61.   Smoking decreases the delivery of oxygen to the heart muscle and makes the heart beat faster and more laboriously.

62.   Some trials have involved injecting the genes into the heart muscle or injecting the protein growth factors themselves.

63.   So they wind up sitting in the emergency room or drinking a barium shake for their stomachs while their heart muscle is dying.

64.   Such enzymes reflect the amount of heart muscle destroyed or damaged by a heart attack, usually several hours before the enzyme increases.

65.   Sudden cardiac arrest is usually caused by ventricular fibrillation, which is when the heart muscle starts quivering and fails to pump blood to the brain and vital organs.

66.   Sudden cardiac death is usually caused by restriction of blood flow to the heart, an irregular heartbeat or a deterioration of the heart muscle.

67.   Still, there appeared to be significant arterial blockages that were depriving his heart muscle of adequate blood flow.

68.   Surgeons reach through one or more slits in the chest to get at the heart muscle inside.

69.   Tests showed that what seemed to have been dead heart muscle began contracting, hinting that the thigh muscle cells were now functioning as heart muscle.

70.   The activated stem cells homed in on the damaged heart tissue and grew into new heart muscle, enabling most of the animals to survive the heart attack.