A novel artificial intelligence based algorithm to reduce wearable cardioverter-defibrillator alarms.

BACKGROUND: The wearable cardioverter defibrillator (WCD) is an important tool in mitigating sudden cardiac death (SCD). The WCD provides patient alarms for detected arrhythmias or electrical noise/artifact. Some patients experience frequent alarms for artifact. We sought to evaluate the effects of a novel artificial intelligence algorithm to reduce alarms related to electrical noise or artifact (advanced arrhythmia discrimination algorithm, AArD). METHODS: A retrospective review of a large commercial database of prescribed WCD. Patients prescribed the WCD during the years 2017 (discrimination algorithm, DA group) or during 2019 (advanced arrhythmia discrimination algorithm, AArD) were analyzed. A total of 96,000 patients were sampled, 48,000 in the control group (using standard direct algorithm, DA) and compared to 48,000 in the intervention AArD (4000 per group per month) for 12 months. The AArD further discriminates ECG signals based on a machine-learning algorithm utilizing intensity and frequency beyond the standard DA. Outcomes regarding alarms, arrhythmias, and safety were analyzed. RESULTS: The AArD algorithm was associated with a significant decrease in frequency of alarms over the course of WCD use; 54% of patients in the AARD versus 27% of DA had 0 alarms (P < .001). In the entire cohort, there was a 56% relative reduction in alarms with the use of AArD. Appropriate arrhythmia treatment time was not significantly different between the groups (44 s DA vs 45 s AArD [p = ns]). CONCLUSIONS: A novel artificial intelligence algorithm reduces alarms without delaying appropriate therapy for VT/VF. These changes may improve compliance and quality of life in patients with a WCD.

Composite Index Tagging for PVI in Paroxysmal AF: A Prospective, Multicenter Postapproval Study.

BACKGROUND: VISITAG SURPOINT (VS)-guided ablation of paroxysmal atrial fibrillation has demonstrated good short- and long-term success rates with low rates of complications in recent, predominantly European, studies. However, there is a lack of multicenter data from the United States. OBJECTIVES: This U.S. study evaluated the safety and effectiveness of VS ablation using a contact force-sensing catheter for the treatment of drug-refractory symptomatic paroxysmal atrial fibrillation. METHODS: The prospective, nonrandomized VS postapproval study was conducted at 32 U.S. sites. Ablation consisted of pulmonary vein isolation with recommended VS index targets (anterior, roof, or ridge: 550; posterior or inferior: 380). Additional non-pulmonary vein triggers were ablated at the investigators' discretion. Subjects were followed for 12 months, including a 3-month blanking period. The primary safety endpoint was the primary adverse event rate up to 7 days postablation. The primary effectiveness endpoint was 12-month freedom from atrial tachyarrhythmia recurrence and an additional set of failure modes based on stringent monitoring (weekly transtelephonic monitoring [TTM] [day 91 through month 5], monthly TTM [months 6 to 12], and any symptomatic cardiac episode using TTM, plus electrocardiogram [at discharge, 1 month, 3 months, 6 months, and 12 months] with 24-hour Holter monitoring [12 months]). RESULTS: Of 283 patients enrolled, 261 had the catheter inserted and underwent ablation (safety cohort); 246 met all eligibility criteria (effectiveness cohort). Mean fluoroscopy time was 2.2 minutes. Mean amount of catheter-delivered fluid was 671 mL; only 18.0% of patients utilized a Foley catheter. Primary safety and effectiveness endpoints were met. The raw primary adverse event rate was 4.3% (14 events, n = 11). At 12 months, the Kaplan-Meier estimate of freedom from primary effectiveness failure was 76.4%; estimates of 12-month freedom from documented atrial fibrillation, atrial tachycardia, or atrial flutter recurrence were 81.5% and 92.7% per stringent monitoring and standard-of-care monitoring (excluding TTM), respectively. The first-pass isolation rate was 83.1%, represented by no acute reconnection after the 30-minute waiting period. Freedom from repeat ablation at 12 months was 94.0%. CONCLUSIONS: The VS postapproval study confirms reproducibility of clinical safety and effectiveness of the standardized VS paroxysmal atrial fibrillation ablation workflow with >80% 12-month freedom from atrial tachyarrhythmia recurrence and first-pass isolation rate of 83.1%. Procedures were performed with minimal fluoroscopy. (Evaluation of VISITAG SURPOINT™ Module With External Processing Unit [EPU]; NCT03624881).

Effectiveness of an algorithm-based care pathway for patients with non-valvular atrial fibrillation presenting to the emergency department.

OBJECTIVE: Atrial fibrillation (AF) carries substantial morbidity and mortality. Evidence-based guidelines have been synthesized into emergency department (ED) AF care pathways, but the effectiveness and scalability of such approaches are not well established. We thus evaluated the impacts of an algorithmic care pathway for ED management of non-valvular AF (EDAFMP) on hospital use and care process measures. METHODS: We deployed a voluntary-use EDAFMP in 4 EDs (1 tertiary hospital, 1 cardiac hospital, 2 community hospitals) of an integrated delivery organization using a multifaceted implementation approach. We compared outcomes between patients with AF treated using the EDAFMP and historical and contemporaneous "usual care" controls, using a propensity-score adjusted generalized estimating equation. Patients with an index ED encounter for a primary visit reason of non-valvular AF (and no excluding concurrent diagnoses) were eligible for inclusion. RESULTS: Preimplementation (January 1, 2016-December 31, 2016), 628 AF patients were eligible; postimplementation (September 1, 2017-June 30, 2019), 1296, including 271 (20.9%) treated with the EDAFMP, were eligible. EDAFMP patients were less likely to be admitted than both historical (adjusted odds ratio [aOR], 95% confidence interval [CI]: 0.45, 0.29-0.71) and contemporaneous controls (aOR, 95%CI: 0.63, 0.46-0.86). ED visits and hospital readmissions over 90 days subsequent to index ED encounters were similar between postimplementation EDAFMP and usual care groups. EDAFMP patients were more likely to be prescribed anticoagulation (38% v. 5%, P < 0.001) and be referred to a cardiologist (93% vs 29%, P < 0.001) versus the comparator group. CONCLUSION: EDAFMP use is associated with decreased hospital admission during an index ED encounter for non-valvular AF, and improved delivery of AF care processes.

Positive Clinical Benefit on Patient Care, Quality of Life, and Symptoms After Contact Force-Guided Radiofrequency Ablation in Persistent Atrial Fibrillation: Analyses From the PRECEPT Prospective Multicenter Study.

BACKGROUND: There is limited evidence on the long-term clinical benefits of catheter ablation in patients with persistent atrial fibrillation. METHODS: PRECEPT was a prospective, multicenter, single-arm Food and Drug Administration-regulated investigational device exemption clinical study. Patients were followed up to 15 months after ablation. Outcomes included use of antiarrhythmic drugs, rate of cardioversions and cardiovascular hospitalization, Atrial Fibrillation Effect on Quality-of-Life score, and Canadian Cardiovascular Society Severity of Atrial Fibrillation score. RESULTS: A total of 333 enrolled persistent atrial fibrillation patients underwent ablation. The cardioversion rate decreased by 83% at the 9- to 15-month follow-up. Antiarrhythmic drug utilization decreased by 69% at 12 to 15 months post-ablation. The Kaplan-Meier estimate of freedom from cardiovascular hospitalization was 84.2% (95% CI, 80.2%-88.2%) at 15 months. Consistent improvements in mean Atrial Fibrillation Effect on Quality-of-Life composite (+50.0) were seen at 6 months, sustained at 15 months, and exceeded the minimum clinically important difference. Improvements in Atrial Fibrillation Effect on Quality-of-Life scores were significantly better among participants without documented atrial arrhythmia recurrences. By Canadian Cardiovascular Society Severity of Atrial Fibrillation symptom classification, >80% of patients were asymptomatic (class 0) at 15 months post-ablation compared with only 0.7% at baseline. CONCLUSIONS: Contact force-guided radiofrequency ablation of persistent atrial fibrillation was associated with a significant decrease in antiarrhythmic drug use, cardioversion rate, and hospitalization. Clinically meaningful improvements in quality of life were observed in all patients. The majority of the patients (>80%) were asymptomatic at 15 months post-ablation. The positive clinical impact of improved quality of life and reduced health care utilization may help with shared decision-making in persistent atrial fibrillation treatment. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02817776.

Persistent Atrial Fibrillation Ablation With Contact Force-Sensing Catheter: The Prospective Multicenter PRECEPT Trial.

OBJECTIVES: This study sought to evaluate the safety and effectiveness of catheter ablation of persistent atrial fibrillation (PsAF) using a porous tip contact force-sensing catheter. BACKGROUND: Although the safety and effectiveness of catheter ablation of paroxysmal atrial fibrillation are established, there are limited data on outcomes in patients with PsAF. As such, no ablation catheter is currently approved by the Food and Drug Administration for PsAF ablation. METHODS: The prospective, multicenter, nonrandomized PRECEPT (Prospective Review of the Safety and Effectiveness of the THERMOCOOL SMARTTOUCH SF Catheter Evaluated for Treating Symptomatic PersistenT AF) study was conducted at 27 sites in the United States and Canada. Enrollment criteria included documented symptomatic PsAF and nonresponse or intolerance to ≥1 antiarrhythmic drug (Class I or III). An individualized treatment approach was used including pulmonary vein isolation with ablation of additional targets permitted at the investigators' discretion. To optimize treatment outcomes, a 3-month post-ablation medication adjustment period followed by a 3-month therapy consolidation period were included. Arrhythmia recurrences were stringently monitored by monthly and symptomatic transtelephonic monitoring, electrocardiography, and Holter monitoring for up to 15 months after ablation. RESULTS: Of 381 enrolled participants, 348 had the investigational catheter inserted and underwent ablation. The primary adverse event rate was 4.1% (15 events in 14 participants). Kaplan-Meier analyses estimated a primary effectiveness success rate of 61.7% and a clinical success rate of 80.4% at 15 months. CONCLUSIONS: The results demonstrate the clinical safety and effectiveness of PsAF ablation using contact force-sensing technologies. The primary adverse event was within the expected range and similar to those reported in historical studies of paroxysmal AF ablation. (Prospective Review of the Safety and Effectiveness of the THERMOCOOL SMARTTOUCH SF Catheter Evaluated for Treating Symptomatic PersistenT AF; NCT02817776).

Safety and efficiency of porous-tip contact-force catheter for drug-refractory symptomatic paroxysmal atrial fibrillation ablation: results from the SMART SF trial.

Aims: THERMOCOOL SMARTTOUCH® SF Catheter is a new contact-force (CF)-sensing catheter with 56-hole porous tip designed for improved cooling and reduced fluid delivery compared with a standard 6-hole open-irrigated catheter. The SMART SF study examined the periprocedural safety, acute effectiveness, and procedural efficiency of the catheter for drug-refractory symptomatic paroxysmal atrial fibrillation (PAF) ablation. Methods and results: The prospective, open-label, non-randomized SMART-SF was conducted at 17 US sites. Circumferential pulmonary vein (PV) isolation was performed with confirmation of entrance block in all PVs. Stable ablation sites were identified using CARTO VISITAG™ Module. Primary adverse events (AEs; ≤1 week of index procedure), periprocedural AEs within 30 days of ablation procedure, acute effectiveness (confirmation of entrance block for targeted PVs), CF, and procedural parameters were assessed. Overall, 165 patients were enrolled (mean age, 62.7 years; male, 57.9%; white, 97%; left ventricular ejection fraction, 60.1 ± 7%; left atrium diameter, 38.8 ± 6 mm); 159 underwent radiofrequency ablation and comprised the safety cohort. Primary safety performance criteria were met: primary AE rate was 2.5% (4/159; cardiac tamponade [n = 2], thrombo-embolism [n = 1], transient ischaemic attack [n = 1]). All primary AEs resolved/improved within the 1-month follow-up period. Acute procedural effectiveness was attained in 96.2% (95% confidence interval: 92.0-98.6%) of patients. Procedure time, fluoroscopy time, and fluid delivered were observed in comparison to predecessor catheters. Conclusion: In the SMART-SF trial, the predetermined safety performance goal was met, demonstrating the safety and acute effectiveness of the THERMOCOOL SMARTTOUCH® SF Catheter for PAF ablation.

Pharmacology, benefits, unaddressed questions, and pragmatic issues of the newer oral anticoagulants for stroke prophylaxis in non-valvular atrial fibrillation and proposal of a management algorithm.

This systematic review aims to provide an update on pharmacology, efficacy and safety of the newer oral direct thrombin and factor Xa inhibitors, which have emerged for the first time in ~60 years as cogent alternatives to warfarin for stroke prophylaxis in non-valvular atrial fibrillation. We also discuss on four of the most common clinical scenarios with several unsolved questions and areas of uncertainty that may play a role in physicians' reluctance to prescribe the newer oral anticoagulants such as 1) patients with renal failure; 2) the elderly; 3) patients presenting with atrial fibrillation and acute coronary syndromes and/or undergoing coronary stenting; and 4) patients planning to receive AF ablation with the use of pulmonary vein isolation. New aspects presented in current guidelines are covered and we also propose an evidence-based anticoagulation management algorithm.