Kitaoka Hiroaki, Doi Yoshinori, Casey Susan A, Hitomi Nobuhiko, Furuno Takashi, Maron Barry J
Department of Medicine and Geriatrics, Kochi Medical School, Kochi, Japan.
Am J Cardiol. 2003 Nov 15;92(10):1183-6. doi: 10.1016/j.amjcard.2003.07.027.
The morphologic apical form of hypertrophic cardiomyopathy (HC), in which left ventricular (LV) wall thickening is confined to the most distal region at the apex, has been regarded as a phenotypic expression of nonobstructive HC largely unique to Japanese patients. To investigate this question further, we directly compared unselected and regional hospital-based cohorts of adult patients with HC ( > or =18 years of age) from Japan (Kochi; n=100) and from the United States (US) (Minneapolis; n=361). Japanese and American patients with HC had similar clinical features and did not differ significantly with regard to the severity of symptoms and frequency of outflow obstruction. Although Japanese and American patients also showed similar maximum LV thickness, they differed significantly with respect to the distribution of LV hypertrophy. In particular, the segmental form of HC, with hypertrophy confined to the LV apex, was more frequent in Japanese patients (i.e., apical HC, 15% in Japan vs 3% in US, p<0.0001). Giant negative T waves were also more common in Japanese patients with HC (26% vs 2%, p<0.001), including those with the apical form (64% vs. 30%, p<0.05). Each patient with apical HC had either no or only mild symptoms, and all survived. The morphologic form of nonobstructive HC with hypertrophy limited to the LV apex (apical form of HC) was 5 times more common in an unselected Japanese population. These findings document variability in the phenotypic expression of HC between countries and races, which may be due to differences in environmental factors or genetic background. Patients with the apical form of HC had a benign clinical course.
肥厚型心肌病（HC）的形态学心尖部表现形式，即左心室（LV）壁增厚局限于心尖最远端区域，一直被认为是非梗阻性HC的一种表型表达，在日本患者中较为独特。为了进一步研究这个问题，我们直接比较了来自日本高知县（n = 100）和美国明尼阿波利斯（n = 361）的非选择性和基于地区医院的成年HC患者队列（年龄≥18岁）。日本和美国的HC患者具有相似的临床特征，在症状严重程度和流出道梗阻频率方面无显著差异。尽管日本和美国患者的左心室最大厚度也相似，但他们在左心室肥厚的分布方面存在显著差异。特别是，肥厚局限于左心室心尖的节段性HC形式在日本患者中更为常见（即心尖部HC，日本为15%，美国为3%，p<0.0001）。巨大负T波在日本HC患者中也更常见（26%对2%，p<0.001），包括心尖部形式的患者（64%对30%，p<0.05）。每个心尖部HC患者要么没有症状，要么只有轻微症状，且全部存活。在非选择性日本人群中，肥厚局限于左心室心尖的非梗阻性HC形态学形式（HC的心尖部形式）的发生率要高5倍。这些发现证明了HC表型表达在不同国家和种族之间存在差异，这可能是由于环境因素或遗传背景的不同所致。心尖部HC患者的临床病程较为良性。
