Sick sinus syndrome – lessons from endurance athletes

Use of If blockade to assess the contribution of sinoatrial node electrical remodelling to the resting bradycardia of endurance athletes - potential insights into the aetiology of acquired sick sinus syndrome

Gwilym Morris (lead researcher)

Manchester, University of

Start date: 01 April 2014 (Duration 2 years)

Dr Gwilym Morris from the University of Manchester is to do a 2-year study looking at a condition called sick sinus syndrome (SSS). SSS affects the function of the heart’s natural internal pacemaker called the sinoatrial node. This node normally initiates a current that enables the heart to beat in a regular and coordinated way. Disruption of the node in SSS leaves patients at risk of a dangerous irregular heart rhythm often requiring a pacemaker to be fitted to correct the heart rhythm. The incidence of SSS increases in older people, but one other cause is endurance exercise and the condition is more common in endurance athletes such as cyclists than in the general population. This team’s previous research showed that in animals endurance training decreased an electrical current (called the funny current, or If for short) in the node.

Now Dr Morris and colleagues will assess whether long-term endurance training in humans can lead to electrical changes in the heart’s sinoatrial node. The group will study competitive male cyclists or triathletes who train for at least 8 hours a week. Their heart rate and heart electrical activity (including behaviour of the If current) will be monitored in the laboratory and compared with the activity of control volunteers. The researchers will be looking for evidence that endurance training in the athletes has affected their heart’s electrical activity and that the profile of this activity differs from the controls. Understanding the disease process leading to SSS will help lead to new ways to detect, prevent and treat this disease in those most at risk.

Project details

Grant amount £28,720
Grant type Project Grant
Start Date 01 April 2014
Duration 2 years
Reference PG/13/99/30233
Status Complete

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