ABC | Volume 111, Nº3, September 2018

Original Article Kanar et al RV function after pulmonary rehabilitation program Arq Bras Cardiol. 2018; 111(3):375-381 were excluded from the analyses due to the poor quality of their echocardiographic records. In the remaining patients, the apical segment of the RV free wall and the apical septum could not be analyzed in 3 and in 2 patients, respectively. All patients had a previous diagnosis of symptomatic COPD. The control group included 32 healthy volunteers. Patients with impairment of LV systolic function (ejection fraction < 55%), significant valvular heart disease, cardiomyopathy, history of coronary artery disease, and malignancy were excluded. The investigation complies with the principles outlined in the Declaration of Helsinki. The study was approved by the local Ethics Committee and written informed consent was obtained from all participants. Adult patients with COPD with medically optimized symptomatic lung disease, admitted to the outpatient PR program, were referred by respiratory physicians after an initial multidisciplinary assessment clinic with a respiratory or rehabilitation physician, cardiology physician, nurse, and physiotherapist. Before starting the PR program, we obtained medical histories and performed physical examination of all patients. Specific measurements recorded at the beginning and end of PR program included 6-minute walk test (6MWT), mMRC (modified Medical Research Council) dyspnea scale, the BODE index – body mass index (BMI), degree of obstruction (FEV 1 ), dyspnea (mMRC scale), exercise capacity. The PR program consisted of 2 sessions each day for 6 days per week for a total of 4 weeks. Each session lasted 30 minutes and included symptom-limited exercise training (walking or cycling). All 6MWTs were performed on a flat surface, enclosed, temperature-controlled corridor using standardized instructions. 10,11 Two6MWTs andechocardiographic examinations were performed at the beginning of the pre‑rehabilitation and post-rehabilitation assessments at the end of PR program due to possible learning effect. The best 6MWT was recorded and used for analysis. The 6MWTD∆ (delta) was determined by the difference between pre- and post‑rehabilitation of 6MWTs. The effect of the 6MWT after the PR programwas evaluated by BODE index and the mMRC score. Conventional and speckle-tracking echocardiography All echocardiographic examinations of patients and healthy controls were performed in accordance with the American Society of Echocardiography guidelines using an ultrasound system (IE33, Philips Medical Systems, Andover, MA, US). 12 Estimation of systolic pulmonary artery pressure (sPAB) was based on tricuspid regurgitation peak velocity using the simplified Bernoulli equation: 4x(tricuspid regurgitation peak velocity) 2 + right atrial pressure (RAP). Estimation of RAP was done on the basis of the inferior vena cava diameter and collapse index. 2 Tricuspid annular plane systolic excursion (TAPSE) is defined as the total excursion of the tricuspid annulus from end-diastole to end-systole, and it is measured typically at the lateral annulus using M-mode Isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT), myocardial performance index (MPI) (calculated as [IVRT + IVCT]/ejection time), and ejection time intervals were measured using either pulsed-wave Doppler (PWD) or Doppler tissue imaging (DTI) at the lateral tricuspid annulus. RV and LV ejection fractions from 2D methods were calculated as (end-diastolic volume - end-systolic volume)/end-diastolic volume. The general principles that underlie 2D speckle‑tracking modalities have been previously described. 13,14 2D echocardiographic grayscale apical 4-chamber images and a frame rate of 70 to 80 frames/s were obtained, which seems to be the best compromise between appropriate temporal resolution and acceptable spatial definition of the LV lateral wall and RV free wall. In postprocessing analysis, the region of interest was obtained by tracing the RV endocardial borders at the level of the septum and the free wall in a still frame at end‑systole. An automated software program calculated the frame-to-frame displacements of speckle pattern within the region of interest throughout the cardiac cycle. Longitudinal strain (LS) curves were obtained from six RV segments (basal, mid, and apical segments of the RV free wall and septum); the global RV strain curve was based on the average of the six regional strain curves, and longitudinal strain curves of the lateral LV wall were obtained by repeating the same analysis (Fig. 1). The extent of myocardial deformation (defined as global or regional longitudinal strain) was expressed as a percentage of the longitudinal systolic shortening compared with diastolic shortening for each segment of interest. All analyses were repeated twice one day later by the same observer in order to assess intraobserver variability, which was calculated as the average difference between the 10 measurements taken. A second independent observer repeated the analyses for the assessment of interobserver variability, which was calculated as the absolute difference divided by the average of the two observations of all parameters. The intraobserver and interobserver variability were 5% and 7 %, respectively. Statistical analysis All statistical tests were performed with a commercially available software program (SPSS 16.0 for Windows; SPSS, Inc., Chicago, IL, USA). The variables were investigated using visual (histograms, probability plots) and analytical methods (Kolmogorov-Smirnov/Shapiro-Wilk test) to determine whether or not they are normally distributed. In sample size calculation, 46 COPD patients and 32 healthy subjects in each group would be needed to detect a 2-point difference in DAN scale, with a power of 80% and 1% of significance level. Categorical variables are presented as numbers and percentages and continuous data expressed as mean ± standard deviation. Since all variables were normally distributed, correlation coefficients and their significance were calculated using the Pearson test, and comparisons of quantitative data performed by a paired sample t-test. A p-value of less than 0.05 was set as statistically significant. Results In our study, 46 patients (mean age: 60.8 ± 10.2 years; gender: 28 male, 18 female) with moderate to very severe COPD undergoing PR and 32 healthy subjects (mean age: 58.5 ± 8.9 years; gender: 13 male, 19 female) were enrolled. Baseline characteristics are shown in Table 1. Age and sex distributions were similar between the two groups. 376