Atrial low voltage areas: A comparison between atrial fibrillation and sinus rhythm

[EN] Background: Atrial fibrosis can promote atrial fibrillation (AF). Electroanatomic mapping (EAM) can provide information regarding local voltage abnormalities that may be used as a surrogate marker for fibrosis. Specific voltage cut-off values have been reproduced accurately to identify fibrosis in the ventricles, but these values are not well defined in atrial tissue. Methods: This study is a prospective single-center study. Patients with persistent AF referred for ablation were included. EAM was performed before ablation. We recorded bipolar signals, first in AF and later in sinus rhythm (SR). Two thresholds delimited low-voltage areas (LVA), 0.5 and 0.3 mV. We compared LVA extension between maps in SR and AF in each patient. Results: A total of 23 patients were included in the study. The percentage of points with voltage lower than 0.5 mV and 0.3 mV was significantly higher in maps in AF compared with maps in SR: 38.2% of points < 0.5 mV in AF vs. 22.9% in SR (p < 0.001); 22.3% of points < 0.3 mV in AF vs. 14% in SR (p < 0.001). Areas with reduced voltage were significantly larger in maps in AF (0.5 mV threshold, mean area in AF 41.3 ± 42.5 cm2 vs. 11.7 ± 17.9 cm2 in SR, p < 0.001; 0.3 mV threshold, mean area in AF 15.6 ± 22.1 cm2 vs. 6.2 ± 11.5 cm2 in SR, p < 0.001). Conclusions: Using the same voltage thresholds, LVA extension in AF is greater than in SR in patients with persistent AF. These findings provide arguments for defining a different atrial fibrosis threshold based on EAM rhythm.Andrés Lahuerta, A.; Roberto, C.; Saiz Rodríguez, FJ.; Cano, Ó.; Martínez-Mateu, L.; Alonso, P.; Saurí, A.... (2022). Atrial low voltage areas: A comparison between atrial fibrillation and sinus rhythm. Cardiology Journal. 29(2):252-262. https://doi.org/10.5603/CJ.a2021.0125S25226229

Personalized assessment of the cumulative complication risk of the atrial fibrillation ablation track: The AF-TRACK calculator

Atrial fibrillation (AF) ablation strategy is associated with a non-negligible risk of complications and often requires repeat procedures (AF ablation track), implying repetitive exposure to procedural risk.The purpose of this study was to develop and validate a model to estimate individualized cumulative risk of complications in patients undergoing the AF ablation track (Atrial Fibrillation TRAck Complication risK [AF-TRACK] calculator).The model was derived from a multicenter cohort including 3762 AF ablation procedures in 2943 patients. A first regression model was fitted to predict the propensity for repeat ablation. The AF-TRACK calculator computed the risk of AF ablation track complications, considering the propensity for repeat ablation. Internal (cross-validation) and external (independent cohort) validation were assessed for discrimination capacity (area under the curve [AUC]) and goodness of fit (Hosmer-Lemeshow [HL] test).Complications (N = 111) occurred in 3.7% of patients (2.9% of procedures). Predictors included female sex, heart failure, sleep apnea syndrome, and repeat procedures. The model showed fair discrimination capacity to predict complications (AUC 0.61 [0.55-0.67]) and likelihood of repeat procedure (AUC 0.62 [0.60-0.64]), with good calibration (HL χ2 12.5; P = .13). The model maintained adequate discrimination capacity (AUC 0.67 [0.57-0.77]) and calibration (HL χ2 5.6; P = .23) in the external validation cohort. The validated model was used to create the Web-based AF-TRACK calculator.The proposed risk model provides individualized estimates of the cumulative risk of complications of undergoing the AF ablation track. The AF-TRACK calculator is a validated, easy-to-use, Web-based clinical tool to calibrate the risk-to-benefit ratio of this treatment strategy.© 2022 Heart Rhythm Society. Published by Elsevier Inc

Correspondence of Myocardial Strain with Torrent-Guasp’s Theory. Contributions of New Echocardiographic Parameters

Background: Strain, assessed by speckle tracking echocardiography, may be used to evaluate left ventricular mechanics and could establish reference values together with new indices of myocardial function. Objective: The aim of this study was to demonstrate the correspondence of echocardiographic strain values with TorrentGuasp’s single band theory. Methods: A prospective observational study was conducted in 54 healthy volunteers. The three apical projections were used to determine longitudinal strain. Radial strain, circumferential strain and rotation were assessed in transverse planes at the level of the mitral valve, the papillary muscles and the apex. Results: Mean age was 52±10.1 years. Global left ventricular longitudinal strain was -20.8%±2.4%. Postsystolic longitudinal strain mainly affects interventricular septal segments. Radial strain was 36.5%±10.7%, with basal values prevailing over apical ones, extending its duration to the early phase of diastole. Circumferential strain was -20.8%±3.8%, with larger values towards the apex. Twist was 18.4°±6°, torsion 2.2°±0.8°/cm and the torsion index (twist/mitral annular plane systolic excursion) 13.1°±4.4°/cm. The combined strain index includes the “strain product” (-387°±147° × %), and the “strain index” (-0.9°±0.3°/%) calculated as twist × longitudinal strain and twist/longitudinal strain, respectively. Conclusions: New strain parameters may be useful in the study of ventricular mechanics. The anatomical arrangement described by the myocardial band theory is echocardiographically supported by the presence of larger radial strain at the basal-medial level (prevalence of transverse fibers), while the variable arrangement of oblique fibers are responsible for longitudinal strain, circumferential strain and ventricular torsion.Introducción y objetivos. El Strain, o Deformación, evaluado mediante ecocardiografía Speckle Tracking, puede utilizarse para estudiar la mecánica del ventrículo izquierdo. El objetivo fue demostrar la correspondencia de los valores ecocardiográficos con la teoría de la banda única de Torrent-Guasp. Métodos. Estudio prospectivo observacional de 54 voluntarios sanos. Se utilizaron las tres proyecciones apicales para determinar el Strain Longitudinal (SL). El Strain Radial (SR), Circunferencial (SC) y la rotación se determinaron en planos transversales a nivel de válvula mitral, músculos papilares, y ápex. Resultados. Edad media 52,5±10,1 años. El SL global del ventrículo izquierdo fue -20,8±2,4%. Una Deformación Postsistólica en el SL afecta fundamentalmente a segmentos del septo interventricular. El SR fue 36,5±10,7%, con valores basales predominantes sobre los apicales, extendiendo su duración hasta la protodiástole. El SC fue -20,8±3,8%, con valores mayores hacia el ápex. El Giro o Twist fue 18,4±6º, la Torsión 2,2±0,8º/cm y el Índice de Torsión (Giro/excursión sistólica del anillo mitral o MAPSE) 13,1±4,4º/cm. El Índice Combinado de Deformación incluye el “Producto de Deformación” (-387±147 º x %), y el “Índice de Deformación” (-0,9±0,3 º/%) calculados como Giro x SL y Giro/SL, respectivamente. Conclusión: Nuevos parámetros de Deformación pueden ser útiles en el estudio de la mecánica ventricular. La disposición anatómica descrita por la teoría de la banda miocárdica se ve apoyada ecocardiográficamente por la presencia de mayor Strain Radial a nivel basal-medial (predominio de fibras transversales), mientras que la disposición variable de las fibras oblicuas son las responsables del Strain Longitudinal, Circunferencial y Torsión ventricular

Myocardial Contraction during the Diastolic Isovolumetric Period: Analysis of Longitudinal Strain by Means of Speckle Tracking Echocardiography

Background: According to the ventricular myocardial band model, the diastolic isovolumetric period is a contraction phenomenon. Our objective was to employ speckle-tracking echocardiography (STE) to analyze myocardial deformation of the left ventricle (LV) and to confirm if it supports the myocardial band model. Methods: This was a prospective observational study in which 90 healthy volunteers were recruited. We evaluated different types of postsystolic shortening (PSS) from an LV longitudinal strain study. Duration of latest deformation (LD) was calculated as the time from the start of the QRS complex of the ECG to the latest longitudinal deformation peak in the 18 segments of the LV. Results: The mean age of our subjects was 50.3 &plusmn; 11.1 years. PSS was observed in 48.4% of the 1620 LV segments studied (19.8%, 13.5%, and 15.1% in the basal, medial, and apical regions, respectively). PSS was more frequent in the basal, medial septal, and apical anteroseptal segments (&gt;50%). LD peaked in the interventricular septum and in the basal segments of the LV. Conclusions: The pattern of PSS and LD revealed by STE suggests there is contraction in the postsystolic phase of the cardiac cycle. The anatomical location of the segments in which this contraction is most frequently observed corresponds to the main path of the ascending component of the myocardial band. This contraction can be attributed to the protodiastolic untwisting of the LV