More on ECG screening to prevent sudden death in the young: On risk, the Italian experience, and notes from the real world

May 6, 2012 09:44 EDT

Earlier this week, I wrote about one of my favorite topics in medicine: the ECG. This 12-pronged view of cardiac vectors catapulted my interest in the human heart. I love everything about ECGs. I see them as beautiful instruments for the diagnosis and treatment of heart disease. Niftier yet, ECG skills cannot be Googled; they must be gathered with mentoring and time. The story relayed in those squiggles has yet to be digitized. I like that too.

That's why it hurts to take the view that mandating the use of screening ECGs will not completely eliminate the chance that a young person dies suddenly. The buzz generated from my posts (here and here) earlier this week inspired me to again review the actual evidence. I have learned tons more and thought that I would share this incremental knowledge.
I am interested in hearing your thoughts, too.

On the rareness of sudden death in the young

In our country alone, tens of millions of young people go out to play each day. The incidence of sudden death published in most studies range from one to two deaths per 100 000 patient-years. Another way of saying this: over a decade, the chances of a youngster dying from cardiac causes are one to two in a million. That's the problem; it's like lightning strikes. Imagine comparing strategies that could prevent one from dying from lightning. Other than never going outside (not ever playing), how would one show one avoidance strategy better than another? And what if the avoidance strategy caused problems in many more than the one in a million saved?

The Italian strategy

Much of the excitement about using ECGs for screening comes from the "evangelical zeal" with which Italy screens its young athletes. I spent a great deal of time learning the specifics of what happens in Italy. They do things very differently. As mandated by Italian law, all those who participate in sport must undergo a preparticipation evaluation, including an ECG. Unlike in the US, where any licensed medical person can certify a sports physical, in Italy, these evaluations are done in selected sports centers by specially trained experts. The Italian government funds the evaluations, and Italian doctors hold the final say as to whether a kid is disqualified.

The Italian data: Results

I was surprised to learn that data supporting the Italian experience comes from only one observational study from the Veneto region of Northern Italy, a small area that comprises only 8% of the population of Italy. The results of this 2006 JAMA study serve as an example of how relative risk reduction paints a different picture from that of absolute risk reduction. The Italian researchers reported that sudden death in athletes was reduced by 89% after an ECG screening program was instituted. That sounds impressive. But consider this: over a decade, the absolute number of deaths went from thirty in a million to four in a million. The question is not whether this is significant—any life saved is—it's whether these tiny absolute changes were the result of mandatory ECG screening.

The Italian data do not support the use of mandated and widespread screening ECGs? Here are three lines of reasoning.

First, the Italian findings cannot be corroborated in other countries. US researchers found that sudden death rates in non–ECG-screened Minnesotans did not differ from those in Veneto. When researchers from Israel compared the sudden death rates in the decade before mandatory ECG screening with the decade after, they found no difference. In Denmark, the presports evaluation is neither systematic nor mandated. Despite these lax requirements, this study found young Danes had the same (very low) sudden death rates as those in Italy and the US. What's more, this Danish trial revealed that sudden death occurred more often in nonathletes—a finding that supports Dr Barry Maron's recommendation that screening for sudden death must not be limited to young athletes.

The second counterargument centers on how Italian researchers compared death rates before and after the policy change. Mandatory ECG screening in Italy began in 1981. The researchers compared death rates in only the two years before (1979–81) with the 25 years after. That's not a good comparison. Among other potential confounders is the fact that rare events can vary greatly year to year. For example, in the Israeli study, if only the two years before ECG screening were used, there would have been a significant difference. When they used the 10-year window before and after, there was no difference.

Another confounding variable in the Italian study is the chance that improvements in resuscitation abilities over the past two decades caused the lower death rates. That's the problem with observational trials done over decades—it's hard to sort out what caused the difference, or if it was a real difference at all.

That's a lot of information. Let's summarize: The Italian experience, reported from a small homogenous region of a country with socialized medicine, shares no similarities to our risk-averse US healthcare system. The Italian thesis, that ECG screening saves lives, stems from one observational trial that cannot be confirmed by other researchers in other countries.

My messages

To parents who ask what are the best means to screen their young one, I'd have to answer that I don't know. It depends on your inherent feelings about risk. There's the risk of missing a rare heart disorder that may or may not increase the risk of sudden death. But then, there is—in the US for sure—a greater chance that "playing it safe" risks making your well child sick. There's also the chance that even an ECG would not find the abnormality—as in the third-leading cause of sudden death in the young, an anomalous coronary artery.

To US doctors clearing young athletes for sport, I'd recommend four focus points:

• Ask about heart symptoms, like fainting, rapid heartbeats, and chest pain. I know; this isn't as easy as it sounds—because the overwhelming majority of cross-country runners who faint or cry in pain after a race don't have heart disease. (Personal observation from years as a cross-country coach.)
• Ask about a family history of sudden death or fainting—an important clue for long-QT syndrome.
• Pay close attention to heart tones. Really listen for the murmur of hypertrophic cardiomyopathy.
• If you feel an ECG is needed, find a cardiologist that is both comfortable with ECG interpretation and gutsy enough to say normal is normal.

 

Big picture

The debate about how much sudden death risk we—as a society, as parents, as doctors—can tolerate speaks to where medicine is and where it is going. We can prod, and measure, and image, and worry, so much. But in the end, too much bubble wrap risks ruining the fun of life.

I'm sorry for not being more hopeful. I just can't see that mass ECG screening in the US would work. Do you? Yes, it's a paradox. While our medical advances have been breathtaking, we struggle mightily with the simple stuff. We need help with our risk aversion. For most doctors, even me, at this moment, it's so hard, so very hard, so risky, so scary, to say, "Yep, it's okay, you are good, no problems, you won't die."

So we don't say that. We say, "You need more tests; you need a signal-averaged ECG, an MRI, a genetic test." Or worse, we decree, "You can't play."

I'm open to hope on this matter. For the record, I have read reports of privately funded pilot projects in small enclaves of enlightened communities. Still, I am unconvinced about the effectiveness of mandates and widespread screening on a large scale.

Let's finish on an upbeat note.

At this time, the most actionable and effective means to prevent death from cardiac arrest is to advocate for AEDs and CPR education. Inexpensive AEDs improve survival—of the old and young as well as the athletic and nonathletic. We can all agree that widespread education on the importance of a rapid delivery of a shock (or effective CPR) to a person suffering cardiac arrest deserves more emphasis and funding. It's hard to see the downsides of having more lifesaving devices and more educated people around to use them.

JMM

References

Corrado D and Thiene G. Protagonist: Routine screening of all athletes prior to participation in competitive sports should be mandatory to prevent sudden cardiac death. Heart Rhythm 2007; 4:520–524.

Corrado D, Basso C, Pavei A, et al. Trends in sudden cardiovascular death in young competitive athletes after implementation of a preparticipation screening program. JAMA 2006; 296:1593–15601.

Fisher WG. The dark side of EKG screening in athletes. May 2, 2012. Available here.

Holst AG, Winkel BG, Theilade J, et al. Incidence and etiology of sports-related sudden cardiac death in Denmark: Implications for preparticipation screening. Heart Rhythm 2010; 7:1365–1371.

Maron BJ, Haas TS, Doerer JJ, et al. Comparison of US and Italian experiences with sudden cardiac deaths in young competitive athletes and implications for preparticipation screening strategies. Am J Cardiol 2009; 104:276–280.

Maron BJ. Diversity of views from Europe on national preparticipation screening for competitive athletes. Heart Rhythm 2007; 7:1372–1373.

Steinvil A, Chundadze T, Zeltser D, et al. Mandatory electrocardiographic screening of athletes to reduce their risk for sudden death: Proven fact or wishful thinking? J Am Coll Cardiol 2011; 57:1291–1296.

Suissa S. Immortal time bias in pharmacoepidemiology. Am J Epidemiol >2008; 167: 492–499

Viskin S. Antagonist: Routine screening of all athletes prior to participation in competitive sports should be mandatory to prevent sudden cardiac death. Heart Rhythm 2007; 4:525–528.