Book Review: Haywire Heart

 

 

 

 

 

 

 

 

Check out the recently published “The Haywire Heart” by Chris Case, John Mandrola, MD, and Lennard Zinn.  The book is available at Amazon and other outlets.

You may recall that Case, Mandrola, and Zinn authored an article in VeloNews, entitled “Cycling to Extremes:  Are endurance athletes hurting their hearts by repeatedly pushing beyond what is normal?”  This was a terrific read.  I wrote a previous blog post sharing my thoughts about the article and about the issue of arrhythmias and endurance sport, more generally.  Their article generated much discussion in the cycling and broader endurance sports communities and the interest of readers served as the motivation for their new book.

This is a book about electrical problems in the heart–the various arrhythmias.  Case, Mandrola, and Zinn are in a unique position to bring this topic to life because each has dealt personally with some form of arrhythmia.  And as long time cyclists (and perhaps with some triathlon experience as well), they’re able fashion the discussion to the avid endurance athlete.  From the medical perspective, the field of arrhythmias is rather complicated, both in terms of the underlying mechanisms of disease and the evaluation and treatment of affected patients, but here the authors have found a writing style that is captivating and accessible to the non-medical reader, while retaining much medical detail that will be of interest.  I give them credit because this is hard to do!

I love the title.  With an arrhythmia, the heart is truly “haywire.”  Ignore the line on the cover, though, about “How too much exercise can kill you.”  That’s unlikely to happen and there’s little in the book about that particular issue.  Instead, focus on “what you can do to protect your heart.”  That’s where the value lies here.

The book is organized into 9 chapters.  In Chapters 1-3, the authors describe in detail how the normal heart works, outline how the heart adapts over time to endurance exercise, and introduce the medical aspects of heart attack and arrhythmias, especially for the endurance athlete.  These sections are well-illustrated and are a great primer for any athlete interested in learning more about the heart.

Chapters 4-6 focus on the evidence of a link between long-time endurance exercise and arrhythmias, what to look for in yourself, and what it’s like to receive the diagnosis of an arrhythmia.  Here, the authors speak from personal experience and their observations and advice are valuable.

Chapter 7 deals with the issue of exercise addiction.  We know that exercise is generally healthy, but most of the benefits of exercise accrue with the first few hours per week.  Why, then, do athletes exercise more?  When does one become addicted?  What are the implications?  This is an interesting and pertinent discussion and might provoke some warranted introspection.

Chapter 8 covers the various treatment options for athletes with various arrhythmia problems.  For athletes who don’t have trouble with arrhythmias, the discussion is educational in a broad sense.  For those who do have arrhthymias, though, there is ample detail here to become educated and be better engaged with your doctor(s) as you sort out the best treatment for you.

Finally, in Chapter 9, the authors wrap up with their “takeaway” on how we might prevent arrhythmia problems.

One of my favorite aspects of the book is the inclusion of Case Studies sprinkled throughout the text, where the authors illustrate their points in a side bar with the personal account of an athlete.  These stories bring us the human side of arrhythmias and show how difficult these problems can sometimes be.

This book is for….

  • the athlete with an arrhythmia problem.  There’s a lot of familiar territory here as well as the opportunity to learn more.  An educated patient is the ideal patient.
  • the athlete with simply an interest in the heart.  I can’t think of a better resource to become educated about the workings of the heart, particularly as they relate to the endurance athlete.
  • the athlete (or the athlete’s spouse or parent) who’s afraid of causing harm to the heart through exercise.  Be forewarned and be vigilant.

 

Related Posts:

  1. Heart to Start, by James Beckerman, MD
  2. The Exercise Cure, by Jordan Metzl, MD
  3. Cardiac Athletes, by Lars Andrews

Interesting Research Studies from the ACC’16 Meeting

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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