Myocardial stunning

Myocardial stunning

Myocardial stunning is reversible myocardial dysfunction after ischemia and reperfusion. It is different from myocardial hibernation in which persistent chronic ischemia causes myocardial dysfunction which is reversible after revascularization.

Mechanism of myocardial stunning is thought to be either due to oxygen free radicals or calcium overload produced by the ischemia reperfusion sequence. Myocardial stunning is the reason for persistent left ventricular dysfunction for hours and even up to a few days after successful reperfusion in acute myocardial infarction. This can be noted after reperfusion by thrombolysis or percutaneous coronary intervention.

Repetitive episodes of stunning secondary to ischemia can lead on to hibernation. Lower myocardial necrosis as suggested by a lower peak creatinine kinase level has been shown to be an independent predictor of recovery of ventricular function [1].

Though almost half of the recovery of left ventricular function occurs later, the ejection fraction achieved on third day after myocardial infarction is predictive of survival [2].

Reference

1. Solomon SD, Glynn RJ, Greaves S, Ajani U, Rouleau JL, Menapace F, Arnold JM, Hennekens C, Pfeffer MA. Recovery of ventricular function after myocardial infarction in the reperfusion era: the healing and early afterload reducing therapy study. Ann Intern Med. 2001 Mar 20;134(6):451-8.
2. Sheehan FH, Doerr R, Schmidt WG, Bolson EL, Uebis R, von Essen R, Effert S, Dodge HT. Early recovery of left ventricular function after thrombolytic therapy for acute myocardial infarction: an important determinant of survival. J Am Coll Cardiol. 1988 Aug;12(2):289-300.