Ventricular remodeling following myocardial infarction

Ventricular remodeling following myocardial infarction

Ventricular remodeling is the changes in geometry of the left ventricle which occurs in the long term following a myocardial infarction. As time progresses, there is progressive infarct expansion and dilatation of rest of the ventricle. The ellipsoid shape of the left ventricle gets converted to a more globular shape. This progressive change in shape and size of the left ventricle leads to heart failure. Ventricular remodeling can be prevented by unloading the left ventricle with angiotensin converting enzyme inhibitors or angiotensin receptor blockers which reduce the afterload of the left ventricle.

Though ventricular remodeling is initially beneficial by increasing the stroke volume by the Frank-Starling mechanism which mentions that force of contraction increases with increasing myocardial fibre length to a certain extent. But increase in fibre length beyond an optimal level leads to ventricular failure. A patent infarct related artery is also thought to influence the ventricular remodeling in a favourable way, meaning less of left ventricular dysfunction.

Infarct expansion was demonstrated in an experimental study by Hochman et al [1]. It was also noted that a critical size of 17% for the infarct to initiate the process and the degree of expansion correlated with the infarct size.

Reference

1. J S Hochman, B H Bulkley. Expansion of acute myocardial infarction: an experimental study. Circulation. 1982 Jun;65(7):1446-50.