What is Commotio Cordis in Baseball?
USA Baseball Medical/Safety Advisory Committee
Commotio cordis or cardiac concussion is a cause of sudden death in young baseball players. It is the result of a low velocity impact to the chest from a thrown or batted ball travelling usually at a speed of between 20-50 mph. It can also occur as a result of impact with any projectile and has been reported with softballs, lacrosse balls, hockey pucks, and even a fist. The impact must occur directly over the heart, the closer to the center the greater the risk. The injured player does not have pre-existing heart disease and there is no structural damage to either the heart, chest cavity or chest wall as a result of the impact. The cause of death is the development of an abnormal rhythm, ventricular fibrillation, though there may be some affect on the blood circulation to the heart as well. For the catastrophic event to occur, the impact has to be precisely timed to strike the heart during a 15-30-millisecond phase of the electrical cycle (during repolarization or just before the peak of the T-wave).
Commotio cordis is fortunately a rare event. The Consumer Product Safety Commission recorded 51 baseball-related deaths between 1973-1983, in children 5-14. Twenty-one were the result of chest impact, 11 in an organized competitive game. Pitcher's (8), batter's (6), and catcher's (2) were most frequently the victims. Janda and colleagues recorded 88 deaths between 1973-1995. Sixty-eight were the result of ball impact. Of these 68, 38 were related to ball impact to the chest. The above studies indicated a baseball related rate of two-three/year due to chest impact. With an estimated 19 million children playing baseball, the rarity of the event becomes apparent. An U.S. Commotio Cordis Registry has been established by Maron, Link and colleagues and from 1998 to September 2001, 128 deaths were recorded. Baseball accounted for 41% and softball 11%. The mean age was 13.6 years with a range from 3 months to 45 years. Ninety-five percent of the victims were male and 79 (62%) were engaged in an organized competitive activity. This registry reported an approximate rate of 13 chest impact deaths per year in all baseball and 6 per year in organized competitive baseball. No age limitation was employed. Commercially available chest protectors were impacted in 7 cases.
Can a player with commotio cordis be saved? Commotio cordis is associated with a death rate of 90%. The lack of response of these young health baseball players to CPR is unexpected and remains unexplained, but it is clear that a rapid response is essential. This response is probably required in three-five minutes. A practiced emergency response plan should exist and be implemented immediately. The recommended "chain of survival" dictate the immediate notification of the emergency medical service and the initiation of CPR, optimally by two separate individuals. Some advocate a chest thump be added to the traditional chest compression and breathing support. Electrical defibrillation of the heart must be accomplished as quickly as possible. EMS units can provide defibrillation in addition to advanced life support. The advent of AED's (automated electronic defibrillators) can possibly allow for a quicker response.
An AED is a device that discharges a low energy waveform with a biphasic structure. The devices have been demonstrated to be effective in correcting ventricular fibrillation. They are automated so that after placement of pads on the chest the unit reads the victims heart rhythm and orders an electrical defibrillating charge if it is indicated. The units are lightweight, small, and easily transportable and contain instructions for use, including placement of the provided self-adhesive pads. It contains non-rechargeable lithium batteries that can last five years and that signal when power is low. The cost of a unit has been decreased from $4,000 to $2,000 and will probably decline further. Several studies have shown that AED's are effective in reversing ventricular fibrillation.
Due to the need for rapid defibrillation and the ease of the use of the units, there has been a call for public access to defibrillation, a program that has named PAD. This would permit nontraditional first responders and the general public to administer potentially life-saving defibrillation. The units have been placed in airports, airplanes (40% survival rate) casino (53% survival rate) and sports venues as well as many other locations. Studies have shown that police, firefighters, ski patrol, teenagers and children as young as nine can effectively work an AED.
Should all sports fields have an AED available in case an athlete sustains commotio cordis or more likely, a spectator suffers a heart attack? Several issues must be addressed in this important decision. Volunteers have to be selected and trained in the use of the units combined with CPR and be retrained, if necessary. A well planned and rehearsed emergency action plan including both emergency attention to the stricken athlete and calling 911 should exist and the location of the AED known at all times. An optimal response time to defibrillate is no more than three or possibly five minutes so that retrieving the unit and getting to the site of the victim is critical. Therefore the site of placement is critical and should be known and clearly marked. Can the unit be transported, placed on the victim and discharged in the appropriate time by a non-medical volunteer? How many units will be required at a sports venue? Will police, firemen or EMS who have AED's and experience reach a site and discharge the unit faster than the site volunteers? Currently there are no answers to these questions, though studies are ongoing to audit the use and survival outcome of public mainstream access to AED's or "PAD". Litigational issues have been addressed with at least 48 states providing legal protection under Good Samaritan laws.
Can commotio cordis be prevented? Prevention of commotio cordis is currently best provided by appropriate coaching. Batters should learn ball avoidance and turn away from an inside pitch and not open chest to the impact, as is so typically the case. Avoidance while bunting requires special attention. Pitchers as well should be coached in proper fielding positions and ball avoidance when necessary. Chest wall protectors that are commercially available have not been demonstrated to prevent commotio cordis. Studies with baseballs seems to indicate that lighter and softer balls may diminish the risk, but their acceptability for play by older children is of question.
In conclusion, commotio cordis is a risk for all sports in which a projectile can strike the chest of a participant, but fortunately it is a very rate event.