What's With the Stethoscope? Heart Murmurs in Athletes

Athletes: should a heart murmur be cause for concern? Learn the difference between physiological and pathological murmurs.

Dermot Phelan, M.D. Ph.D., is a staff cardiologist and the director of the Sports Cardiology Center within the Sydell and Arnold Miller Family Heart & Vascular Institute at the Cleveland Clinic. His specialty interests include cardiac care in athletes, hypertrophic cardiomyopathy (HCM), valvular heart disease, cardiomyopathy and cardiovascular imaging.

It's your physical and your doctor is coming at you with a cold stethoscope, ready to "listen" to your heart. But what does your heart have to say? Potentially, a lot.

Composed of four chambers and four valves, the heart is careful to keep blood flowing in one direction. The valves work like one-way swinging doors that let blood move to the next chamber or to the major arteries of the body, but never backward.

Most of the time, the blood flow is so calm that it's inaudible. But sometimes, the flow becomes turbulent, and like a churning river, makes a little "whoosh" or "swish" sound. That's a heart murmur.

Are Heart Murmurs Innocent or Cause for Concern?

In athletes, most murmurs are called physiological, or innocent. They can be a sign of increased cardiovascular fitness rather than a harmful heart abnormality. As a result of intensive exercise regimens, athletes' hearts can adapt by becoming slightly enlarged, which allows them to move a greater amount of blood with each beat. That amount, called stroke volume, can be so great in highly trained athletes that it causes a gushing noise that a physician can hear simply by placing a stethoscope to the chest. This tends to be especially true in young athletes and aerobic and endurance athletes.

However, that swishing sound can also be related to a problem with the heart. The murmur may represent turbulent flow related to narrowing or leaking of one or more of the heart valves or, indeed, a small hole in the heart. It could also be due to a condition called hypertrophic cardiomyopathy, which can cause abnormal thickening of the heart muscle and result in narrowing of the outflow tract of the heart. So, when the doctor hears a heart murmur, it's important that he or she look into why the sound is occurring. Is it innocent? Or is it caused by another pathology? On a rare occasion, a murmur may be a sign of a greater problem that would place an athlete at risk of sudden cardiac death or other health issues.

Physicians can typically tell the difference between a physiological murmur (considered a normal and benign finding) and pathological murmur (cause for follow-up), based on the timing and pitch of the murmur. However, if there's still any question of how significant the murmur is, then your physician will likely order an echocardiogram. This is an ultrasound of the heart performed by placing a special wand on the chest that uses sound waves to create a computerized picture of the heart as it beats. It's the same technology used for pregnant women when looking at a fetus in the womb. An echo shows the size of the heart's chambers, how well the heart is pumping, and how efficiently the valves are opening and snapping back shut.

Pathologies and Performance

If you do have a pathological heart murmur, your doctor will inform you if you need treatment (not all require action) and how it may or may not affect your day-to-day activities, including sports participation. In most instances, people with murmurs have no symptoms. However, the most common symptoms, experienced by athletes with significant valve disorders, include shortness of breath or chest pain with activity and a decrease in exercise capacity. Others can experience lightheadedness and fainting episodes. These symptoms occur because the forward flow of blood is limited, and without adequate blood (and its cargo of nutrients and oxygen) reaching the active muscles and organs, performance declines.

However, it's also important to know that pathological heart murmurs can, in some instances, exclude patients from sports participation. Vigorous exercise can increase the stress placed on the heart, and in some cases may lead to arrhythmias or a more rapid deterioration in its function. For that reason, you may need a procedure to fix your heart prior to getting back to play. On rare occasions, if a detected abnormality carries a significant risk of long-term damage to the heart or sudden cardiac death, you may need to stay off the field for your health.

So what's your heart saying?

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