239Right ventricular long-axis response to different chronic loading conditions: its relevance to clinical symptoms

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Background: Current recommendations for interventions timing of atrial septal defect (ASD) or pulmonary valvular stenosis (PVS) are largely depend on the presence of symptoms instead of the degree of right ventricular (RV) damage. RV long-axis function measured by M-mode echocardiography at tricuspid annulus (TAPSE) is more sensitive to ejection fraction in revealing RV myocardial dysfunction. We aimed to explore the impact of different loading conditions on RV long-axis function and its relations to patients' symptoms.Methods: Echocardiography was done in normal controls and patients with isolated secundum ASD or PVS. Significant volume- and pressure-overloading were defined as the ratio of M-mode measured RV/left ventricular end-diastolic dimension >0.5 and continuous Doppler-derived pulmonary arterial systolic pressure >40 mmHg, respectively.Results: Thirty-nine normal controls and 105 patients were studied. 41 (32%) had normal RV loading (Group 1; 39 controls, 2 ASD patients); 25 (20%) had isolated volume-overloading (Group 2, all ASD patients); 23 (18%) had isolated pressure-overloading (Group 3; 2 ASD and 21 PVS patients) and 38 (30%) had both overloading conditions (Group 4; 21 ASD and 17 PVS patients) (χ2=205,p<0.001). TAPSE was the lowest in Group 3 and the highest in Group 2 (Table). The prevalence of RV long-axis dysfunction (TAPSE<1.6 cm) in abnormal loading groups were 0 (0%, Group 2), 21 (93%, Group 3) and 22 (58%, Group 4) respectively (χ2=54, p<0.001). Patients with RV dysfunction were more symptomatic (67% vs. 19%, χ2=29, p<0.001). RV long-axis dysfunction was the strongest associated factor of the presence of symptoms (odds ratio=9.30; p<0.001).Conclusion: RV long-axis function behaved differently in patients with chronic increase in preload or afterload, which may account for different prevalence of symptoms in ASD and PVS. Assessment of RV-long axis function may provide additional information aiding clinical decision.

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