Interesting Research Studies from the ACC’16 Meeting


This year’s annual meeting of the American College of Cardiology (ACC) was held recently in Chicago.  This year I was able to attend the meeting, so I can share what I learned, first-hand.  I became a member of ACC at the meeting and I also had the opportunity to be a co-author of a poster presentation on triathlete fatalities that I will describe below.  Like I’ve done for the past couple years, I’ll share here a round-up of some of the sports cardiology studies that caught my eye.  In the months ahead, we can look forward to seeing the published reports.  Here are my Top 5:


1. Fatalities in United States triathlons:  An expanded profile.  I joined with Kevin Harris and colleagues from the Minneapolis Heart Institute to report on 106 fatalities in American triathlons since 1985.  The average age of victims was 47 years–approximately 12 years older, on average, than participants as a whole.  The majority of victims (85%) were male.  The approximate fatality rate was 1.52 per 100,000 participants, with a rate of 2.05 per 100,000 participants in men and 0.71 per 100,000 participants for women.  The majority of deaths (71%) occurred during the swim portion of events, with smaller numbers during the bike or run segments, or immediately after the race.  Trauma was the most common cause of death during the bike segment.  The vast majority of other deaths involved cardiac arrest at the race venue.  Autopsy information was collected for 41 victims.  Among those autopsies, significant cardiovascular disease (coronary artery disease, hypertrophic or dilated cardiomyopathy, coronary artery anomaly, Wolfe-Parkinson-White syndrome, arrhythmogenic right ventricular cardiomyopathy [ARVC]) that caused or contributed to death was found in 55%.

My take:  This is the most comprehensive look yet at triathlon fatalities.  The findings remind us of the critical importance of safety planning and execution on the part of event organizers during the swim portion of events.  The preponderance of deaths among men, particularly those of middle age, and the preponderance of cardiovascular disease among victims suggests that targeted cardiac screening might be helpful for reducing the number of fatalities.  We’re working hard on preparing a full-length article.  I’ll report back when it’s published.


2.  Automated cardiac arrest detection and alerting system using a smartphone and standard Bluetooth chest strap heart rate monitor during exercise:  The “Parachute” app.  Nicola Gaibazzi and colleagues from University Hospital in Padua, Italy report on their initial experience–essentially, a feasibility study–with a smartphone app/Bluetooth heart rate strap that can detect cardiac arrest and automatically alert emergency response services by SMS, reporting a GPS location for the incapacitated athlete.  The authors make special note that no special hardware is needed since many runners and cyclists likely already carry a cell phone.  The investigators report that the system has been tested in 10 athletes for a total of 32 hours of running and 52 hours of cycling.  During that period, there were no “false alarms,” where an emergency message was sent unnecessarily.  The system has also been tested in the laboratory with equipment that simulates a fatal arrhythmia and the system’s arrhythmia detection system was 100% effective in recognizing ventricular fibrillation (VF).

My take:  As somebody who often runs or cycles alone, there is obvious appeal.  Additional testing, particularly in the field, will be needed to sort out the issue of possible “false alarms” and to be certain the arrhythmia detection algorithm is truly robust.  Given the pace of technological development related to heart rate monitors, I suspect that we will see more systems like this become commercially available in the near term.  I wonder, though, about what impact such devices/systems might have on the survivability of unwitnessed cardiac arrest, where the importance of prompt CPR and defibrillation are known to be essential.


3.  A novel pre-participation questionnaire for young competitive athletes. Despite years of study and a considerable literature based on expert opinion, there is still no consensus in this country about whether–and how to–screen young competitive athletes for hidden, unsuspected heart conditions that place such athletes at risk for sudden cardiac death (SCD) during sports activities.  The American Heart Association (AHA) currently recommends a 12-item questionnaire that combines medical history and physical examination (PE) findings.  The European  Society of Cardiology (ESC) currently recommends a medical history, PE, and a resting ECG.  In this study by James McKinney and colleagues from the University of British Columbia, one group of 686 young (age 12-35 years) athletes underwent screening with the AHA 12-item questionnaire, PE, and ECG.  Another group of 674 young athletes underwent screening with a new, novel questionnaire and an ECG, but did not have a PE.  In the first group, 59 athletes (8.6%) required follow-up testing because of abnormal findings during the screening process; 5 (8.9%, 5/59) of these athletes were actually found to have significant heart conditions.  In the second group, 31 athletes (4.6%) required follow-up testing because of abnormal findings during the screening process; 6 (19.4%, 6/31) of these athletes were actually found to have significant heart conditions.  So, perhaps surprisingly, the positive predictive value of the new approach (that omitted a PE) was significantly and considerably better.  By reducing the false-positive rate of the screening process, this new approach might be potentially more efficient, less costly, and cause less disruption in the sports routine for athletes while additional testing is obtained.

My take:  False positives during a screening process for rare conditions can be very costly in terms of additional testing and time lost from sports participation, so strategies to reduce the frequency of false-positives would be welcome.  The study points out what we’re taught early on in medical school:  90% of diagnosis can be derived from a conversation with the patient!


4.  Electrocardiogram utilization in the marathon medical tent.  Jennifer Michaud Finch and colleagues from Massachusetts General Hospital and Northwestern University report on the utilization rate and clinical impact of ECG in the medical tent of the 2015 Chicago Marathon.  There were 37,000 finishers.  A total of 12 ECGs were performed:  5 for chest pain, 2 for pre-syncope, 1 for exertional syncope, and 1 for post-exertional syncope.  One case of ST segment elevation and T wave changes, suggestive of acute coronary syndrome, was identified and the athlete was transferred to the hospital.  Much more commonly, though, the ECG was useful for reducing the concern for an acute cardiovascular problem.  Medical tent providers rated the clinical value of the medical tent ECG as an 8 on a 10-point scale.  The authors concluded that, although performed very infrequently, medical tent ECGs were very helpful in making decisions about athlete diagnosis and triage.

My take:  It appears that the ability to perform an ECG in the medical tent for a large, urban marathon is important.  Obviously, expert interpretation is needed in order to make correct decisions about diagnosis, on-site treatment, and potential transfer to the hospital.  It is important to remember, though, that the ECG was used for only 1 per 3,080 runners.  For smaller races, then, which may have less sophisticated (or no) medical tents, consideration might be given for triage to the hospital emergency room in the unusual case where an ECG is thought to be needed.


5.  The impact of age and completion of a moderate distance running race on cardiac function:  Results from P.E.A.C.H. (Profiling the Effects of Aging on Exercise-induced CHanges in Cardiac Mechanics).  We know from previous reports that there is release of cardiac enzymes into the blood stream as well as a transient decrease in the pumping strength of both ventricles after long endurance events such as triathlon, long-distance cycling, or long-distance running.  This phenomenon is sometimes referred to as “cardiac fatigue.” Much less information, though, has been reported about potential adverse cardiac outcomes after moderate distance running races, despite the huge popularity and participation in such events.  Jonathan Kim and colleagues from Emory University report on a group of 73 athletes who participated in the 2015 Peachtree 10k running race in Atlanta, Georgia.  Each athlete underwent a limited echocardiogram 24-48 hours before the race and then again immediately (within 5 minutes of finish) after the race.  There were no decreases in the important echocardiographic indices of cardiac function after the race, for either the left or the right ventricle.

My take:  This is an intriguing finding.  One might wonder what is so different about a 10k race, compared to a half marathon for instance.  We do know that, with long-distance events, cardiac enzymes return to normal and changes in cardiac function detected by echocardiogram return to normal within days after the event.  The long-term consequences, if any, remain unclear.  Some have theorized that repeated “episodes” of transient cardiac damage, arising from participation in many such events over a lifetime, might result in harm to the heart.  The findings of the current study suggest that participation in shorter events may not carry the same long-term risk.


Related Posts:

1.  Interesting Research Studies from the ACC’15 Meeting

2.  Interesting Research Studies from the ACC’14 Meeting

Interesting Research Studies from the ACC ’14 Meeting






This year’s annual meeting of the American College of Cardiology was held in Washington, D.C. last week.  I wasn’t able to attend the meeting, but the results of several studies related to sports cardiology caught my attention.  Here are my Top 8:

1. Prodromal symptoms, exercise, and sudden cardiac arrest (SCA).  In a study reported by Lawless CE et al., questionnaires were distributed to known survivors of SCA.  Prodromal, or warning, symptoms surveyed included chest pain, shortness of breath, and evidence of arrhythmia (syncope, dizziness, palpitations).  Such prodromal symptoms were present in 31% during the month preceding the SCA episode.  Half of the prodromal symptoms occurred at rest and half occurred during exercise.  We’ve known about the importance of recognizing exercise-related arrhythmias, but the important new finding here is the importance of arrhythmic symptoms at rest as a potential warning sign for later SCA.

2. Exercise blood pressure in Olympic athletes.  Little is currently known about blood pressure during exercise for elite athletes.  In a study reported by Caselli S et al., 1,140 Olympic athletes from the 2008 or 2012 Games were divided into 4 groups depending upon their sport:  skill disciplines, power disciplines, mixed disciplines, or endurance disciplines.  These athletes underwent a battery of cardiovascular testing that included measurement of the blood pressure during a maximal bicycle exercise test.  For the entire group, the peak systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 190+/-21 mm Hg and 76 +/- 7 mm Hg, respectively.  Interestingly, there were no differences between athletes of the 4 sporting groups.  A total of 102 athletes had either SBP or DBP above the 95th percentile for the group (220 mmHg and 85 mmHg, respectively).  This new information may allow for better identification of elite caliber athletes with hypertension that should be treated.

3. Maximal heart rate in men and women.  We often use the calculation of 220 minus age to give an estimate of an individual’s maximal heart rate.  This number has bearing in clinical cardiology testing as well as for setting up training zones for endurance athletes.  Based on the observations in more than 25,000 individuals undergoing exercise stress tests, Sydo N. et al. reported that more accurate estimates for individuals older than 40 years may come from these equations:  Men, 216 minus 93% of age; Women, 200 minus 67% of age.  These new equations may provide better estimates for athletes who want to establish appropriate training zones.

4. Cardiovascular health and marathon training.  Zilinski JL et al. reported on a group of 45 male recreational runners who undertook a relatively short 18-week, structured training program leading up to the 2013 Boston Marathon.  Each of the runners had at least one known cardiovascular risk factor at the outset.  They underwent clinical evaluation, echocardiography, VO2max testing, and laboratory evaluation before and again after the training period.  There were significant improvement in:  peak oxygen consumption, body-mass index (BMI), serum triglyceride level, serum low density lipoprotein (LDL) level, serum total cholesterol, and one particular index of ventricular function based on echocardiography.  The results suggest, perhaps not surprisingly, that marathon training may be a useful strategy for improving conventional cardiovascular risk factors.

5. Running and longevity.  A couple recent studies have documented a so-called “U-shaped” relationship between the amount of running and longevity among long-time runners, where individuals with moderate amounts of running enjoyed better longevity compared to those with larger (>20 miles per week) amounts of running.  These previous studies have suggested some sort of “sweet spot” with respect to healthy amounts of exercise.  The reasons and potential mechanisms for this observation remain unclear, though.  In a study reported by Bell AC et al., an update was provided for the ongoing MASTERS Athletic Study, a longitudinal study of runners aged 35 and older.  The investigators tested the hypothesis that perhaps decreased longevity among the highest-volume runners might be due to adverse cardiovascular risk factors (eg, family history of heart disease, high blood pressure, abnormal serum lipid levels, diabetes, smoking) rather than to the amount of running.  It turns out, though, that these factors did not account for the difference in mortality for the 2 groups.  So the reason(s) behind the U-shaped longevity curve (if it’s not due simply to the amount of running) remain unclear.

6. Pre-participation screening.  There have been several guidelines about the utility of pre-participation cardiovascular screening for athletes, including the 4th PreParticipation Physical Evaluation monograph in 2010, the 2007 American Heart Association (AHA) reparticipation screening recommendations, and the Proceedings of the 36th Bethesda Conference in 2005.  In a study reported by Lawless CE et al., 190 Nebraska primary care providers (PCPs) were surveyed about their use of these guidelines in the evaluation of athletes.  The percentage of PCPs who “consistently used” the guidelines were only 7.9%, 11.4%, and 3.2%, respectively.  The percentage of PCPs who were unaware of the guidelines were surprisingly 73.0%, 48.0%, and 76.4%, respectively.  The results suggest that the guidelines are under-utilized and the investigators recognize a potential opportunity for improved screening with better education about the available guidelines.

7. Smartphone apps and silent arrhythmias.  A variety of smartphone apps related to heart rhythm monitoring have become available in recent years.  In a study reported by Sawant AC et al., 103 patients being treated in an outpatient setting used a smartphone app to record their EKG and then also underwent conventional EKG recording in the doctor’s office.  The smartphone app correctly identified atrial fibrillation in almost 90% of cases where the arrhythmia was silent (did not produce symptoms).  This technology will undoubtedly continue to evolve and may enable recording of both silent and symptomatic arrhythmias in the outpatient setting in a much easier and less costly fashion that traditional Holter monitoring.

8. Endurance exercise and cardiac remodeling.  Many different sports qualify for being “endurance” activities, but each has its own unique make-up of so-called dynamic and static exercise components.  In a study reported by Wasfy MM et al., 38 long distance runners were compared to 33 rowers in terms of their cardiac structure and function.  The investigators found that runners had larger left ventricular (LV) volumes but lower LV muscle wall thickness than the rowers.  The function of the LV was similar for the 2 groups.  It’s important to keep in mind that, as far as the heart is concerned, all endurance sports are not created equal!

We can expect more detailed reporting on these studies as they make their way into print form in a scientific journal over the next year or so.  Stay tuned.