Interesting Research Studies from the ACC’16 Meeting

MeetingGIF

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

In the Medical News: Athletes and ICD’s

In this week’s edition of the American Heart Association medical journal, Circulation, Dr. Rachel Lampert and her colleagues from Yale University School of Medicine published a report entitled “Safety of Sports for Athletes with Implantable Cardioverter-Defibrillators.”  This report is important because it is the most careful description yet of what happens to athletes with these devices who continue to participate in sports.

Background

Internal cardioverter-defibrillators (ICDs) are sophisticated medical devices that are implanted near the heart, usually with leads (electrodes) that are threaded into the heart, and are designed to provide a shock in the event that its owner’s heart develops a fatal arrhythmia.  You can read more about the ICD and view some diagrams that show how these devices are implanted in an article by the National Heart, Lung, and Blood Institute (NHLBI).

These ICD devices are a treatment for patients who have had–or who are at high risk for–sudden cardiac death (SCD), the abrupt onset of a fatal arrhythmia.  From the new report, the list of reasons that subjects had received an ICD was pretty long, and included:  long Q-T syndrome, hypertrophic cardiomyopathy (HCM), arrhythmogenic right ventricular dysplasia (ARVD), coronary artery disease (CAD), idiopathic arrhythmias in a structurally normal heart, dilated cardiomyopathy, congenital heart disease, and valvular heart disease, among others.

Conventional wisdom has held that athletes with an ICD should be restricted to low-intensity sports such as golf.  Consensus guidelines for athletes with an ICD are summarized in the Proceedings of the 36th Bethesda Conference on Eligibility Recommendations for Competitive Athletes with Cardiovascular Abnormalities.  These cautious guidelines stemmed primarily from a concerns about 1) the efficacy of the ICDs to deliver a shock appropriately during intense exercise and 2) the possibility of damage to the device or leads during physical contact that might render the device ineffective.

Interestingly, in 2006 these same investigators conducted a survey of Heart Rhythm Society members and found that more than 40% of respondents reported having at least 1 athlete patient with an ICD who was continuing to participate in competitive or vigorous sports despite recommendations to the contrary.

The Study

In 2006 the investigators started a registry that would enroll and follow athletes with an ICD who were known to be continuing to participate in sports of moderate or high intensity.  Often, this would be a situation where the athlete patient was participating in these sports despite their doctor’s recommendation not to do so.  The investigators eventually enrolled 372 athletes.  Of these, 211 were enrolled by medical institutions in the United States (41) or Europe (16).  The remaining 161 were self-enrolled–that is, the athlete contacted the Yale investigators directly and asked to be enrolled.  The median age was 33 years and 33% were female.

The median follow-up was 31 months.  Twenty-one patients did not complete the study:  9 were lost to follow-up, 6 withdrew, 4 stopped exercising because of worsening heart problems, and 2 died.

The important findings were:

1.  There were no occurrences of death, resuscitated cardiac arrest, or arrhythmia- or shock-related injury during sports.
2.  Thirty-six individuals (10% of the athletes studied) had shocks during practice or competition.  Of these, 30% stopped participating in 1 or more sports as a result.
3.  Twenty-nine individuals (8% of the athletes studied) had shocks during other physical activity.  Twenty-three individuals (6% of the athletes studied) had shocks at rest.
4.  There were 13 definite and 14 possible lead malfunctions and no generator malfunctions.  This lead malfunction rate is similar to non-athlete populations.
5.  There were no significant athlete injuries stemming from shocks during exercise.

My Thoughts

Creating this ICD registry was a great idea.

This report offers the most detailed look yet at what happens when athletes with an ICD continue to participate in sports.  The results provide a basis for thoughtful conversation between physician and athlete-patient regarding the risks of continued sports participation with an ICD.

Although a small number of athletes experienced both appropriate and inappropriate shocks, it should be reassuring that the ICDs terminated all episodes of ventricular arrhythmias and there were no athlete deaths. Although it certainly remains a possibility, it is fortunate that there were no significant injurties to athletes receiving a shock during exercise.  This is an area, though, where due caution is still well-advised because circumstances could be unforgiving for even a brief period of unconsciousness in activities such as cycling, rock climbing, swimming, etc.  Lastly, the results suggesting that generator and lead malfunction are uncommon, even among athletes who were participating in sports that involve physical contact should allay fears that the ICD could be rendered inoperative during sporting activities.

My congratulations to Dr. Lampert and her colleagues!