Diastolic Dysfunction in Congenital Heart Disease: Clinical Impact and Basic Evaluation

Abstract

Heart failure (HF) symptoms are induced by low cardiac output or congestion. Cardiac output is generally maintained by a compensation mechanism, with the exception of shock cases, meaning most HF symptoms are induced by congestion. Diastolic dysfunction or abnormal loading conditions are major causes of congestion in patients with congenital heart disease (CHD). Pressure-volume relationships clearly demonstrate preload, afterload, and cardiac systolic and diastolic function, as well as their relationships on a single plane. This information would be particularly useful in analysis of pathophysiology, therapy selection, and prediction of therapeutic effect for patients with CHD. Ejection fraction approximately represents systolic function, but no such single index represents diastolic function. Furthermore, diastolic function parameters obtained by echocardiography do not exactly reflect diastolic function. However, it is important to assess diastolic function despite these difficulties. A systematic approach enables diastolic function assessment based on the understanding of three important points: (1) pressure-volume relationship and filling dynamics; (2) relaxation and stiffness; and (3) the relationship between non-invasive and invasive indices. This review summarized these factors in CHD and in the pathophysiology of HF with preserved ejection fraction in children.