擴(kuo)(kuo)張(zhang)(zhang)型(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)至今(jin)病(bing)(bing)(bing)(bing)(bing)因(yin)不明，可(ke)能(neng)(neng)與下列因(yin)素有(you)關。一、病(bing)(bing)(bing)(bing)(bing)毒(du)性(xing)(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)炎的轉化。動物模(mo)型(xing)顯示嗜心(xin)(xin)(xin)(xin)(xin)性(xing)(xing)柯薩奇b族(zu)病(bing)(bing)(bing)(bing)(bing)毒(du)或腦(nao)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)炎病(bing)(bing)(bing)(bing)(bing)毒(du)感(gan)染引起(qi)(qi)的心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)炎，可(ke)發(fa)展(zhan)為擴(kuo)(kuo)張(zhang)(zhang)型(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)。有(you)報(bao)(bao)道，約(yue)百分(fen)之十(shi)五(wu)的心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)炎患(huan)(huan)者(zhe)(zhe)可(ke)演變為擴(kuo)(kuo)張(zhang)(zhang)性(xing)(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)，大約(yue)百分(fen)之十(shi)的擴(kuo)(kuo)張(zhang)(zhang)型(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)患(huan)(huan)者(zhe)(zhe)的心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)內(nei)膜(mo)，心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)活(huo)檢中呈(cheng)現(xian)有(you)炎癥(zheng)浸潤的心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)炎癥(zheng)證(zheng)(zheng)據。二、免疫功能(neng)(neng)異(yi)(yi)常(chang)。在(zai)(zai)擴(kuo)(kuo)張(zhang)(zhang)型(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)患(huan)(huan)者(zhe)(zhe)血(xue)清中能(neng)(neng)檢測到(dao)抗(kang)肌(ji)(ji)凝(ning)蛋白抗(kang)體(ti)(ti)、抗(kang)線離體(ti)(ti)腺苷載體(ti)(ti)、抗(kang)m七(qi)抗(kang)原(yuan)抗(kang)體(ti)(ti)等(deng)(deng)多種抗(kang)體(ti)(ti)。這(zhe)些免疫異(yi)(yi)常(chang)有(you)認為可(ke)能(neng)(neng)是以往的病(bing)(bing)(bing)(bing)(bing)毒(du)性(xing)(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)炎有(you)關。總之，體(ti)(ti)驗免疫和(he)(he)細胞免疫調節(jie)作用在(zai)(zai)擴(kuo)(kuo)張(zhang)(zhang)性(xing)(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)發(fa)病(bing)(bing)(bing)(bing)(bing)中所起(qi)(qi)的作用，至今(jin)未明。三、遺(yi)傳因(yin)素。通過家(jia)(jia)系(xi)調查和(he)(he)超聲心(xin)(xin)(xin)(xin)(xin)動圖(tu)對(dui)擴(kuo)(kuo)張(zhang)(zhang)性(xing)(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)患(huan)(huan)者(zhe)(zhe)家(jia)(jia)族(zu)篩查證(zheng)(zheng)實，百分(fen)之二十(shi)五(wu)到(dao)百分(fen)之五(wu)十(shi)的患(huan)(huan)者(zhe)(zhe)為家(jia)(jia)族(zu)性(xing)(xing)擴(kuo)(kuo)張(zhang)(zhang)性(xing)(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)。四、心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)能(neng)(neng)量代(dai)謝紊亂。擴(kuo)(kuo)張(zhang)(zhang)型(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)，倉鼠心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)內(nei)atp降低，心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)內(nei)葡(pu)萄糖分(fen)解代(dai)謝障礙，不能(neng)(neng)提(ti)供足夠(gou)的丙酮酸進入(ru)三羧酸循環氧化、磷酸化。亦有(you)報(bao)(bao)道，心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)炎病(bing)(bing)(bing)(bing)(bing)患(huan)(huan)者(zhe)(zhe)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)及血(xue)液內(nei)肉(rou)堿明顯低下，給予(yu)大量L-肉(rou)堿制(zhi)劑患(huan)(huan)者(zhe)(zhe)臨(lin)床(chuang)癥(zheng)狀明顯改善，血(xue)漿肉(rou)堿水(shui)平提(ti)高。五(wu)、交感(gan)神(shen)經系(xi)統異(yi)(yi)常(chang)，在(zai)(zai)擴(kuo)(kuo)張(zhang)(zhang)性(xing)(xing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)病(bing)(bing)(bing)(bing)(bing)心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)膜(mo)內(nei)出現(xian)一致性(xing)(xing)鳥嘌呤核(he)苷酸結核(he)蛋白阿法(fa)亞基增(zeng)多現(xian)象。由此，可(ke)促使內(nei)源性(xing)(xing)兒茶酚胺(an)的作用降低，心(xin)(xin)(xin)(xin)(xin)肌(ji)(ji)收縮功能(neng)(neng)不全。綜上所述，病(bing)(bing)(bing)(bing)(bing)毒(du)感(gan)染、免疫反應失調、遺(yi)傳基因(yin)的存在(zai)(zai)是目(mu)前最主要的發(fa)病(bing)(bing)(bing)(bing)(bing)學說(shuo)。勞累、感(gan)染、毒(du)素、酒精、血(xue)壓(ya)增(zeng)高等(deng)(deng)可(ke)能(neng)(neng)為誘發(fa)因(yin)素。