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Much of the understanding of the clinical and pathophysiologic aspects of commotio cordis is the result of work by N.A. Mark Estes III, MD, and Mark S. Link, MD, from the New England Cardiac Arrhythmia Center at the Tufts University School of Medicine in Boston, Massachusetts and data derived from the National Commotio Cordis Registry (Minneapolis, Minnesota).
Recent data from the registry of the Minneapolis Heart Institute Foundation show that commotio cordis is one of the leading cause of sudden cardiac death in young athletes, exceeded only by hypertrophic cardiomyopathy and congenital cornoary artery abnormalities.
Commotio cordis typically involves young, predominantly male, athletes in whom a sudden, blunt, nonpenetrating and innocuous-appearing trauma to the anterior chest results in immediate cardiac arrest and sudden death from ventricular fibrillation. The rate of resuscitation is low but improving.
Although commotio cordis usually involves impact from a baseball, it has also been reported during hockey, softball, lacrosse, karate, and other sports activities in which a relatively hard and compact projectile or bodily contact caused impact to the person's precordium. Nearly 250 cases have been reported to the National Commotio Cordis Registry.[2, 3] Despite a recent increase in registry cases because of increased awareness, the entity is still probably underreported.
Without going into the details of the physiology, the essence of the problem seems to be that when a blow lands on the anterior chest there is about a one percent chance that it will land during a vulnerable period in the heart's electrical cycle.
(For you medical types reading this, it's the crest of the T wave, although whether the ascending or descending portion of it makes up the vulnerable interval seems to be in debate.) While not all blows that land during this vulnerable period cause cardiac arrest, and indeed it appears that few do, the risk is nonetheless there.
Unfortunately, there is no practical way (that I know of, anyway) to time a blow to the chest so that it does not land during this period. I know of no precaution equivalent to "wear a condom" if one is going to participate in this practice.
Even worse, it seems to induce a from of cardiac arrest that is exceptionally resistant to resuscitation. The "stunned" heart muscle appears to be especially resistant to being shocked back into operation.
<The risk would probably be reduced by improved coaching techniques, such as teaching young batters to turn away from the ball to avoid errant pitches, according to doctors. Defensive players in lacrosse and hockey are now taught to avoid using their chest to block the ball or puck.
Chest protectors and vests are designed to reduce trauma from blunt bodily injury, but this does not offer protection from commotio cordis and may offer a false sense of security. Almost 20% of the victims in competitive football, baseball, lacrosse and hockey were wearing protectors. This ineffectiveness has been confirmed by animal studies. Development of adequate chest protectors may prove difficult.
There is also something else to be taken into consideration, and that is the problem of possible unbeknownst underlying congenital conditions, i.e.,abnormalities in cardiac depolarization and repolarization that might render an individual susceptible or contribute to the commotio cordis.
Several people have been convicted of involuntary manslaughter in cases involving insufficient and slow medical help to athletes who experienced commotio cordis during sports events, as well as in cases of intentional delivery of contusive blows. <
The lay public and newcomers to the martial arts tend to consider the most serious injuries that a person may inflict upon another to be percussive injuries such as the breaking of bones or head injuries. However, strikes that may not even cause bruising could possibly lead to serious injury or even death. [Stephen Drehobl]
The karate style, "Uechi Ryu Karate- Do" contains such a movement that contemporary practitioners still struggle to understand. The strike is called Boshuken Morote Zuki in Japanese, which simply means, "thumb-knuckle strike with both hands".
Can the shock of the Boshuken Morote Zuki directly affect the heart’s rhythm?
In order to understand the implications of the Boshuken Morote Zuki, we will examine the anatomy and physiology of the heart beat cycle.
The SA node (sinoatrial node) lies in the right atrium beneath the opening of the superior vena cava. See figure 18-2a. Each cardiac cycle is initiated by the SA node and sets the basic pace for the heart rate. The SA node is the pacemaker of the heart. The SA node initiates electrical impulses that spread out over both atria causing them to contract.
The impulse then passes to the AV (atrioventricular node) located near the bottom of the interatrial septum. (Between the atrium and ventricle.) Contraction of ventricles is stimulated by the Purkinje fibers. [Principles of Anatomy and Physiology Gerard J. Tortora, Nicholas P. Anagnostakos ]
The operation of the SA node can be disrupted by shock, such as a physical strike to that area of the torso. When something disrupts the SA node the AV node takes over to initiate a basic pace for the heart rate. When both the SA node and the AV node are Almost simultaneously disrupted, the heartbeat can be dangerously affected. The heart could be profoundly affected to the point of cessation of function.
When the right hand strikes the Ilium a shock wave radiates across the torso, while at the opposite "corner" of the torso, the left hand strikes, which also generates a shock wave across the torso in the opposite direction. The proximity to the heart and the SA and AV nodes may allow the shock waves of the strikes to disrupt the operation of the SA, AV nodes and thereby disrupt the timing of the heartbeat cycle. How serious the strike is depends on where in the heart beat cycle the subject is when hit.
The intensity of the strike may not have to be very strong in order to have devastating results. An interesting subtlety was noted by Mr. James Thompson, who pointed out that the potential energy in this movement is amplified by the whiplike phenomenon of the hand corresponding to the forward foot always striking almost simultaneously before the hand corresponding to the rear foot. [Oral seminar communication ]
In training, I was struck very lightly with the Boshuken Morote Zuki, and observed that my heart fluttered and that some light headedness occurred. The strike appeared to disrupt the rhythm of my heart. From my perspective as a registered nurse, I believe that the results of this strike could be very serious, even lethal .
Severe disruption of the heart's life sustaining function is not confined to the martial arts.
In the Philadelphia area alone, several recent newscasts have reported that baseball players struck in the chest by the baseball subsequently lost consciousness and died. A five year old girl in Kyoto, Japan playing catch with friends died after having been struck in the chest by a rubber ball [Mainichi Shimbin, March 17, 2002]
Lesser amounts of conditioning in other areas that also occasional become hit, such as, the stomach, pectorals, and the latissimus dorsii muscles, is also undertaken.
This and other extreme methods of conditioning seems to be a recent introduction to Uechi Ryu. In conditioning the pectoral region of women care must be taken to avoid the breast tissue as bruising can cause fat necrosis. Besides the undisireablibity of necrosis, these post trauma, necrotic, lumps may potentially lead to a cancerous lump being missed or confused in manual breast examination.
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