<prompt> The most impoant factor that influences the outcome of penetrating cardiac injuries isComminuted tear of a single chamberMultiple-chamber injuriesCoronary aery injuryTangential injuries  <response>: 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 