Atrial Tachyarrhythmia Episodes Research Articles

Relationship between predictive factors and atrial high-rate episodes in heart failure with reduced ejection fraction patients with cardiac implantable electronic devices.

Atrial high-rate episodes (AHRE) are atrial tachyarrhythmia episodes detected by implanted cardiac devices, characterised by an atrial rate exceeding 180-190 beats per minute. Recent studies have linked AHRE to the development of atrial fibrillation (AF) and increased stroke risk, especially when episodes last longer than 5-6 min. This study aimed to evaluate the relationship between predictive factors and the occurrence of AHRE in heart failure with reduced ejection fraction (HFrEF) patients with cardiac implantable electronic devices (CIEDs). This single-centre, retrospective study included a cohort of 155 consecutive HFrEF patients with CIEDs, but without a diagnosis of AF, enrolled between January 2023 and December 2023. Patients were stratified based on the presence of AHRE detected during device interrogation. The average age of the patients was 54 ± 14 years, and 83.2% of the study population were male. Patients with AHRE had a reduced left ventricular ejection fraction (LVEF) (p = 0.026) and an increased left atrial diameter (p < 0.001) compared to the group without AHRE. Patients with AHRE had elevated levels of creatinine, uric acid, and TSH compared to those without AHRE (p = 0.006, p = 0.021, p = 0.009, respectively). In the univariable logistic regression analysis, LVEF (HR = 0.690, 95% CI = 0.610-0.913, p = 0.013), left atrial diameter (HR = 8.215, 95% CI = 1.557-43.34, p < 0.001), creatinine (HR = 7.369, 95% CI = 1.749-31.05, p = 0.006), uric acid (HR = 1.073, 95% CI = 1.062-1.196, p = 0.020), total cholesterol (HR = 0.989, 95% CI = 0.979-0.999, p = 0.031), and C-reactive protein levels (HR = 1.146, 95% CI = 1.002-1.131, p = 0.047) were identified as independent predictors of AHRE. In multivariable logistic regression analysis, left ventricular ejection fraction (HR = 0.890, 95% CI = 0.795-0.998, p = 0.046), left atrial diameter (HR = 8.215, 95% CI = 1.557-43.34, p < 0.001), and uric acid concentration (HR = 1.650, 95% CI = 1.063-2.561, p = 0.025) were identified as predictors of atrial high-rate events. LVEF, left atrial diameter, and uric acid level were found to be independent predictors of AHRE in patients with HFrEF. Identifying AHRE is crucial for risk stratification and guiding therapeutic decisions to improve patient outcome.

Pulsed Field Ablation to Treat Paroxysmal Atrial Fibrillation: Safety and Effectiveness in the AdmIRE Pivotal Trial.

Evidence from clinical trials of early pulsed field ablation (PFA) systems in treating atrial fibrillation has demonstrated their promising potential to reduce complications associated with conventional thermal modalities while maintaining efficacy. However, the lack of a fully integrated mapping system, a staple technology of most modern electrophysiology procedures, poses limitations in lesion creation and workflow options. A novel variable-loop PFA catheter integrated with an electroanatomic mapping system has been developed that allows for real-time nonfluoroscopic procedural guidance and lesion indexing as well as feedback of tissue-to-catheter proximity. AdmIRE (Assessment of Safety and Effectiveness in Treatment Management of Atrial Fibrillation With the Bosense-Webster Irreversible Electroporation Ablation System), a multicenter, single-arm, Food and Drug Administration investigational device exemption study, evaluated the long-term safety and effectiveness of this integrated PFA system in a large United States-based drug-refractory symptomatic paroxysmal atrial fibrillation patient population. Using the PFA catheter with a compatible electroanatomic mapping system, patients with drug-refractory symptomatic paroxysmal atrial fibrillation underwent pulmonary vein isolation. The primary safety end point was primary adverse event within 7 days of ablation. The primary effectiveness end point was a composite end point that included 12-month freedom from documented atrial tachyarrhythmia (ie, atrial fibrillation, atrial tachycardia, atrial flutter) episodes, failure to achieve pulmonary vein isolation, use of a nonstudy catheter for pulmonary vein isolation, repeat procedure (except for one redo during blanking), taking a new or previously failed class I or III antiarrhythmic drug at higher dose after blanking, or direct current cardioversion after blanking. At 30 centers, 277 patients with paroxysmal atrial fibrillation (61.5±10.3 years of age; 64.3% male) in the pivotal cohort underwent PFA. More than 25% of the procedures were performed without fluoroscopy. Median (Q1, Q3) pulmonary vein isolation procedure, fluoroscopy, and transpired PFA application times were 81.0 (61.0, 112.0), 7.1 (0.00, 14.3), and 31.0 (24.8, 40.9) minutes, respectively. The primary adverse event rate was 2.9% (8 of 272), with the most common complication being pericardial tamponade. The 12-month primary effectiveness end point was 74.6%. The 1-year freedom from atrial fibrillation, atrial tachycardia, or atrial flutter recurrence rate after blanking was 75.4%. Substantial improvements in quality of life were observed as early as 3 months after the procedure, concurrent with a reduction in multiple health care use measures. AdmIRE confirmed the safety and effectiveness of the variable-loop PFA catheter, with short procedure and PFA application times and low fluoroscopy exposure. URL: https://www.clinicaltrials.gov; Unique identifier: NCT05293639.

Risk stratification of postoperative atrial fibrillation in isolated off-pump coronary artery bypass grafting: focus on left atrial strain characteristics

Aim. To explore the potential of using left atrial strain parameters obtained through transthoracic speckle-tracking echocardiography for predicting new-onset postoperative atrial fibrillation (POAF) in patients undergoing off-pump coronary artery bypass grafting (CABG).Material and methods. The study included 111 patients with coronary artery disease referred for elective CABG. There were following exclusion criteria: recurrent or combined cardiac surgery, cerebral stroke, prior atrial tachyarrhythmia episodes, on-pump CABG, patients with NYHA class 4 heart failure. Patients included in the study underwent transthoracic speckle tracking echocardiography before surgery to assess the reservoir, conduit and contractile left atrial (LA) functions. After off-pump CABG, patients were prospectively observed until discharge from the hospital to record the primary end point — the first-time persistent POAF episode.Results. During follow-up, POAF was recorded in 11 patients (10%). The median endpoint registration was 4 days. The groups formed depending on the end point achievement were comparable in basic clinical and demographic characteristics and analyzed ultrasound parameters. In the majority of the patients studied, a decrease in LA function was detected. Disorders of the conduit (n=94, 85%) and reservoir functions (n=85) were dominant.Conclusion. The results obtained may indicate that there is no relationship between the LA myocardial strain parameters obtained during preoperative screening and the risk of POAF in patients with coronary artery disease who underwent off-pump CABG.

The effect of amiodarone given periprocedurally on the effectiveness of catheter ablation in patients with persistent atrial fibrillation refractory to cardioversion

Abstract Background Rhythm control strategy in patients with persistent atrial fibrillation refractory to electrical cardioversion (AF-REC) poses an important clinical problem. Little is known about the effect of amiodarone therapy given periprocedurally with catheter ablation on maintaining sinus rhythm in this group of patients. Purpose This study aimed to determine whether initial amiodarone therapy introduced prior to AF ablation and continued for one month after the procedure affects the long-term effectiveness of the rhythm control strategy in patients with AF-REC. Methods We conducted a retrospective case-control study of medical records of AF-REC patients treated periprocedurally with amiodarone in addition to pulmonary vein isolation. Data on comorbidities, transthoracic echocardiogram results, and short- and long-term effectiveness of ablation was extracted. Patients were followed up in the out patient clinic with the use of a 72-hour Holter monitoring and telephone interviews. AF recurrence was defined as ≥ 30s episode of atrial tachyarrhythmia. Results The analysis comprised 56 patients: 37 in the amiodarone and 19 in the control group; 12 women, mean age 57 years, mean follow-up of 39.5 months. Amiodarone was discontinued after 1 month at the most after the ablation in all of the patients. The primary endpoint (AF-free survival) was achieved in 17 (45,9%) pts in the amiodarone group and 3 (15,8%) pts in the control group (p=0.026). On multivariable analysis, amiodarone therapy was the only variable correlating with the primary endpoint: OR 6.8 (95% CI: 1.4 - 33.9), p=0.019. Conversion of AF from persistent to paroxysmal or no AF in the follow-up was achieved in 32 pts (86,5%) in the amiodarone group and 9 pts (47,4%) in the control group: OR 8.0 (95% CI: 2.1 - 30.0), p=0.002. Patients in the amiodarone group experienced a borderline better increase of left ventricular ejection fraction: ∆ 5.2% (95% CI: -0.1 - 10.5), p= 0.054. Conclusion Periprocedural use of amiodarone in patients ablated due to persistent atrial fibrillation refractory to electrical cardioversion may lead to significantly better long-term efficacy of catheter ablation in this group of patients.

Efficacy and safety of Saireito (TJ-114) in patients with atrial fibrillation undergoing catheter ablation procedures: A randomized pilot study.

Early arrhythmia recurrences commonly occur after atrial fibrillation (AF) ablation because of irritability and inflammation of left atrium. We hypothesized that short-term use of Saireito would be effective in reducing frequent atrial tachyarrhythmias in the early-phase post-ablation. One hundred patients undergoing catheter ablation for symptomatic AF were randomly assigned to either a 30-day use of Saireito or control group. The primary endpoint was total number of episodes of frequent atrial tachyarrhythmias including definite recurrent AF and frequent premature atrial contractions during the 30-day treatment period post-ablation. Three (6.0%) out of 50 patients treated with Saireito discontinued the drug because of adverse symptoms. The Saireito group was associated with a numerically lower number of episodes of frequent atrial tachyarrhythmias than the control group (3.1 versus 5.2 times, P = 0.17). The mean daily episodes of frequent atrial tachyarrhythmias were significantly fewer in the Saireito group during Day-6 to Day-10 (0.12/day versus 0.27/day, P = 0.03), and during Day-11 to Day-15 (0.08/day versus 0.24/day, P = 0.001). The prevalence of adverse symptoms during the 30-day treatment period was significantly higher in the Saireito group (18.0% versus 2.0%, P = 0.005). Thirty-day use of Saireito following AF ablation was associated with a tendency toward reduced number of episodes of frequent atrial tachyarrhythmias during the treatment period, with more pronounced effect in the first two weeks.

Abstract 16806: Transcatheter Edge-to-Edge Repair Lessens Atrial Fibrillation Burden by Ameliorating Left Atrial Strain in Moderate-to-Severe Mitral Regurgitation Patients

Introduction: trans-catheter edge-to-edge repair (TEER) represents a therapeutic possibility in patients with moderate-severe mitral regurgitation (MR) considered at high surgical risk. Only in recent years, it has been realized that left atrial (LA) function plays a prognostic role in these patients. Hypothesis: since atrial fibrillation (AF) depends in part on LA geometry, we considered that two-dimensional speckle-tracking-echocardiography analysis could predict AF burden. Aim: we therefore evaluated the AF occurrence long term after TEER. Methods: one hundred nine patients treated by TEER between February ‘15 and April ’22 underwent reservoir (R_s), conduct (D_s), and contractile (C_s) evaluations strains before and 1,6,12 months after TEER. Cardiac rhythm was monitored through 24 hours Holter-ECG or previously implanted cardiac devices, when available. Statistical analysis was performed with SPSS. Comparisons were carried out by ANOVA and MANOVA. Results: to the permanent AF group (n=35), no paroxysmal (N=15), nor persistent (N=8) case was added during follow-up after TEER. Among the sinus rhythm (N=51) group, one episode of atrial tachyarrhythmia was found at device interrogation and one patient developed paroxysmal AF (2/51; 3,9%). Significant improvements in total cohort were observed at 12 months follow-up for R_s (from 10,77±5,74% to 16,28±6,93%; p&lt;0,0001), D_s (from -6,72±4,44% to -9,73±4,48%; p=0,0003) and C_s (from -5,21±5,11% to 7,72±5,4%; p=0,0184) compared to baseline. AF burden in paroxysmal AF (baseline: 9,2±4,7 hours, follow-up: 5,8±4,2 hours; p&lt;0,001) was significantly reduced as well as ventricular rate (baseline 88±14 bpm; 12 months 76±13 bpm; p&lt;0,001) in permanent AF group. Conclusions: MR reduction following TEER dictates positive LA remodelling and significant improvement of LA strain. Overall, the impact on LA geometry contributed to lessen incidence and burden of AF.

Atrial fibrillation progression after cryoablation vs. radiofrequency ablation: the CIRCA-DOSE trial.

Atrial fibrillation (AF) is a chronic progressive disorder. Persistent forms of AF are associated with increased rates of thromboembolism, heart failure, and death. Catheter ablation modifies the pathogenic mechanism of AF progression. No randomized studies have evaluated the impact of the ablation energy on progression to persistent atrial tachyarrhythmia. Three hundred forty-six patients with drug-refractory paroxysmal AF were enrolled and randomly assigned to contact-force-guided RF ablation (CF-RF ablation, 115), 4 min cryoballoon ablation (CRYO-4, 115), or 2 min cryoballoon ablation (CRYO-2, 116). Implantable cardiac monitors placed at study entry were used for follow-up. The main outcome was the first episode of persistent atrial tachyarrhythmia. Secondary outcomes included atrial tachyarrhythmia recurrence and arrhythmia burden on the implantable monitor. At a median of 944.0 (interquartile range [IQR], 612.5-1104) days, 0 of 115 patients (0.0%) randomly assigned to CF-RF, 8 of 115 patients (7.0%) assigned to CRYO-4, and 5 of 116 patients (4.3%) assigned to CRYO-2 experienced an episode of persistent atrial tachyarrhythmia (P = .03). A documented recurrence of any atrial tachyarrhythmia ≥30 s occurred in 56.5%, 53.9%, and 62.9% of those randomized to CF-RF, CRYO-4, and CRYO-2, respectively; P = .65. Compared with that of the pre-ablation monitoring period, AF burden was reduced by a median of 99.5% (IQR 94.0%, 100.0%) with CF-RF, 99.9% (IQR 93.3%-100.0%) with CRYO-4, and 99.1%% (IQR 87.0%-100.0%) with CRYO-2 (P = .38). Catheter ablation of paroxysmal AF using radiofrequency energy was associated with fewer patients developing persistent AF on follow-up.

Healthcare utilization and quality of life for atrial fibrillation burden: the CIRCA-DOSE study.

Atrial tachyarrhythmia recurrence ≥30 s remains the primary endpoint of clinical trials; however, this definition has not been correlated with clinical outcomes or pathophysiological processes. This study sought to determine the atrial tachyarrhythmia duration and burden associated with meaningful clinical outcomes. The time and duration of every atrial tachyarrhythmia episode recorded on implantable cardiac monitor were evaluated. Healthcare utilization and quality of life in the year following ablation were prospectively collected. Three hundred and forty-six patients provided 126 110 monitoring days. One-year freedom from recurrence increased with arrhythmia duration thresholds, from 52.6 (182/346) to 93.3% (323/346; P < 0.0001). Patients with atrial fibrillation (AF) recurrence limited to durations ≤1 h had rates of healthcare utilization comparable with patients free of recurrence, while patients with AF recurrences lasting >1 h had a relative risk for emergency department consultation of 3.2 [95% confidence interval (CI) 2.0-5.3], hospitalization of 5.3 (95% CI 2.9-9.6), and repeat ablation of 27.1 (95% CI 10.5-71.0). Patients with AF burden of ≤0.1% had rates of healthcare utilization comparable with patients free of recurrence, while patients with AF burden of >0.1% had a relative risk for emergency department consultation of 2.4 (95% CI 1.9-3.9), hospitalization of 6.8 (95% CI 3.6-13.0), cardioversion of 9.1 (95% CI 3.3-25.6), and repeat ablation of 21.8 (95% CI 9.2-52.2). Compared with patients free of recurrence, the disease-specific quality of life was significantly impaired with AF episode durations >24 h, or AF burdens >0.1%. AF recurrence, as defined by 30 s of arrhythmia, lacks clinical relevance. AF episode durations >1 h or burdens >0.1% were associated with increased rates of healthcare utilization.

The atrial fibrillation burden during the blanking period is predictive of time to recurrence after catheter ablation.

ObjectiveThis study aimed to assess whether atrial fibrillation (AF) occurrence or its corresponding daily mean burden (in minutes/day) during the mid to late blanking period after pulmonary vein isolation (PVI), predicts AF recurrence.MethodsAnalysis of consecutive first PVI ablation patients undergoing prolonged electrocardiogram (ECG) monitoring during the second and third months after PVI. The clinical variables, total AF burden, and their relationship with time to recurrence were studied.Results477 patients with a mean age of 56.9 (SD = 12.3) years (63.7 % male; 71.7 % paroxysmal AF), from which 317 (66.5 %) had an external event recorder between 30 and 90 days after ablation. Median follow-up of 16.0 (P 25:12.0: P 75:33.0) months, 177 (37 %) patients had an AF recurrence, with 106 (22.2 %) having the first episode after 12 months of follow-up. In the group of patients with an event recorder, 80 (25.2 %) had AF documented during the blanking period. Multivariable analysis showed that AF during the blanking period was associated with a 4-fold higher risk of recurrence (HR: 3.98; 95 %CI: 2.95–5.37), and, compared to patients in sinus rhythm, those with an AF burden ≥ 23 min/day had an approximately 7-fold higher risk of recurrence (HR estimate: 6.79; 95 %CI: 4.56–10.10).ConclusionsThe probability of experiencing AF recurrence can be predicted by atrial tachyarrhythmia episodes during the second and third months after PVI. Atrial arrhythmias burden > 23 min/day has a high predictive ability for recurrence.

Cardioversion of Post-Ablation Atrial Tachyarrhythmia with Ibutilide and Amiodarone: A Registry-Based Cohort Study.

Patients with recurrence of atrial tachyarrhythmia after catheter ablation for atrial fibrillation or atrial flutter constitute a rapidly growing cohort, but study-driven treatment recommendations are lacking. The present study aimed to compare the cardioversion success of ibutilide and amiodarone in patients with post-ablation atrial tachyarrhythmia. We included all episodes of post-ablation atrial tachyarrhythmia in patients treated with either intravenous ibutilide or amiodarone at an academic emergency department from 2010 to 2018. The primary endpoint was the conversion to sinus rhythm. The conversion rates were stratified by arrhythmia type, and multivariable cluster-adjusted logistic regression was used to estimate the effect of ibutilide and amiodarone on cardioversion success, given as the odds ratio (OR) with 95% confidence intervals (95% CI). In total, 109 episodes of 72 patients were analyzed. The conversion rates were 37/49 (76%) for ibutilide and 16/60 (27%) for amiodarone. Compared to amiodarone, ibutilide was associated with higher odds of conversion (multivariable cluster-adjusted OR 5.6, 95% CI 1.3–24.3). The cardioversion success of ibutilide was the highest in atrial flutter (crude OR 19.5, 95% CI 3.4–112.5) and focal atrial tachycardia (crude OR 8.3, 95% CI 1.5–47.2), but it was less pronounced in atrial fibrillation (crude OR 4.5, 95% CI 1.2–17.2). Randomized trials are warranted to confirm our findings.

Characteristics of successful reactive atrial-based antitachycardia pacing in patients with cardiac implantable electronic devices: History of catheter ablation of atrial fibrillation as a predictor of high treatment efficacy.

Reactive atrial-based antitachycardia pacing (rATP) in patients with cardiac implantable electronic devices (CIEDs) suppresses the progression of atrial fibrillation (AF) to the persistent form. However, the clinical factors associated with successful reactive atrial-based antitachycardia pacing (rATP) treatment are unknown. This study aimed to examine the predictors of high rATP efficacy in patients with CIEDs. The data of 101,325 rATP-treated atrial tachyarrhythmia (AT/AF) episodes in 51 patients, obtained through remote monitoring and device interrogation, were analyzed. The study population was divided into the high and low efficacy groups based on the overall median success rate of rATP. Clinical characteristics were compared between the two groups. During a follow-up period of 28.6 ± 8.6 months, the median success rate was 43.7% (31.5%-64.9%). The prevalence of a history of catheter ablation of AF was significantly higher in the high efficacy group than in the low efficacy group (73.0% vs. 44.0%, p = .048) and was the only independent predictor of high rATP efficacy (odds ratio, 3.45; p = .038). The rATP success rate in patients with (n = 30) and without (n = 21) a history of catheter ablation was 53.9% (40.0%-67.5%) and 36.4% (22.2%-47.7%), respectively (p = .012). The effect of rATP after ablation was more pronounced in patients with long cycle length episodes (≥75% of AT/AF sequences having a cycle length of 200-449 ms) (67.3% [46.0%-73.6%] vs. 30.6% [18.1%-60.3%], p = .027). The high efficacy group had a significantly lower incidence of AT/AF lasting ≥1, ≥7, and ≥30 days than the low efficacy group. rATP combined with catheter ablation therapy is effective in suppressing AT/AF.

Change in health related quality of life is different in obese versus non-obese patients with atrial fibrillation after thoracoscopic ablation

Abstract Funding Acknowledgements Type of funding sources: Other. Main funding source(s): Received research grants (through institution) from Atricure Inc, Bayer, Boston Scientific, Daiichi Sankyo, Johnson&amp;Johnson, Medtronic Received honoraria/speaker/consultancy fees from Abbott, AtriaN Medical, Atricure Inc, Bayer, Biotronik, CVOI, Daiichi Sankyo, IPP Med, Itreas, Medtronic, Novartis, Servier Background Obesity is an important risk factor for atrial fibrillation (AF), and negatively affects health-related quality of life (QoL) and treatment efficacy. The impact of obesity on the improvement of QoL and on AF recurrence in patients undergoing thoracoscopic AF ablation is unknown. Purpose To assess the change in QoL and the risk of AF recurrence in obese and non-obese patients with atrial fibrillation undergoing thoracoscopic ablation Methods Patients undergoing thoracoscopic AF ablation were prospectively included. Holters were performed before and at 3, 6, 9 and 12 months after the procedure. AF recurrence was defined as any atrial tachyarrhythmia episode &amp;gt;30 seconds during one year of follow-up. QoL and AF recurrence rate were assessed for normal weight (BMI ≤ 24,9 kg/m2), overweight (25,0 – 29,9 kg/m2) and obese (≥ 30,0 kg/m2) patients. QoL was measured by the Short Form 36 questionnaire at baseline and at one year follow-up. Results Four hundred and eight patients were included for analysis. Six out of eight QoL domains scored lower in obese versus non-obese patients before the procedure. In all patients, six out of eight domains increased after the procedure (p&amp;lt;0.01 for most domains). Obese patients showed a larger improvement of emotional related QoL (p=0.01) and a trend towards a larger improvement of mental QoL (p=0.07), while physical QoL increased similarly to non-obese patients (figure). In obese patients, QoL increased similarly for those with and without AF recurrence (p=0.78), whereas in non-obese patients, AF recurrence was associated with less improvement in mental QoL. AF recurrence at 1-year was similar in all groups (normal weight 72.4%, overweight 68%, obese 70.4%, p=0.692). Conclusion After thoracoscopic ablation, obese patients have a similar AF freedom rate as non-obese patients, but a greater improvement in mental quality of life, irrespective of AF recurrence status, after thoracoscopic ablation.

The mitral inflow E/A ratio before the procedure may predict late recurrence after pulmonary vein isolation using second-generation cryoballoon

Abstract Funding Acknowledgements Type of funding sources: None. Background The left ventricular (LV) diastolic dysfunction (DD) increases the risk of atrial fibrillation (AF) development. Some studies investigated whether a relationship between DD and late recurrence after catheter ablation for AF, but they found conflictory results. Such studies had relatively short follow-up duration and they did not have a standard ablation protocol. Some patients were taken to PVI only, while additional linear lesions in localizations such as the left atrial (LA) roof, LA isthmus, and cavotricuspid isthmus were added in others. Purpose The mitral inflow E/A ratio is a simple and practical method commonly used to evaluate LV DD. We aimed to investigate whether the E/A ratio before the procedure was predictive for late recurrence in patients with AF undergoing pulmonary vein isolation (PVI) with cryoballoon (CB). Methods A total of 100 patients undergoing AF ablation for the first time using second-generation CB were included. Only patients with paroxysmal AF and sinus rhythm the day before the procedure, and with pre-procedural pro-B natriuretic peptide levels within normal limits were included. The patients with and without late recurrence were compared in terms of basal characteristics and procedural features. Any atrial tachyarrhythmia episode longer than 30 s after the blanking period was defined as late recurrence. Results The patients [age: 58.0 (50.2-62.0) years, 53 female] were followed up for a median of 44.5 (14.2-62.7) months and late recurrence developed in 25 patients. Female gender (72.0% vs 46.7%), hypertension (72.0% vs 48.0%), and the frequency of early recurrence (20.0% vs 4.0%) were found to be higher in patients with late recurrence than in those without it (p =0.028, 0.037 and 0.022, respectively). The CHA2DS2-Vasc score was higher [2.0 (1.0-3.0) vs 1.0 (0-2.0)], AF duration was longer (27.8 ± 9.4 vs 22.0 ± 8.4 months) and the E/A ratio was lower [0.5 (0.4-1.2) vs 1.4 (0.6-1.7)] in patients with late recurrence than in those without it (p=0.014, 0.006 and 0.001, respectively) (Figure 1). The groups were similar in terms of precedural features. A multivariate analysis showed that female gender (HR: 4.46, 95%CI: 1.24-15.97, p=0.021), early recurrence (HR: 10.22, 95% CI: 2.49-41.99, p=0.001), and E/A ratio (HR: 0.25, 95%CI: 0.11-0.57, p=0.001) were independent predictors for late recurrence (Figure 2). Receiver operating characteristic analysis showed that the optimal cut-off level of the E/A ratio was 0.84. Any ATa free survival rate was significantly lower in patients with E/A ratio &amp;lt;0.84 than in those with ≥0.84 (56.1% vs 88.1%, log-rank p&amp;lt;0.001). Conclusions Female gender, early recurrence, and E/A ratio are independent predictors of late recurrence in patients with AF undergoing PVI using second-generation CB. Measuring the E/A ratio in patients with sinus rhythm before AF ablation may help to predict future recurrences.

Catheter Ablation for Atrial Fibrillation in Patients ≤30 Years of Age

Pulmonary vein (PV) automaticity is an established trigger for paroxysmal atrial fibrillation (PAF), making PV isolation (PVI) the cornerstone of catheter ablation. However, data on triggers for atrial fibrillation (AF) and catheter ablation strategy in very young patients aged <30 years are sparse. A total of 51 young patients (mean age 24.0 ± 4.2 years, 78.4% men) with drug-refractory PAF underwent electrophysiology (EP) study and ablation at 5 EP centers. None of the patients had structural heart disease or family history of AF. EP study induced supraventricular tachycardia (SVT) in 12 patients (n=12, 23.5%): concealed accessory pathway mediated orthodromic atrioventricular reentrant tachycardia in 3 patients, typical atrioventricular nodal reentrant tachycardia in 6 patients, left superior PV tachycardia in 1 patient, left atrial appendage tachycardia in 1 patient, and typical atrial flutter in 1 patient. In patients with induced SVTs, SVT ablation without PVI was performed as an index procedure, except for the patient with atrial flutter who received cavotricuspid isthmus ablation in addition to PVI. Remaining patients underwent radiofrequency (n=15, 29.4%) or second-generation cryoballoon-based PVI (n=24, 47%). There were no major complications related to ablation procedures. Follow-up was based on outpatient visits including 24-hour Holter-electrocardiogram at 3, 6, and 12 months after ablation, or additional Holter-electrocardiogram was ordered in case of symptoms suggesting recurrence. Recurrence was defined as any atrial tachyarrhythmia (ATA) episode >30 seconds after a 3-month blanking period. A total of 2 patients with atrioventricular nodal reentrant tachycardia, 1 with left atrial appendage tachycardia, experienced AF recurrence within the first 3 months and received PVI. After the 3-month blanking period, during a median follow-up of 17.0 ± 10.1 months, 44 of 51 patients (86.2%) were free of ATA recurrence. In the PVI group, 33 of 39 patients (84.6%) experienced no ATA recurrence. In conclusion, SVT substrate is identified in around a quarter of young adult patients with history of AF, and targeted ablation without PVI may be sufficient in the majority of these patients. PVI is needed in the majority and is safe and effective in this population.

High-Normal Thyroid Function and Recurrence of Atrial Fibrillation after Catheter Ablation: A Prospective Observational Study

Background: Thyroid function is increasingly recognized as an important modifiable factor for atrial fibrillation (AF); however, it is unclear if the changes in thyroid hormones, even within the normal range, are associated with AF recurrence after catheter ablation. Methods: Consecutive paroxysmal AF patients who underwent catheter ablation were enrolled. Patients with abnormal thyroid hormones or previous thyroid illnesses were excluded. Patients were followed for 12 months or until they presented with the first episode of atrial tachyarrhythmia after a blanking period. Results: The study included 448 patients with a mean age of 61 (14) years, and 46% were women. After a 1-year follow-up, 104 (23.2%) patients experienced atrial tachyarrhythmia recurrences after an ablation procedure. Recurrence was significantly different among quartile groups of thyroid function, with highest FT₄ and FT₃ levels associated with the greatest risk of recurrence (p < 0.001 and p = 0.024, respectively). FT₄ and FT₃ levels were independent predictors of atrial tachyarrhythmia recurrence (hazard ratio 1.07 per 1 pmol/L increase in FT₄, 95% confidence interval [CI] 1.01–1.15, p = 0.036 and 1.31 per 1 pmol/L increase in FT₃, 95% CI 1.01–1.71, p = 0.032). Conclusions: High-normal FT₃ and FT₄ levels are associated with AF recurrence after catheter ablation in this Chinese population. Attention to thyroid hormones could be valuable to assist in the management of AF.

Catheter ablation for atrial fibrillation in very young patients

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Pulmonary vein automaticity is an established trigger of paroxysmal atrial fibrillation (PAF) making pulmonary vein isolation (PVI) the cornerstone for catheter ablation. However, data on triggers of AF and catheter ablation strategy in very young (&amp;lt;30 years old) patients are sparse. Methods and results: Sixteen young patients (mean age 25.2 ± 4.9 years; 75% men) with recurrent drug refractory PAF underwent EP study and ablation at 3 EP centers. None of the patients had structural heart disease or family history of AF. EP study revealed degeneration of induced supraventricular tachycardia (SVT) into AF in 5 patients (n = 5, 31.2%). Induced SVTs were left lateral concealed accessory pathway mediated orthodromic AVRT in two patients, typical AVNRT in two patients, and left superior PV tachycardia in one patient respectively. In patients with induced SVTs, SVT ablation without PVI was performed as an index procedure. Remaining patients underwent second generation cryoballoon (CB-2) based PVI (n = 11, 68.7%). There were no major complications related to ablation procedures. Follow-up was based on outpatient visits including 24-h Holter-ECG at 3, 6 and, 12 months post ablation, or additional Holter-ECG was ordered in case of symptoms suggesting recurrence. Recurrence was defined as any atrial tachyarrhythmia (ATA) episode &amp;gt;30s following a 3-month blanking period. After a median follow-up of 18.3 ± 6.2 months, 13 of 16 (81.2%) patients were free of ATA recurrence. None of the patients belonging to SVT ablation only group experienced ATA recurrence. Three patients with previous CB-2 PVI recurred, one had typical atrial flutter and underwent CTI ablation, remaining 2 patients had AF recurrence and medically followed. Conclusion In a considerable fraction of young adult patients with history of PAF SVTs may be responsible and SVT ablation without PVI may be sufficient as an index procedure. Catheter ablation AF seems to be safe and effective in this population.

Atrial Fibrillation Burden and Clinical Outcomes in HeartFailure: The CASTLE-AF Trial.

This subanalysis of the CASTLE-AF (Catheter Ablation vs. Standard Conventional Treatment in Patients With LV Dysfunction and AF) trial aimed to address the association between atrial fibrillation (AF) recurrence, AF burden, and hard clinical outcomes in heart failure (HF) patients with AF. The CASTLE-AF trial demonstrated the benefit of CA compared to pharmacological treatment in decreasing mortality and CV hospitalizations in patients with AF and HFrEF. However, the impact of AF recurrence and AF burden after ablation on long-term treatment benefit remains unknown. The CASTLE-AF protocol randomized 363 patients with coexisting HF and AF in a multicenter prospective controlled fashion to catheter ablation (n=179) versus pharmacological therapy (n=184). Two hundred eighty patients were included in this subanalysis (as-treated), 128 of them underwent ablation and 152 received pharmacological treatment. All patients had implanted dual chamber or biventricular implantable defibrillators with activated home monitoring capabilities. The individual AF burden was calculated as the percentage of the atrial arrhythmia time per day. AF burden at baseline was not predictive of the primary endpoint (p=0.473) or all-cause mortality (p=0.446). AF recurrence (defined as any episode >30 s) did not show any relationship with the primary endpoints of mortality and occurrence of HF, irrespective of the treatment arm. An AF burden below 50% after 6months of catheter ablation, was associated with a significant decrease in primary composite outcome (hazard ratio [HR]: 0.33; 95% confidence interval [CI]: 0.15 to 0.71; p=0.014) and all-cause mortality (HR: 0.23; 95% CI: 0.07 to 0.71; p=0.031). The risk of the primary endpoint or mortality was directly related to a low (<50%) or high (≥50%) AF burden at 6months post-ablation. AF burden at 6months was predictive of hard clinical outcomes in HF patients with AF. The first recurrent atrial tachyarrhythmia episode >30s after ablation was not associated with improvement in mortality andhospitalization for HF. (Catheter Ablation vs. Standard Conventional Treatment in Patients With LV DysfunctionandAF [CASTLE-AF]; NCT00643188).

Cardiac Autonomic Dysfunction and Incidence of de novo Atrial Fibrillation: Heart Rate Variability vs. Heart Rate Complexity.

BackgroundThe REACT DX registry evaluates standard therapies to episodes of long-lasting atrial tachyarrhythmias and assesses the quality of sensing and stability of the lead and the implantable cardioverter-defibrillator (ICD) (BIOTRONIK Lumax VR-T DX and successors) over at least a 1-year follow-up period.ObjectiveTo study the association between the risk of de novo device-detected atrial fibrillation (AF), the autonomic perturbations before the onset of paroxysmal AF and a 7-days heart rate variability (7dHRV) 1 month after ICD implantation.MethodsThe registry consists of 234 patients implanted with an ICD, including 10 with de novo long-lasting atrial tachyarrhythmias with no prior history of AF. The patients were matched via the propensity-score methodology as well as for properties directly influencing the ECGs recorded using GE CardioMem CM 3000. Heart rate variability (HRV) analysis was performed using standard parameters from time- and frequency-domains, and from non-linear dynamics.ResultsNo linear HRV was associated with an increased risk of AF (p = n.s.). The only significant approach was derived from symbolic dynamics with the parameter “forbidden words” which distinguished both groups on all 7 days of measurements (p < 0.05), thereby quantifying the heart rate complexity (HRC) as drastically lower in the de novo AF group.ConclusionCardiac autonomic dysfunction denoted by low HRC may be associated with higher AF incidence. For patients with mild to moderate heart failure, standard HRV parameters are not appropriate to quantify cardiac autonomic perturbations before the onset of AF. Further studies are needed to determine the individual risk for AF that would enable interventions to restore autonomic balance in the general population.

The frequency spectrum of sympathetic nerve activity and arrhythmogenicity in ambulatory dogs

Sympathetic nerve activity, heart rate (HR), and blood pressure (BP) all have very low frequency (VLF), low frequency (LF), and high frequency (HF) oscillations. The purpose of this study was to test the hypothesis that the frequency spectra of subcutaneous nerve activity (ScNA), stellate ganglion nerve activity (SGNA), HR, and BP are important to cardiac arrhythmogenesis. We used radiotransmitters to record SGNA, ScNA, HR, and BP in 6 ambulatory dogs and determined the dominant frequency and paroxysmal atrial tachyarrhythmias (PATs) episodes in 3-minute windows over a 24-hour period. The frequency spectra determined in ScNA reflected that in SGNA. HF oscillations were present in both ScNA and SGNA at all time but could be overshadowed by the much larger LF and VLF burst activities. The dominant frequency could occur in any of the 3 frequency bands. There were circadian variations with more frequent occurrences of HF oscillations at night. HF oscillations in HR and BP matched HF oscillations in SGNA and ScNA. PATs occurred only when dominant frequencies of SGNA and ScNA were in the LF and VLF bands. HF oscillations in BP and HR correlate with HF oscillations in sympathetic nerve activity and are present at all time. HF oscillations can be overshadowed by the much larger LF and VLF burst activities. PATs occur only when LF or VLF, but not when HF, is the dominant frequency. The frequency spectra determined in ScNA reflect that in SGNA.

Remote monitoring for the early detection of changes in patient status using the Home Monitoring technology

Aims: To perform the analysis of adverse events (AE) rate and trends of physiologically meaningful parameters in patients with cardiac implantable electronic devices (CIEDs) with the mobile remote monitoring option.Methods: In 9 clinical centers of the Russian Federation and 2 clinical centers of the Republic of Kazakhstan, 126 patients with an implantable cardioverter-defibrillator (ICD) or a pacemaker (PM) equipped with the Home Monitoring (HM) technology (BIOTRONIK, Berlin, Germany) were enrolled. Based on the daily data transmission, all alarm alerts, all HM options changes and all AE were recorded with dated alert content and undertaken measures.Results: The study patients, followed up at least for one year, experienced 42 adverse events (AE), of which 26 were serious AE (SAE) and 3 SAE were defined as device-related (SAED). ICD patients (N=90) with concomitant coronary artery disease (CAD) had a statistically significantly higher SAE prevalence (p=0.0249). Patients with CRT-D had a lower SAE rate than patients with dual- or single-chamber ICD (р=0.046). Downloads of Home Monitoring parameters for retrospective mathematical analysis were available for 60 ICD patients, of which 47 had episodes of ventricular tachycardia (VT), ventricular fibrillation (VF) and/or atrial tachyarrhythmia (AT). Machine learning analysis of the trends of the physiologically meaningful parameters revealed correlations between changes and arrhythmia episodes, with the random forest and gradient boosting methods demonstrating the random effect of the results.Conclusion: Home Monitoring of CIED patients enables the evaluation of different devices applications and their clinical advantages. This might implement the prevention of adverse events and iatrogenic effects of pacing. Based on daily transmission of physiologically meaningful Home Monitoring parameters, the study results demonstrate the feasibility of developing a prediction algorithm for adverse events.