It is estimated that in the US, there are about 190,000 injuries per year relating to gunshot wounds (suicidal, homicidal, or accidental). Overall, about 20% of these cases are fatal. Gunshot wounds to the heart are among the most serious, with an overall mortality rate of about 70-80%. On a more positive note, of people with gunshot wounds to the heart who arrive at the hospital with signs of life, there is a survival rate of 70-90%.

The prognosis for injury to the heart was not always this good. Prior to the 1800’s, no serious attempts were made to surgically repair cardiac injuries, as trauma to the heart was regarded as uniformly fatal. It was not until the second half of the nineteenth century that interest in surgical repair of the heart grew. In 1896, Ludwig Rehn performed the first successful repair of a cardiac injury. Today, most patients who arrive at the hospital before going into cardiac arrest survive. For this reason, rapid transport of a victim to a hospital is essential to their survival. Once in the hospital, treatment varies widely depending on the condition of the patient, which may range from having no symptoms at all to severe shock. Most patients are unstable, due either to blood loss or pericardial tamponade. Pericardial tamponade results when the heart bleeds into the pericardial sac which surrounds it. Because the sac cannot expand, the accumulation of blood in the sac begins to compress the heart, preventing it from filling appropriately with blood and pumping properly. Removal of this blood with either a needle or surgery almost always results in significant improvement in the patient’s condition.

If the patient is stable (normal blood pressure and heart rate, no trouble breathing), doctors will perform tests such as chest x-ray, CT scan, or echocardiogram (sonogram of the heart) to determine the extent of injury. Projectiles that have entered a chamber of the heart must be removed so that they don’t get flushed out of the heart and lodged in a blood vessel. Projectiles that are lodged entirely within the muscular wall of the heart may sometimes be left in if they are causing no disturbance.

The patient’s prognosis depends greatly on where the heart was injured and what type of firearm was involved. Those shot by smaller firearms such as BB guns or .22 calibers fare better, as the wounds are smaller. Sometimes the wounds produced by these weapons are small enough that they spontaneously seal themselves and stop bleeding, if only temporarily. This is more likely to happen if the patient is shot in the thick-walled ventricles of the heart, as opposed to the thinner walled atria.

People shot in the heart by large firearms (.38 cal and larger) tend to have extensive damage and gaping holes in the heart which are not capable of healing spontaneously. The vast majority of these patients bleed uncontrollably and go into cardiac arrest before reaching the hospital. Those who arrive at the hospital alive are taken to surgery immediately for repair.

Reference:
Gunshot Wounds to the Heart - Fatal and Potentially Deadly Injuries of the Heart, diagnosisheart.com