LONDON – Left ventricular adaptation to intensive exercise is gender specific, and this novel observation could be useful in identifying female athletes who harbor a serious cardiac condition such as hypertrophic cardiomyopathy, Dr. Sanjay Sharma said at the annual congress of the European Society of Cardiology.
“Although the presence of concentric remodeling or hypertrophy in male athletes engaged in dynamic sports is a common phenotype, it should raise suspicion of underlying cardiomyopathy in female athletes,” declared Dr. Sharma, professor of inherited cardiac diseases in sports cardiology at St. George’s University of London and medical director of the London Marathon.
Dr. Sanjay Sharma
He drew this conclusion from a study he and his coinvestigators conducted in 1,082 white elite athletes, including 439 females, all of whom had an ECG and underwent echocardiography. The athletes were placed into one of three groups based upon the nature of the exercise entailed in their sport: dynamic exercise, as in endurance events such as distance running or bicycle racing; static exercise, such as weight lifting and wrestling; and sports involving a mix of both.
Normal left ventricular geometry was seen in 70% of male and female athletes. However, important gender-based differences in LV geometry were noted in the athletes participating in dynamic sports. The male athletes were far more likely to exhibit concentric hypertrophy or remodeling, which takes the form of increased LV wall thickness with little or no increase in LV mass, compared with norms. Indeed, 15% of male athletes specializing in dynamic sports had echocardiographic evidence of concentric hypertrophy or remodeling, compared with a mere 4% of female athletes in dynamic sports. In contrast, female athletes were far more likely to exhibit eccentric hypertrophy, featuring a normal LV relative wall thickness with an increased LV cavity size – although not to an extreme degree – when scaled for body surface area.
“In our study, a relative wall thickness greater than 0.5 or an LV mass greater than 145 g/m2 was not detected in any female. These data could be very important in differentiating between physiology and pathology in female athletes presenting potential cardiac symptoms,” according to Dr. Sharma.
He noted that people who exercise intensively for about 4 hours per week or more develop a constellation of structural and functional changes in the heart that allow generation of the large stroke volumes required to deliver sustained high cardiac output. Age and the type of sport play a large role in the magnitude of these changes. And it now appears that gender influences the form these changes will take.
Why do gender differences exist in remodeling in response to exercise? Dr. Sharma speculated that male athletes’ much higher levels of testosterone – an anabolic hormone – might explain their proclivity for LV wall thickening. Also, males are known to have a higher blood pressure response to exercise, which might promote wall thickening.
“An important point I want to make is that death in sport amongst females is extremely rare. The male to female ratio for death in competitive sports is 10:1, and among recreational athletes it’s 20:1,” the cardiologist said.
To help put that in perspective, he noted that among the 1 million runners of the London Marathon during the last 35 years there have been 14 cardiac deaths among male participants and none among females.