Sudden death

Sudden death in athletes:

This is a brief explanation. There are dozens of heart conditions from arrhythmia's, to congenital/familial heart diseases, to myopathy syndromes, etc. I will not get into detail of the many types of heart problems that are potentially life threatening. Only the most common problems and misnomer's that have been described in the media.

A primary cause of sudden death in athletes is related to cardiac arrhythmia or congenital anomaly (hypertrophic cardiomyopathy)

Athletes with "enlarged hearts" being at risk is another media hype to get people to read their stories.

I myself had "enlarged heart" in middle school, because I started running at an early age. However, my heart chamber was not enlarged...only the muscle tissue, which made my heart look more dense on x-rays.

I also had an EKG at a later time which showed "third degree heart block" a dangerous arrhythmia that is life threatening without a pacemaker.
I saw 2 cardiologists. The first freaked out and scheduled me for heart catheterization, electrostimulation tests, etc. I was not happy with this so got a second opinion from a cardiologist that actually deals with athletes, as opposed to 95% of cardiologists that deal with diabetics, obesity, hypertensive older patients.

The second cardiologist within 2 minutes of looking at my ekg said, "you have a typical athletic heart". He put me on the treadmill with the ekg attached and watched my Heart rate. Sure enough, at a resting rate of below 40 my ekg looked very abnormal. However, when jogging, as soon as my HR hit 60 beats per minute, my ekg reverted to a normal rhythm. This is the key...when my heart beat reached a "normal" rate of 60 or higher, my heart rhythm became normal. The explanation is simple. You have 2 major pacers in your heart, places in your heart the regulate rhythm. One is the SA node which regulates your heart rate at about 60 beats per minute or higher. The second, the AV node, is a 'backup' pacemaker, that regulates your heart typically in the 40-60 beat range.

Now, if you get fit enough to get your resting heart rate down to 32-36 beats per minute? This is lower than the pacing ability of both the SA or AV nodes. So, your heart has to develop an ectopic pacer, usually somewhere in the left ventricle. This is a normal response to anyone with long standing low heart rate. This is why the ekg looked so ominous on me. Because my heart electrical impulses were originating from an unusual place, not the typical SA or AV node.

Now, the key factor? My heart rhythm returned to normal as soon as my heart rate got up to over 60. This means that my SA node "took over" my heart rhythm normally as it should as my heart rate increased. Now, if my ekg didn't return to normal when I ran on the treadmill that day? Then I would have had a true heart arrhythmia at which I would have required treatment.

Now, what about my "enlarged heart"? I pushed the cardiologist for an echocardiogram. This is an ultrasound of your heart. Very important difference in enlarged athletic heart vs. a congenital cardiomyopathy (cardiomyopathy means "enlarged heart tissue"). My outlet from my ventricles to my pulmonary artery and aorta were perfectly normal, not thickened. Additionally, the internal chamber of my heart was normal size. It was only the muscle tissue of my heart the was thickened. This is a normal response to chronic aerobic exercise, and does not put you at risk for any heart problems later in life. Those with congenital enlarged heart typically have an enlarged chamber of the heart too. This chamber holds the blood and expels the blood with each heart beat, in systole. If the chamber is too big, and the muscular walls dilated, you get poor output of blood from the heart. This can lead to congestive heart failure, heart attack, and arrythmia. This is far different than having a normal chamber size with a thickened vascular heart muscle from prolonged exercise.

In testing out our new CT cardiac scanner at the hospital last year, I had a CT coronary angiogram, to look at the blood vessels in my heart. My right coronary artery was 3 X the size of normal, as was my left anterior descending artery. I had innumerable collateral vessels feeding my thick heart muscle. Still my chamber is normal size. In discussing with a cardiologist, he stated I would likely never die of a heart attack. If I did block a vessel, I have so many collateral vessels that I may not even recognize the blockage. Regardless, this doestn mean that I can eat anything I want. Runners are still at life time risk of atherosclerosis (narrowing) of blood vessels to the brain and heart. This is regulated by both family history, blood cholesterol and fat levels, as regulated by family history and diet. I still have a strong family history of healthy vessels, and low cholesterol. I still control my diet to less than 15 grams of saturated fat and total of less than 50 grams of total fat per day. Regardless of your activity level, dietary fats and cholesterol still play a role in developing narrowing of the arteries that supply the heart and brain.

Now, there are many athletes that have actual arrhythmia's. I know 2 people this past summer that went to their doctor because of "racing heart". They both had an abnormal pacer in their heart that was causing their heart rate to spike very high. One girl's heart rate was hitting 220 beats per minute at rest. Now, they both underwent cardiac ablation, to basically 'burn out' the ectopic abnormal cells that were causing the arrhythmia. Now, their normal SA and AV nodes have taken over their heart rate regulation.

Had these 2 girls continued to run without seeking out a doctor? Likely nothing. But yes, there is a possibility of an event occuring during a race and spiking their heart rate to a very high level, thus diminishing the outflow of blood from the heart, and resulting in decreased perfusion of the heart, and sudden death.

I am certain there are many athletes out there who have arrythmia's (there are millions of athletes and they are at the same risk as the normal population). Nothing may never happen, but catching a possible fatal arrythmia can save your life down the line. Feeling "fluttering" for prolonged periods, becoming short of breath when just sitting around, feeling your heart racing, are some of the symptoms of a potential arrythmia. Fainting of course is a more obvious symptom.

Now what about heart attack:
Being an endurance athlete markedly decreases the risk of heart disease. However, family history is most important. If you have parents or siblings that have had heart disease, high cholesterol, heart attack, then its worth getting checked out by a doctor before initiating prolonged exercise.

What about those that take up exercise late in life:
See a doctor before initiating exercise. This is because you may have build up of plaque in your blood vessels (atherosclerosis) and may have pre-existing narrowing of your coronary arteries. Now, if you stress them by increasing demands of oxygen flow to the heart in prolonged exercise, you could cause a heart attack or sudden death.

Take home notes:

Heart problems and disease is primarily congenital, or familial. There have been reports of runners dying of heart attacks in their early 50's, but whose parents died of heart attack in their 40's. Thus the runner child out lived their parents by a decade, likely due to long term aerobic exercise.

Heart disease is still a risk for those athletes that eat high fats, cholesterol, trans fats, etc. Running may help, but does not make you immune to heart disease if you have a poor diet.

If you have dizzy spells, chest pains, fainting, racing heart rate, shortness of breath that occurs at rest or with simple activity...get checked out by a doctor. Have an ekg and a physical exam.

Endurance athletes are by far the least risk for ACQUIRED heart disease. However, we are not immune to congenital or previously acquired heart disease, hypercholesterolemia, etc.