The heart of the matter
David Prior cares deeply for what he calls the ‘architecture of the heart’. In his practice, he looks after some very unwell patients but he also shows an interest in the fittest of the species; elite athletes and how their hearts function.
Deputy Director of Cardiology at St Vincent’s Melbourne, Professor Prior and his research team have discovered that despite this vast divergence of fitness levels, some information can lead to new learnings.
“Exercise is a safe activity and has additional health benefits for all of us,” he says. “It creates wellness and is known to help prevent conditions such as Type 2 diabetes.
“But looking at elite athletes in particular allows us to understand what happens to the heart during exercise.”
As endurance sports such as Iron Man events have become more popular, doctors have become interested in heart function in this group, and it is now not uncommon for athletes to be asked to submit to testing pre- and post-race.
“In blood tests of athletes, certain markers could be detected that are also found in patients who have suffered heart attacks,” he explains. “A week post-race however, these markers had disappeared. It was also discovered that the right side of the heart, responsible for pumping into the lungs and facilitating oxygen production, showed changes after exertion.”
There are several factors that influence how the heart reacts under such stress: the level of fitness of the individual athlete, the length of the event and the length of time the heart has endured stress.
“In our research we found that pressure in the lungs increases during exercise. In elite athletes, pressure was high as they have the capacity to exercise harder, there is an increase in blood flow and we see that exercise increases the pressure load on the right side of the heart,” Professor Prior says. “An additional load can make the heart work harder.”
In some countries, for example Italy and Israel, children must be screened by a doctor and have a certificate before they can engage in organised sport.
However, the results may only be as accurate as the effectiveness of the screening tools.
“The reason behind this sort of screening is to pick up cases of unknown and undetected heart conditions. While it is desirable to prevent sudden and catastrophic heart conditions that lead to death, the numbers are quite low. We have one or two in 100,000 people in this category,” he says.
Causes of sudden and unexplained cardiac-related deaths vary from country to country. But in an examination of over 1000 Australian elite athletes electrocardiography (ECG) indicated that significant abnormalities were uncommon (only three in 1000) and it was found that athletic activity changed the results of the ECG.
Research into athletes is adding clarity to cardiac function in Professor Prior’s own heart failure clinic.
“Our iron men and women function at an elite level but their bodies are also informing us of the complex mechanisms responsible for changes in the heart; in well and unwell populations.”
www.mdhs.unimelb.edu.au