心尖部位在先天已矯正的大動脈轉位對左心室出口阻塞之影響

Abstract

心尖部位一直被認為與依序分節診斷無關，其臨床意義只停留在心尖部位之觸摸， 心電圖或超音波檢查需要在右位心或左位心之上進行檢查之階段而已。但實際上複雜性 先天性心臟病常伴隨心尖部位之異常位置，其含義不為人所知。尤其在針對先天已矯正 之大動脈轉位之雙轉換手術日益流行的今天，兩心室出口並沒有被轉換重建；徹底了解 在心尖旋轉至與下腔靜脈同側時右心室有無包圍位於其後之左心室出口有其必要性。我 們利用極快速電腦斷層掃描分析比較65 例先天已矯正的大動脈轉位合併心尖部位異常 之病例，配合臨床及血管造影之觀察，確定心尖部位旋轉對左心室出口阻塞之影響。我 們發現心尖旋轉至與下腔靜脈同側時右心室會包圍位於其後之左心室出口(n = 31)，其 中93.5% (n = 29)有左心室出口阻塞。但是在心尖沒有旋轉至與下腔靜脈同側時(n = 34) 右心室沒有包圍位於其後之左心室出口，其中73.5% (n = 25)有左心室出口阻塞。這個 差異在統計上有意義(p = 0.03)；在心房正位時(p = 0.01)比心房反位(p = N.S.) 更加明 顯。我們認為心尖旋轉至與下腔靜脈同側時高壓力的右心室會包圍位於其後之左心室出 口，造成左心室出口阻塞；在心房正位時特別容易發生。施行雙轉換手術時兩心室出口 並沒有被轉換重建，在這種病例有無必要施行雙轉換手術應重新考慮。

Apical position (Apex) is alleged to be independent of sequential segmental analysis, thus its clinical role was neglected. The right ventricle in congenitally corrected transposition with apicocaval ipsilaterality might wrap around the left ventricular outflow tract (LVOT). To delineate LVOT was compressed or not by the systematic ventricle in this setting, we carried out the following study. We analyzed 65 patients of congenital congenitally corrected transposition with various apical positions from 1981 to 2000. They were divided into 4 Groups according to the ventricular looping (Loop) and Apex: Group A, D-loop with levocardia; Group B, L-loop with dextrocardia, the direction of Loop and Apex are opposite to each other; Group C, D-loop with dextrocardia; Group D, L-loop with levocardia, the direction of Loop and Apex are to the same direction. Electron beam computed tomography was used to define left-right and ventro-dorsal relationship of left and right ventricular outflow tracts. Apicocaval ipsilaterality was found in 31 patients. (Group A, n = 15; Group B, n = 16), the right ventricle wrapped around LVOT in all cases. Among them, 93.5% (n = 29) 2 had LVOT obstruction (pulmonary atresia or stenosis). Whereas 73.5% of 34 patients without apicocaval ipsilaterality (Group C, n = 9; Group D, n = 25) had LVOT obstruction. The difference was statistically significant (p = 0.03).Further analysis found that this difference is more significant in the setting of situs solitus (Group B & D, p = 0.01) than situs inversus (Group A & C, p = N.S.). We concluded that LVOT obstruction is prone to occur in congenitally corrected transposition with situs solitus and (Group B) and apicocaval ipsilaterality, whereas in Group D, LVOT was not wrapped around by the systemic-pressured right ventricle had less incidence of LVOT obstruction. In the latter setting, to perform a double switch without exchanging ventricular outflow tract should be reconsidered.