By Todd Chapman, MD, FACS
Pound-for-pound, a boxer's heart is the most powerful engine in the world. Consider: beating over 100,000 times a day, it pumps almost 2,000 gallons of blood every 24 hours. These are averages at rest. Studies in young boxers (1) have shown that during a non-contact training session, pulse rises to 178 beats per minute, effectively doubling, and sometimes tripling the work output of the heart.
It is imperative to identify hidden cardiac abnormalities in boxers before they subject their hearts to this sort of demand, because of the risk of sudden cardiac death.
In reviewing 1,500 forensic autopsies after sudden cardiac death in Lyon, France, Tabib identified 80 such deaths following sports activity (two). These included rugby, jogging, gymnastics, tennis, swimming, cycling, soccer, and boxing. In those under 30 years old, the cardiac pathology was most often a cardiomyopathy (55.5%,) followed by non-atherosclerotic coronary abnormalities (14.8%,) aortic stenosis (7.4%,) atrial septal defect (3.7%,) atherosclerotic coronary artery disease (3.7%,) and conduction abnormalities (3.7%.). In victims over 30 years old, the predominant finding was atherosclerotic coronary artery disease (49%,) followed by cardiomyopathies (28.5%,) myocardial bruise scar (4%,) and conduction abnormalities (3.7%.).
These data give us a list of suspects. The question is how best to identify them before they can put our boxers at risk. In reviewing 115 young American athletes with sudden cardiac death who had pre-participation standard history and physical examination, Maron reported that in only 3% of those screened was there any suspicion of cardiac disease (three). Clearly, history and physical is not enough.
Dr. Colin Fuller prospectively studied 5,615 high school athletes in Reno, Nevada, for risk factors associated with sudden cardiac death (four). He makes an eloquent argument for a systematic approach, including history and physical, blood pressure, routine electrocardiogram, and, if any red flags are raised by these, then echocardiogram, and sometimes treadmill exercise test.
The 26th Bethesda Conference on Recommendations for Determining Eligibility for Competition in Athletes with Cardiovascular Abnormalities (five) outlined approaches for those with known cardiac abnormalities. They list many ECG findings, including ventricular pre-excitation, bundle branch block, premature ventricular contractions, and prolonged QT interval, for which they recommend further evaluation prior to approval for athletics.
Following these guidelines, Fuller screened 3,375 males and 2,240 females aged 13 to 19 over a three year period. 582 (10%) of these athletes had an abnormal finding on history, physical, blood pressure, or ECG. They subsequently had echocardiography. 538 of these were normal. Forty-three had minor and one had serious abnormalities. Sixteen patients had treadmill exercise tests.
With this approach 99.6% were approved for athletics. There were 18 males and four females (0.4%) who were not approved. These included 15 arrhythmias or conduction abnormalities, one severe aortic regurgitation, five severe hypertensions and one supraventricular tachycardia treated with ablation.
On the basis of these data, I recommend that in addition to the current medical exam required before each fight, boxers should have annual electrocardiograms. In the event of abnormal findings, the responsible physician may order an echocardiogram or refer the boxer for a cardiology evaluation.
A pertinent question is the cost-effectiveness of such a program. Fuller has examined this in detail in another paper (six). An electrocardiogram can be performed by a technician with computer analysis for about 10 dollars. An echocardiogram costs about 350 dollars, and an exercise treadmill exam, 225 dollars. The estimated cost of an in-office cardiology consultation is 150 dollars. Fuller calculated the average cost of following up an abnormal ECG at 365 dollars.
The cost analysis clearly indicates ECG as an inexpensive, yet useful screen. The more expensive tests can be reserved for those with history and physical, blood pressure, or ECG abnormalities.
1. Gosh, A.K., A. Goswami, and A. Ahuja. Heart rate and blood lactate response in amateur competitive boxing. Indian J. Med. Res. 102: 179-183, 1995.
2. Tabib, A., A. Miras, P. Taniere, and R. Loire. undetected cardiac lesions cause unexpected sudden cardiac death during occasional sport activity. A report of 80 cases. Eur. Heart J. 20: 900-903, 1999.
3. Maron, B.J., J. Shirani, L.C. Poliac, R. Mathenge, W.C. Roberts, and F.O. Mueller. Sudden death in young competitive athletes. JAMA 276: 199-204, 1996.
4. Fuller, C.M., C.M, Mcnulty, D.A. Spring, K.M. Arger, S.S. Bruce, B.E, Chryssos, E.M. Drummer, F.P. Kelley, M.J. Newmark, and G.H. Whipple. prospective screening of 5,615 high school athletes for risk of sudden cardiac death. Med. Sci. Sports Exerc. 29: 1131-1138, 1997.
5. Mitchell, J.H., B.J. Maron, and P.B. Raven. 26th Bethesda Conference: Recommendations for determining eligibility for competition in athletes with cardiovascular abnormalities. Med. Sci. Sports Exerc. 26: 223-283, 1994.
6. Fuller, C.M. Cost-effectiveness analysis of screening of high school athletes for risk of sudden cardiac death. Med. Sci. Sports Exerc. 32: 887-890, 2000.
Dr. Chapman is a cardiac surgeon in Reno, Nevada. He did his residency at the Mayo Clinic in Rochester, Minnesota, and was on the Mayo faculty in Scottsdale, Arizona. In 1989, he moved to Nevada as a founding partner of Reno Heart Surgeons. He began as a ringside physician with collegiate and Golden Gloves amateur boxing, then started working professional bouts for the Nevada Athletic Commission in 2001.
Dr. Todd Chapman is a Cardiac Surgeon and has been a resident of Reno, Nevada since 1989. He initially began as Ringside Physician with collegiate and Golden Gloves boxing. He became a Professional Ringside Physician with the Nevada State Athletic Commission in 2001. Although he is a boxing official for the Nevada State Athletic Commission, all of the views, opinions, and/or recommendations contained herein are solely his own and do not necessarily reflect those of the Nevada State Athletic Commission. All readers are strongly cautioned that the information contained herein is not intended to, and never should, substitute for the necessity of seeking the advice of a qualified medical, legal, or financial professional whenever a boxer or his/her representatives have specific questions regarding the best course of action that a boxer should take. Furthermore, since it is possible that general information herein may pertain only to a law, regulation, rule or acceptable standard of practice for a particular jurisdiction, a boxer or his/her representatives must always inquire with the appropriate licensing jurisdiction to determine the applicable laws, regulations, rules, and acceptable standards of practice for each jurisdiction.
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