myocardial stunning
Temporary myocardial dysfunction that persists after restoration of blood flow following ischemia.
Full Definition
Myocardial stunning refers to reversible mechanical dysfunction of the heart muscle that occurs after reperfusion following a period of ischemia, despite restoration of normal or near-normal coronary blood flow. This phenomenon is characterized by depressed contractile function that gradually improves over hours to days. In cardiac surgery, stunning commonly occurs after cardioplegic arrest and reperfusion, contributing to postoperative low cardiac output syndrome. The mechanism involves calcium overload, oxidative stress, and altered excitation-contraction coupling. Management focuses on mechanical support and time for recovery, as the dysfunction is typically reversible with appropriate supportive care.
Usage
Usage note: Distinguish from hibernating myocardium and irreversible myocardial damage.
In Context
- "The patient's reduced ejection fraction was attributed to myocardial stunning following prolonged cardioplegic arrest." — Postoperative consultation