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Oct 15, 2002
Diagnosis of hypertrophic cardiomyopathy in young athletes made easier by new study
London, UK - Differentiating the normal effect of athletic training on the hearts of teenagers from potentially lethal hypertrophic cardiomyopathy has been made much easier by a new study published in the October 16 issue of the Journal of the American College of Cardiology.[1]
The study represents the first time that anyone has identified physiologic upper limits for left ventricular wall thickness (LVWT) in adolescent athletes, and the findings can be put to immediate practical use in screening young athletes to identify those at risk of hypertrophic cardiomyopathy.
The authors, led by Dr Sanjay Sharma (University Hospital Lewisham and St George's Medical School, London), explain that regular intensive physical training in endurance sports can be associated with a physiologic increase in left ventricular wall thickness, which can sometimes resemble hypertrophic cardiomyopathy (HCM). Detecting the difference between a normal athletic heart and hypertrophic cardiomyopathy is crucial because intense exercise is contraindicated in HCM as it causes sudden cardiac death. Because HCM is difficult to identify in young athletes, it often goes unnoticed and is responsible for about one third of all exercise-related sudden cardiac deaths in trained athletes under 35 years of age, they note.
Although most of these deaths occur during adolescence, definition of the normal upper limits of physiologic hypertrophy in the athlete's heart has largely been based on echocardiographic studies performed in adults, and these reference values cannot easily be extrapolated to younger athletes, who are less physically mature and are exposed to shorter periods of intense training, the researchers point out.
They performed ultrasound examinations of the hearts of 720 elite athletes and 250 controls between the ages of 14 and 18 years. Results showed that, compared with controls, athletes had greater left ventricular wall thicknesses, but no female athlete had an LVWT above 11 mm and only 3 trained male athletes had LVWTs above 12 mm (0.4%).
Noting that trained athletes also tend to have large left ventricular cavity sizes, whereas adolescents with HCM show small or normal-sized LV chamber size, the researchers note that all the athletes in this study with an LVWT of more than 12mm also had chamber enlargement, effectively ruling out HCM. "Hypertrophic cardiomyopathy should be considered strongly in any trained adolescent male athlete with LVWT over 12mm (females over 11 mm) and a nondilated left ventricle," they conclude.
They say that defining the upper limits of normal in the thickness of the left ventricle in young athletes' hearts should help avoid sudden deaths in young athletes who do have HCM and should also prevent normal young athletes without HCM but with a larger-than-average heart from being deprived of the many physical, psychological, and financial benefits of athletic competition.
However, the researchers caution that this study included mostly whites so cannot really be extrapolated to other ethnic and racial athletic populations. "I would suggest that at this point we don't extrapolate these findings for all races but use them only for Caucasians or exercise great caution before we extrapolate them to other racial groups," Sharma said.
Another barrier to putting the study results to wide use is cost, with a typical echocardiographic study costing $600 or more, which puts routine screening beyond the reach of most high school sports budgets.Nevertheless, Sharma says this study is the most clinically relevant research he has ever been involved in, since clinicians can apply it immediately to either save a life or save the career of an adolescent athlete with a larger-than-average heart.
Diagnosis of hypertrophic cardiomyopathy in young athletes made easier by new study
London, UK - Differentiating the normal effect of athletic training on the hearts of teenagers from potentially lethal hypertrophic cardiomyopathy has been made much easier by a new study published in the October 16 issue of the Journal of the American College of Cardiology.[1]
The study represents the first time that anyone has identified physiologic upper limits for left ventricular wall thickness (LVWT) in adolescent athletes, and the findings can be put to immediate practical use in screening young athletes to identify those at risk of hypertrophic cardiomyopathy.
The authors, led by Dr Sanjay Sharma (University Hospital Lewisham and St George's Medical School, London), explain that regular intensive physical training in endurance sports can be associated with a physiologic increase in left ventricular wall thickness, which can sometimes resemble hypertrophic cardiomyopathy (HCM). Detecting the difference between a normal athletic heart and hypertrophic cardiomyopathy is crucial because intense exercise is contraindicated in HCM as it causes sudden cardiac death. Because HCM is difficult to identify in young athletes, it often goes unnoticed and is responsible for about one third of all exercise-related sudden cardiac deaths in trained athletes under 35 years of age, they note.
Although most of these deaths occur during adolescence, definition of the normal upper limits of physiologic hypertrophy in the athlete's heart has largely been based on echocardiographic studies performed in adults, and these reference values cannot easily be extrapolated to younger athletes, who are less physically mature and are exposed to shorter periods of intense training, the researchers point out.
They performed ultrasound examinations of the hearts of 720 elite athletes and 250 controls between the ages of 14 and 18 years. Results showed that, compared with controls, athletes had greater left ventricular wall thicknesses, but no female athlete had an LVWT above 11 mm and only 3 trained male athletes had LVWTs above 12 mm (0.4%).
Noting that trained athletes also tend to have large left ventricular cavity sizes, whereas adolescents with HCM show small or normal-sized LV chamber size, the researchers note that all the athletes in this study with an LVWT of more than 12mm also had chamber enlargement, effectively ruling out HCM. "Hypertrophic cardiomyopathy should be considered strongly in any trained adolescent male athlete with LVWT over 12mm (females over 11 mm) and a nondilated left ventricle," they conclude.
They say that defining the upper limits of normal in the thickness of the left ventricle in young athletes' hearts should help avoid sudden deaths in young athletes who do have HCM and should also prevent normal young athletes without HCM but with a larger-than-average heart from being deprived of the many physical, psychological, and financial benefits of athletic competition.
However, the researchers caution that this study included mostly whites so cannot really be extrapolated to other ethnic and racial athletic populations. "I would suggest that at this point we don't extrapolate these findings for all races but use them only for Caucasians or exercise great caution before we extrapolate them to other racial groups," Sharma said.
Another barrier to putting the study results to wide use is cost, with a typical echocardiographic study costing $600 or more, which puts routine screening beyond the reach of most high school sports budgets.Nevertheless, Sharma says this study is the most clinically relevant research he has ever been involved in, since clinicians can apply it immediately to either save a life or save the career of an adolescent athlete with a larger-than-average heart.
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