Biomechanics of Myocardial Ischemia and Infarction

Each year, over seven million people suffer a myocardial infarction (heart attack). For those who survive the initial event, the mechanical properties of the scar tissue that gradually replaces the damaged muscle are a critical determinant of many life-threatening sequelae, such as infarct rupture and the development of heart failure. Thus, understanding the mechanics of healing infarct scar, its interaction with the rest of the heart, and the resulting changes in heart function are critical to devising effective therapies. Computational models play an essential role in understanding these potentially complex interactions. The first section of this chapter reviews the structure and mechanical properties of the normal heart and the methods used to study those properties. The second section discusses the structure and mechanical properties of healing post-infarction scar. The remaining sections review landmark analytical and computational models that provided insight into the functional consequences of myocardial infarction and potential therapies. Finally, we briefly consider emerging models of wound healing in the infarct region and growth and remodeling in the surviving myocardium that are beginning to predict the long-term effects of infarction and post-infarction therapies. In the future, multi-scale models that capture such remodeling in addition to the beat-to-beat mechanics of the heart hold great promise for designing novel therapies, not only for myocardial infarction but also for a wide range of cardiac pathologies.