Qing-Shan Lin

The Chinese University of Hong Kong, Hong Kong, Hong Kong

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Publications (4)31.47 Total impact

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    ABSTRACT: Mitral and aortic valves are coupled via fibrous tissue. This coupling is considered to be important for cardiac function before and after mitral valve surgery. The relationship between mitral-aortic coupling and different types of mitral regurgitation (MR) is not completely understood. Real-time three-dimensional transesophageal echocardiography (RT3D-TEE) was performed in 133 subjects: 30 normal subjects, 15 patients with Carpentier type I MR (annular dilatation and congenital cleft), 40 type II (mitral valve prolapse), 20 type IIIa (rheumatic) and 28 type IIIb (ischemic mitral regurgitation). Custom software was used to track mitral (MA) and aortic annuli (AoA) in 3D space throughout cardiac cycle, allowing measurement of changes in mitral and aortic valve morphology. Normal mitral-aortic coupling is characterized by reciprocal changes in the annular areas throughout cardiac cycle, with systolic reduction of the angle between the two annular planes. In Carpentier type II patients, not only MA but also AoA areas were increased (P < 0.05 vs normal), but the reciprocal pattern of mitral-aortic coupling was preserved. In both type I IMR and IIIb patients, MA and AoA areas were both increased (P < 0.05 vs normal) and the reciprocal behavior of mitral-aortic coupling was lost. Only MA area was increased in type IIIa patients. The extent of mitral-aortic angle reduction during systole was diminished in all 4 Carpentier groups (P < 0.05 vs normal). Mitral valve diseases may affect normal mitral-aortic coupling and aortic valve function. Different patterns of abnormal mitral-aortic coupling are associated with different Carpentier types of MR.
    Clinical Research in Cardiology 04/2015; DOI:10.1007/s00392-015-0851-2 · 4.17 Impact Factor
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    ABSTRACT: Introduction: In functional mitral regurgitation (FMR), effective regurgitant orifice area (EROA) displays a dynamic pattern. The impact of dynamic changes of annulus dysfunction and leaflets tenting on phasic EROA was explored with real-time three-dimensional transesophageal echocardiography (RT3D-TEE). Methods: RT3D-TEE was performed in 52 FMR patients and 30 controls. Mitral annulus dimensions and leaflets tenting were measured throughout systole (TomTec, Germany). Phasic EROA was measured by proximal isovelocity surface area (PISA) method. Results: Mitral annulus had the minimal area and an oval shape with saddle configuration during early systole in controls, which enlarged and became round and flattened towards mid and late systole (P < 0.05). In contrast, annulus in FMR was significantly larger, rounder and flatter (P < 0.001), which further dilated and became more flattened at late systole (P < 0.05 vs control). Leaflet tenting height in FMR decreased in mid systole and remains unchanged towards late systole. The leaflet tenting volume peaked at early and late systole with a mid-systolic trough in both FMR and controls. But tenting volume of patients with FMR was significantly larger than that of controls (all P < 0.001 vs control in whole systole). Further analysis demonstrated that early tenting volume (beta value = 0.053, P < 0.05) was a predictor of early EROA, whereas late tenting volume (beta value = 0.031, P < 0.05) and late annular displacement velocity were predictors of late EROA. Conclusions: The early and late peak EROAs of FMR was primarily contributed by tenting volume at early systole and late systole respectively. These findings would be of value to consider in interventions aimed at reducing the severity of FMR.
    International Journal of Cardiology 08/2014; 176(3). DOI:10.1016/j.ijcard.2014.08.001 · 6.18 Impact Factor
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    ABSTRACT: BACKGROUND: Few data exist regarding the relation of the 3-dimensional (3D) morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse (MVP). METHODS AND RESULTS: Real-time 3D transesophageal echocardiography of the mitral valve was acquired in 112 subjects including 36 patients with MVP and significant MR (≥3+; MR+ group), 32 patients with MVP but no or mild MR (≤2+; MR- group), 12 patients with significant MR due to non-prolapse pathologies (non-prolapse group), and 32 normal subjects. The 3D geometry of mitral valve apparatus was measured with dedicated quantification software. Compared to normal and MR- groups, MR+ group had more dilated mitral annulus (p<0.0001), reduced annular height-to-commissural width ratio (AHCWR) (p<0.0001) indicating flattening of annular saddle-shape, redundant leaflet surfaces (p<0.0001), greater leaflet billow volume (p<0.0001) and billow height (p<0.0001), longer lengths from papillary muscles to coaptation (p<0.0001), and more frequent chordal rupture (p<0.0001). Prevalence of chordal rupture increased progressively with annulus flattening (7% vs 24% vs 42% for AHCWR>20%, 15%~20%, and <15%, respectively; p=0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture (r(2)=0.66, p<0.0001). MR severity correlated strongly with leaflet billow volume (r(2)=0.74, p<0.0001) and inversely with AHCWR (r(2)=0.44, p<0.0001). In contrast, annulus dilatation but not flattening occurred in non-prolapse MR patients. An AHCWR<15% (odds ratio=7.1, p=0.0004) was strongly associated with significant MR in MVP. CONCLUSIONS: Flattening of annular saddle-shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture, and may be important in pathogenesis of MR in MVP.
    Circulation 12/2012; 127(7). DOI:10.1161/CIRCULATIONAHA.112.118083 · 14.95 Impact Factor
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    ABSTRACT: PURPOSE: Late-onset atrial arrhythmia after successful closure of atrial septal defect (ASD) is not uncommon. Right atrial (RA) enlargement and increased electrocardiographic P-wave dispersion (Pd) independently predict the development of atrial arrhythmia. Data on the degree of right atrial (RA) geometrical and electrical remodeling following device closure of ASD are limited. METHODS: Echocardiography and electrocardiography (ECG) were performed in 58 consecutive patients (47±17years) before and at 3months after ASD closure. Persistent RA enlargement was defined as RA volume index (RAVI) ≥21ml/m(2) at 3months. Pd was calculated as the difference between maximal and minimal P-wave durations in 12-lead ECG. RESULTS: RA size reduced (RAVI: 50±28 vs. 26±16ml/m(2), p<0.001) and Pd on ECG decreased (53±17 vs. 49±20ms, p<0.05) significantly at 3months when compared to baseline. However, persistent RA enlargement remained evident in 31 patients (53%). As a group, they were older with higher pulmonary arterial systolic pressure, larger Qp/Qs, longer maximal P-wave duration and Pd than those with normalized RA. Pd reduction only occurred in patients with normalized RA size. The 3-month Pd (hazard ratio: 1.033, p<0.001) predicted the presence of incomplete RA geometrical remodeling. ROC curve revealed that Pd ≥45ms at 3months was 77% sensitive and 86% specific in revealing residual RA enlargement. CONCLUSION: Both atrial geometrical and electrical reverse remodeling were evident at 3months following ASD closure. However, only half of the included patients had normalization of RA size which could be revealed by a simple ECG surrogate of intra-atrial conduction disturbance.
    International journal of cardiology 10/2012; 168(1). DOI:10.1016/j.ijcard.2012.09.119 · 6.18 Impact Factor