Cardiac Monitoring Research Articles

Timing of detection of atrial fibrillation recurrence in patients with transient new-onset atrial fibrillation detected during hospitalization for noncardiac surgery or medical illness

Abstract Background Approximately one third of patients who experience transient new-onset atrial fibrillation (AF) during a hospitalization for noncardiac surgery or medical illness will have recurrent AF within 1 year. Purpose To estimate the expected rate of detection of AF recurrence using different durations of continuous ECG monitoring during follow-up of patients who have had AF occurring transiently during physiologic stress. Methods We used continuous ECG data from participants enrolled in the AFOTS Follow-up Study. Participants had transient new-onset AF while hospitalized for noncardiac surgery or medical illness and were discharged from hospital in sinus rhythm. We calculated the median time to detection of the first recurrent AF episode and the proportion of recurrent AF events that would be captured with an ECG monitor worn for 24 h, 48 h, 7 days and 14 days, and with a repeated 14-day monitor worn approximately 6 months after the first monitor. Results A total of 139 participants (41.0% female, median CHA2DS2-VaSC Score 3.0 (Interquartile Range [IQR] 2.0- 4.0)) wore at least one ECG monitor for a median of 13.5 days (IQR 11.7-13.8). A second ECG monitor was worn by 83 (59.7%) participants for a median of 12.9 days (IQR 10.0-13.9); the second monitor was worn a median of 175.0 days (IQR 153.0-216.0) after the first monitor. Among the study participants in whom recurrent AF was detected (n = 40, 28.8%), the median time to AF lasting at least 30 seconds was 128.0 hours (IQR 32.5-232.5). The proportion of AF recurrences detected after more than 24 hours of monitoring was 75.0% (n = 30). The yield of AF detection increased with longer monitoring times (Figure 1). AF was detected in 5.0% of participants at 24 hours, 5.8% at 48 hours, 6.5% at 72 hours, 12.2% at 7 days, 21.6% at 14 days and in 28.8% of participants by the end of the second 14-day monitor. Conclusions In patients who have experienced transient new-onset AF during a hospitalization for noncardiac surgery or medical illness, the rate of capture of AF recurrence in follow-up increases with longer monitoring durations. 14-day monitors capture nearly 4 times as many AF events as 48 h monitors.

Cost-effectiveness of atrial fibrillation detection with insertable cardiac monitors in large-artery or small-vessel disease stroke in the United Kingdom

Abstract Background The randomised STROKE-AF trial demonstrated clinical effectiveness of continuous cardiac monitoring to detect atrial fibrillation (AF) with insertable cardiac monitors (ICMs) for patients with ischemic stroke attributed to large-artery or small-vessel disease (LAD/SVD). ICMs were ten-fold more effective at detecting AF compared to the standard of care (SoC). However, cost-effectiveness of this monitoring strategy is unknown. Purpose The aim of this economic evaluation was to assess the cost-effectiveness of long-term continuous cardiac monitoring via ICMs, for detection of AF (and, in event of AF diagnosis, subsequent anticoagulation), in patients with ischemic stroke attributed to large-or-small vessel disease compared to the SoC of conventional follow up in the United Kingdom. Methods We constructed a Markov model with a cycle length of three months and a lifetime horizon to conduct the cost-effectiveness analysis, from the National Health Service (NHS) perspective. Costs and health-related benefits were discounted at an annual rate of 3.5%. We expressed outcomes in terms of quality-adjusted life-years (QALYs). Patient characteristics in the analysis and detection probabilities were based on the STROKE-AF trial. Detection of AF resulted in a switch in treatment from antiplatelet to direct oral anticoagulant (DOAC). Risk of cerebrovascular events were dependent on a patient’s AF detection status and subsequent treatment. Scenario, deterministic, and probabilistic sensitivity analyses were conducted to test the robustness of the base-case incremental cost-effectiveness ratio (ICER) and account for uncertainties in the model. We stratified patients into risk groups based on CHA2DS2-VASc scores and risk of AF detection. Results The base case incremental cost-effectiveness ratio of the implantation of an ICM was £15,485 per QALY, substantially under the NICE willingness-to-pay threshold of £20,000-£30,000 per QALY. ICM implantations resulted in 0.139 QALYs gained per patient at an incremental cost of £2,147. There were 0.054 fewer stroke events per patient in the ICM arm versus SoC. Results were robust under sensitivity analysis. Conclusion ICMs were cost-effective compared to SoC for detection of AF in patients with LAD/SVD stroke in the United Kingdom driven largely by more stroke events avoided. Subgroup analysis showed that ICMs were more cost-effective in patients with higher CHA2DS2-VASc scores and those with a higher individual risk of AF.Markov Model SchematicSummary ICER Results and Events avoided

Cardioneuroablation guided by extracardiac vagal stimulation for cardioinhibitory vasovagal syncope

Abstract Introduction Vasovagal Syncope (VVS) is often linked to abnormal autonomic reflexes, with hypervagotonia identified as a key mechanism, especially in cases with pronounced cardioinhibition. Cardioneuroablation (CNA), which involves radiofrequency ablation of cardiac vagal ganglia, targets parasympathetic hyperactivity, offering a promising treatment for recurrent VVS. This study evaluates the effectiveness and safety of anatomically guided CNA, which may provide an alternative treatment option to pacemaker implantation for younger patients with severe cardioinhibitory VVS. Methods Consecutive patients between January 2019 and October 2023 who underwent CNA at two cardiology centers were enrolled. All patients had a history of recurrent syncope, predominantly cardioinhibitory and unresponsive to conventional treatments. Patients showed no signs of conduction system disease, evidenced by normal rate responses in treadmill stress tests and 24-hour Holter monitoring. Electroanatomic mapping of the left atrium and pulmonary veins was performed. Extracardiac vagal stimulation (ECVS) through the right internal jugular vein, with or without atrial pacing, was utilized to assess baseline responses of the sinus and atrioventricular (AV) nodes. The ablation strategy was tailored based on rhythm disturbances triggered by ECVS, using sequential and anatomically guided ablation of ganglionated parasympathetic plexuses. Radiofrequency ablation, conducted with an irrigated catheter, was guided by the ablation index. Acute success was defined as the absence or significant reduction of cardiac parasympathetic response to ECVS, indicated by the elimination of asystole, severe bradycardia, or AV block. The primary endpoint was syncope recurrence during follow-up. Results The study included 25 patients (16 males; mean age 36 ± 12 years). All had documented cardioinhibition, identified through ECG monitoring (N=12), implantable loop recorders (N=5), or head-up tilt tests (N=8). The average number of syncopal episodes per patient in the year preceding ablation was 2.7, ranging from 1 to 10. Ablation was acutely successful in all cases. Post-ablation, there were no immediate complications related to the procedure, except for one convulsion deemed unrelated. Over a mean follow-up of 17 ± 14 months, 23 patients remained syncope-free. Two patients experienced syncope recurrence; despite undergoing a repeat ablation, they eventually required pacemaker implantation. Conclusion The results of this study suggest that CNA guided by ECVS, may offer a promising treatment for patients with refractory cardioinhibitory VVS. While the procedure showed a high rate of acute success and a notable reduction in syncope recurrence, further research is warranted to fully establish its role as an alternative to pacemaker implantation.

Useful aid or futile hassle - continuous rhythm monitoring following acute myocardial infarction

Abstract Background Patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) face an increased risk of cardiac events, including arrhythmias. Current guidelines therefore recommend ECG monitoring for at least 24 hours after AMI in patients with ST segment elevation myocardial infarction (STEMI) and high-risk non-ST segment elevation myocardial infarction (NSTEMI). However, in the last decades medical treatment of AMI has been substantially improved, limiting the risk of arrhythmias post-PCI. Furthermore, continuous ECG monitoring puts additional strain on healthcare personnel during an international healthcare crisis. Purpose To evaluate the contemporary burden of ventricular arrhythmias (VA) in AMI patients post-PCI. Methods This is a retrospective analysis of consecutive patients undergoing PCI for AMI between 2016 and 2020 at a secondary care centre. We defined the primary endpoint as any VA requiring intervention (electric cardioversion or pharmacologic treatment) after PCI. Baseline characteristics and outcome were compared in patients with NSTEMI vs. STEMI. Results A total of 931 patients were included in the analysis, with a mean age of 65 years and 28.6% were female. Patients with NSTEMI (47.3%) were older (median 66 vs. 63 years) and had significantly more comorbidities: hypertension (67.5% vs. 52.1 %), diabetes mellitus (25.4% vs. 15.8%), chronic obstructive pulmonary disease (11.5% vs. 6.7%), and peripheral arterial disease (11.4% vs. 5.3%, p<0.05 for all). VAs requiring intervention occurred in 3.6% vs. 7.1% (p = 0.017) before PCI and in 0% vs. 2.2% (p < 0.001) during PCI in NSTEMI vs. STEMI patients. After PCI the primary endpoint occurred in no NSTEMI patient and in 1.6% of patients with STEMI (p = 0.004). Discussion In a cohort of contemporary AMI patients, ventricular arrhythmias occurred rarely and significantly less often in NSTEMI patients compared to STEMI patients. Due to the low risk of VAs in patients with NSTEMI after PCI, the need for post-procedural rhythm monitoring in NSTEMI patients may be questioned. The identification of predictors for VA after AMI should be subject for future trials.

Diagnostic yield of cardiac monitors in patients with suspected arrhythmias: systematic literature review and network meta-analysis

Abstract Objective To demonstrate the diagnostic yield (DY) across cardiac rhythm monitors stratified by monitoring duration for symptomatic patients with suspected cardiac arrhythmias (palpitations, dizziness, syncope, presyncope, lightheadedness). Methods PubMed, Embase, and Scopus were searched to identify published randomized and observational studies between January 1, 2000, and November 28th, 2021. DY data were extracted for comparative studies. The DY of cardiac monitors in these patients was reviewed for Any Arrhythmia, Clinically Relevant Arrhythmia, Explained Episodes (symptomatic and clinically relevant), New Onset Atrial Fibrillation, and Symptomatic Events. Clinically Relevant Arrhythmia was defined by the study and included atrial fibrillation, atrial flutter, atrial tachycardia, other SVT, VT, pause, and bradycardia. Patients who had a history of prior stroke or transient ischemic attack were excluded. Network meta-analysis (NMA) was used to pool estimates. Cardiac monitoring duration was categorized into the following 3 timeframes: 3 days or less (≤3 d), greater than 3 days to less than 30 days (>3 d), and 30 days or greater (≥ 30 d). Results Inclusion and exclusion criteria identified a pooled population of 1696 patients in 6 comparative studies, 2 Randomized Controlled Trials (RCTs) and 4 non-RCTs (Figure 1). NMA results for comparative studies show that monitoring durations of >3 d and ≥30 d provided significant better DY than ≤3 d (Table 1). The odds ratio for DY of >3 d as compared to ≤3 d was 5.75 (95% CI 2.05-19.38) in patients with Any Arrhythmias, 5.99 (95% CI 2.10 - 7.79) in patients with Clinically Relevant Arrhythmias, 10.22 (95% CI 0.61 - 4343.00) in patients with Explained Episodes, and 2.74 (95% CI 1.12 - 7.53) in patients with New Onset Atrial Fibrillation. As only a single study provided results on Symptomatic Events, NMA was not possible for this measure. The odds ratio for DY of >3 d as compared to ≥30 d was 0.02 (95% CI 0.00 - 0.15) in patients with Any Arrhythmias, 0.03 (95% CI 0.00 - 0.10) in patients with Clinically Relevant Arrhythmias, 0.04 (95% CI 0.01 - 0.13) in patients with Explained Episodes, and 0.17 (95% CI 0.03 - 0.66) in patients with diagnosis of New Onset Atrial Fibrillation. Conclusion NMA indicates that >3 d and ≥30 d provide significantly better DY than ≤3 d for identifying Any Arrhythmia, Clinically Relevant Arrhythmia, and New Onset AF. Despite favorable odds ratios for ≥30 d over >3 d, these values were associated with uncertainty due to the limited studies available for monitoring durations of ≥30 d. Overall, in patients experiencing symptoms of palpitations, dizziness, syncope, and without prior stroke or transient ischemic arrest, >3 d of monitoring improved DY compared with shorter monitoring durations.Figure 1.Prisma Flow DiagramTable 1.Diagnostic Yield Comparison.

Continuous QT interval monitoring using insertable cardiac monitors during antiarrhythmic loading hospitalization: Results from the "LINQ QT" Study

Abstract Background QT interval prolongation is associated with the development of potentially lethal cardiac arrhythmias. An implantable cardiac monitor (ICM) capable of longitudinal QT monitoring may allow for mobile assessment of dynamic changes in QT and assist in predicting long term cardiotoxicity. Objective Determine feasibility of continuous QTc interval monitoring in patients with ICM hospitalized for antiarrhythmic drug loading. Methods The previously described QT detection algorithm for an ICM determines the QT interval for every beat thus providing continuous long-term QT trends. QT intervals detected from continuously collected ICM ECG data from patients enrolled in a prospective clinical study from three sites was analyzed with the primary objective of studying the long-term QT interval trends in patients undergoing antiarrhythmic drug loading in an inpatient setting. The ICM ECG was processed through the QT detection algorithm which calculates the QTc interval for every beat to generate continuous long term QTc trends. Metrics including mean and median QTc, minimum and maximum QTc, and magnitude of QTc change were studied during the hospitalization period. Continuous QTc interval trend is presented from a patient displaying increase in QTc interval following antiarrhythmic drug loading during the hospitalization period. Results 5 out of 17 patients enrolled (avg. age 71±7.3 years, 40% females) in the QT clinical study had continuous telemetered ICM ECG data available during the index antiarrhythmic loading hospitalization period. All patients were loaded with Sotalol during the hospitalization. All 5 patients had hypertension and atrial fibrillation (AF). 3 patients (60%) had a history of myocardial infarction (MI), congestive heart failure (CHF), and coronary artery disease (CAD) while 1 patient (20%) had diabetes. The magnitude of change in QTc over the hospitalization period was 139±42 msec with over 100 msec QTc change noticed in 4 of 5 patients (80%) (figure 1). Figure 2 shows continuous QTc interval trend observed from a patient (Male; Age:75; history of AF, hypertension, CHF, stroke) from this study showing a continuous increase in QTc interval. Overall, there was over 150 msec change in QTc observed for this patient during the hospitalization period. Premature ventricular complexes (PVCs) in a pattern of bigeminy were observed from ICM ECG for a 3-hr period from 12 pm-3 pm following the second antiarrhythmic dose which coupled with QT prolongation could indicate early signs of cardiotoxicity (figure 2). The five static 12-lead ECG measurements taken for this patient during the hospitalization period is also reported with the difference between these 12-lead QTc measurements and algorithm measured QTc being 22±8 msec. Conclusion ICM QT monitoring performed utilizing a QT interval detection algorithm can provide longitudinal and long-term dynamic QT trends in patients implanted with ICM.

Electrophysiology-guided algorithm for patients with conduction abnormalities post TAVR: one-year follow-up

Abstract Introduction Transcatheter aortic valve replacement (TAVR) revolutionized the treatment of aortic stenosis [1]. Although TAVR is an effective treatment for AS patients, it is associated with high incidence of new-onset conduction disturbances and pacemaker implantations. The two most common conduction disturbances after TAVR are new onset left bundle branch block (LBBB) and high-degree atrioventricular block (HDAVB) [2]. While patients with HDAVB require a permanent pacemaker implantation (PPM), the management of LBBB is not completely established yet. According to the ESC 2021 guidelines, a PPM is indicated in patients with persistent HDAVB or new onset alternating BBB after TAVR. Yet, the recommendations regarding other conduction abnormalities are not well defined. In patients with persistent new onset LBBB, ambulatory continuous ECG monitoring or electrophysiology study (EPS) are recommended [3]. Purpose To evaluate the clinical outcomes of patients with conduction disorders after TAVR who were managed according to electrophysiology-guided algorithm (Figure 1), including mortality, late pacemaker’s implantations, and heart failure hospitalizations. Predictors of periprocedural LBBB and HDAVB were also assessed. Methods Retrospective population-based cohort study including all patients who developed new onset LBBB after TAVR at a tertiary University Medical Center from October 1, 2018, to December 31, 2022, and were managed according to specific electrophysiology-guided algorithm. Results The study cohort included 230 consecutive patients who underwent TAVR. Mean age was 80.3 and 56.5% were females (Figure 2). Twenty patients (8.7%) developed HDAVB and required a PPM, whereas 40 patients (17.4%) developed persistent LBBB. According to the algorithm, 8 patients (20%) with a QRS<130ms were discharged without PPM [group A], 20 patients (50%) with a QRS of 130-160ms underwent EPS, and 12 patients (30%) with a QRS>160ms [Group C] received a PPM. Among the EPS group: 9 patients (22.5%) with HV>65ms underwent PPM [group B2], while 11 patients with HV<65ms (27.5%) were discharged without PPM [group B1]. During a one-year follow-up only one patient required late PPM [group B1]. Mortality was higher among the subgroups with PPM [B2 and C] compared to the subgroups without a PPM [A and B1]: 4 vs. 1 patient accordingly. Conclusions The presented electrophysiology-guided algorithm for patients with persistent LBBB after TAVR appears safe and efficient, with a modest incidence of PPM (17.6% of the total cohort) during hospitalization and a minimal need for late PPM at one year follow-up. Importantly, there was no excess of mortality among patients who were discharged without a pacemaker implantation. Thus, we suggest that the presented algorithm may serve as a reliable strategy to distinguish between individuals with new onset persistent LBBB after TAVR who require PPM compared to those in whom a PPM can be safely avoided.

Ten-year follow-up results of patients with persistent atrial fibrillation treated by combined pulmonary vein isolation and complex fractionated atrial electrocardiogram ablation

Abstract Background For persistent atrial fibrillation (AF), pulmonary vein isolation (PVI) alone is associated with lower success rate compared to paroxysmal AF and additional strategies are needed. Ablation targeting on complex fractionated atrial electrograms (CFAE) is an alternative method. Although clinical benefits of the strategy combined PVI and CFAE ablation have not been shown by large trials, clinical situations and consequences of this approach have not been clearly demonstrated during very long term follow-up. Purpose This study aimed to retrospectively investigate clinical outcomes of patients with persistent AF treated by the approach combined PVI and CFAE ablation during a follow-up period of 10 years. Methods 73 patients (59.4±8.1 years, 64 male, AF history 5.5 years) with persistent (23, 31.5%) and long-standing persistent AF (50, 68.5%) who underwent combined PVI and CFAE ablation in the first procedure were included. Structural heart disease was found in 9 patients, and a history of ablation for typical atrial flutter (AFL) in 4. A complete CFAE mapping in the left atrium and coronary sinus was performed with a 3-D mapping system (EnSite NavX). All CFAEs defined as electrograms with continuous activities or mean cycle length detected by the system <80 ms were eliminated. All patients were controlled regularly during the first year with 12-lead ECG and Holter monitoring and followed by annual control. The electronic health records for all patients were extensively investigated and the patients were interviewed in 2020-2022. Any documented atrial tachyarrhythmia (ATA) after 3-month blanking period was regarded as recurrence. Results Mean 2.2±1.2 (1-5) ablation procedures were performed in each patient. After index ablation, 18 (24.7%) were free of ATAs during 10-year follow-up. 26 (35.6%) had recurrence of only AF, 6 (8.2%) of only AFL and 23 (31.5%) had both AF and AFL. The proportion of AFL was 39.7% with 6 typical AFL. After multiple ablation procedures, 33 (45.2%) patients were free of ATA during the follow-up. 23 (31.5%) had recurrence of only AF, 5 (6.8%) of only AFL and 12 (16.4%) of both AF and AFL. The proportion of AFL was 23.2% with no typical AFL. At 1-year follow-up, freedom of ATAs in persistent AF was higher than that in long-standing AF (65.2 vs. 40.0%, p=0.033) and no significant difference was found after 2 years (47.8 vs. 34.0%, p=0.129) until 10 years (30.4 vs. 22.0%, p=0.167, Figure 1). No difference was observed between these subgroups after multiple procedures at 10-year follow-up (47.8 vs. 44.0%, p=0.708, Figure 2). Conclusions PVI plus CAFE ablation in patients with persistent AF led to a high recurrence of ATA after index ablation. Difference of ATA-freedom between persistent and long-standing persistent AF groups was found only 1 year after the index procedure, but not during further follow-up. Incidence of post-ablation AFL was particularly high, even after multiple ablation procedures.Figure 1Figure 2

Value of 24h ambulatory ECG for prediction of sufficient number of premature ventricular complexes during catheter ablation

Abstract Introduction Successful catheter ablation (CA) of premature ventricular complexes (PVCs) depends on identification of the site of origin (SOO), but no parameter suggested for prediction of success from CA have been sufficiently validated in previous studies. Activation mapping and pace-mapping are invasive methods for the identification of SOO, and the burden of PVCs is critical for activation mapping to identify SOO. The number of PVCs in 24h ambulatory ECGs is claimed to predict occurrence of PVCs during the procedure, and hence procedural success, but the predictive value remains unknown. Purpose The primary objective of this study was to quantify the predictive value of pre-procedural of 24h ambulatory ECG with regard to sufficient number of PVCs during the CA procedure. Methods Patients admitted for CA of PVCs at our hospital from 2011-2020 were included. Data were retrospectivity collected from electronic health records. Clinical characteristics, results from clinical pre-procedural examinations, including 24h ambulatory ECG, exercise testing and echocardiogram, as well as acute outcomes were recorded. Results A total of 332 patients were included, CA was performed in 285 (86 %) patients, while 47 (14 %) patients had insufficient number of PVCs to allow adequate identification of SOO. Neither clinical characteristics nor results of cardiac imaging separated patients with sufficient and insufficient number of PVCs for CA, respectively. Patients with sufficient number of PVCs had nominally more PVCs in the preceding 24h ambulatory ECG, although the difference was not statistically significant (16007 (6509-26205) vs. 8332 (3066-20974), p = 0.055). A receiver operating characteristics (ROC) curve analysis of sufficient number of PVCs during CA and number of PVCs in the preceding 24h ambulatory ECG had an area under curve (AUC) of 0.610 (0.95% CI 0.498-0.722, p = 0.055). The commonly clinically used cut-off of >10 000 PVCs/24h had a positive predictive value of 67 % and a negative predictive value of 57 % for sufficient number of PVCs during CA. The median period from the 24h ambulatory ECGs to CA was 183 days (6 months). The positive and negative predicative values for >10 000 PVCs in 24h ambulatory ECG performed >6 months prior to the procedure were 67 % and 71 %, respectively, compared to 53 % and 61 % for 24h ECGs performed <6 months prior to the procedure. The ROC curve for sufficient number of PVCs during the procedure and number of PVCs in a 24h ambulatory ECG performed >6 months and <6 months prior to the procedure did not differ, with had AUC values of 0.665 and 0.584, respectively (p = 0.4). Conclusion In this retrospective analysis of a large cohort of patients admitted for CA of PVCs, number of PVCs in 24h ambulatory ECGs recorded prior to the procedure had a low predictive value for presence of PVCs during CA. Others parameters need to be evaluated to improve prediction.

Morphological identification of brugada type 1 pattern using loop recorder: a feasibility study

Abstract Introduction The presence of spontaneous type 1 Brugada pattern (BP1) is associated with an elevated risk of arrhythmic events. Diagnosis of this condition is often underestimated due to its intermittent nature. While periodic ambulatory ECG monitoring can distinguish patients with pharmacologically induced patterns from those with spontaneous patterns, the diagnostic capabilities of this method are limited. Implantable cardiac monitors (ICM), designed to continuously record heart rhythm, may offer higher sensitivity in detecting patients with intermittent patterns. However, the ICM's ability to morphologically identify the ST segment elevation associated with BP1 remains uncharted. Purpose This study aimed to assess the ICM's capacity to morphologically identify the ST segment elevation associated with BP1. Methods We enrolled all patients who underwent ajmaline testing (AT) between November 2022 and September 2023 in our centre. For positive patients, the external simulator of a loop recorder was utilized to evaluate four positions (I-II left intercostal space at a 45° tilt, II-III left intercostal space at a 45° tilt, II-III right parasternal intercostal space, and II-III left parasternal intercostal space). These positions were selected to capture the trace with the most significant ST segment elevation at the J point during the peak positivity of the ECG during the ajmaline test. Measurements from the recorded traces were acquired using dedicated software. Results Out of 50 patients, 21 (male-to-female ratio 1.62:1, mean age 43.4±13.1 years) had a positive AT result. Seventeen patients exhibited ST segment elevation in the simulator trace during the highest ajmaline dose. Among these patients, the optimal recording position was in the I-II left intercostal space at a 45° tilt in 66.7% of cases. The median ST segment elevation recorded by the simulator was 0.9 mm (interquartile range 0.6-1.1 mm). Notably, there was no observed correlation between the extent of ST segment elevation in the ECG and that recorded by the simulator trace (Pearson linear coefficient = 0.09). Conclusions ICM may offer the potential to record BP1, a finding that holds significant diagnostic and prognostic implications for asymptomatic patients with pharmacologically induced BP1. Further research is needed to develop useful programming algorithms for the automatic recording of this pattern.

Post-operative atrial fibrillation after noncardiac surgery: diagnostic role of ambulatory rhythm monitoring for recurrent arrhythmia after hospital discharge

Abstract Introduction Postoperative atrial fibrillation (POAF) after noncardiac surgery constitutes 10-15% of all cases of incident atrial fibrillation (AF) in the community and has been associated with an increased risk of stroke. The risk of subsequent AF among patients with POAF is not well defined. Purpose To evaluate the role of systematic 30-day electrocardiographic (ECG) monitoring in the detection of AF recurrence after POAF. Methods In a prospective interventional study, patients who underwent major noncardiac surgeries and had new AF documented by ECG in the post-operative period between May 2022 and April 2023 were identified. For these patients, a 30-day ambulatory ECG monitor was recommended upon discharge, with final ordering deferred to the primary inpatient teams. Rates of recurrent AF of any duration detected by 30-day monitoring plus routine care versus routine care alone after the surgery were compared. Results Eighty-five patients with new-onset POAF were included (mean age 72 years, male 67%). Of these, 35 (41%) patients underwent up to 30 days [median 23 (IQR 6-27) days] of continuous ECG monitoring after hospital discharge. There were no significant differences in baseline characteristics between patients who did or did not undergo monitoring (Table 1). During median 281 (IQR 197-385) days of follow-up, recurrent AF was documented in 14/35 (40%) patients in the monitoring group as opposed to 7/50 (14%) patients in the usual care group (log-rank p=0.003, Figure 1). The median time from day of surgery until documented AF recurrence was 25 (IQR 6-53) days in the monitoring group and 66 (IQR 25-145) in the usual care group. Overall, 81% of recurrent AF events in both groups were detected in the first 3 months after surgery. The median burden of AF in the cardiac monitoring group was 7% (IQR 1-15), with the longest AF event lasting a median of 6 (IQR 2-18) hours. Anticoagulation for AF was prescribed in 24/64 (37%) patients with POAF without recurrence and in 16/21 (76%) patients with recurrent AF. Conclusion Recurrent AF following POAF is common and detected most frequently in the first 3 months after noncardiac surgery. Systematic ambulatory rhythm monitoring is associated with a higher rate of AF detection following hospital discharge and may identify a patient subgroup who might benefit from anticoagulation therapy.Table 1Figure 1

Utilization of implantable cardiac monitors in detecting type 1 patterns in brugada syndrome

Abstract Introduction In individuals with Brugada syndrome, the presence of the type 1 pattern (BP1) is linked to an elevated risk of severe arrhythmias. However, the identification and measurement of BP1 can be challenging due to its intermittent nature. Implantable cardiac monitors (ICMs) provide extended continuous monitoring, potentially overcoming the limitations of intermittent ambulatory ECG monitoring in detecting spontaneous BP1. Nevertheless, their specific application for this purpose remains unevaluated. Methods From November 2022 to September 2023, all patients presenting with pharmacologically induced BP1 were enrolled at our centre. An ICM was surgically placed in the left second intercostal space at a 45° angle, enabling readings with a morphology similar to the right precordial ECG leads during ajmaline testing (AT). Patients were remotely monitored, and in addition to routine automatic transmissions, each patient was provided with a remote control to transmit in case of fever or symptomatic events. Transmissions were scrutinized to detect: 1) ST-segment elevation; 2) ventricular arrhythmias; 3) burden of ventricular extrasystoles (PVC). A reading was classified as positive for BP1 if it bore a similar morphology to that recorded during AT. The frequency of BP1-positive transmissions was evaluated across four hourly intervals. Results The ICM was successfully implanted in 21 patients (male-to-female ratio 1.62:1, mean age 43.9±13.1 years). Over an average follow-up of 168±70.6 days, a total of 7818 transmissions were received, evenly spread across hourly intervals (minimum of 1296 transmissions per interval). Among these, 173 transmissions were identified as BP1 positive (2.2%), originating from 6 patients (28.6% of the total, all newly diagnosed with spontaneous BP1). The median duration between implantation and the diagnosis of spontaneous BP1 was 16.5 days (range 2-23). The median number of days with at least one positive transmission was 30.2 (range 13.4-73.9). The evening period (6 pm to midnight) displayed a significantly higher rate of positive transmissions compared to the morning (p=0.04) and afternoon (p=0.01); however, not in contrast to the nighttime (p=0.8). No sustained ventricular arrhythmias were observed, and there were no significant differences in PVC burden among patients. Conclusions The utilization of ICM for continuous monitoring in patients with pharmacologically induced BP1 led to the identification of spontaneous BP1 patterns in almost 30% of cases during an approximately 6-month follow-up. Evening and nighttime periods exhibited the highest incidence of BP1. This methodology shows promise in quantifying BP1 incidence and could serve as a tool for stratifying arrhythmic risk in individuals with Brugada syndrome.

Spontaneous atrial fibrillation occurrence following transesophageal atrial burst pacing in rats

Abstract Purpose Animal models play a crucial role in elucidating the complex pathophysiology of atrial fibrillation (AF) and in identifying and testing novel antiarrhythmic strategies. We aimed to develop and characterize a new experimental rat model of AF, induced by long-term transesophageal atrial electrical stimulation, and to investigate whether the "AF begets AF" concept applies to small rodent hearts. Method Twelve adult male Wistar rats were randomized into two groups: Sham (n = 5) and AF (n = 7). All rats were implanted at the beginning of the study with ECG radiotelemetry devices and underwent continuous ECG monitoring throughout the study. To induce AF, the rats in the AF group underwent atrial pacing for 10 consecutive days (15 successive cycles of stimulation/day, 20 s each, with a free interval of 5 min between cycles; 4,000 stimuli/min, stimulus duration 6 ms, voltage 3 V above the diastolic threshold). A similar procedure was applied to the Sham group, but without performing the actual electrical stimulation. The number and duration of spontaneous AF episodes were evaluated based on continuous ECG monitoring prior to, during, and for one week after transesophageal atrial pacing. The inducibility of AF and the occurrence and duration of spontaneous AF episodes were evaluated and compared between the two groups. Results Atrial fibrillation was induced in 85.7% of the rats subjected to atrial electrical pacing (Figure, A), with an average global inducibility of 44.0% ± 16.9% and a mean AF duration of 123.2 ± 96.3 s. No induced or spontaneous AF episodes were recorded in any of the Sham animals. In the AF group, none of the animals presented spontaneous AF before transesophageal atrial pacing. However, in the AF rats, after atrial electrical stimulation initiation, the number of atrial premature beats significantly increased (21.3 ± 6.8 / 24-h post-stimulation vs. 7.3 ± 6.5 / 24-h at baseline; p< 0.01; Figure, B), and all rats presented spontaneous AF episodes (Figure, C). At the end of the study, AF rats presented a total number of 23.9 ± 2.3 AF episodes / 24-h (Figure, D), with a mean AF burden of 337.7 ± 25.06 s / 24-h. Conclusions Our data demonstrate that, despite the small size of the atria, the "AF begets AF" concept is applicable in small rodents. The study presents a novel rat model of AF, in which spontaneous AF occurs following long-term atrial electrical stimulation. Given that the model is relatively rapid and easy to implement, it provides a setup for further investigation of AF pathophysiology, and for identifying and testing novel therapeutic strategies for AF.Figure 1

Trans-catheter cryoablation of parahisian accessory pathways: a single centre experience

Abstract Introduction Transcatheter radiofrequency (RF) ablation of perinodal accessory pathways (parahisian/midseptal APs) is still challenging especially in young patients due to a high risk for inadvertent atrioventricular block (AVB) requiring permanent pacing. Recently, cryo-ablation (CA) has evolved as an RF alternative, thanks to a safer profile and a better catheter stability. Purpose To evaluate the safety, efficacy and outcomes of CA in patients with parahisian/midseptal APs. Methods 73 pts undergoing a first ablation of septal APs at our institution were retrospectively analyzed. Among these, we selected 20 patients with a diagnosis of para-hisian/midseptal AP confirmed by EP study (EPS) and 3D-electro-anatomic mapping (EAM), ablated using cryoenergy. Before delivering CA, a cryomapping (CM) at the target AP site was performed at −30°C using a 6- mm-tip catheter. Successful CM was defined as: (1) loss of delta wave in case of manifest pre-excitation, (2) termination of a sustained AVRT, (3) retrograde conduction block through the AP during ventricular pacing in case of concealed AP. CA was initiated following successful CM, at a temperature of −75°C for 300 s with an additional "bonus" CA application (300s). Acute procedural endpoint was permanent complete abolition of AP conduction; long-term clinical endpoint was defined as no recurrence of delta wave or AVRT on serial ECG monitoring at follow-up (1, 6, 12 months). RESULTS Baseline characteristics are summarized in Fig. 1. Fifty-five % were pediatric patients, only 3/20 presented a structural HD. Up to 90% of the patients experienced a symptomatic AVRT, while delta-wave was present at baseline ECG in 19/20 patients. EPS combined with 3D-EAM showed a para-hisian AP in 80% and a mid-septal AP in 20%. Mean distance between His bundle electrogram and AP site was 5.72 mm (4-6.8 mm, Fig. 2). Orthodromic AVRT was induced in all the 20 pts. Maen procedural and fluoroscopy times were, respectively, 103.4 ± 26.4 and 3.15± 1.76 min . Acute success was achieved in 20/20 patients (100%) with AP block of conduction obtained within few seconds (<10s) after a mean CM number of 3.3 ± 1.2 (Fig. 2). Two patients developed transient 2:1 AV block and 1 patient transient RBBB during CM, with immediate recovery within 20s from CM termination. No peri-procedural complications or permanent AV block were observed. One patient had an early AP re-conduction (6 hours later) and was successfully re-ablated the following day. During a mean FU of 361 ± 34 days, only two patients (10%) experienced an AVRT recurrence and underwent a second successful CA. Conclusions Cryoablation of parahisian and midseptal APs is a safe and effective alternative to RF, resulting in a low risk of recurrence over 12-months-follow-up with no incidence of permanent AV block. A near-zero fluoroscopy approach combining CA and 3D-EAM is feasible and should be considered especially in very young patients with parahisian APs.Fig. 1Fig. 2

Improved procedural workflow for catheter ablation of paroxysmal AF with high density mapping system and advanced technology: insights from a multicenter, international study

Abstract Background A high incidence of pulmonary vein (PV) reconnection has been reported in patients with clinical recurrences of AF. Low-voltage activity beyond PVs (e.g. antral activity potentials, RAP) likely represent vulnerabilities in antral lesion sets and they may contribute to ablation failures. Purpose The aim of this study is to validate a structured application of an approach that includes the complete abolition of any antral potential achieving electrical quiescence in antral regions. Methods DELETE AF is a prospective, single-arm, international post-market cohort study. Consecutive patients from 10 centers who were undergoing radiofrequency ablation of paroxysmal AF were included. The Lumipoint map-analysis tool was used sequentially on each PV component. Post-ablation, all patients were monitored with ambulatory event monitoring, starting within 30 days post-ablation to proactively detect and manage any recurrences within the 90-day blanking period, as well as Holter monitoring at 3, 6, 9, and 12 months post-ablation. Additional ECG monitoring were performed as indicated by patient symptoms. The ablation endpoint was PV isolation (PVI). Long-term outcome was the recurrence of AF over follow-up. Data are reported as median [IQ range]. Results One-hundred ten cases of AF ablation were analyzed: 28 (25.5%) females, age=63[56-69] years, 24 (21.8%) patients with a history of AT/AFL. The procedure duration was 58[24-76] min (RF delivery time=18[12-28] min, number of ablation spots=77[44-101]) and the fluoroscopy time was 13[9-19] min. Thirty-eight (34.5%) were repeat ablation: in these patients after initial mapping a total of 114 PV gaps (PVGs) in 29 (76.3%) patients and 69 RAPs in 15 patients (39.5%) were found. After ablation, a total of 5 early PVGs in 2 (1.8%) patients (all in de novo procedures) and a total of 10 RAPs in 7 (6.3%) patients (3 out 38 -7.9%- of repeat ablations vs 4 out 72 -5.6%- of de novo cases, p=0.690) were detected after first remapping. Each residual PVG was first targeted and additional focal ablations were performed at any low-voltage propagation suspected within the region of previous antral ablation. Acute procedural success was 100%, with all PVs successfully isolated and RAPs completely abolished in all study patients except for one that still exhibited a residual low-voltage antral signal after adenosine infusion with no PV conduction. Eighty-six (78.2%) patients had complete follow-up information. During the 90-day blanking period, 8 (9.2%) patients experienced an early recurrence. After the blanking period, over a follow-up of 357[190-380] days, 13 patients (15.1%) suffered an AF recurrence (time to recurrence: 207[144-300] days). No major complications or adverse events occurred. Conclusion A structured ablation workflow for catheter ablation, with consistent high-density mapping and improved diagnostic tools to guide the ablation, proved to be safe and effective in paroxysmal AF.

Weight change does not impact the long-term outcomes following pulmonary vein isolation in obese patients with atrial fibrillation

Abstract Background Weight loss has been shown to reduce the burden of atrial fibrillation (AF) in obese patients. However, there are limited data on the impact of weight loss on long-term outcomes in patients with atrial fibrillation (AF) who undergo pulmonary vein isolation (PVI). Objective To understand the impact of weight change, as assessed by freedom from recurrent AF, in obese patients undergoing cryoballoon (CB) PVI. Methods We enrolled consecutive obese (BMI ≥ 30 kg/m2) patients with AF who underwent CB PVI; all patients had an implantable loop recorder (ILR) for long-term ECG monitoring. The cohort was divided into 3 groups based on their weight change 1-year after ablation: (1) weight loss (WL) > 3% weight decrease; (2) no weight change (NWC) - weight change < 3%, (3) weight gain (WG) > 3% weight increase. We assessed long-term AF recurrences, after excluding an initial 3-month post-ablation blanking period. Results Out of total of 137 pts with obesity, 61 pts had weight available at the ablation and at 1-year follow-up (65 ± 9 years; 41 [67%] male; 23 [38%] PAF; CHA2DS2-VASc 2.9 ± 1.7). There were no differences in baseline characteristics. At follow-up, 24 (39%), 26 (43%), and 11 (18%) pts lost, had no change, or gained weight, respectively. Of the 24 pts who lost weight, 3 pts lost > 10% body weight. During a follow-up of 964 ± 512 days, 41 (67%) pts had recurrent AF; the change in weight did not impact outcomes (Figure), including those who lost > 10% body weight. Conclusions During 3-years of follow-up, 2/3 of obese patients had objective evidence of AF recurrence following CB PVI. Weight change in the first-year post ablation did not alter long-term outcomes. Other strategies may be needed in these patients to improve outcomes.

Impact of restoration of sinus rhythm after catheter ablation of atrial fibrillation on reverse cardiac remodelling

Abstract Introduction Catheter ablation (CA) with pulmonary vein isolation (PVI) has become widely used for the treatment of atrial fibrillation (AF). Restoration of sinus rhythm in patients with AF is of vital importance, because AF induces the development of heart failure (HF) through various pathophysiological mechanisms, one of them is epicardial adipose tissue (EAT). EAT is a type of visceral adipose tissue that is in direct contact with the myocardium. Under pathological conditions it serves as a direct and indirect factor in pathogenesis of AF. It is also an established prognostic factor after CA of AF recurrence. Since cardiac magnetic resonance (CMR) represent the gold standard for the measurement of volume and muscle mass, it has been used more and more for the assessment of EAT volume lately. Purpose The aim of our study was to investigate the impact of restoration of sinus rhythm on EAT volume, and cardiac function and morphology evaluated by the CMR. Methods We prospectively included 17 patients with paroxysmal and persistent AF that were referred for CA. All patients underwent cardiac magnetic CMR prior to radiofrequency CA with PVI and 6 months thereafter in order to quantify periatrial EAT volumes and evaluate cardiac morphological and functional characteristics. AF recurrence rate was diagnosed by serial ECG recordings, Holter ECG monitoring and AF suggestive symptoms within 6 months of follow-up period. Results 17 patients, mainly male (76.5 %) with an average age of 62.35 ± 12.10 years were included in our study. The average body mass index (BMI) was 29.0 ± 4.71 kg/m2. Most patients had paroxysmal AF prior to CA (88.2 %). The recurrence rate of AF was 35.3 % after 6 months of follow-up. By performing CMR after 6 months of CA we observed lower median periatrial EAT volume (36.00 mL (IQR 38.25 mL) vs. 27.45 mL (IQR 30.94 mL); p= 0.004) and lower median left ventricular mass (LVM) (104.0 g/m2 (IQR 38 g/m2) vs. 100.0 g/m2 (IQR 42 g/m2); p= 0.019). Furthermore, when patients were stratified based on the AF status after the follow-up period, we observed that the patients who remained AF-free had significantly lower median periatrial EAT volumes (38.90 mL (IQR 43.84 mL) vs. 26.83 mL (IQR 33.25 mL); p= 0.003) and median LVM (96 g/m2 (IQR 35 g/m2) vs. 90 g/m2 (IQR 29.8 g/m2); p= 0.041) compared to the group of patients who relapsed where we did not observe a significant change in periatrial EAT volume (23.76 mL (IQR 26.84 mL) vs. 31.28 mL (IQR 27.84); p= 0.345) or LVM (117.5 g/m2 (IQR 34 g/m2) vs. 112 g/m2 (IQR 28.6 g/m2); p= 1.0). Significant correlation was observed between BMI and periatrial EAT volume (p= 0.029). Conclusions Restoration of sinus rhythm after CA of AF is associated to lower periatrial EAT volume and LVM. Patients who relapsed did not show reverse cardiac remodelling. Periatrial EAT volume significantly correlates with BMI.

Additional factors associated with sudden cardiac death in HCM patients

Abstract Background Hypertrophic cardiomyopathy (HCM) is a primary myocardial disease characterized by an increase in the thickness of the left ventricular (LV) wall, which is not explained only by abnormal loading conditions. Sudden cardiac death (SCD) is the most devastating complication of HCM occurring in asymptomatic or younger patients without warning. Purpose To evaluate additional SCD risk factors in Ukrainian population of HCM patients. Materials and methods We retrospectively evaluated 350 consecutive HCM patients that were followed from 2006 to 2021 in our Cardiological Department. General clinical examination, standard 12-lead ECG, transthoracic echocardiography and 24 hours Holter ECG monitoring data were estimated. The 5-year SCD risk was calculated according to the HCM Risk-SCD score. The endpoint of the study was SCD and its surrogates, including adequate performance of the implantable cardioverter-defibrillator and successful resuscitation. Results Follow-up time was 5.0 (1.5-9.5) years. During this time, 16 patients (4.6%) reached the end point, which was 0.9%/year. According to the HCM Risk-SCD score, 5 (31.3%) of this group had a high risk of SCD (≥ 6%) and 3 (18.8%) had an intermediate risk (≥ 4% and < 6%). In multivariable Cox regression analysis adjusted for conventional SCD risk factors it was found that independent predictors of SCD were unexplained syncope (HR 3.81, 95% CI 1.11-13.12, p=0.034), systolic blood pressure (SBP) (HR 0.97 , 95% CI 0.94- 0.99, p=0.026), "infarct-like" ST elevation on ECG (HR 6.81, 95% CI 2.09-22.16, p=0.001) and PQ interval duration (HR 1.03, 95% CI 1.01-1.05, p=0.002), Harrell's C-index 0.84, 95% CI 0.73-0.95, p < 0.0001). Conclusions In our study HCM Risk-SCD score predicted SCD or surrogates only in 50% of cases. In order to improve the risk stratification some additional independent predictors of SCD can be proposed. ECG parameters ("infarct-like" ST elevation and PQ interval duration) and level of SBP were found to have SCD predictive value.

Efficacy of smart device heart rhythm monitoring to detect spontaneous conversion to sinus rhythm in patients scheduled for electric cardioversion of atrial fibrillation. Kardiover Study

Abstract Introduction the management of patients with recent-onset atrial fibrillation (AF) is to achieve sinus rhythm (SR) by electrical or pharmacological cardioversion (CV). However, frequently SR is spontaneously restored, making scheduled admission and/or transesophageal echocardiogram (TEE) unnecessary and therefore causing misutilization of healthcare resources. Emerging medical technology has allowed for monitoring of heart rhythm abnormalities. Objective A prospective multicenter study was designed to evaluate the diagnostic ability of a smart device ECG monitor to detect spontaneous conversion to SR in AF patients, preventing unnecessary admission and providing an earlier management. Methods A prospective multicenter study was designed including patients with first diagnosed, paroxysmal or persistent AF scheduled for ambulatory electrical cardioversion in cardiology departments of 7 hospitals of Spain. Patients were asked to submit ECG recordings to a central Corelab daily, twice a day and whenever they present symptoms, until cardioversion (spontaneous or scheduled) and a week afterwards. Whenever a spontaneous conversion to SR was detected, investigators were contacted to confirm SR and abort admission, likewise when AF recurrence after cardioversion was detected. Patients’ satisfaction was evaluated using a test for perceived utility and value, convenience, and accessibility. Results A total of 62 patients were enrolled (age 62±10 years). Baseline characteristics of the study population are described in the Table. Fifteen patients (24%) did not undergo CV as they showed spontaneous conversion to SR. Among 47 patients admitted for CV, it was successful in 41 (87%). One patient aborted CV because of atrial thrombus on TEE. During follow up after conversion to SR (spontaneous or electrical), recurrences of AF occurred in 20 of 56 patients (36%) correctly detected by the devices. At the end of the follow-up 41 of 56 patients (73%) remained in SR. Due to the early detection of spontaneous conversion to SR, a total of 15 admissions and 9 TEE were prevented and these resources used for other patients. Adherence was high with a rate of ECG transmission over 80% in 56 patients (90%). Perceived satisfaction was also high with an overall punctuation of 9 over 10 in the patient’s feedback test. Conclusion Digital devices for heart rhythm monitoring can optimize the management of AF patients scheduled for CV, avoiding unnecessary admissions and providing a more rational use of healthcare resources.Table

Effectiveness of a stepwise approach for screening of atrial fibrillation after stroke: insights from the SAFAS study

Abstract Background Detection of atrial fibrillation (AF) is critical after ischemic stroke, providing information regarding the mechanism of the event and leading to modification in the antithrombotic strategy. While most guidelines recommend screening patients for AF with 12-lead ECG, telemetry, long-duration Holter monitoring and implantable cardiac monitor (ICM), the optimal timing and combination of such screening tools remain unclear. Objective This study aimed at investigating the suitability of a sequential combination of screening techniques (12-lead ECG, telemetry, in hospital long-lasting Holter monitoring, and ICM in the detection of AF after stroke. Methods Patients without previously known AF admitted to the Dijon University Hospital stroke unit for acute ischemic stroke were prospectively enrolled. After a stepwise screening approach for AF based on admission ECG, telemetry monitoring during the stroke unit stay and long-duration Holter monitoring during hospital stay, cryptogenic stroke patients were implanted of an ICM. Primary endpoint was the presence of AF detected during the 3-year period after stroke based on this sequential screening approach. Results A total of 240 patients were included. Among them, 104 (43.3%) patients had a documented cause of stroke non-related to AF. Among the remaining 136 patients (53.7% male, 70.8±13.7 yo), AF was detected in 82 (60%) patients over the acute screening phase or the 3-year follow-up with ICM. AF was diagnosed using 12-lead ECG, in-hospital telemetry, and in hospital long-lasting Holter monitoring in 17 (13%), 25 (18%), and 18 (13%) patients, respectively. AF was detected after the first 24 hours on the long-lasting Holter monitoring in 66% of patients. Among the 76 (56%) patients classified as cryptogenic after the complete stroke work-up and implanted from an ICM, AF was detected in 22 (29%) patients. AF occurred during the first, second, and third years of implantable monitoring in 14 (18.4%), 5 (6.6%), and 3 (3.9%) patients, respectively (Figure 1). Mean time from ICM implantation to AF diagnosis was 308+/-279 days. Finally, among all AF detected, 72% (60/83) were found during the initial intensive in-hospital screening. Conclusion A stepwise approach for AF screening after ischemic stroke allows the early detection of AF in a substantial number of patients during hospital stay. Even with such proactive initial monitoring strategy, invasive monitoring remains complementary to non-invasive screening tools not to overlook more distant AF episodes. Studies focusing on the relative risk of ischemic stroke recurrence according to AF timing and burden are needed.Figure 1