Association between high-density mapping of atypical atrial flutter, clinical outcomes and healthcare utilization.

BACKGROUND: Success of atypical atrial flutter (AAFL) ablation has historically been limited by difficulty mapping the complex re-entrant circuits involved. While high-density (HD) mapping has become commonplace in clinical practice, there are limited data on outcomes of HD versus non-HD mapping for AAFL ablation. OBJECTIVE: To compare clinical outcomes and healthcare utilization using HD mapping versus non-HD mapping for AAFL ablation. METHODS: Retrospective analysis of all AAFL procedures between 2005 and 2022 at an academic medical center was conducted. Procedures utilizing a 16-electrode HD Grid catheter and Precision mapping system were compared to procedures using prior generation 10-20 electrode spiral catheters and the Velocity system (Abbott, IL). Cox regression models and Poisson regression models were utilized to examine procedural and healthcare utilization outcomes. Models were adjusted for left ventricular ejection fraction, CHA2DS2-VASc, and history of prior ablation. RESULTS: There were 108 patients (62% HD mapping) included in the analysis. Baseline clinical characteristics were similar between groups. Use of HD mapping was associated with a higher rate of AAFL circuit delineation (92.5% vs. 76%; p = .014) and a greater adjusted procedure success rate, defined as non-inducibility at procedure end, (aRR (95% CI) 1.26 (1.02-1.55) p = .035) than non-HD mapping. HD mapping was also associated with a lower rate of ED visits (aIRR (95% CI) 0.32 (0.14-0.71); p = .007) and hospitalizations (aIRR (95% CI) 0.32 (0.14-0.68); p = .004) for AF/AFL/HF through 1 year. While there was a lower rate of recurrent AFL through 1 year among HD mapping cases (aHR (95% CI) 0.60 (0.31-1.16) p = .13), statistical significance was not met likely due to the low sample size and higher rate of ambulatory rhythm monitoring in the HD group (61% vs. 39%, p = .025). CONCLUSION: Compared to non-HD mapping, AAFL ablation with HD mapping is associated with improvements in the ability to define the AAFL circuit, greater procedural success, and a reduction in the number of ED visits and hospitalization for AF/AFL/HF.

Implementation of an intravenous sotalol initiation protocol: Implications for feasibility, safety, and length of stay.

INTRODUCTION: Oral sotalol initiation requires a multiple-day, inpatient admission to monitor for QT prolongation during loading. A 1-day intravenous (IV) sotalol loading protocol was approved by the United States Food and Drug Administration in March 2020, but limited data on clinical use and administration currently exists. This study describes implementation of an IV sotalol protocol within an integrated health system, provides initial efficacy and safety outcomes, and examines length of stay (LOS) compared with oral sotalol initiation. METHODS: IV sotalol was administered according to a prespecified initiation protocol to adult patients with refractory atrial or ventricular arrhythmias. Baseline characteristics, safety and feasibility outcomes, and LOS were compared with patients receiving oral sotalol over a similar time period. RESULTS: From January 2021 to June 2022, a total of 29 patients (average age 66.0 ± 8.6 years, 27.6% women) underwent IV sotalol load and 20 patients (average age 60.4 ± 13.9 years, 65.0% women) underwent oral sotalol load. The load was successfully completed in 22/29 (75.9%) patients receiving IV sotalol and 20/20 (100%) of patients receiving oral sotalol, although 7/20 of the oral sotalol patients (35.0%) required dose reduction. Adverse events interrupting IV sotalol infusion included bradycardia (seven patients, 24.1%) and QT prolongation (three patients, 10.3%). No patients receiving IV or oral sotalol developed sustained ventricular arrhythmias before discharge. LOS for patients completing IV load was 2.6 days shorter (mean 1.0 vs. 3.6, p < .001) compared with LOS with oral load. CONCLUSION: IV sotalol loading has a safety profile that is similar to oral sotalol. It significantly shortens hospital LOS, potentially leading to large cost savings.

Esophageal temperature management during cryoballoon ablation for atrial fibrillation.

INTRODUCTION: Esophageal thermal injury (ETI) is a well-recognized complication of atrial fibrillation (AF) ablation. Previous studies have demonstrated that direct esophageal cooling reduces ETI during radiofrequency AF ablation. The purpose of this study was to evaluate the use of an esophageal warming device to prevent ETI during cryoballoon ablation (CBA) for AF. METHODS: This prospective, double-blinded study enrolled 42 patients with symptomatic AF undergoing CBA. Patients were randomized to the treatment group with esophageal warming (42°C) using recirculated water through a multilumen, silicone tube inserted into the esophagus (EnsoETM®; Attune Medical) (WRM) or the control group with a luminal single-electrode esophageal temperature monitoring probe (LET). Patients underwent upper endoscopy esophagogastroduodenoscopy (EGD) the following day. ETI was classified into four grades. RESULTS: Baseline patient characteristics were similar between groups. Procedural characteristics including number of freezes, total freeze time, early freeze terminations, coldest balloon temperature, procedure duration, posterior wall ablation, and proton pump inhibitor and transesophageal echocardiogram use before procedure were not different between groups. The EGD was completed in 40/42 patients. There was significantly more ETI in the WRM group compared to the LET group (n = 8 [38%] vs. n = 1 [5%], p = 0.02). All ETI lesions were grade 1 (erythema) or 2 (superficial ulceration). Total freeze time in the left inferior pulmonary vein was predictive of ETI (360 vs. 300 s, p = 0.03). CONCLUSION: Use of a luminal heat exchange tube for esophageal warming during CBA for AF was paradoxically associated with a higher risk of ETI.

Patient-reported outcomes after cryoballoon ablation are equivalent between moderate sedation and general anesthesia.

INTRODUCTION: Moderate sedation (MS) during cryoballoon ablation (CBA) avoids risks of general anesthesia (GA) and improves electrophysiology (EP) lab throughput. However, one barrier to the use of MS is the potential for patient discomfort. The objective of this study was to compare patient-reported outcome measures following CBA for paroxysmal atrial fibrillation (pAF) under MS and GA. METHODS AND RESULTS: Consecutive patients undergoing a first CBA for pAF under GA or MS were prospectively enrolled. The sedation method was assigned based on patient and provider preference, and perceived airway risk. The primary outcomes were quality of recovery (measured using a validated 40 question survey; QoR-40) and likelihood to recommend (LTR) the procedure and sedation method (measured by Likert scale). Secondary outcomes were acute pulmonary vein (PV) isolation rate, procedure, fluoroscopy and ablation times, and complication rates. Forty-seven GA and 53 MS patients were included. The mean age was 64.9 ± 9.4 years and mean CHA2 DS2 -VASc score was 2.0 ± 1.4. QoR-40 scores were 184.6 ± 16.4 for GA and 187.6 ± 10.2 for MS (P = .28). LTR responses were similar between groups. Mean procedure times were 148.2 ± 56.0 minutes for GA and 129.4 ± 31.4 minutes for MS (P = .038). Fluoroscopy and ablation times were similar between groups. A total of 100% (409/409) of PVs were acutely isolated. One hemopericardium occurred in the MS group requiring pericardiocentesis. CONCLUSION: MS for CBA offers an alternative to GA that is safe and well-tolerated by patients with comparable success rates and improved EP lab throughput.

Long-term electrical performance of Attain Performa quadripolar left ventricular leads with all steroid-eluting electrodes: Results from a large worldwide clinical trial.

BACKGROUND: Steroid-eluting (SE) electrodes suppress local inflammation and lower pacing capture thresholds (PCT); however, their effectiveness on quadripolar left ventricular (LV) leads in the cardiac vein is not fully studied. We evaluated the effectiveness of SE on all four LV pacing electrodes in human subjects enrolled in the Medtronic Attain® Performa™ quadripolar LV lead study. METHODS: A total of 1,097 subjects were included in this evaluation. At each follow-up visit (1, 3, 6, and 12 months), LV PCT and pacing impedance were measured using either manual or automated testing methods. Summary statistics for PCT and impedance values were obtained for implant and each scheduled follow-up visit for all lead models. RESULTS: Average extended bipolar (LV electrode to right ventricular Coil) PCTs for the four LV SE pacing electrodes (LV1, LV2, LV3, and LV4) on the three shapes of the quadripolar LV leads were 1.06 ± 0.97 V, 1.38 ± 1.26 V, 1.51 ± 1.33 V, and 2.25 ± 1.63 V, respectively, at 0.5-ms pulse width. PCTs remained low and stable throughout the 12-month follow-up period. CONCLUSION: This clinical trial demonstrated that SE on all LV pacing electrodes is associated with low and stable PCTs for all quadripolar LV lead electrodes, resulting in multiple viable vectors for LV pacing. The large number of available vectors facilitates basal pacing, avoidance of PNS, and potentially prolongs generator longevity due to lower PCTs.

Moderate Sedation Reduces Lab Time Compared to General Anesthesia during Cryoballoon Ablation for AF Without Compromising Safety or Long-Term Efficacy.

BACKGROUND: Cryoballoon ablation (CBA) for paroxysmal atrial fibrillation (pAF) can be performed under general anesthesia (GA) or moderate sedation (MS). Our objective was to compare the effectiveness, safety, procedure duration, and time spent in the electrophysiology (EP) laboratory for CBA performed under GA and MS. METHODS: Patients undergoing a first CBA for pAF were identified. Patients received either GA administered by an anesthesiologist or MS with midazolam and fentanyl administered by EP laboratory staff. Total time in laboratory (sum of procedure and nonprocedure time); fluoroscopy time; freedom from documented AF, atrial flutter, and atrial tachycardia (FFAF); acute pulmonary vein isolation (PVI) rate; and 30-day complication rate were assessed. RESULTS: A total of 55 patients received GA and 119 patients received MS. PVI success rate was 100% in GA and 98.1% in MS (P = 0.04). Total laboratory time was longer for GA (280.4 ± 54.1 minutes vs 245.5 ± 54.7 minutes; P < 0.001), related to longer nonprocedure time (92.2 ± 28.8 minutes GA vs 71.0 ± 30.0 minutes MS; P < 0.001), but not procedure time (188.3 ± 49.3 minutes GA vs 174.5 ± 50.2 minutes MS; P = 0.09). FFAF was not significantly different over a median follow-up duration of 0.9 (interquartile range 0.4-1.9) years (61.8% GA vs 63.0% MS; log-rank P = 0.90). There was no significant difference in complication rate. CONCLUSION: Compared to GA, MS during CBA for pAF was independently associated with shorter total EP laboratory time without compromising FFAF or complication rates.

Cryoballoon versus radiofrequency catheter ablation for paroxysmal atrial fibrillation.

BACKGROUND: Catheter ablation is an established treatment for atrial fibrillation (AF). Cryoballoon ablation (CBA) has emerged as an alternative to radiofrequency ablation (RFA). However, there are few data comparing these modalities for treatment of paroxysmal AF (pAF) in the U.S. POPULATION: The purpose of this study was to compare procedural times, safety, and efficacy of CBA against RFA. METHODS: A single-center prospective cohort study evaluated patients who underwent catheter ablation for pAF using CBA or RFA between January 1, 2010 and October 31, 2013. Patients with prior ablation and those without rhythm follow-up for at least 3 months were excluded. The primary end point was freedom from AF, atrial flutter, and atrial tachycardia (FFAF) >30 seconds after a 3-month blanking period without requirement for antiarrhythmic drugs. We also compared rates of successful pulmonary vein isolation (PVI), fluoroscopy and procedure times, and major complication rates. RESULTS: A total of 201 patients were included (CBA = 101, RFA = 100). The rate of successful PVI was 99.3% in CBA versus 97.4% in RFA (P = 0.08). Procedure times were shorter with CBA (192.9 ± 44.0 minutes vs 283.7 ± 78.0 minutes, P < 0.001) as well as total fluoroscopy times (46.0 ± 22.4 minutes vs 73.0 ± 30.1 minutes, P < 0.001). Overall complication rates were equivalent; however, fewer cardiac perforations occurred with CBA (0% vs 4%, P = 0.042). The 1-year FFAF rates were 60.3% for CBA and 61.1% for RFA (log rank P = 0.93). CONCLUSION: CBA was associated with equivalent 1-year FFAF rate as RFA for pAF. Procedure and fluoroscopy times were shorter for CBA and fewer cardiac perforations occurred.

Prevalence and predictors of cable extrusion and loss of electrical integrity with the Riata defibrillator lead.

INTRODUCTION: Recently, a medical advisory was issued regarding the Riata and Riata ST silicone endocardial defibrillator leads (St. Jude Medical, Sylmar, CA, USA) addressing the issue of conductor cables extruding in an "inside-out" fashion from the main body of the lead. However, little data exist to guide our management of patients with these leads. METHODS AND RESULTS: A retrospective analysis was performed of 84 patients with a Riata lead who underwent cine-fluoroscopy and electrical evaluation as part of a screening program to assess for cable extrusion. All leads screened were dual-coil except for one single-coil lead. Of 84 patients, 23 patients (27.4%) had fluoroscopic evidence of cable extrusion. Multivariate analysis showed that the duration of time since lead implant and the presence of multiple right ventricular leads were significantly associated with cable extrusion. All 23 patients had normal electrical parameters on routine device interrogation. Fifteen of these 23 patients (65%) with extruded cables had high-voltage shocks within 12 months of lead screening; only one patient demonstrated postshock electrical abnormalities. CONCLUSIONS: The prevalence of cable extrusion in dual-coil Riata leads is significantly higher at 27.4% than previously reported. The duration of time since implantation and the presence of multiple right ventricular leads are associated with cable extrusion. High-energy shocks did not reveal electrical abnormalities in most patients with cable extrusion.

Initial experience using a radiofrequency powered transseptal needle.

INTRODUCTION: The purpose of this study was to determine the safety and efficacy of using a novel radiofrequency (RF) powered transseptal needle to perform transseptal puncture (TSP). METHODS: TSP was performed in 35 consecutive patients undergoing left-sided catheter ablation (mean age = 51 years; male = 71%) using a RF powered transseptal needle (NRG, Adult Large and Standard Curve C1, 71 cm, Baylis Medical Company, Inc.). Prior TSP had been performed in 34% of patients. The transseptal apparatus was positioned with the tip of the dilator engaged in the fossa ovalis. RF energy was delivered to the tip of the transseptal needle using a proprietary RF generator at 10 W for 2 seconds as gentle pressure was applied to the needle. RESULTS: In 5 of the 41 TSPs, the needle crossed into the left atrium before RF energy was delivered. In 35 of the remaining 36 punctures, the needle was successfully advanced into the left atrium after application of RF current. In 1 patient, the TSP with the powered needle was unsuccessful but was accomplished using a standard needle. The only complication was a transient right atrial thrombus, which occurred in 2 patients. CONCLUSION: A radiofrequency powered transseptal needle can be used to perform TSP safely and successfully without the need for significant mechanical force, even in patients who have undergone TSP previously. Additional studies are needed to determine whether a powered transseptal needle should be used routinely.