Pro football players susceptible to arrhythmias, structural heart changes
ORLANDO, Fla. — Two studies presented at the American College of Cardiology Scientific Session suggest that heart rhythm disorders and structural disorders of the heart are significantly more common among former professional football players compared with the general population.
“The majority of research in sports cardiology is performed on currently active young athletes. In recent years, there have been more studies evaluating the cardiac effects of long-term endurance training with little data on the strength or mixed trained athlete and yet this is a large and expanding population,” Dermot Phelan, MD, PhD, from the sports cardiology center at Cleveland Clinic, told Cardiology Today. “There have been multiple studies showing strong associations between long-term endurance sporting participation and the risk of atrial fibrillation, for example. It was important to us to assess whether such an association was also found in a more strength-trained athletic cohort.”
Risk for arrhythmia disorders
In one study, former National Football League players were five times more likely than the general population to have arrhythmia disorders such as atrial fibrillation later in life.
Phelan and colleagues conducted a cross-sectional study to compare cardiac conduction and prevalence of arrhythmias in 460 former NFL players (mean age, 56 years; 47% black) vs. a control group of 925 non-athletes (mean age, 54 years; 53% black) from the Dallas Heart Study-2. All participants underwent screening for CV history, blood work, 12-lead ECG and an echocardiogram.
The researchers calculated an OR for AF of 5.5 (95% CI, 2.-15.4) among former NFL players on multivariable regression analysis controlling for age, race, BMI and hypertension. Age (OR = 1,08; 95% CI, 1.04-1.13) and BMI (OR = 1.13; 95% CI, 1.05-1.22) were identified as independent predictors of AF, but there was no predictive relationship with race, hypertension and diabetes, according to data presented.
Former NFL players were 10 times more likely to require pacemaker implantation compared with the control group (2% vs. 0.2%; P < .01).
Former athletes also had lower resting heart rates, increased rates of first-degree atrioventricular block and longer QRS intervals. Ventricular beats were higher among retired athletes, but the same was not observed with atrial ectopic beats.
Risk for structural changes
In another study, Jonathan Kim, MD, chief of sports cardiology and assistant professor of medicine at Emory University and lead cardiologist for the Atlanta Falcons, and colleagues found that structural changes to the heart, including enlargement of the aortic root were more common among collegiate football players after a single season of play.
Kim and colleagues performed echocardiography and vascular applanation tonometry on 136 collegiate freshman football players compared with 44 freshmen who did not play football, before and after a complete college football season.
Analysis demonstrated significant post-season aortic root size and weight, systolic BP, pulse wave velocity and left ventricular diastolic tissue velocity (P < .001 for all).
Post-season weight (P = .01) and E’ (P = .01) were independently associated with increased post-season aortic root size, according to multivariable analysis adjusting for age, height, BP, pulse wave velocity and pre-season aortic root size.
Enlargement of aortic root may not be completely tied to exercise training and the observed changes may not be detrimental to the player’s health. Kim and Phelan noted in a press release that further research is needed to elucidate the underlying mechanisms involved in the outcomes observed in these two studies. They also suggested that football players of all ages receive regular medical checkups to identify early signs of CVD.
“It is important for former NFL players and their treating physicians to be aware of these data, but we also need to be careful not to sensationalize these data,” Phelan said. “We should put this into the context of a paper recently published in the Medicine & Science in Sports & Exercise journal, where Lincoln et al showed that mortality in former NFL players was lower than the general population.”
“We often think of football players, like all athletes, as the picture of health, but we’re gaining this body of knowledge that signals some maladaptive cardiovascular changes and potentially even early cardiac risk in some of these players,” Kim said in the release. “It suggests we need to pay close attention to heart health of young football players. Also, future studies will need to focus on understanding the clinical significance of our findings.” – by Dave Quaile
Aagaard, P, et al. Abstract 1317M-07.
Kim J, et al. Abstract 1121-333. Both presented at: American College of Cardiology Scientific Session; March 10-12, 2018; Orlando, Fla.
Disclosures: Kim and Phelan report no relevant financial disclosures.