Sex-Related Differences in Atrial Remodeling in Patients With Atrial Fibrillation: Relationship to Ablation Outcomes

Background: Population studies have demonstrated a range of sex differences including a higher prevalence of atrial fibrillation (AF) in men and a higher risk of AF recurrence in women. However, the underlying reasons for this higher recurrence are unknown. This study evaluated whether sex-based electrophysiological substrate differences exist to account for worse AF ablation outcomes in women. Methods: High-density electroanatomic mapping of the left atrium was performed in 116 consecutive patients with AF. Regional analysis was performed across 6 left atrium segments. High-density maps were created using a multipolar catheter (Biosense Webster) during distal coronary sinus pacing at 600 and 300 ms. Mean voltage and conduction velocity was determined. Complex fractionated signals and double potentials were manually annotated. Results: Overall, 42 (36%) were female, mean age was 61±8 years and AF was persistent in 52%. Global mean voltage was significantly lower in females compared with males at 600 ms (1.46±0.17 versus 1.84±0.15 mV, P <0.001) and 300 ms (1.27±0.18 versus 1.57±0.18 mV, P =0.013) pacing. These differences were seen uniformly across the left atrium. Females demonstrated significant conduction velocity slowing (34.9±6.1 versus 44.1±6.9 cm/s, P =0.002) and greater proportion of complex fractionated signals (9.9±1.7% versus 6.0±1.7%, P =0.014). After a median follow-up of 22 months (Q1–Q3: 15–29), females had significantly lower single-procedure (22 [54%] versus 54 [75%], P =0.029) and multiprocedure (24 [59%] versus 60 [83%], P =0.005) arrhythmia-free survival. Female sex and persistent AF were independent predictors of single and multiprocedure arrhythmia recurrence. Conclusions: Female patients demonstrated more advanced atrial remodeling on high-density electroanatomic mapping and greater post-AF ablation arrhythmia recurrence compared with males. These changes may contribute to sex-based differences in the clinical course of females with AF and in part explain the higher risk of recurrence.

Utilising electroanatomic mapping during ablation in patients with CHD to reduce radiation exposure

Background: Patients with CHD can be exposed to high levels of cumulative ionising radiation. Utilisation of electroanatomic mapping during catheter ablation leads to reduced radiation exposure in the general population but has not been well studied in patients with CHD. This study evaluated the radiation sparing benefit of using three-dimensional mapping in patients with CHD. Methods: Data were retrospectively collected from the Catheter Ablation with Reduction or Elimination of Fluoroscopy multi-institutional registry. Patients with CHD were selected. Those with previous ablations, concurrent diagnostic or interventional catheterisation and unknown arrhythmogenic foci were excluded. The control cohort was matched for operating physician, arrhythmia mechanism, arrhythmia location, weight and age. The procedure time, rate of fluoroscopy use, fluoroscopy time, procedural success, complications, and distribution of procedures per year were compared between the two groups. Results: Fifty-six patients with congenital heart disease and 56 matched patients without CHD were included. The mean total procedure time was significantly higher in patients with CHD (212.6 versus 169.5 minutes, p = 0.003). Their median total fluoroscopy time was 4.4 minutes (compared to 1.8 minutes), and their rate of fluoroscopy use was 23% (compared to 13%). The acute success and minor complication rates were similar and no major complications occurred. Conclusions: With the use of electroanatomic mapping during catheter ablation, fluoroscopy use can be reduced in patients with CHD. The majority of patients with CHD received zero fluoroscopy.

Mechanical dispersion identifies patients with extensive electroanatomic abnormalities in Brugada syndrome

Background Brugada syndrome (BrS) was initially described as a pure electrical disorder caused by ion channel abnormalities in the absence of structural heart disease. However, imaging, autopsy and endomyocardial biopsy studies have increasingly demonstrated in patients with BrS the presence of myocardial structural alterations of the right ventricle (RV), particularly in the outflow tract. Indeed, electroanatomic mapping studies identified electroanatomic abnormalities of the RV outflow tract in both unipolar and bipolar maps with a significant correlation between the extension of low-voltage areas and the inducibility of arrhythmias at electrophysiological study or the incidence of malignant arrhythmias during the follow up. New echocardiographic parameters have been proposed to identify subtle myocardial alterations associated with arrhythmic events. Mechanical dispersion (MD) of the left ventricle (LV) has been identified as a prognostic marker in the arrhythmic risk stratification in various cardiac diseases including some cardiomyopathies. Purpose In this study we evaluated MD and global longitudinal strain (GLS) of RV and LV in patients with BrS to identify echocardiographic correlates of the abnormalities detected by electroanatomic mapping. Methods We performed 2D-Echocardiography with speckle tracking analysis of RV and LV in patients with BrS previously submitted to RV electroanatomic mapping. All studies were performed by investigators blind to clinical features and electrophysiological findings. Echocardiographic data were compared with electroanatomic mapping and electrophysiological study findings and with clinical data. Results We enrolled 18 patients (52±11 years, male 44%). Patients with a LV MD value ≥40 ms showed a pathological unipolar area with voltage &lt;5.5 mV significantly more extended than patients with a LV MD value &lt;40 ms (28.49±21.06 vs 10.47±8.22; p=0.03). Patients with LV MD ≥40 ms also showed a trend to greater extension of the unipolar area with voltage &lt;4 mV (13.94±13.11 vs 4.94±3.12; p=0.07), a greater extension of the bipolar area with voltage &lt;1.5 mV (6.24±5.22 vs 2.24±3.15; p=0.07) and higher inducibility at programmed ventricular stimulation (70% vs 37.5%, p=0.34). No correlation was observed between RV MD or GLS values and the extent of the low-voltage areas or with the presence of genetic mutations associated with BrS. Conclusions In patients with BrS a LV MD ≥40 ms is associated with a greater extension of low-voltage areas at unipolar mapping. Echocardiographic evaluation with MD analysis may represent a valuable non-invasive tool to identify electroanatomic alterations prompting further invasive studies including electronatomic mapping and electrophysiological study. Prospective studies on larger series may further clarify the potential role of MD and electroanatomic mapping in the prognostic stratification of patients with BrS. FUNDunding Acknowledgement Type of funding sources: None. Figure 1 Figure 2