Left Atrial Sphericity Index Predicts Early Recurrence of Atrial Fibrillation After Direct‐Current Cardioversion: An Echocardiographic Study

Abstract

Background: Attempts to achieve rhythm control using direct-current cardioversion (DCC) are common in those with persistent atrial fibrillation (AF). Although often successful, AF recurs within 1 month in as many as 57% of patients. The aim of this study was to assess whether a baseline left atrial sphericity index (LASI) acquired by 2-dimensional transthoracic echocardiography (TTE) could be used as a predictor of AF recurrence after successful DCC. Hypothesis: A baselline LASI assessed by 2D TTE can predict AF recurrence after successful DCC in patients with persistent AF. Methods: A total of 124 consecutive patients with persistent AF lasting <120 days underwent successful DCC. Other than β-blockers, no other antiarrhythmic treatment was administered. Prior to DCC, all patients underwent thorough TTE, and LASI was calculated as the fraction of the left atrial width/length of the largest possible left atrial volume in a 4-chamber view. The primary outcome was a TTE-estimated baseline LASI as a predictor of AF recurrence after successful DCC for persistent AF. Results: Anatomically, a more spherical shape of the left atrium (LASI >0.9) proved to be a strong and independent predictor of AF recurrence, with an odds ratio between 4.1 (95% confidence interval: 1.6-11.9, P = 0.005) and 7.6 (95% confidence interval: 3.3-19.7; P = 7.2 × 10 −6 ). The receiver operating characteristic curve indicated good power for distinguishing between recurring and nonrecurring AF, and we chose a cutoff of 0.9 because high specificity was a priority for clinical reasons. Conclusions: In conclusion, baseline LASI >0.9 was associated with significantly greater AF recurrence throughout the 12-month follow-up period.

Left atrial shape predicts recurrence after atrial fibrillation catheter ablation

“…Our study does not identify the mechanism by which shape impacts recurrence of AF after ablation. Both we and others have proposed that LA shape is a maker of tissue level remodeling that affects the incidence and maintenance of AF. Further study into whether there are characteristic histopathologic changes in the LA wall associated with LA shape could be informative.…”

“…Use of particle based modeling for shape analysis is complex and computationally expensive. Several other quantitative measures of shape have been proposed, and if these were equivalent in predictive power would likely be preferable given their greater simplicity. We created a simple measure of left atrial spherical shape, the ratio of the depth (anterior–posterior direction) to the width (left–right direction) of the LA, similar to that performed by Osmanagic et al .…”

3D electroanatomical mapping is less sensitive to atrial remodeling in estimation of true left atrial volume than echocardiography

“…More indices describing LA shape remodeling have been introduced as predictors of effectiveness of catheter ablation [ 19 , 27 ] or arrhythmia recurrence after DC cardioversion [ 28 ]. Site to IS, the asymmetry index describing ratio between volume of anterior portion of LA and total LAV has been proved as better prognostic tool [ 27 ].…”

Experience Applying the Guidelines for Reporting Reliability and Agreement Studies (GRRAS) Indicated Five Questions Should Be Addressed in the Planning Phase from a Statistical Point of View

“…Unfortunately, the planning of such sub-studies regularly fails to precede the data collection process, and researchers are not aware of the complementary nature of intrarater variability analysis on the one hand (focusing on one specific observer—a question of internal validity) and interrater variability analysis on the other hand (investigating differences between several observers—a question of external validity). Central terms are regularly used interchangeably, and the conceptual difference of agreement (targeting the degree to which scores or ratings are identical) and reliability (relating to the ability of the scores of a measuring device to differentiate among subjects or objects) is often unclear, but has direct implications on which statistical measures to use (Table 1, with data from [4,5,6,7]; see also Table 2 in [1]).…”