Comparison of the origin and coupling interval between ectopy with and without atrial fibrillation initiation

Prediction model for the new onset of atrial fibrillation combining features of 24-hour Holter electrocardiogram with 12-lead electrocardiogram

Background

Several factors that predict new-onset atrial fibrillation (AF) have been investigated using the 24-hour Holter electrocardiogram (ECG) and 12-lead ECG; however, these have been based on each test independently. The aim of this study was to combine findings from the two tests to create a comprehensive, easy-to-use score and to examine its validity.

Methods and Results

A total of 502 patients underwent 24-hour Holter ECG and 12-lead ECG were followed up for 6.2 ± 3.5 years, and 66 patients developed new-onset AF. Multivariate Cox regression analyses revealed that total number of supraventricular extrasystoles (SVEs) ≥ 100 beats/day and SVE's longest run ≥ 3 beats on 24-hour Holter ECG and PR interval ≥ 185 ms, amplitude ratio of P wave (aVR/V1) < 1.0 and amplitude of RV5 + SV1 ≥ 2.2 mV on 12-lead ECG were significant independent predictors for developing AF (all p < 0.01). Using these cut-off points, the PAAFS (acronym for risk factors) score was constructed by adding one point for each parameter if the patient met each of the criteria. The area under the curve (AUC) of the PAAFS score was 0.80, compared to the AUCs of 24-hour Holter ECG-only factors (0.73) and 12-lead ECG-only factors (0.72), indicating an improvement in score. The annual incidence of AF for each PAAFS score were 0.0%, 0.2%, 0.7%, 1.9%, 5.6%, and 11.1%/year for scores 0 to 5, respectively.

Conclusion

The PAAFS score, which combines findings from 24-hour Holter ECG and 12-lead ECG, was superior to 24-hour Holter ECG and 12-lead ECG alone in predictive accuracy for new-onset AF.

Electrophysiological characteristics of non-pulmonary vein triggers excluding origins from the superior vena cava and left atrial posterior wall: Lessons from the self-reference mapping technique

Background

The detailed electrophysiological characteristics of atrial fibrillation (AF) initiating non-pulmonary vein (PV) triggers excluding origins from the superior vena cava (SVC) and left atrial posterior wall (LAPW) (Non-PV-SVC-LAPW triggers) remain unclear. This study aimed to clarify the detailed electrophysiological characteristics of non-PV-SVC-LAPW triggers.

Methods

Among 446 AF ablation procedures at 2 institutions, patients with reproducible AF initiating non-PV-SVC-LAPW triggers were retrospectively enrolled. The trigger origin was mapped using the self-reference mapping technique. The following electrophysiological parameters were evaluated: the voltage during sinus rhythm and at the onset of AF at the earliest activation site, coupling interval of the trigger between the prior sinus rhythm and AF trigger, and voltage change ratio defined as the trigger voltage at the onset of AF divided by the sinus voltage.

Results

Detailed electrophysiological data were obtained at 28 triggers in 21 patients. The median trigger voltage at the onset of AF was 0.16mV and median trigger coupling interval 182msec. Normal sinus voltages (≧0.5mV) were observed at 16 triggers and low voltages (<0.5mV) at 12 triggers. The voltage change ratio was significantly lower for the normal sinus voltage than low sinus voltage (0.20 vs. 0.60, p = 0.002). The trigger coupling intervals were comparable between the normal sinus voltage and low sinus voltage (170ms vs. 185ms, p = 0.353).

Conclusions

The trigger voltage at the onset of AF was low, regardless of whether the sinus voltage of the trigger was preserved or low.

Short coupling interval with high burden of atrial ectopy predicts recurrence after atrial fibrillation ablation

Atrial ectopy (AE) with a short coupling interval (S-AE) causes atrial fibrillation (AF). A higher burden of AE is associated with recurrence after AF ablation. However, a few reports have evaluated the prognostic impact of both AE burden and S-AE after the acute phase of ablation. This study aimed to assess the characteristics of AE beyond the blanking period in predicting the recurrence. We retrospectively analyzed 173 patients who underwent first catheter ablation for AF and 24-h Holter recording following a 3-month blanking period. AE was defined as a narrow QRS complex occurring < 75% earlier than the prior reference R-R interval. We investigated the relationship between the AE's characteristics in Holter recordings and atrial arrhythmia recurrence. Forty-two patients (24%) had a recurrence during a median 488-day follow-up. Patients with S-AE (minimum coupling interval ratio of AE ≤ 45%) had a higher recurrence rate than those without S-AE (44.9% vs. 16.1%, p < 0.001). Moreover, patients with AE ≥ 241/day exhibited a significantly higher recurrence rate than those with AE < 241/day (44.3% vs. 10.7%, p < 0.001). In multivariate analysis, S-AE with a higher AE burden was an independent predictor of recurrence (hazard ratio 5.82, 95% confidence interval: 2.64-12.82, p < 0.001). Kaplan-Meier analysis showed that patients with S-AE and a higher AE burden had the worst prognosis for recurrence (p < 0.001). The combination of a higher AE burden with S-AE could be an efficient predictor of recurrence. These results can help to develop follow-up strategies after AF ablation.

Novel Score to Predict Very Late Recurrences After Catheter Ablation of Atrial Fibrillation

Various predictors of atrial fibrillation (AF) recurrence have been shown based on the baseline characteristics before catheter ablation (CA). This study aimed to develop a novel scoring system for predicting very late recurrences of AF (VLRAFs) after an initial CA, taking the postprocedural clinical data into account and reassessing VLRAFs in 12-month patients' condition using previously known preprocedural predictors of AF recurrences. We retrospectively studied 327 patients who underwent an initial CA with freedom from AF for over 12 months. We elucidated the predictors of VLRAFs and created a new score to predict VLRAFs in the discovery AF cohort (n = 181). Thereafter, we investigated whether the new scoring system could accurately predict VLRAFs in the validation AF cohort (n = 146). In the discovery AF cohort, VLRAFs were observed in 53 patients (29%) during the follow-up period (mean follow-up duration: 55 months). The univariate and multivariate Cox proportional-hazards model demonstrated that non-pulmonary vein foci, early recurrences of AF (ERAFs), atrial premature contraction (APC) burden ≥ 142/24 hours, and minimum prematurity index of the APCs ≤ 48% were associated with VLRAFs after CA. We created a new scoring system to predict VLRAFs, the n-PReDCt score (non-pulmonary vein: 1 point, early recurrences of AFs (Recurrences of AF in early phase after CA): 1 point, APC burden ≥ 142/24 hours: 1 point, and minimum prematurity index (= Coupling interval) of the APCs of ≤ 48%: 1 point). The n-PReDCt score was significantly associated with VLRAFs by a Kaplan-Meier analysis in the discovery AF and validation AF cohorts (p < 0.0001 and p < 0.0001, respectively).

New Predictor of Very Late Recurrence After Catheter Ablation of Atrial Fibrillation Using Holter Electrocardiogram Parameters

This study aimed to evaluate the predictors of very late recurrence of atrial fibrillation (VLRAF) after an initial AF catheter ablation (CA) by analyzing the follow-up Holter electrocardiogram. We retrospectively studied patients (n = 253, mean age: 66 years, woman: 30%, paroxysmal AF: 73%) without recurrence of AF within 12 months and the use of antiarrhythmic drugs. In the Holter electrocardiogram analysis, the atrial premature complexes (APCs) burden, the profile of the APCs run and prematurity index of the APCs were evaluated. Fifty-one patients (20%) had VLRAF during the follow-up period (mean follow up: 46 months). Patients with VLRAF had a significantly greater APCs burden (0.318% [0.084 to 1.405] vs 0.132% [0.051 to 0.461], p = 0.022), longer number of APCs run (5 [3 to 11] vs 4 [0 to 7], p = 0.019), and shorter minimum prematurity index of the APCs (47 ± 7 vs 51 ± 6, p = 0.001) than those without VLRAF. The optimal cutoff value for the APCs burden, maximum number of APCs run, and minimum prematurity index of the APCs to predict VLRAF was 0.159%, 10, and 48%, respectively. The minimum prematurity index of the APCs (≤48%) was significantly associated with VLRAF in the multivariate analysis. In conclusion, the minimum prematurity index of the APCs (≤48%) at 12 months after CA was shown to be an independent predictor of VLRAF in patients without antiarrhythmic drugs. Although the index is a very simple parameter automatically calculated by analysis software, it can be an important index for following patients after CA over the long-term.

Impact of the extent of low-voltage zone on outcomes after voltage-based catheter ablation for persistent atrial fibrillation

BACKGROUND

Low-voltage zones (LVZs), as measured by electroanatomic mapping, are thought to be associated with fibrosis. We reported the efficacy of atrial fibrillation (AF) ablation aiming to homogenize left atrial (LA) LVZ. The purpose of this study was to evaluate the impact of LVZ extension outcomes after LVZ homogenization in patients with nonparoxysmal AF.

METHODS

This prospective observational cohort study included 172 patients with nonparoxysmal AF undergoing their initial ablation. LVZ was defined as an area with bipolar electrograms <0.5mV during sinus rhythm. LVZ extent was calculated as the percentage of LA surface area, and subsequently, LVZ was categorized into stages I (<5%), II (≥5% to <20%), III (≥20% to <30%), and IV (≥30%). Patients with LVZs underwent LVZ ablation aimed at homogenization of ≥80% of LVZs following pulmonary vein isolation. The primary endpoint was atrial tachyarrhythmia recurrence-free survival after a single procedure at 18 months off antiarrhythmic drugs. The association of %LVZ with recurrence-free survival was examined using Cox proportional hazard models.

RESULTS

The survival rates were 76%, 74%, 57%, and 28% in patients with stages I, II, III, and IV LVZ, respectively. The difference was significant between stages I and IV (log-rank, p<0.001), while not significant between stages I vs. II and I vs. III (p=0.843, p=0.073, respectively). Cox proportional hazard model revealed that %LVZ was an independent predictor of recurrence-free survival (hazard ratio, 1.025 per 1% increase, p<0.001; unadjusted model). The results were similar after demographic and clinical covariate adjustments and after excluding 12 patients who did not achieve homogenization of ≥80% of LVZ.

CONCLUSIONS

The extent of LVZ is an independent predictor for recurrence even after LVZ homogenization.