A second study which drew attention was carried out by researchers at Eagle Lodge cardiology clinic in Limerick and St James Hospital Cardiology Department, Dublin.
Latest research shows that the lower resting values of right ventricular percentage strain may represent physiological changes rather than subclinical myocardial damage.
The aim of this study was to test this hypothesis.
Cardiac technician at Eagle Lodge, Dr Brian McLoughlin explained:” When people were examining the athletes’ heart they found out there was a percentage reduced myocardial strain in the right ventricle, so the alarm bells went off. The question to be asked was, is it a pathological response to endurance training over a long period of time, or is it a physiological response because of the remodeling of the ventricle? What I looked at was isovolumic acceleration of the wall while it’s unloaded and we found there was an increase in the isovulimic acceleration of the free wall in the elite athletes compared to the normal control group.”
“Previous studies compared isovolumic acceleration with functional reserve, so this meant they were maintaining their functional reserve even though their strain rate was reduced, so this was not then a pathological response but more of a physiological response and rather than measuring percentage strain in the future, we will use the isovolumic acceleration as a more robust measurement of left ventricular behaviour,” he added.
The study involved 24 footballers with a mean age of 24 and 18 elite athletes with a mean age of 22. RV% strain and RV free wall isovolumic acceleration (IVA) was measured .
Standard 2D echo were used to measure RV parameters including the index Tei (systolic and diastolic function) and the total annular plane systolic excursion (TAPSE) of the RV annulus NT-proBNP was measured by an electrochemiluminescence assay.
The study showed the RV diameter was increased in the footballers and elite athletes compared to controls while RV wall size was greater in the elite athletes compared to controls and footballers.
The peak IVA of the RV was higher in the elite athletes, compared to the footballers and to controls.
The mean RV% strain was lower in the elite athletes and the footballers compared to controls.
The study reaffirmed the hypothesis that the reduction in RV% strain is a physiological response which is counterbalanced by an increase in acceleration during the isovolumic phase.
Exercise strain rate imaging demonstrates normal right ventricular contractile reserve and clariﬁes ambiguous resting measures in endurance athletes.
“The clinical implications would be in screening clinics we can now measure their isovolumic acceleration and determine whether it’s reduced because of long term remodeling and exercise, rather than a pathological response. Normally, you would get a global percent strain rate of about 25 per cent and these athletes were coming in with global per cent strain of about 15 which is when the alarm bell was ringing. We looked at BNP in the group and found no myocardial damage. There was a significant increase in the isovolumic acceleration in the athletes compared with the control group. Reduced myocardial strain is a consequence of a physiological response and not myocardial damage. Going forward we plan to link up with centres in Massachusetts and look at both short term and longitudinal studies looking at the athletic heart over the long term,” he added.