Sustained Arrhythmia Research Articles

Safety and efficacy of a temperature-controlled ablation system for ventricular tachycardia: first results from the TRAC-VT study

Abstract Background Catheter ablation using radiofrequency (RF) energy, is a well-recognized treatment option for patients with ventricular arrhythmias. However, procedural complications may be high, and efficacy is often suboptimal with high recurrence rates. Purpose The TRAC-VT study evaluated safety and efficacy of the DiamondTemp Ablation (DTA) System for the treatment of patients with ventricular arrhythmias by catheter ablation. Methods A temperature-controlled, irrigated RF catheter (with six thermocouples and an internal network of diamond coatings) was utilized to treat subjects with either sustained monomorphic ventricular tachycardia (VT) and structural heart disease or with frequent monomorphic symptomatic ventricular premature beats (VPBs) and normal hearts. Patients were enrolled at five hospital centers in five European countries and were followed for 6 months. Ablation was performed in temperature-control mode with an irrigation flow of 8 mL/min for all power deliveries. The target temperature was set to 55 or 60 °C with a power output limited to 50 Watts. RF energy was applied for a maximum of 45 seconds per target site, depending on impedance drop and electrogram abatement. Results The study enrolled 49 subjects (age 67±12 years, 80% male) in total (38 with sustained monomorphic VT and structural heart disease and 11 with symptomatic VPBs). In all cases, mapping and navigation was used with EnSite systems (Abbott). The average ablation time (defined as time from the insertion of the DTA catheter until removal from body) was 87 ± 44 minutes. During this time, RF energy was applied for an average of 28.2 ± 10.2 seconds with a power of 44.0 ± 7.0 W and a temperature of 50.9 ± 3.9 °C during 35.0 ± 23.2 applications. Acute procedural success was 100% (93%-100%), and it was defined as the elimination of VPBs or non-inducibility for sustained VT (using solely the DTA catheter). The primary safety procedure-related endpoint was an evaluation of cardiovascular-related death, stroke / TIA, cardiac tamponade/perforation, bleeding complication, myocardial infarction, thromboembolism, and pulmonary edema. In total review of the primary safety endpoint, one subject had a confirmation of a stroke / TIA event. Regarding longer term procedural efficacy, the 6-month follow-up was completed in 92% of subjects. For the whole study population chronic success from recurrence of ventricular arrhythmia (faster than 100 beats/min after 6 months) was 73.4% (58.6%-83.6%) for non-sustained ventricular arrhythmias (≥3 beats) and 87.7% (74.7%-94.3%) for sustained ventricular arrhythmias (≥30 sec). Conclusions VT/VPBs ablation using a temperature-controlled irrigated RF catheter was safe and effective with low VT recurrence at 6 months of follow-up.

Safety and efficacy of pulse field ablation of atrial fibrillation in patients aged over 75 years

Abstract Introduction Pulse-field ablation (PFA) is an emerging atrial fibrillation (AF) ablation technology associated with a favorable safety profile and short procedural times. Elderly patients, in whom AF ablation indications are expanding, may be particularly suitable to PFA. However, in a recent large multicenter trial, patients older than 75 years were not included, so that data on PFA safety and efficacy in this population are scarce. Methods Consecutive patients who underwent PFA of AF at a single academic center were prospectively included in a local registry. Written informed consent was obtained. Clinical, imaging and procedural data was collected and routine care follow-up was performed locally. Results From 2022, out of 345 consecutive patients who underwent PFA of, 42 (13%) were aged ≥75 years. As compared to <75 years-old patients (mean age 61±3 years), elderly patients (mean age 78±4 years) were more frequently females (21 [51%] vs 121 [40%], P=0.02), had more frequently non-paroxysmal AF (27 [65%] vs 164 [54%], P=0.01), significant cardiac comorbidities (9 [21%] vs 33 [11%], P=0.01), and larger indexed left atrial volumes (65 mL/m2 [interquartile range (IQR) 54-76] vs 61 [IQR 54-68], P=0.04). With regards to procedural parameters, the total procedural length was comparable, while elderly patients received more frequently PFA applications outside the pulmonary veins. The rate of major complications was comparable, but 3 cardiac tamponades occurred in patients aged over 75 years, while none occurred in younger patients. After a median follow-up time of 185 days (IQR 65 – 202), the cumulative freedom from sustained atrial arrhythmia recurrence was not statistically different between patients aged over 75 years (75%, 95% confidence interval (CI) [62-84%]) and under 75 years (75%, 95% CI [62-84%], P=0.11). Conclusions PFA appear as a safe and effective technique for AF ablation in elderly patients, although there was an excess of cardiac tamponades in this group

Electrocardiographic characteristics and catheter ablation of premature ventricular complex- mediated ventricular fibrillation

Abstract Background Premature ventricular contractions (PVCs) can trigger ventricular fibrillation (VF) in patients with/or without structural heart disease. There are limited data on coexisting electrocardiographic (ECG) features and catheter ablation outcomes in these patients which could suggest the concomitant presence of an abnormal electrical and structural substrate. Purpose We investigated ECG and electroanatomic characteristics and clinical outcomes in patents who underwent catheter ablation of PVCs triggering VF. Methods We analyzed data from a consecutive series of patients who underwent catheter ablation between 08/2019 and 04/2023 for PVCs triggering VF. On the 12-lead ECG, we assessed the following abnormalities: (a) Early repolarization (ER) pattern in either inferior or lateral leads (Figure 1), or (b) QRS Notching of either the native sinus beat or PVC (Figure 2). Post-ablation follow up outcomes were collected using a combination of ICD interrogation, remote transmission and clinical follow up. Results The cohort included 15 patients: age 52.1±16.8 years, 46.7% females, and 26.7% presenting with VF storm. On average, there were 3.8 HV shocks/per patient from an ICD prior to the index ablation procedure (range: 0-19 shocks). On the 12-lead ECG, the mean coupling interval of the PVC leading to VF was 204±82 ms, and an overall narrow PVC morphology with a mean QRS duration of 107±17 ms. We observed early repolarization (ER) in 6 (40%) of the cohort. In most patients (n=11; 73.3%), at least one of the 2 ECG abnormalities were present. An endocardial-only approach was adequate in all patients, and during catheter ablation, Purkinje potentials were targeted in 10 (66%) of the patients. Based on activation and pace-mapping, the PVCs were localized to the following sites: (a) left ventricular (LV) septum in 11 (73.3%), (b) papillary muscles in 2 (13.3%), and (c) other sites such as the Moderator band and right ventricular outflow tract in the remaining 2 (13.3%) patients. The ablation locations on the LV septum extended from basal to mid-septum. After an average of 1.7 ablation procedures targeting PVC-triggering VF, 12 (80%) patients remained free of sustained ventricular arrhythmias and ICD shocks, over a mean follow up of 479±395 days. Conclusion In most patients with PVCs-triggering VF, there was an evidence of an ECG abnormality either in the form of an ER pattern or notching of either the Sinus QRS or the PVC complex on pre-ablation ECG. During ablation, Purkinje potentials and PVCs were mapped to and ablated in the region of the LV interventricular septum and papillary muscles. Over long-term follow up, catheter ablation seemed durable and effective in reducing VF episodes and ICD shocks.Presence of Early Repolarization patternPresence of a notching pattern in the Si

Patient-tailored low-voltage-guided ablation of atrial fibrillation: initial experience using a novel ultra-low-temperature cryoablation system

Abstract Introduction The ideal ablation strategy for patients (pts) with persistent atrial fibrillation (PersAF) is still debated. In recent randomized studies, strategies of ablating electrically abnormal atrial regions in addition to pulmonary vein isolation (PVI) have shown promise, and a novel ultra-low-temperature cryoablation (ULTC) system might overcome the limitations of radiofrequency (RF) energy to create transmural lesions in diseased tissue. Purpose Aim of this study is to report procedural aspects, acute efficacy, and safety of our initial experience in treating AF pts with this novel ULTC system. Methods Patients scheduled for catheter ablation who had a high likelihood of having left atrial (LA) low voltage zones (LVZ) underwent ablation with the ULTC system. A detailed high-density LA 3D-electronatomical map was created in sinus rhythm using a multi-electrode catheter. Bipolar LVZs were defined as at least 1cm2 surface of bipolar voltage <0.5mV. The ablation strategy consisted of PVI and linear ablation of the LVZs, transecting (if narrow) or isolating (if broad) the areas of abnormal signals and anchoring these lines to electrically silent structures (PVs or mitral valve ring). Electrical isolation and block across linear ablations were tested as universally accepted. Continuous variables are expressed as median (and interquartile ranges). Results From April to September 2023, 25 pts (10 female) were included (see table for patients´ and procedural characteristics). Procedure duration was 210 (135-270) min, and diminished over time from initially (in the first 12 pts) 260 (203.75-302.50) min to 190 (135-235) min (p=0.047). PVI was achieved in 15/18 pts (83%) using the ULTC, in the remaining 3 pts RF energy touch-up was needed. Linear ablation and isolation of LVZs were always (41/41 in 22pts, 100%) successfully achieved with the ULTC (see figure for an example). Except for 1 right phrenic nerve palsy, no major acute complications were observed. Post-procedural chest pain was not reported by any patient, in 1 patient mild pericardial effusion was detected and treated conservatively. During the 48h post-procedural ECG-monitoring, no sustained atrial arrhythmias occurred. Conclusions This is the first report of patient-tailored low-voltage-guided AF-ablation using a novel ULTC system. Despite representing our initial clinical experience, acute efficacy was very good (95% of acute bidirectional block across lines). Procedure-duration decreased over time, indicating an initial learning curve. Acute safety was reassuring but particular attention should be paid for phrenic nerve function during ablation of the right PVs. The absence of post-procedural pain, pericardial effusion, or acute post-procedural arrhythmias indicates limited ablation-induced inflammation.Result of ULTC ablation in a diseased LA

The circadian pattern of atrial fibrillation onset

Abstract Background/Introduction Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia affecting 2% of the population. Within the broad spectrum of AF symptomatology, there is a particular subset of patients that show a predominant or even exclusive nocturnal onset of paroxysmal AF. Purpose The aim of this study is to assess the timing of onset of AF in the 24-hour cycle and to assess whether a circadian rhythm is present in the onset of AF. Methods The MEDLINE, EMBASE, and CENTRAL databases, searched from inception to September 2023, provided 18 studies detailing the onset of AF in a 24-hour cycle. Patients had either paroxysmal or persistent AF. Studies performed in ICU populations (n=3) were omitted due to different triggers for AF. Time of AF onset was determined either by Cardiac Implantable Electronic Device (CIED) (n=5), Holter (n=7) or minute history taking (n=3). The presence and statistical significance of a 24-hour periodicity is tested using the cosinor analysis: Y(t)= A ⋅ sin(2πft + α) + β where the amplitude, frequency, phase and error (A, f, α and β, respectively) are computed by single harmonic regression using a nonlinear least-squares method. Goodness of fit is estimated using R2, the statistical significance of the model is tested using a zero-amplitude test. Results The 15 studies included 2.080 patients with 11.886 onsets of AF. The blue bars in Figure 1 represent the total of AF onsets from all studies per hour. The pattern of onset AF can be approximated well by a single sine function (Onset(t)= 95.7915 ⋅ sin((2π ⋅ 0.0417 ⋅ t) – 1.8386) + 510.5500, R2 0.77, P = 0.03) with a 24-hour period, clearly establishing the 24-hour rhythmicity in the onset of AF (Figure 1, red line). Hours with significantly more onset of AF compared to the mean, assessed by residual Chi2 testing, are exclusively nocturnal (22.00-7.00, indicated by a moon symbol in Figure 1) while hours with significantly less onset are exclusively during daytime (7.00-22.00, indicated by a sun symbol in Figure 1). Conclusion Despite the potential limitations due to the methods used, such as arrhythmia discrimination in CIED-studies and asymptomatic episodes in case of history taking, the overall picture of predominance of nocturnal AF onset is clearly established. Multiple pathophysiological mechanisms might underlie this circadian pattern and nocturnal predominance, like obstructive sleep apnea and increased vagal tone, which should be subject of further research.time of onset of AF over a 24h period

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.

Artificial Intelligence-based Electrocardiogram prediction for duration of Atrial Fibrillation

Abstract Introduction Atrial fibrillation (AF) is the most common sustained arrhythmia and is associated with poor clinical outcomes, including stroke, acute coronary events, and heart failure. Recent studies have shown that early rhythm treatment of new-onset atrial fibrillation improves the patient's prognosis. However, atrial fibrillation is often asymptomatic, and it is difficult to determine its duration accurately. Recently, AI-bsed ECG has been studied for various cardiovascular diseases. Hypothesis We sought to develop and validate a predictive model of the ECG for the duration of atrial fibrillation. Methods All patients aged 18 years older with at least one ECG were included in the study. Only patients with sinus rhythm with ECG prior to atrial fibrillation with ECG were selected. An ECG within 1 year from AF was first documented in ECG was defined as new onset AF. After dividing our datasets into training (and test sets, we developed an end-to-end deep neural network to predict for the duration of AF. Performance evaluation was conducted using various metrics, including AUROC, AUPRC, sensitivity, specificity, F1 score. Results The dataset consisted of 83,525 ECGs from 16,193 patients from two hospitals. The AUROC for discriminating old AF and new-onset AF is 0.8186 (0.8181 - 0.8190) on internal validation set and 0.7967 (0.7966 - 0.7969) on external validation set. Sensitivity, Specificity, and F1 score are 0.7126((0.7118-0.7134), 0.7697 (0.7693-0.7701) and 0.5751 (0.5745-0.5757) on internal validation set and 0.7309 (0.7307-0.7311), 0.7225 (0.7224-0.7227) and 0.6354 (0.6352-0.6356)on external validation set. Conclusion Our deep learning model can be used to predict atrial fibrillation's duration. Additional studies are ongoing to understand the relative importance of ECG features.

Pulsed-field ablation of atrial fibrillation in elderly and frail patients: procedural efficacy and safety from a single-center experience

Abstract Introduction The demographic data shows a growing population, mostly elderly and with multiple comorbidities, therefore becoming increasingly frail. In this context Atrial fibrillation (AF) is the predominant sustained arrhythmia, and over the years trans-catheter isolation of pulmonary veins (PVI) has become a crucial approach in AF treatment. Among the technologies and energy resources employed through the years to perform atrial fibrillation transcatheter ablation, a novel technique has recently begun to gain ground, specifically pulsed-field ablation (PFA). PFA employs sequential brief and high amplitude electrical pulses to induce selective and irreversible electroporation of the myocardium, leading to cell death. The high selectivity of the lesion, ensured by the lower electroporation threshold of myocardial tissue compared to adjacent anatomic structures, allows for a decrease in potential complications associated with conventional thermal ablation. Purpose To assess the efficacy and safety in the use of pulsed field ablation in a selected population of elderly and frail patients undergoing atrial fibrillation ablation. Method We conducted a retrospective study focusing on elderly and frail patients admitted to our centre for paroxysmal or persistent AF ablation. The inclusion criteria were: age greater than 75 years and a Clinical Frailty Scale ≥ 5. The study population consisted of 26 patients [male gender 18, mean age 78 ± 3 years] including 8 who were affected by an oncological or haematological disease at the time of admission. The majority of patients were affected by paroxysmal AF while two of them presented persistent AF (9%). The primary ablation endpoint was the pulmonary vein isolation (PVI) that was achieved by delivering an energy of 2 kV over 8 applications, employing an alternating approach between the two configurations of the basket and flower catheter for each individual vein. Results The short-term success, represented by the complete and verified electrical isolation of the veins was achieved in all 26 patients without any periprocedural complications. First-pass pulmonary vein isolation (FPI) was universally achieved among the patient in study, with a mean skin-to-skin procedural time of 70 ± 30 minutes. From the procedural data perspective, ablation was achieved using an average fluoroscopy time of 22 ± 8.4 minutes and an average dose area product (DAP) of 1320 cGy×cm2. Conclusions In elderly and frail patients, we assessed the efficacy and safety of ablative procedures using the PFA technique. Successful electrical PVI was achieved without additional touch-ups, thanks to a high FPI rate. This results in lower procedural times and shorter intra-operative radiation exposure. These data confer an augmented value within the elderly-frail population, wherein shorter procedural times contribute to a better postoperative course, characterized by reduced bed rest and shorter intra-hospitalization periods.

Definition and management of arrhythmia-induced cardiomyopathy: findings from the EHRA SIC survey

Abstract Background Arrhythmia-induced Cardiomyopathy (AiCM) represents a subtype of heart failure (HF) in the context of a sustained arrhythmia. However, clear definitions and management recommendations for AiCM are lacking. Purpose The European Heart Rhythm Association Scientific Initiatives Committee (EHRA SIC) conducted a survey to determine the current definitions and management of patients with AiCM among European and non-European electrophysiologists. Methods A 25-item online questionnaire was developed and distributed among EP research network centres between September 4th and October 5th 2022. Results Out of the 206 respondents, 16% were females and the most (33%) were between 40-49 years old. Most of the respondents were EP-Specialists (81%) working at a University Hospital (47%). While most participants (67%) agreed that AiCM should be defined as a left ventricular ejection fraction (LVEF) impairment after new onset of an arrhythmia and/or LVEF recovery after treatment of the culprit arrhythmia, only 35% identified a specific LVEF drop/improvement to diagnose AiCM, the majority (50%) agreeing with a 10% change in LVEF (Figure) but with the rest of the experts choosing a wide range of values (from 5 to 20% LVEF drop). Most respondents used all available therapies in AiCM patients: catheter ablation was chosen by 93%, electrical cardioversion by 83%, antiarrhythmic drugs by 76% and adjuvant HF treatment were used by 76%. 83% of respondents indicated that adjuvant HF treatment should be started at first diagnosis of HF prior to antiarrhythmic treatment and 84% agreed that the therapy should be stopped within six months after LVEF normalization. Responses for the optimal time point for the first reassessment of LVEF during FU varied markedly (1 day to over 6 months after antiarrhythmic treatment). Conclusion This EHRA Survey reveals varying practices in defining and managing AiCM among European and non-European physicians. There is an unmet need for a consensus in the definition and management of AiCM patients to improve patient care.Figure

High-resolution repolarization changes preceding short-coupled ectopy in idiopathic ventricular fibrillation, and effects of quinidine

Abstract Background Idiopathic ventricular fibrillation (VF) is linked to early repolarization, increased repolarization heterogeneity, and (short-coupled) premature ventricular complexes (PVCs). Quinidine, an antiarrhythmic drug with class-IA and -III effects, reduces the occurrence of PVCs and VF, but its effects on repolarization have not yet been studied at the whole-heart level in idiopathic-VF patients. Purpose To study dynamic changes in repolarization preceding short-coupled PVCs using noninvasive electrocardiographic imaging (ECGI) in a patient with idiopathic VF, and the antiarrhythmic effects of quinidine. Methods ECGI was performed during sinus rhythm in a 61-year-old male with an ICD (secondary prevention; 2.5 mg nebivolol daily) two days after recurrent idiopathic VF (Fig. A). This was done 1) at baseline, 2 minutes before short-coupled ectopy ("baseline"); 2) at baseline, 10 seconds before the short-coupled PVC ("pre PVC"); and 3) at 2 hours after start of quinidine 200 mg ("on-quinidine"). The ECGI procedure consisted of a 224-electrode body surface potential map and a contrast-enhanced CT scan to obtain torso and heart geometries. After reconstruction of epicardial unipolar electrograms (UEGs), local activation and repolarization times (ATs and RTs) were derived from UEGs by assessing the steepest downslope of the QRS complex and steepest upslope of the T waves, respectively, of 10-second signal-averaged beats. AT and RT duration (first to last AT or RT) were assessed. Results At baseline, QRS duration and QT interval measured 107 ms and 343 ms, respectively, on the standard 12-lead ECG. ECGI-derived epicardial AT duration was 72 ms, and RT histogram span 92 ms. The coupling interval of the PVC that triggered VF in the ICD readout was 340 ms (Fig. A). During 44 minutes of ECGI, 157 short-coupled PVCs from the moderator-band region were recorded (Fig. B; no tachycardia or VF). Just prior to a PVC, epicardial early repolarization at the PVC origin decreased by 26 ms (star in Figs. C-E), and the RT histogram broadened to 109 ms (Fig. E). While on-quinidine, (25 minutes; QRS duration 107 ms, QT interval 419 ms), epicardial repolarization was prolonged (Fig. C/D), also at the site of abnormal impulse formation. Quinidine had increased the epicardial AT duration to 79 ms, and RT histogram span to 133 ms. PVCs were completely suppressed. The patient remained free of sustained arrhythmias while on-quinidine. Conclusion(s) In this case of short-coupled idiopathic VF, epicardial early repolarization shortened momentarily prior to abnormal impulse formation. We found dynamic substrate-trigger characteristics that likely facilitate reentrant excitation. Quinidine prolonged the duration of epicardial activation and repolarization, suppressing the ectopy and VF recurrence.

Pulsed Field Energy in Atrial Fibrillation Ablation: From Physical Principles to Clinical Applications.

Atrial fibrillation, representing the most prevalent sustained cardiac arrhythmia, significantly impacts stroke risk and cardiovascular mortality. Historically managed with antiarrhythmic drugs with limited efficacy, and more recently, catheter ablation, the interventional approach field is still evolving with technological advances. This review highlights pulsed field ablation (PFA), a revolutionary technique gaining prominence in interventional electrophysiology because of its efficacy and safety. PFA employs non-thermal electric fields to create irreversible electroporation, disrupting cell membranes selectively within myocardial tissue, thus preventing the non-selective damage associated with traditional thermal ablation methods like radiofrequency or cryoablation. Clinical studies have consistently shown PFA's ability to achieve pulmonary vein isolation-a cornerstone of AF treatment-rapidly and with minimal complications. Notably, PFA reduces procedure times and has shown a lower incidence of esophageal and phrenic nerve damage, two common concerns with thermal techniques. Emerging from oncological applications, the principles of electroporation provide a unique tissue-selective ablation method that minimizes collateral damage. This review synthesizes findings from foundational animal studies through to recent clinical trials, such as the MANIFEST-PF and ADVENT trials, demonstrating PFA's effectiveness and safety. Future perspectives point towards expanding indications and refinement of techniques that promise to improve AF management outcomes further. PFA represents a paradigm shift in AF ablation, offering a safer, faster, and equally effective alternative to conventional methods. This synthesis of its development and clinical application outlines its potential to become the new standard in AF treatment protocols.

Epidemiology and comprehensive economic impact of atrial fibrillation and associated stroke in Slovakia.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. It is also a major risk factor for ischemic stroke. The main objective of our study was to identify direct and indirect costs of AF and AF-related stroke in Slovakia. We conducted a retrospective population-based study of AF and stroke related costs both from the third-party healthcare payers and societal perspective. The prevalence and incidence of AF and stroke were determined from central government run healthcare database. Further we estimated both indirect and direct costs of AF and stroke. All costs and healthcare resources were assessed from 2015 through 2019 and were expressed in the respective year. Over the 5-year study period, the prevalence of AF increased by 26% to a total of 149,198 AF cases in 2019, with an estimated total annual economic burden of €66,242,359. Direct medical costs accounted for 94% of the total cost of AF. The total cost of treating patients with stroke in 2019 was estimated at €89,505,669. As a result, the medical costs of stroke that develops as a complication of AF have been estimated to be €25,734,080 in 2019. Our study shows a substantial economic burden of AF and AF-related stroke in Slovakia. In view of the above, both screening for asymptomatic AF in high-risk populations and effective early management of AF with a focused on thromboprophylaxis rhythm control should be implemented.

ARRHYTHMOGENIC RIGHT VENTRICULAR CARDIOMYOPATHY AND CARDIAC SARCOIDOSIS: THE GREY ZONE

Abstract Cardiac sarcoidosis (CS) is a rare multisystem disorder characterized by granulomatous infiltration of the myocardium, whose clinical manifestations can be extremely heterogeneus. We report the case of a 47–year–old man with a previous diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVD). In history he had a marked arrhythmic pattern with multiple episodes of sustained ventricular arrhythmias, biventricular disfunction (LVEF 37%, RVEF 32%) and extensive biventricular transmural late–gadolinium enhancement (greater than 50%) at cardiac RMN. At EKG epsilon wave mainly seen in precordial leads. In November 2022 he was implanted with bicameral defibrillator and in March 2023 he underwent ablation procedure for ventricular tachycardia with RF with endo–epicardial approach. In May 2023 he arrived at our Centre for acute decompensated heart failure. At restored hemodynamic stability, screening for the possible inclusion in transplant list was started. Right heart catheterization (RHC) showed low cardiac index with no pulmonary hypertension. Chest CT unexpectedly showed the presence of multiple micronodules with perilymphatic distribution with confluent appearance compatible with pulmonary sarcoidosis. In consideration of this result, the transplant program was temporarily postponed and investigations for possible cardiac involvement of an inflammatory nature were started. 18F–FDG PET–CT showed pulmonary, splenic, lymphonodal and especially cardiac uptake in the mid–distal segment of the lateral wall of the left ventricle and in the inferior–apical site suspicious for inflammatory pathology. Unfortunately, both lymphonodal and cardiac biopsies were inconclusive because of insufficient material. Nevertheless, the clinical scenario satisfied the Japanese criteria for possible CS; therefore, treatment with prednisone 1 mg/kg was started and a 18F–FDG PET–CT was planned after 3 months of steroid therapy. CS can disguise as a phenocopy of arrhythmogenic right ventricular cardiomyopathy because of several common characteristics, especially arrhythmic presentation. Due to these similarities, a careful overall evaluation of each patient with ARVD is mandatory as several transplant centers have reported cases of CS in explanted heart with a pretransplant misdiagnosis of ARVD or dilated cardiomiopathy. Performing a chest CT in all ARVD patients as part of transplant screening may be considered.

STEMI antiplatelet pretreatment strategy - national multicenter registry experience

Abstract Funding Acknowledgements None. Background/Introduction Antiplatelet therapy is the cornerstone treatment for ST-segment elevation myocardial infarction (STEMI). Dual antiplatelet therapy (DAPT) including aspirin and a potent P2Y12 inhibitor (P2Y12i) is recommended as the default strategy. However, the timing of DAPT remains controversial: European Cardiology Society (ESC) guidelines ceased recommending pretreatment with P2Y12i in STEMI, based on ATLANTIC trial results. Purpose This study aims to evaluate the effect of DAPT with potent P2Y12i pretreatment DAPT in STEMI patients, comparing with DAPT with clopidogrel and aspirin only pretreatment. Methods We have analyzed the antiplatelet pretreatment strategy results of a retrospective cohort of 2283 STEMI patients, from a multicenter national registry, from 2011 till 2019. We compared 3 groups: DAPT with potent P2Y12i, DAPT with clopidogrel and aspirin only. Primary endpoints were death, major adverse cardiovascular events (MACE), including reinfarction, heart failure, sustained ventricular arrhythmia, cardiogenic shock, mechanical complication and stroke, and successful PCI. Safety endpoint was major hemorrhagic events between different strategies. Results A total of 2283 STEMI patients where included, with a mean age of 66±13 years and 27% (n=627) were female. The population was divided in 3 groups, according with pretreatment strategy: DAPT with potent P2Y12i, DAPT with clopidogrel and aspirin only. 334 patients undergone DAPT with potent P2Y12i, and 86% (n=296) had a successful PCI, 21% (n=69) had a MACE and 9% (n=31) died in hospital. The group of patients submitted to DAPT with clopidogrel were 1815, and 80% (n=1448) had a successful PCI, 29% (n=527) had a MACE and 11,5% (n=209). The group pretreated only with aspirin were 124 patients, of which, only 14% (n=17) had a successful PCI, 38% (n=47) had a MACE and 39% (n=49) died. Regarding safety outcomes, 1,5% (n=5) patients with DAPT with potent P2Y12i had a significant hemorrhage, comparing with 3% (n=53) of patients with DAPT with clopidogrel and 3% (n=4) of aspirin only group of patients. There was a statistically significant higher rate of successful PCI with DAPT with potent P2Y12i (p<0,05 OR 2), a statistically significant lower number of MACE (p<0,05 OR 0,6) and in hospital deaths (p=0,04 OR 0,67), comparing with DAPT with clopidogrel and aspirin only groups. There was no statistically significant difference between groups in terms of hemorrhagic events (p=0,7). According to our retrospective multicenter national registry, pretreatment with potent P2Y12i is associated with better results, namely higher rate of successful PCI, less MACE and in hospital death, contrary to recent trials. Our study has some bias: the pretreatment with DAPT was standard of care during the registry, and the choice for aspirin only strategy might be due to higher risk patients, as the choice was not randomized.Antiplatelet treatment comparison

Definition and management of arrhythmia-induced cardiomyopathy: findings from the European Heart Rhythm Association survey.

Arrhythmia-induced cardiomyopathy (AiCM) represents a subtype of acute heart failure (HF) in the context of sustained arrhythmia. Clear definitions and management recommendations for AiCM are lacking. The European Heart Rhythm Association Scientific Initiatives Committee (EHRA SIC) conducted a survey to explore the current definitions and management of patients with AiCM among European and non-European electrophysiologists. A 25-item online questionnaire was developed and distributed among EP specialists on the EHRA SIC website and on social media between 4 September and 5 October 2023. Of the 206 respondents, 16% were female and 61% were between 30 and 49 years old. Most of the respondents were EP specialists (81%) working at university hospitals (47%). While most participants (67%) agreed that AiCM should be defined as a left ventricular ejection fraction (LVEF) impairment after new onset of an arrhythmia, only 35% identified a specific LVEF drop to diagnose AiCM with a wide range of values (5-20% LVEF drop). Most respondents considered all available therapies: catheter ablation (93%), electrical cardioversion (83%), antiarrhythmic drugs (76%), and adjuvant HF treatment (76%). A total of 83% of respondents indicated that adjuvant HF treatment should be started at first HF diagnosis prior to antiarrhythmic treatment, and 84% agreed it should be stopped within six months after LVEF normalization. Responses for the optimal time point for the first LVEF reassessment during follow-up varied markedly (1 day-6 months after antiarrhythmic treatment). This EHRA Survey reveals varying practices regarding AiCM among physicians, highlighting a lack of consensus and heterogenous care of these patients.

Hypoxia Alters Sympathetic Terminal Function and Innervation Patterns in the Rat Left Atrium

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia (Hindricks et al., 2021). Emerging evidence suggests that the association of AF with conditions such as obstructive sleep apnoea, COPD and heart failure may be partly attributable to atrial autonomic remodelling in the setting of chronic hypoxia (CH) and chronic-intermittent hypoxia (CIH) (Saleeb-Mousa et al. 2023). In particular, hypoxic remodelling of the atrial autonomic system is associated with a shift towards sympathetic predominance. We hypothesised that sympathetic remodelling in CH and CIH is characterised by altered regulation of prejunctional terminal function. Procedures were performed in accordance with the UK Animals (Scientific Procedures) Act 1986. A novel confocal fluorescence assay was employed to dynamically monitor single-terminal noradrenaline handling in vitro (Cao et al. 2020). This technique utilises the neurotransmitter transporter uptake assay (NTUA, Molecular Devices), a fluorescent monoamine mimetic which accumulates in sympathetic terminals by entering via the noradrenaline transporter (NAT). Experiments were performed in atrial tissues derived from male adult Wistar rats (200-300g) kept in normoxia (N; n=24), CH (FIO2=0.1-0.12, 9-10 days; n=9) and CIH (FIO2=0.06-0.21, 15 cycles hour−1, 8 hours day−1, 21-24 days; n=4) using a hypoxia chamber. Hearts were excised under non-recovery terminal inhalation isoflurane (3-5% in O2, flow rate 1.5L min−1) with death by cervical dislocation. Tissues were dissected into left atrial appendage (LAA), left atrial posterior wall (LAPW), right atrium (RA), right atrial appendage (RAA) and pulmonary veins. Sections were pinned flat and transferred to a confocal microscope. Tissues were superfused with NTUA and images were captured over 15 minutes to allow for quantification of fluorescence uptake. To determine innervation density, additional imaging of NTUA-loaded tissues was performed at low magnification in each region. Further structural images were captured in an additional group of rats (nN=2, nCH=6) using an anterograde tracing technique. Tissues were excised with sympathetic chains intact, and a dextran-conjugated fluorophore (Dextran Texas Red, Invitrogen) was loaded over 21 hours into either the left or right stellate ganglion. Tissues were subsequently dissected and confocal imaging was performed to visualise atrial sympathetic fibres. Analysis of fluorescence uptake in all tissues revealed a two-phase association characterized by an initial 6-minute linear uptake followed by a plateau phase. In preliminary CIH experiments, no significant changes in NTUA uptake were observed (p>0.05). In CH tissues, linear uptake was not significantly different compared with N (p=0.09). CH was associated with an increase in maximum fluorescence (p=0.0004); however, a significant effect was only observed in the LAA (p=0.008). CH tissues also demonstrated a sympathetic hyperinnervation (p<0.0001), with post-hoc testing revealing a significant effect in the LAPW (p=0.0007). Stellate tracing in all animals revealed diffuse innervation of the LAPW, but an absence of fluorescence in the RA, LAA and RAA. Overall, our data demonstrate regionally dependent functional and structural adaptations of the cardiac sympathetic system to hypoxia. Further work should aim to determine the contribution of atrial autonomic heterogeneity to arrhythmogenesis in conditions associated with CH. This research was funded by the Kennedy Trust, grant number KENN 20 21 04-Saleeb-Mousa, and the British Heart Foundation, grant number FS/PhD/20/29093. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Chinese guidelines for the diagnosis and management of atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, significantly impacting patients' quality of life and increasing the risk of death, stroke, heart failure, and dementia. Over the past two decades, there have been significant breakthroughs in AF risk prediction and screening, stroke prevention, rhythm control, catheter ablation, and integrated management. During this period, the scale, quality, and experience of AF management in China have greatly improved, providing a solid foundation for the development of the guidelines for the diagnosis and management of AF. To further promote standardized AF management, and apply new technologies and concepts to clinical practice timely and fully, the Chinese Society of Cardiology of Chinese Medical Association and the Heart Rhythm Committee of Chinese Society of Biomedical Engineering jointly developed the Chinese Guidelines for the Diagnosis and Management of Atrial Fibrillation. The guidelines comprehensively elaborated on various aspects of AF management and proposed the CHA2DS2‑VASc‑60 stroke risk score based on the characteristics of the Asian AF population. The guidelines also reevaluated the clinical application of AF screening, emphasized the significance of early rhythm control, and highlighted the central role of catheter ablation in rhythm control.

Right heart strain in arrhythmogenic right ventricular cardiomyopathy: implications for cardiovascular outcome.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by progressive myocardial dysfunction and associated with an increased risk of major cardiovascular (CV) events. To determine right heart strain (ventricular and atrial global longitudinal strain (RVGLS and RAGLS) in patients with definite ARVC and its association with adverse events during follow-up. RVGLS and RAGLS were analysed in focused right heart apical views from 70 patients using TomTec ImageArena and association with a composite endpoint was determined (sustained ventricular arrhythmia and cardiovascular death). Over a median follow-up duration of 4.9 years, 26 (37%) patients met the endpoint. RVGLS was significantly impaired in the event group (-11.5 [-13.3 to -10.2] %) vs. the no-event group (-15.8 [-17.1 to -14.5] %, P < 0.001), and so was RAGLS (22.8 [21.4-27.4] % vs. 31.5 [25.1-39.6] %, respectively, P < 0.001). In Cox regression, RVGLS (HR 1.36, P < 0.001) and RAGLS (HR 0.92, P = 0.002) were associated with a higher risk of adverse events. In multivariable Cox regression models, RVGLS and RAGLS remained independent of and were incremental to age, gender, and conventional RV parameters, and model fitness was improved when RVGLS and RAGLS were applied together rather than alone. RVGLS and RAGLS are more impaired in patients with adverse events and associated with adverse events independent of age, gender, and conventional RV parameters. When RVGLS and RAGLS are applied together, prediction models are improved suggesting that right heart strain may form part of the echocardiographic routine protocol in patients with ARVC.

Ventricular response as a predictor of the termination of sustained paroxysmal atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained atrial arrhythmia. Accurate detection of the timing and possibility of AF termination is vital for optimizing rhythm and rate control strategies. The present study evaluated whether the ventricular response (VR) in AF offers a distinctive electrocardiographic indicator for predicting AF termination. Patients experiencing sustained paroxysmal AF for more than 3h were observed using 24-h ambulatory Holter monitoring. VR within 5min before AF termination (VR 0-5min, BAFT) was compared with VR observed during the 60th to 65th min (VR 60-65min, BAFT) and the 120th to 125th min (VR 120-125min, BAFT) before AF termination. Maximum and minimum VRs were calculated on the basis of the average of the highest and lowest VRs across 10 consecutive heartbeats. Data from 37 episodes of paroxysmal AF revealed that the minimum VR0-5min, BAFT (64±20bpm) was significantly faster than both the minimum VR120-125min, BAFT (56±15bpm) and the minimum VR60-65min, BAFT(57±16bpm, p<.05). Similarly, the maximum VR0-5min, BAFT (158±49bpm) was significantly faster than the maximum VR120-125min, BAFT (148±45bpm, p<.05). In the daytime, the minimum VR0-5min, BAFT (66±20bpm) was significantly faster than both the minimum VR60-65min, BAFT (58±17bpm) and minimum VR120-125min, BAFT(57±15bpm, p<.05). However, the mean and maximum VR0-5min, BAFT in the daytime were similar to the mean and maximum VR120-125min in the daytime, respectively. At night, the minimum, mean, and maximum VR0-5min, BAFT were similar to the minimum, mean, and maximum VR120-125min, respectively. Elevated VR rates during AF episodes may be predictors for the termination of AF, especially during the daytime and in patients with nondilated left atria. These findings may guide the development of clinical approaches to rhythm control in AF.

Atrial fibrillation: real-life experience of a rhythm control with electrical cardioversion in a community hospital

BackgroundAtrial fibrillation is the most prevalent sustained cardiac arrhythmia. Electrical cardioversion, a well-established part of the rhythm control strategy, is probably underused in community settings. Here, we describe its use, safety, and effectiveness in a cohort of patients with atrial fibrillation treated in rural settings.MethodsIt is a retrospective cohort study. Data on all procedures from January 1, 2016, till December 1, 2022, in Tarusa Hospital, serving mostly a rural population of 15,000 people, were extracted from electronic health records. Data on the procedure’s success, age, gender, body mass index, comorbidities, previous procedures, echocardiographic parameters, type and duration of arrhythmia, anticoagulation, antiarrhythmic drugs, transesophageal echocardiography, and settings were available.ResultsAltogether, 1,272 procedures in 435 patients were performed during the study period. The overall effectiveness of the procedure was 92%. Effectiveness was similar across all prespecified subgroups. Electrical cardioversion was less effective in patients undergoing the procedure for the first time (86%, 95% CI: 82-90) compared to repeated procedures (95%, 95% CI: 93-96), OR 0.39 (95% CI: 0.26-0.59). Complications were encountered in 13 (1.02%) procedures but were not serious.ConclusionsElectrical cardioversion is an immediately effective procedure that can be safely performed in community hospitals, both in inpatient and outpatient settings. Further studies with longer follow-up are needed to investigate the rate of sinus rhythm maintenance in these patients.