A slip of the hand and life ebbs away.The balance between life and death is so delicate, and the heart surgeon walks that rope between the two. In the operating room there is no time for doubt. It is flesh, blood, rib-retractors and pumping the vital organ with your bare hand to squeeze the life back into it. An off-day can have dire consequences - this job has a steep learning curve, and the cost is measured in human life. Cardiac surgery is not...