The most impoant factor that influences the outcome of penetrating cardiac injuries is

Multiple studies in the literature confirm that injuries to the coronary aeries are the most impoant factor in determining outcome after a penetrating cardiac injury. Tangential injuries are the least serious. Injury to a single chamber--even if comminuted--or to multiple chambers is less likely to be fatal than are injuries that involve a major coronary aery. ref - Harrisons 20th ed