ABC | Volume 112, Nº3, March 2019

Original Article Baroncini et al Right ventricle and left atrial volume Arq Bras Cardiol. 2019; 112(3):249-257 Table 3 – Between-group comparison of baseline echocardiographic parameters in the study group and control group Variable Classification Group p-value* Control (n = 25) Study (n = 25) LVDD Normal 25 (100%) Grade I 21 (84%) Grade II 4 (16%) - LVH Normal 25 (100%) 19 (76%) Concentric (c) 0 (0) 5 (20%) Eccentric (e) 0 (0) 1 (4%) - LVH Normal 25 (100%) 19 (76%) Hypertrophy (c/e) 0 (0) 6 (34%) 0.022 RV TAPSE (mm) Normal (> 16) 25 (100%) 25 (100%) Altered (≤ 16) 0 (0) 0 (0) 1 RV lateral S' (cm/s) Normal (> 9.5) 25 (100%) 25 (100%) Altered (≤ 9.5) 0 (0) 0 (0) 1 RVDD (mm) Normal (16 a 30) 25 (100%) 25 (100%) Altered (< 16 or > 30) 0 (0) 0 (0) 1 Left atrial size (mm) Normal (< 40) 23 (92%) 16 (64%) Altered (≥ 40) 2 (8%) 9 (36%) 0.037 LAV (ml/m 2 ) Normal (< 34) 20 (80%) 18 (72%) Altered (≥ 34) 5 (20%) 7 (28%) 0.742 Results expressed as frequency and percentage. Fisher’s exact test (categorical variables); p < 0.05. LVDD: left ventricular diastolic dysfunction; LVH: left ventricular hypertrophy; RV: right ventricular TAPSE: tricuspid annular plane systolic excursion with M-mode; RVDD: right ventricular diastolic diameter; LAV: left atrial volume of the right ventricle resulting from LV contraction and effects of heart translation in the chest. 13 Left atrial enlargement due to pressure and volume overload causes structural changes in the other chambers, including concomitant tricuspid annulus dilation, increased mobility of the tricuspid leaflets and tricuspid regurgitation. 14,15 One hypothesis is that tricuspid annular dilatation, as a consequence of enlarged LA, could change TAPSE and lateral S’ due to displacement of mitral annulus. This would result in RV remodeling and affect RV longitudinal shortening, as the site used for TAPSE and S’ measurements is the lateral insertion site of the tricuspid valve. However, we cannot rule out the possibility that such changes in cardiac chambers induced by the enlargement of the LA could also affect the ultrasonic angle beam, leading to changes in tissue Doppler imaging results. One interesting finding was that although the linear dimension of the LA was greater in the study group than in controls, LAV was practically normal in both groups. It is known that this linear measure of the LA has low accuracy and reproducibility due to technical limitations including the angle of the ultrasound beam, and the left atrial irregular geometry. 4 It is also worth pointing out that the reference values for LAV are derived from international studies involving individuals with higher height; no study involving LAV measurements in a large Brazilian population has been performed so far. 16 However, even small changes in the LAV caused changes in both TAPSE and RV lateral S’ values. Due to the strict exclusion criteria, no signs of RV dysfunction were expected in either study or control group. This was confirmed by the normal values of TAPSE and lateral S’ of the right ventricle in all participants. In the study by Bruhl et al. 17 evaluating 51 healthy individuals, with no past history of cardiac disease, found that TAPSE, mitral annular plane of systolic excursion (MAPSE), and tissue Doppler imaging measurements of the right and left ventricles were stable across age, gender, and body surface area. These findings illustrate the ventricular relationship and systolic interdependence. RV size and function correlate with the symptoms and physical capacity of patients with many clinical conditions. An accurate echocardiographic assessment of the right ventricle allows early detection of cardiac diseases, improves risk stratification and may indicate the right moment to start drug therapy. 18,19 Zakir et al., 20 addressed, appropriately and in detail, the correlation of LV diastolic function with RV systolic dysfunction, based on the invasive measurement of the pulmonary venous system. LV diastolic dysfunction causes an increase in left atrial filling pressure, which can be transmitted backwards, leading to pulmonary arterial hypertension and RV pressure overload. According to Simon et al. 21 the first stage of RV dysfunction is pulmonary hypertension, which causes RV hypertrophy and ultimately right systolic dysfunction. However, in the present study, even patients with LVDD grade II showed normal TAPSE and RV lateral S’. In addition, difficulties in the analysis of the RV function may also result from RV 252