Cryoballoon ablation for paroxysmal atrial fibrillation: mid-term outcome evaluated by ECG monitoring with an implantable loop recorder

Continuous Monitoring with Implantable Loop Recorders After Cryoballoon Ablation: Impact on Atrial Fibrillation Recurrence and Therapeutic Management in Era of Artificial Intelligence

Objectives: Atrial fibrillation (AF) is the most common sustained arrhythmia associated with stroke, heart failure, and increased mortality. Due to its efficacy and safety, cryoballoon ablation (CBA) is widely accepted for rhythm control; however, long-term AF recurrence remains a challenge. Continuous monitoring with implantable loop recorders (ILRs) enhanced by artificial intelligence (AI) can detect both symptomatic and asymptomatic episodes, potentially optimizing patient management. This analysis assessed the long-term effectiveness of CBA in maintaining sinus rhythm and investigated the role of ILR-guided monitoring in enhancing therapeutic decisions. Methods: Data from 91 patients with paroxysmal or persistent atrial fibrillation (AF) who underwent pulmonary vein isolation using cryoballoon ablation at four Italian centers between April 2022 and April 2024 were analyzed. All patients received an insertable loop recorder (ILR) before or during hospitalization for ablation, allowing for the continuous remote monitoring of arrhythmias. Baseline demographics, procedural details, AF occurrence, AF burden (calculated as the total duration of all AF episodes occurring within a day and categorized by episode duration), therapeutic adjustments, and the effect of artificial intelligence (AI) on data processing were evaluated. Results: The cohort's average age was 62.4 years, with 24.2% of participants being female. Physician-confirmed AF recurrence was noted in 26.7% of patients at 12 months and 49.5% at 24 months. The device data indicated a daily AF burden of ≥6 min in 47.2% at 12 months, with 25.9% surpassing 1 h. AI algorithms decreased false-positive alerts by 21%, resulting in an estimated saving of 19 clinician hours. In patients with pre-ablation ILR data, the median AF burden significantly decreased from 7% to 0.2% (p = 0.017). ILR-guided monitoring affected treatment adjustments, leading to the discontinuation of antiarrhythmic therapy in 36 patients and redo ablations in 8. Conclusions: Continuous ILR monitoring, combined with AI-driven analysis, enables the detection of AF recurrences and burden, thereby facilitating timely therapeutic adjustments.

False-positive alarms in patients with implantable loop recorder followed by remote monitoring: A systematic review

Remote Monitoring (RM) has been shown to provide useful information about arrhythmic events in patients with implantable loop recorders (ILRs), however there is few and conflicting data about the false positive (FP) alarms burden and characteristics among ILR recipients. The aim of the present systematic review was to evaluate incidence and characteristics of FP alarms among ILR patients followed by RM. We developed a systematic research in Embase, MEDLINE and PubMed databases and selected all papers focused on false positive ILR transmissions published from June 1, 2013 to June 1, 2023. Case reports, meeting summaries, posters and simple reviews were excluded. Twelve reports were finally selected, including five prospective and seven retrospective studies. Information about population characteristics, device type and setting, overall transmissions and FP alarms and any adopted strategies to reduce them were extracted from an overall population of 3.305 patients. FP alarms were 59.7% of the overall remote transmissions and were found in 1/5 of the analyzed population. FP alarms for atrial fibrillation were the most common cause of false transmissions and were mainly due to premature atrial and ventricular complexes. No clinical predictors of FP alarms were identified, except for nonparasternal ILR implantation site. Since the overload work due to FP alarms might reduce the benefit of remote monitoring of ILR patients, the device optimization is an important step until an help from machine-learning algorithms is available.

Prevalence and Impact of Poorly Controlled Modifiable Risk Factors Among Patients Who Underwent Atrial Fibrillation Ablation

Managing atrial fibrillation (AF) risk factors (RFs) improves ablation outcomes in obese patients. However, real-world data, including nonobese patients, are limited. This study examined the modifiable RFs of consecutive patients who underwent AF ablation at a tertiary care hospital from 2012 to 2019. The prespecified RFs included body mass index (BMI) ≥30 kg/m², >5% fluctuation in BMI, obstructive sleep apnea with continuous positive airway pressure noncompliance, uncontrolled hypertension, uncontrolled diabetes, uncontrolled hyperlipidemia, tobacco use, alcohol use higher than the standard recommendation, and a diagnosis-to-ablation time (DAT) >1.5 years. The primary outcome was a composite of arrhythmia recurrence, cardiovascular admissions, and cardiovascular death. In this study, a high prevalence of preablation modifiable RFs was observed. More than 50% of the 724 study patients had uncontrolled hyperlipidemia, a BMI ≥30 mg/m², a fluctuating BMI >5%, or a delayed DAT. During a median follow-up of 2.6 (interquartile range 1.4 to 4.6) years, 467 patients (64.5%) met the primary outcome. Independent RFs were a fluctuation in BMI >5% (hazard ratio [HR] 1.31, p = 0.008), diabetes with A_1c ≥6.5% (HR 1.50, p = 0.014), and uncontrolled hyperlipidemia (HR 1.30, p = 0.005). A total of 264 patients (36.46%) had at least 2 of these predictive RFs, which was associated with a higher incidence of the primary outcome. Delayed DAT over 1.5 years did not alter the ablation outcome. In conclusion, substantial portions of patients who underwent AF ablation have potentially modifiable RFs that were not well controlled. Fluctuating BMI, diabetes with hemoglobin A_1c ≥6.5%, and uncontrolled hyperlipidemia portend an increased risk of recurrent arrhythmia, cardiovascular hospitalizations, and mortality after ablation.

Mechanism and management of atrial fibrillation in the patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) is a highly prevalent disorder in patients with atrial fibrillation (AF). Although there has been an increase in the incidence of AF due to the aging population, it has been reported that OSA is still underdiagnosed because many patients remain asymptomatic or unaware of the symptoms associated with OSA, such as daytime sleepiness. Untreated OSA reduces the effectiveness of AF treatment, regardless of pharmacological or non-pharmacological modes of therapy, such as catheter ablation. Experimental and clinical studies have shown that OSA pathophysiology is multifactorial, comprising of hypoxemia, hypercapnia, autonomic dysfunction, negative intrathoracic pressure changes, and arousals of OSA, and lead to AF. Both the acute and long-term effects of obstructive apnea episodes are involved in the development of an arrhythmogenic substrate of AF. Undiagnosed OSA causes underutilized opportunities for more effective AF management. Therefore, it is important to screen for OSA in all patients being considered for rhythm control therapy. However, regardless of the growing evidence of the negative prognostic impact of OSA, there is a lack of awareness regarding this connection not only among patients but also among cardiologists and arrhythmia specialists. There is a barrier to performing a systemic screening for OSA in clinical practice. Therefore, it is important to establish a comprehensive OSA care team for the efficient diagnosis and treatment of OSA. This review provides the current understanding of OSA and its relationship to AF and the importance of the diagnosis and management of OSA in AF.

Implantable loop recorders in patients with atrial fibrillation

INTRODUCTION

Implantable loop recorders (ILRs) provide practitioners with high-quality electrocardiographic data over an extended monitoring period. These data can guide the diagnosis and management of patients with atrial fibrillation (AF).

AREAS COVERED

This review summarizes the available evidence and consensus statements supporting the use of ILRs in the detection of AF, as well as monitoring of patients with known AF. Future directions for research are also discussed.

EXPERT OPINION

ILRs are the gold standard for detecting AF, providing superior diagnostic yield compared to other modes of ambulatory electrocardiography monitoring. Both experimental evidence and consensus statements support the use of ILRs in clinical settings where the diagnosis of AF may significantly change management, or where a high degree of sensitivity is needed. ILRs may also be used to monitor patients following AF ablation. More evidence is needed to better inform how ILR-detected AF should change management.

[Potential risk factors of atrial fibrillation recurrence after cryoballoon ablation]

Aim      To identify risk factors for recurrence of atrial fibrillation (AF) following cryoballoon ablation (CBA).Material and methods  This prospective study included patients with paroxysmal AF who had undergone CBA (141 patients, median age 60 years, 3% men). The evaluation prior to CBA included clinical instrumental parameters (electrocardiography (ECG), 24-h ECG monitoring, echocardiography, contrast-enhanced cardiac multispiral computed tomography). Also, possible intraoperative indexes that could affect the CBA effectivity, were evaluated. The postoperative follow-up duration was 12 months. Effectivity was assessed during in-person visits at 3, 6, and 12 months, when questioning of patients and 24-h ECG monitoring were performed. CBA was considered ineffective if the patient had recurrences of any atrial tachyarrhythmia longer than 30 sec after the end of the 3-month "blind" period.Results During the 12-month follow-up, recurrences of atrial tachyarrhythmia were observed in 46 (32.6 %) patients. Patients with ineffective CBA more frequently had AF during the first 3 months (71.7 % vs. 11.6 %; р<0.001). Such patients had a history of multiple ineffective treatments with antiarrhythmic drugs (AAD), common pulmonary venous (PV) collector (41.3 % vs. 20.0 %; р=0.008), and stroke/recurrent ischemic attacks (15.2 % vs. 5.2 %; р=0.047). Multifactorial regression analysis showed that the factors of AF recurrence included common PV collector (relative risk (RR) 2.35; 95 % confidence interval (CI) 1.29-4.25; р=0.005), multiple ineffective AADs (RR 1.42; 95 % CI 1.08-1.86; р=0.011), and early AF recurrence (RR 7.57; 95 % CI 3.84-14.90; р<0.001).Conclusion      Common PV collector and multiple ineffective AADs are risk factors of ineffective CBA. Early recurrences during the first 3 postoperative months are a significant risk factor of long-term AF recurrences.

Outcomes of Implantable Loop Monitoring in Patients <21 Years of Age

Rhythm-symptom correlation in pediatric patients with syncope/palpitations or at risk cohorts can be difficult, but important given potential associations with treatable or malignant arrhythmia. We sought to evaluate the use, efficacy and outcomes of implantable loop recorders (ILR) in pediatrics. We conducted a retrospective study of pediatric patients (<21 years) with implanted ILR. Patient/historical characteristics and ILR indication were obtained. Outcomes including symptom documentation, arrhythmia detection and ILR based changes in medical care were identified. Comparison of outcomes were performed based on implant indication. Additional sub-analyses were performed in syncope-indication patients comparing those with and without changes in clinical management. A total of 116 patients with ILR implant were identified (79 syncope/37 other). Symptoms were documented 58% of patients (syncope 68% vs nonsyncope 35%; p = 0.002). A total of 37% of patients had a documented clinically significant arrhythmia and 25% of patients had a resultant change in clinical management independent of implant indication. Arrhythmia type was dependent on implant indication with nonsyncope patients having more ventricular arrhythmias. Pacemaker/defibrillator implantation and mediation management were the majority of the clinical changes. In conclusion, IRL utilization in selected pediatric populations is associated with high efficacy and supports clinical management. ILR efficacy is similar regardless of indication although patients with nonsyncope indications had a higher frequency of ventricular arrhythmias as opposed to asystole and heart block in syncope indications. The majority of arrhythmic findings occurred in the first 12 months, and new technology that would allow for less invasive monitoring for 6 to 12 months may be of value.