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Technical FAQ: Zdeněk Štybar’s cardiac ablation and timeline for return to cycling

Whether Štybar can race again at his former level — only time will tell.

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Have a question for Lennard? Please email him at veloqna@comcast.net to be included in Technical FAQ.

Dear Lennard,
I saw that Zdeněk Štybar “underwent a minor operation Wednesday at a Brussels hospital after doctors diagnosed heart arrhythmia.” The article makes it sound like it is no big deal and that he almost considered doing Tour of Flanders until he was advised against it and seems to be saying that he will be racing again fairly soon. I’m a cyclocross racer who has followed Stybar’s career for many years. Another multiple world champion, Niels Albert, hung up racing due to heart arrythmia, and I’m wondering why he had to quit and Stybar doesn’t.

Since you wrote the book on it, I was hoping that you could explain why Stybar thinks it’s no big deal and why Albert counts himself as lucky to be alive. And is it realistic that Stybar could race again soon after heart surgery?
— Mike

Dear Mike,
Ever since I started doing research to write The Haywire Heart, I have known that I would hear about many other athletes being diagnosed with cardiac arrhythmias. It still comes as a shock for me every time I see it happen to another pro rider, and Stybar is no exception. I keep a list of prominent athletes with arrhythmias; it is a long one and has gotten longer since I compiled this list.

Albert has a ventricular arrhythmia, and, judging by the relatively relaxed way he is approaching it, Štybar must have an atrial one. Atrial arrhythmias generally are far more survivable than ventricular ones.

The ventricles are the lower chambers of the heart; they pump blood to the body and to the lungs. If the ventricles do not function properly, the person can die, since sufficient blood won’t get to the body or to the lungs, or both. (Cause of death, in this case, would be cardiac arrest.) Media reports constantly confuse cardiac arrest with a heart attack (myocardial infarction), which is when blood flow is cut off to a portion of the heart muscle, thus damaging it. The recent death of the entertainer DMX is an example of this confusion; many news reports cited a heart attack as his cause of death, while others cited cardiac arrest.

The atria, by contrast, are the upper chambers of the heart that collect blood from the body and from the lungs. Upon each heartbeat, the atria push blood through valves into the ventricles. If the atria are not beating at proper timing, gravity will still get some blood to the ventricles; cardiac output may be reduced by such an arrhythmia, but the person is not likely to die from it.

Albert has an implantable cardioverter-defibrillator (ICD) implanted under the skin of his chest. If his heart goes into ventricular tachycardia or ventricular fibrillation, the ICD’s battery-powered pulse generator can literally save his life by sending electric shocks to his heart (via electrode leads that go to the heart through a vein) to get it back in sinus rhythm.

Zdeněk Štybar underwent a cardiac ablation procedure forcing him to miss the 2021 Tour of Flanders. Photo: James Startt

Štybar has no such implanted contraption. He underwent an ablation, which is a procedure to kill certain cells (creating a scar) within the heart as a means to block an arrhythmia. Since electrical signals propagate through the heart by one heart muscle cell passing on the impulse to contract to adjacent cells, killing cells stops the conduction of electrical current through that area. If the aberrant current is flowing in a loop, for instance, as in some atrial arrhythmias, burning some cells anywhere on that loop, once the location of the loop is identified, will stop that flow.

During the ablation procedure, the surgeon inserts catheters into one of the femoral veins in the patient’s crotch and slides them up the vein until their ends come out in the heart’s atrium. One of the catheters is for detecting the location of the source of the arrhythmia while the heart is being driven at a rapid rate with drugs and/or electric pulses to induce the defective rhythm. Another catheter kills the thus-identified cardiac muscle cells, either by burning them with radio-frequency radiation (RF ablation) or by freezing them (cryoablation). This freezing or burning can be done in a focused way from the tip of the catheter, or, in the case of atrial fibrillation (AFib), whose source typically is in one or more pulmonary veins, an inflated balloon is placed against the openings of the veins in the rear heart wall, burning or freezing cells around the vein openings, thus creating rings of scar tissue to block the electrical current flowing into the heart from the vein walls.

Relating to how soon an athlete can resume training after the procedure, bleeding is a risk. After the catheters are removed, a nurse holds pressure against the spot in the crotch into which they were inserted into the femoral vein for an agonizingly long period of time (speaking from personal experience) until he or she has ensured that bleeding has stopped. If the athlete resumes training too soon, bleeding in the crotch from the catheter-entry site in the femoral vein can occur. I have an acquaintance who was diagnosed with AFib who did not want to give up the 100-mile mountain bike race he was registered for six weeks later. He started training days after his ablation, and his entire crotch area turned purple due to bleeding from his femoral vein. Hopefully, Štybar had the patience to lay off from training long enough to avoid that unpleasant — and unsightly — occurrence.

It should be noted that ablation is not a guarantee that the heart will return to its prior level of efficiency. Sometimes the scarring created by the ablation is in the wrong spot, or the arrhythmic electrical signal finds its way around the scarring. This may not be immediately known. Whether Štybar can race again at his former level, only time will tell.
― Lennard


Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder (www.zinncycles.com) and purveyor of non-custom huge bikes (bikeclydesdale.com), a former U.S. national team rider, co-author of The Haywire Heart,” and author of many bicycle books including Zinn and the Art of Road Bike Maintenance,”DVD, as well as Zinn and the Art of Triathlon Bikesand Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.” He holds a bachelor’s in physics from Colorado College.

Follow @lennardzinn on Twitter.