were of normal voltage amplitude (1.09mv) but showed increased conduction heterogeneity during extrastimulus pacing (p=0.0480). Conclusion Irregular activation patterns characterised by changing wavefront direction are temporally and spatially stable in contrast with rotational patterns that are transient with least spatial stability. Focal activation appears of intermediate stability. Regions of LIA show increased heterogeneity following extrastimulus pacing and may represent fixed anatomical substrate.
Application of electrocautery to a metal guidewire can be used to perform transseptal puncture (TSP). Dedicated radiofrequency guidewires (RF) may represent a better alternative. This study compares safety and effectiveness of electrified guidewires to a dedicated RF wire. TSP was performed on porcine hearts using an electrified 0.014” or 0.032” guidewire under various power settings compared to TSP using a dedicated RF wire with 5W power. The primary endpoint was the number of attempts required to achieve TSP. Secondary endpoints included the rate of TSP failure, TSP consistency, effect of the distance between tip of the guidewire and the tip of the dilator, and effect of RF power output level. Qualitative secondary endpoints included tissue puncture defect appearance, thermal damage to the TSP guidewire or dilator, and tissue temperature using thermal imaging. The RF wire required 1.10 ± 0.47 attempts to cross the septum. The 0.014” electrified guidewire required 2.17 ± 2.36 attempts (2.0x higher than the RF wire; p<0.01), and the 0.032” electrified guidewire required 3.90 ± 2.93 attempts (3.5x higher than the RF wire; p<0.01). Electrified guidewires had a higher rate of TSP failure, larger defects, more tissue charring, higher temperatures, and greater tissue heating. Fewer RF applications were required to achieve TSP using a dedicated RF wire compared to an electrified guidewire. Smaller defects and lower tissue temperatures were also observed using the RF wire. Electrified guidewires required greater energy delivery and were associated with equipment damage and tissue charring.
We introduced a simple technique to eliminate electromagnetic interference between a left ventricular assist device (LVAD) and an implantable cardioverter-defibrillator (ICD). A 43-year-old male with heart failure and a reduced ejection fraction (HFrEF) who had an ICD presented with decompensated heart failure and received an LVAD as a bridge to transplant. Remote monitoring showed persistent atrial fibrillation causing an inappropriate ICD shock leading to a decision to disable shock therapies. However, an in-office interrogation was unsuccessful due to electromagnetic interference. Patient was instructed to extend his arm above his head on the ipsilateral side of the ICD, thus increasing the distance between LVAD and ICD, eliminating the interaction to allow reprogramming of the device.
Introduction: Catheter ablation is superior to drugs regarding atrial fibrillation (AF) recurrence, symptoms improvement, and mortality reduction in heart failure. POLARx™ is a novel cryoballoon, with technical improvements seeking to improve outcomes. So far, its clinical evidence is restricted to a case report. Methods: To compare the POLARx™ cryoballoon procedural safety and efficacy to the already established Arctic Front Advance PRO™ (AFAP) in a single-center cohort study, consecutive patients undergoing AF cryoablation with the POLARx™ were enrolled. Data were prospectively gathered. POLARx™ patients were compared to a historical cohort of patients submitted to AF cryoablation with the AFAP. Results: Seventy patients were analyzed, 20 in POLARx™, and 50 in the AFAP group. They all underwent first-time pulmonary vein isolation, 77% were male, 94% had paroxysmal AF, median age was 62.5 years, median CHA2DS2-VASc 1, left-atrium size 34ml/m², and 65% were receiving anticoagulation. The primary end-point, all pulmonary veins isolation, was 100% in both groups. The complication rate was similar (0% POLARx™ vs. 5.7% AFAP, p=0.39). The median total procedural time was longer in the POLARx™ group (90min vs. 60min, p<0.001), but the overall time-to-isolation (TTI) (44.8sec vs. 39sec, p=0.253) and ablation time (15min vs. 13.7min, p=0.122) was similar between POLARx™ and AFAP groups, respectively. Despite equal TTI, the POLARx™ had a lower minimal temperature reached (-57ºC vs -47ºC, p<0.001). Conclusion: The novel POLARx™ cryoballoon had similar efficacy and safety compared to the AFAP. It was also associated with longer procedural times, similar TTI, and lower minimum temperature reached.
Background: Powered transvenous lead extraction (TLE) tools are commonly required to remove the leads that have long implant duration due to fibrotic adhesions. However, comparative data are lacking among different types of TLE tools. Aim: To compare the efficacy and safety of two different rotational mechanical dilator sheaths in retrospectively analyzed patients who underwent TLE. Methods and results: A total of 566 lead extractions from 302 patients using TightRailTM (333 lead extractions from 169 patients) and Evolution® (233 lead extractions from 133 patients) mechanical dilator sheaths were performed between July 2009 and June 2018. Acute and long term outcomes of study groups were compared. There is no statistically significant difference between Evolution® and TightRailTM groups in procedural success (93.9% vs. 94%), clinical success (99.2% vs. 98%) and major complications (3.8% vs. 1.2%), respectively (p>0.05). In multivariate regression analysis, lead dwell time, the number of extracted leads, and baseline leukocyte count was found as independent predictors of procedural success (p<0.05). During the median follow-up of 36.6 (0.2-118) months, all-cause mortality was observed in 73 patients (25.6% in the Evolution® vs. 23.1 in the TightRailTM group, p>0.05). Chronic renal disease, heart failure, and coagulopathy were shown as independent predictors of all-cause mortality in multivariate regression analysis (p<0.05). Conclusions: TLE using TightRailTM or Evoluation® mechanical dilator sheaths is a safe and effective therapeutic option. Both mechanical dilator sheaths showed similar efficacy, safety, and all-cause mortality at acute and long-term follow-up of patients who underwent TLE.
Background: The endoscopic ablation system (EAS) is an established ablation device for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). The novel X3 EAS is now equipped with a contiguous circumferential ablation mode (RAPID mode). Aim: To determine the feasibility of single-sweep ablation using X3. Methods: Consecutive patients who underwent AF ablation using X3 were enrolled. We assessed the acute procedural data focusing on “Single-sweep PVI” defined as PVI with a single energy application using RAPID mode to complete the circular lesion set, and on “first-pass isolation” defined as successful visually guided PVI after initial circular lesion set. Results: One-hundred AF patients (56% male, age 68±10 years, 66% paroxysmal AF) were analyzed. A total of 379 of 383 PVs (99%) were isolated with X3. Single-sweep isolation and first-pass-isolation were achieved in 214 PVs (56%) and in 362 PVs (95%), respectively. Single-sweep isolation rates varied across PVs with higher rates at the superior PVs (61.2% vs. inferior PVs:49.5%, P=0.0239) and at PVs with maximal ostial diameter <24mm (57.6% vs. >24mm: 36.8%, P=0.0151). The mean total procedure and fluoroscopy times were 43.0±10 and 4.0±2 mins, respectively. In none of the patients an acute thromboembolic event (stroke or transient ischemic attack) or a pericardial effusion/tamponade occurred. A single transient phrenic nerve palsy was observed. Conclusion: The new X3 EAS allows for single-sweep PVI in 56% of PVs. The new RAPID ablation mode leads to an improved rate of first-pass isolation associated with very short procedure times without compromising safety.