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.