Colbrelli and hearth arrhythmia explained

The image of Sonny Colbrelli collapsing after crossing the finish line of the Volta a Catalunya stage one on Monday, and the use of a defibrillator to reanimate him, sent chills down the spines of those watching. It reminded us how strenuous this sport is, even for the most trained and fit athletes.

Colbrelli's team, Bahrain Victorious, later communicated through a statement that the 31-year-old Italian had been affected by an "unstable cardiac arrhythmia that required defibrillation". Colbrelli, at the time of writing, is still hospitalised in Girona for further tests and he's in a "good" clinical condition. However, the examinations concluded so far, including a magnetic resonance, were not conclusive as to what was the cause of his arrhythmia.

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It's not the first time, and probably won't be the last, that we've heard of a professional cyclist affected by cardiac conditions. In December, 22-year-old Italian track rider and Scratch World Champion, Martina Fidanza, underwent heart surgery (ablation of the right atrium) to eliminate an arrhythmia. Fidanza's heart rate had been spiking during training, up to 245 beats per minute, which is how her condition came to the team's attention.
Sonny Colbrelli (right) launching the sprint moments before collapsing at stage 1 of Volta a Catalunya. Photo: David Ramos/Getty Images.

In January of 2021, something similar happened to sprinter and track specialist Elia Viviani, while in December 2020 fellow Italian rider Diego Ulissi was diagnosed with myocarditis, an inflammation of the heart muscles after an irregular heartbeat was detected during pre-season testing. The above episodes ended positively, but there are several other cases of professional riders who have died of heart attacks while racing and training.

But what are arrhythmias? And why have we seen more of these heart conditions in the pro peloton recently? Are they more common than we think, and are the surgeries to treat them as standard as they've been described? How can we, amateur cyclists, keep an eye on our hearts to prevent these conditions?

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Different types of arrhythmia

Scratch World Champion, Martina Fidanza (22),underwent a surgery to treat atrial arrhythmia only months after winning her world title. Photo: Getty Images.

Arrhythmia is normally defined as a quivering or irregular heartbeat that can lead to blood clots, stroke, heart failure and other complications. However, there are different types of arrhythmia and they are more or less dangerous depending on the person affected. 

The atrial fibrillation arrhythmia (AF or AFib) affects the heart’s upper chambers (atria). During this arrhythmia, the heart's atria beats irregularly and does not effectively move blood towards the heart's lower chambers (ventricles). 

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Another arrhythmia, a more dangerous one, is called ventricular fibrillation (or V-fib). It is caused by disordered electrical activity resulting in quivering or fibrillation of the ventricles, the heart’s lower chambers. In the worst scenarios, ventricular arrhythmia can inhibit the heart to pump blood and can lead to collapse and cardiac arrest.

The majority of arrhythmias are, however, benign, and only rare cases end up with cardiac arrest.

Unstable arrhythmia?

Colbrelli in 2021 celebrating the victory in the European road-race. Photo: Getty Images.

In the case of Sonny Colbrelli, the Bahrain Victorious team has referred to his episode as an “unstable arrhythmia,” but without specifying if that was involving his atria or ventricles.

“Unstable arrhythmias (which we should really call serious arrhythmias) are severe arrhythmias that, in the majority of cases, are correlated to other heart conditions. Rarely it can be primitive, which means it appeared without other pre-conditions,” explains Dr. Francesco Corsetti, surgeon and expert in sports medicine with experience in working with elite athletes and cyclists. Among the preconditions, Corsetti lists hypertrophic cardiomyopathy or arrhythmogenic right ventricular cardiomyopathy (which have genetic components), but a heart attack can also lead to arrhythmia and cardiac arrest in a previous healthy heart; so can inflammations of the myocardium due to a viral infection.

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Dr. Francesco Corsetti, surgeon and expert in sports medicine.

“In the last months we have seen several serious myocarditis that led to severe arrhythmia as effects of Covid,” he says.

In Colbrelli’s case, explains Corsetti, the arrhythmia must first be studied to understand what happened and rule out any preconditions. 

“If the previous pathology can be ruled out, the arrhythmia, even the serious ones, can be ablated [as it happened in Fidanza’s and Viviani’s case], which means being operated through a procedure that uses small burns or freezes to cause some scarring on the inside of the heart to help break up the electrical signals that cause irregular heartbeats,” explains Corsetti.Elia Viviani also underwent the ablation procedure to treat his arrhythmia and recovered fully. Photo: Zac Williams/SW Pix.

The ablation is often described as a standard procedure, however, being heart surgery, it's never easy. “If you’re in expert hands, it can be pretty secure, but it always presents some risks—even though limited,” points out Corsetti.

On the other hand, if there are other underlying cardiac issues, the arrhythmia can’t be treated in the same way and the athlete, at least in Italy, would not be declared fit to race. “If the underlying condition is an inflammation of the myocardium following a viral infection, for example, then the athlete would stop exercising for several moths and then — if the inflammation is completely gone — still be declared fit to race again,” says Corsetti. 

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But that’s not the case with other causes, like genetic ones. Hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy — which are the types that cause more serious arrhytmias — are primitive pathologies that currently don’t have treatments, except the prevention of the arrhythmias through the implant of a cardioverter-defibrillator. Once again, in these cases (at least in Italy) athletes would no longer be legally declared fit to race, but they can in other countries.

Who is most affected?

Many people affected by atrial arrhythmia don't even know it, and if they're not tested regularly like elite athletes — or don't have access to their heart rate like cyclists have daily — they remain unaware of its risks. 

According to the NHS, atrial fibrillation "is the most common sustained cardiac arrhythmia, with an estimated overall population prevalence in England of 2.5%" — with prevalence higher in men (2.9%) than in women (2.0%). In 2016, estimates the NHS, over 1.4 million people in England were living with it. And of these, 425,000 were estimated to be undiagnosed and untreated.

Studies have also shown that middle-aged endurance athletes are more affected by arrhythmia than non-athletes. Still, it's also true that athletes may notice something isn't right because they have access to heart-rate monitors daily and are diagnosed more frequently.

At the same time, it's also possible that endurance training can cause inflammation or scarring of the heart muscles and changes in the electrical pulse of the heartbeats. Or, less intuitively, something usually thought as a positive adaptation of endurance training, an increase in the size of the heart, can lead to creating heart tissues where irregularities could trigger arrhythmia.

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Why are so many Italians affected?

Italian physiologist and cycling coach Marco Orsini.

A possible explanation is that by law, Italian athletes (professional and not) are required to test more. In Italy, since 1982, every athlete keen to compete in any sport at any level (professional and not) must go through yearly sports medicine visits to assess whether they’re fit to race — and the exams include ECG under stress and echocardiogram.

“An ECG under stress highlights cardiac and circulatory problems, plus through blood tests you can check cardiac markers which are molecules released when the heart is damaged or stressed,” explains exercise physiologist and cycling coach Marco Orsini. “The measurement of these markers is used to help diagnose acute coronary syndrome (ACS) and cardiac ischaemia, conditions associated with insufficient blood supply to the heart.”

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But if you can’t go through the thorough Italian procedures (which are also cheap and range around £75 for the full package), what other tests should you book to make sure you stay on top of heart health?

“First of all, a medical examination for competitive sport, which differs from a fitness examination. I would include urine analysis, ECG under stress, spirometry, echocardiogram, spleen and liver echo,” explains Orsini.
Colbrelli, cover in mud, at the Paris-Roubaix 2021. Photo: Getty Images.

In addition to these, there are other biomarkers that can help to gather the stress levels of the sympathetic and para-sympathetic nervous system such as HRV, which you can out more about here.

And don’t forget, if you’re an amateur athlete with a busy life, a stressful job, and family commitments, it might not be a bad idea to ease off a notch. 

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“It is well known and reported that practising sport at a competitive or professional level can be unhealthy, as the body is forced to bear loads that are sometimes beyond its limits,” says Orsini. “This is especially true for amateurs, where in addition to the training stress we have to add work and family. That’s why examinations such as blood tests can help the coach and the athlete to have an indication of the subject's state of health.”

And the lesson for us amateurs? Look after yourself and get regular health checks. Sport should be enjoyable, not life-threatening.