Department of Medicine, Toronto General Hospital, University of Toronto, 9th floor, North Wing, Room 983, 200 Elizabeth Street, Toronto, ON, Canada, M5G 2C4,
Hepatol Int. 2009 Mar;3(1):294-304. doi: 10.1007/s12072-008-9109-7. Epub 2008 Nov 11.
Cirrhotic cardiomyopathy is a recently recognized condition in cirrhosis consisting of systolic incompetence under condition of stress, diastolic dysfunction related to altered diastolic relaxation, and electrophysiological abnormalities in the absence of any known cardiac disease. It can be diagnosed by using a combination of electrocardiograph, 2-dimensional echocardiography, and various serum markers such as brain natriuretic factor. The underlying pathogenetic mechanisms include abnormalities in the beta-adrenergic signaling pathway, altered cardiomyocyte membrane fluidity, increased myocardial fibrosis, cardiomyocyte hypertrophy, and ion channel defects. Various compounds for which levels are elevated in cirrhosis such as nitric oxide and carbon monoxide can also exert a negative inotropic effect on the myocardium, whereas excess sodium and volume retention can lead to myocardial hypertrophy. Various toxins can also aggravate the ion channel defects, thereby widening the QRS complex causing prolonged QT intervals. Clinically, systolic incompetence is most evident when cirrhotic patients are placed under stress, whether physical or pharmacological, or when the extent of peripheral arterial vasodilatation demands an increased cardiac output as in the case of bacterial infections. Acute volume overload such as immediately after insertion of a transjugular intrahepatic portosystemic shunt or after liver transplantation can also tip these cirrhotic patients into cardiac failure. Treatment of cirrhotic cardiomyopathy is unsatisfactory. There is some evidence that beta-blockade may help some cirrhotic patients with baseline prolonged QT interval. Long-term aldosterone antagonism may help reduce myocardial hypertrophy. Future studies should include further elucidation of pathogenetic mechanisms so as to develop effective treatment strategies.
肝硬化性心肌病是一种在肝硬化中发现的新病症,其特征是在应激状态下的收缩功能不全、与舒张期弛豫改变相关的舒张功能障碍以及在无任何已知心脏疾病的情况下出现电生理异常。可以通过心电图、二维超声心动图和各种血清标志物(如脑钠肽)的组合来诊断。潜在的发病机制包括β-肾上腺素能信号通路异常、心肌细胞膜流动性改变、心肌纤维化增加、心肌细胞肥大和离子通道缺陷。肝硬化时升高的各种化合物(如一氧化氮和一氧化碳)也会对心肌产生负性肌力作用,而过多的钠和容量潴留可导致心肌肥大。各种毒素也会加重离子通道缺陷,从而导致 QRS 波群变宽,QT 间期延长。临床上,当肝硬化患者处于应激状态下,无论是体力应激还是药物应激,或者当外周动脉扩张程度需要增加心输出量时(如发生细菌感染),收缩功能不全最为明显。急性容量超负荷,如经颈静脉肝内门体分流术或肝移植后即刻,也会使这些肝硬化患者发生心力衰竭。肝硬化性心肌病的治疗效果并不理想。有一些证据表明,β受体阻滞剂可能有助于一些肝硬化患者的基础 QT 间期延长。长期醛固酮拮抗剂可能有助于减少心肌肥大。未来的研究应包括进一步阐明发病机制,以便制定有效的治疗策略。