Battling Heart and Stroke

The Summer Olympic Games in Beijing have just started. What better way to start this week than talk about athletes’ heart rates?

There are certain tests that professional athletes have to go through before they can complete. I am not only referring to those tests that detect the use of performance enhancing drugs. Athletes also have to go through tests to determine their health status. A major determining test in the preparticipation screening of athletes is the electrocardiogram or ECG which reads the heart’s electrical activity and look at the heart rate patterns. ECG measurements are usually done while at rest. Athletes who have abnormalities in their ECG are disqualified - for their own safety. Many cardiac events happen during sports competition.

Most professional sports and health bodies, including the International Olympic Committee and the European Society of Cardiology endorse the use of ECG in the preparticipation screening of athletes. However, the American Heart Association (AHA) finds that ECG screening has certain limitations including low sensitivity and high rate of false positive results. In addition, recent studies (see this previous post) have shown there are racial differences in ECG patterns of athletes that might complicate interpretation of the results.

Instead, AHA recommends a 12-step screening program that can help detect potential health problems. The screening program requires completion of a questionnaire covering the following:

Personal history

• Chest pain/discomfort upon exertion
• Unexplained fainting or near-fainting
• Excessive and unexplained fatigue associated with exercise
• Heart murmur

Family history

• One or more relatives who died of heart disease (sudden/unexpected or otherwise) before age 50
• Close relative under age 50 with disability from heart disease
• Specific knowledge of certain cardiac conditions in family members: hypertrophic or dilated cardiomyopathy in which the heart cavity or wall becomes enlarged, long QT syndrome which affects the heart’s electrical rhythm, Marfan syndrome in which the walls of the heart’s major arteries are weakened, or clinically important arrhythmias or heart rhythms.

Physical examination

• High blood pressure
• Heart murmur
• Femoral pulses to exclude narrowing of the aorta
• Physical appearance of Marfan syndrome
• Brachial artery blood pressure (taken in a sitting position)

A recent study by Italian researchers indicate that exercise ECG, e.g. ECG measurements done during active exercise should be used because they tend to be more sensitive in detecting cardiac abnormalities than ECG measurement at rest. Looking at over 30,000 athletes, they observed discrepancies between the results of resting ECG and exercise or stress ECG. 1,812 or 6% of the participants showed resting ECG abnormalities, some of which turned out to be “innocent” changes. Only 1,459 (4.9%) of the participants showed abnormalities for exercise ECG. However, exercise ECG detected cardiac anomalies in 1,227 participants not detected by resting ECG. Furthermore, they only observed that these anomalies are more common in athletes older than 30 years old.

In the next days, this blog will feature more health news around the theme of competitive sports and athletics.

Photo credit: morguefile