PDF(Pubmed)
Abstract：
Background: A 25-base pair (25bp) intronic deletion in the MYBPC3 gene enriched in South Asians (SAs) is a risk allele for late-onset left ventricular (LV) dysfunction, hypertrophy, and heart failure (HF) with several forms of cardiomyopathy. However, the effect of this variant on exercise parameters has not been evaluated. Methods: As a pilot study, 10 asymptomatic SA carriers of the MYBPC3 Δ25bp variant (52.9 ± 2.14 years) and 10 age- and gender-matched non-carriers (NCs) (50.1 ± 2.7 years) were evaluated at baseline and under exercise stress conditions using bicycle exercise echocardiography and continuous cardiac monitoring. Results: Baseline echocardiography parameters were not different between the two groups. However, in response to exercise stress, the carriers of Δ25bp had significantly higher LV ejection fraction (%) (CI: 4.57 ± 1.93; p < 0.0001), LV outflow tract peak velocity (m/s) (CI: 0.19 ± 0.07; p < 0.0001), and higher aortic valve (AV) peak velocity (m/s) (CI: 0.103 ± 0.08; p = 0.01) in comparison to NCs, and E/A ratio, a marker of diastolic compliance, was significantly lower in Δ25bp carriers (CI: 0.107 ± 0.102; p = 0.038). Interestingly, LV end-diastolic diameter (LVIDdia) was augmented in NCs in response to stress, while it did not increase in Δ25bp carriers (CI: 0.239 ± 0.125; p = 0.0002). Further, stress-induced right ventricular systolic excursion velocity s\' (m/s), as a marker of right ventricle function, increased similarly in both groups, but tricuspid annular plane systolic excursion increased more in carriers (slope: 0.008; p = 0.0001), suggesting right ventricle functional differences between the two groups. Conclusions: These data support that MYBPC3 Δ25bp is associated with LV hypercontraction under stress conditions with evidence of diastolic impairment.
摘要：
背景：在南亚人（SAs）中富集的MYBPC3基因中的25个碱基对（25bp）内含子缺失是迟发性左心室（LV）功能障碍的风险等位基因，肥大,和心力衰竭（HF）与几种形式的心肌病。然而,该变量对运动参数的影响尚未评估。方法：作为一项试点研究，使用自行车运动超声心动图和连续心脏监测，在基线和运动应激条件下评估了10名MYBPC3Δ25bp变体（52.9±2.14岁）的无症状SA携带者和10名年龄和性别匹配的非携带者（NC）（50.1±2.7岁）。结果：两组基线超声心动图参数无差异。然而,为了应对运动压力，Δ25bp携带者的左心室射血分数(%)明显较高(CI:4.57±1.93;p<0.0001),左心室流出道峰值速度（m/s）（CI：0.19±0.07；p<0.0001），与NC相比，主动脉瓣（AV）峰值速度（m/s）更高（CI：0.103±0.08；p=0.01），和E/A比，舒张顺应性的标志,在Δ25bp携带者中显著较低(CI：0.107±0.102；p=0.038)。有趣的是,NCs对压力的反应增加了LV舒张末期直径（LVIDdia），而在Δ25bp携带者中没有增加(CI：0.239±0.125；p=0.0002)。Further,应力诱导右心室收缩运动速度s'（m/s），作为右心室功能的标志，两组的增幅相似，但是三尖瓣环平面收缩期偏移在携带者中增加更多（斜率：0.008；p=0.0001），提示两组右心室功能存在差异。结论：这些数据支持MYBPC3Δ25bp与压力条件下的左心室过度收缩有关，并有舒张功能受损的证据。
