Valvular Heart Disease in Circulation and the Circulation Subspecialty Journals

Abstract

Summary: Atrial fibrillation (AF) increases risk of stroke, morbidity, and mortality. Current treatments have significant limitations. Studies that identify pathways by which we can prevent the development or progression of AF may lead to improved treatment. AF imposes a The Editors Most Read on the Topic of Valvular Heart Disease e965by guest on May 12, 2018 http://circ.ahajournals.org/ Downloaded from metabolic and hemodynamic strain on the atria. At the same time, increased hemodynamic burden on the atria (as a result of hypertension, mitral regurgitation or heart failure) promotes atrial enlargement and fibrosis, a substrate for AF. Left atrial (LA) enlargement is associated with poor clinical outcomes. Endothelin-1 (ET-1), a well-known vasoconstrictor peptide with mitogenic properties, is increased in the plasma of AF patients with underlying structural heart disease. In this study, both ET-1 gene expression and processing were enhanced in the LA of AF patients, and increased content was associated with increased LA size and volume. More broadly, atrial ET-1 content is increased in conditions associated with increased LA hemodynamic burden. ET-1 levels were associated with AF persistence. Atrial ET-1 mRNA levels were correlated with the mRNA expression of fibrotic mediators (platelet-derived growth factor and connective tissue growth factor), as well as with the atrial mRNA expression of brain natriuretic peptide, a predictor of AF. These associations suggest that ET-1 may promote atrial enlargement and fibrosis and contribute to increased AF persistence. It would be of interest to determine if agents or procedures that reduce ET-1 production or block its receptors have a therapeutic benefit with respect to prevention of AF or slowing its progression.Conclusions: Elevated atrial ET-1 content is associated with increased LA size, AF rhythm, hypertension, and heart failure. ET-1 is associated with atrial dilatation, fibrosis, and hypertrophy and probably contributes to AF persistence. Interventions that reduce atrial ET-1 expression and/or block its receptors may slow AF progression. 16 An Echocardiographic Model Predicting Severity of Aortic Regurgitation in Congenital Heart DiseaseSummary: Echocardiographers have had difficulty accurately predicting the severity of aortic regurgitation (AR), and consequently, Ͼ20 different echocardiographic measures have been suggested to quantify AR. This study defined 2 independent predictors of AR severity by 2D echocardiography in a population of patients with congenital heart disease, using cardiovascular MRI as a reference standard. The 2 parameters, parasternal vena contracta-derived area divided by body surface area (based on the parasternal vena contracta width), and abdominal aorta Doppler retrograde velocity-time integral divided by antegrade velocity-time integral are relatively easy to obtain and can be measured in nearly any patient with congenital heart disease. Furthermore, these metrics adjust for changes in body size and are more relevant to the pediat...