Letters to the editor Value of right ventricular strain in predicting functional capacity in patients with mitral stenosis Marildes L. Castro a , Marcia M. Barbosa b , José Augusto A. Barbosa b , Fernanda Rodrigues de Almeida a , William Antônio de Magalhães Esteves a , Timothy C. Tan c , Maria Carmo P. Nunes a, c, ⁎ a Post-Graduate Program in Infectious Diseases and Tropical Medicine, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil b Ecocenter, Hospital Socor, Belo Horizonte, MG, Brazil c Cardiac Ultrasound Lab, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA article info Article history: Received 22 January 2013 Accepted 31 March 2013 Available online xxxx Keywords: Mitral stenosis Right ventricular function Right ventricular strain Functional capacity Rheumatic heart disease remains a major health problem, particu- larly in developing countries where it causes significant cardiovascular morbidity and mortality in young people [1]. Mitral stenosis (MS) is the predominant form of valve involvement in rheumatic disease, which usually produces pulmonary hypertension and consequently an increase in right ventricular (RV) afterload [2]. Although the hemody- namic consequences of MS affect the RV as mediated by pulmonary hy- pertension, the pathophysiologic mechanisms of RV dysfunction are not well defined. Some studies have shown dissociation between pulmo- nary artery pressures and RV function [3,4]. Several factors may contribute to clinical presentation in MS and symptoms may be inconsistent with the standard measurements of MS severity [5]. Although pulmonary hypertension is considered to be a major determinant of exercise capacity in MS, the value of RV function in predicting effort tolerance is not well established. This study aims to assess RV function in patients with pure severe rheumatic MS using conventional and emerging echocardiographic techniques, and also to determine if RV strain as parameter of RV function is associated with functional capacity in this setting. Consecutive patients referred for management of rheumatic valve dis- ease, were recruited prospectively from a tertiary referral center for heart valve disease. Exclusion criteria included any comorbid conditions which may independently affect RV function including chronic obstructive pulmonary disease, hemodynamically significant non-mitral valvular dis- ease, and congenital heart disease. Patients with atrial fibrillation were also excluded. Twenty-seven age and gender healthy subjects, with nor- mal standard echocardiograms and good quality images were selected as controls. Doppler echocardiogram with color flow mapping and tissue Doppler imaging was performed in all patients using commercially available hardware and software (Vivid 7; GE Vingmed Ultrasound AS, Horten, Norway). Left ventricular (LV) and RV measurements were made according to the recommendations of the American Society of Echocardi- ography [6]. The ejection fraction was calculated using the Simpson bi- plane method. Mitral valve area was obtained by planimetry and concurrently calculated using the pressure half-time method. Peak and mean transmitral diastolic pressure gradients were measured from Doppler profiles recorded in the apical four-chamber view. The continuous-wave Doppler tricuspid regurgitant velocity was used to de- termine systolic pulmonary artery pressure (SPAP) using the simplified Bernoulli equation. Left atrial volume (LAV) was obtained by the biplane area–length method in the apical 4 and 2-chamber views. End-diastolic area of the RV cavity was measured from the apical four-chamber view. Tricuspid annular plane systolic excursion (TAPSE) was deter- mined in the apical four-chamber view, with the M-mode cursor placed through the lateral tricuspid annulus and the maximal systolic displace- ment measured [7]. RV myocardial performance index was calculated as the ratio between total RV isovolumic time (contraction and relaxation) divided by pulmonary ejection time [8]. Peak systolic (S), early, and late diastolic tissue Doppler velocities were acquired at the tricuspid annulus [8]. Doppler-based strain and strain rate were obtained by placing a 10-mm sample volume in the RV at its basal free wall in the apical 4-chamber view [9] (Fig. 1A). To determine the RV two-dimensional (2D) longitudinal strain, the endocardial border of the RV was traced manually and tracked by the software (GE EchoPAC) offline. The RV free wall and interventricular septum were divided in three segments, basal, mid, and apical, for quantification of regional systolic strain. Global longitudinal RV strain was calculated by averaging strain values measured for all 6 segments [9,10] (Fig. 1B). Measurements were made by a single cardiologist (MMB) in three cardiac cycles, and the average was used for statistical analyses. Intra- observer variability in RV Doppler-based strain and 2D longitudinal strain was calculated in a sample of 20 randomly selected individuals. For the analyses of variability, we calculated an adjusted coefficient of variation, International Journal of Cardiology xxx (2013) xxx–xxx ⁎ Corresponding author at: Departamento de Clínica Médica—UFMG, Av Professor Alfredo Balena, 190, Santa Efigênia, 30130 100 Belo Horizonte, MG, Brazil. Tel.: +55 31 34099746; fax: +55 31 34099437. E-mail address: mcarmo@waymail.com.br (M.C.P. Nunes). IJCA-16213; No of Pages 3 0167-5273/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.ijcard.2013.03.181 Contents lists available at SciVerse ScienceDirect International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard Please cite this article as: Castro ML, et al, Value of right ventricular strain in predicting functional capacity in patients with mitral stenosis, Int J Cardiol (2013), http://dx.doi.org/10.1016/j.ijcard.2013.03.181