Right ventricular long-axis response to different chronic loading conditions: its relevance to clinical symptoms

Abstract

Background: The intervention timing in atrial septal defect (ASD) or pulmonary valvular stenosis (PVS) is more dependent on symptoms than right ventricular (RV) damage in clinical practice. RV long-axis function is sensitive in revealing RV myocardial dysfunction. We evaluate the impact of different chronic loading conditions on RV long-axis function and its relationship to patients' symptoms in ASD or PVS.

Methods: Transthoracic echocardiography was performed in normals (n=39) and patients with isolated secundum ASD (n=45) or PVS (n=38). RV volume- and pressure-overloading were defined as the ratio of RV/left ventricular end-diastolic dimension ≥ 0.5 and RV systolic pressure ≥ 40 mmHg, respectively. RV long-axis dysfunction was defined as M-mode tricuspid annular plane systolic excursion (TAPSE) <1.6 cm. New York Heart Association (NYHA) functional class and other symptoms (decreased exercise tolerance, palpitation and chest pain) were recorded.

Results: Thirty-nine (32.0%) had normal loading (Group 1; 39 normals); 24 (19.6%) had isolated volume-overloading (Group 2; all ASDs); 21 (17.2%) had isolated pressure-overloading (Group 3; 21 PVSs) and 38 (31.1%) had both overloading conditions (Group 4; 21 ASDs and 17 PVSs). RV long-axis dysfunction in abnormal loading groups were zero (0%, Group 2), 21 (100%, Group 3) and 22 (57.8%, Group 4) (χ(2)=45.9, p<0.001). Group 3 were more symptomatic (NYHA functional class 2.5 ± 0.6 versus 1.6 ± 0.5, p<0.05) and had lower TAPSE (1.6 ± 0.4 versus 3.0 ± 0.7 cm, p<0.05) than Group 2. RV long-axis dysfunction was the strongest predictor of the presence of symptoms (odds ratio=9.298, p<0.001).

Conclusion: Chronic volume-overloading accentuates while pressure-overloading attenuates RV long-axis excursion and its impairment was associated with the presence of symptoms.