Sleep apnoea sufferers help scientists understand heart disease link

The hearts of one hundred patients with sleep apnoea are being monitored in a new trial to help researchers understand why sufferers are more likely to die from heart disease. 

We have awarded scientists at University of Warwick and the University Hospitals Coventry and Warwickshire NHS Trust nearly £265,000 to carry out the research over three years. 

According to the Sleep Apnoea Trust, as many as 10 million people in the UK suffer from the most common form of the condition called Obstructive Sleep Apnoea (OSA) – with up to four million of these suffering either severely or moderately.    

OSA causes breathing to stop intermittently due to a blockage of the airways at night which can cause excessive sleepiness in the day. It is also known to be associated with higher rates of illness and death linked to the heart.  

The most common way to treat OSA is with a Continuous Positive-Airways Pressure (CPAP) machine which pumps air into the mouth through a mask you wear while you sleep. Although the CPAP machine can help improve sleep and means OSA sufferers feel less tired in the day, research has shown that using the machine doesn’t decrease the risk from heart disease. 

Atrial fibrillation

Scientists now want to find out whether this is because patients with OSA are more likely to suffer with arrhythmias including the most common rhythm disturbance called atrial fibrillation (AF).  

AF happens when the electrical impulses in the top two chambers of the heart fire chaotically when they should be steady and regular, causing them to quiver or twitch (fibrillation).  Although AF on its own may not be dangerous, it can lead to an increased risk of stroke, heart failure or other heart-related problems if left undetected and untreated.  

To study the link between OSA and AF, the scientists will monitor the heart rhythms of patients by implanting tiny devices called implantable loop recorders under their skin. They will also use other methods including Holter monitors which are portable devices that monitor hearts rhythms. 

All participants in the trial will be treated using a CPAP machine as part of their usual-care and the study includes a control group of another 100 patients who will use the machine but not have their hearts monitored. 

Monitoring patients' hearts

Lead researcher Professor Faizel Osman, Consultant Cardiologist/Electrophysiologist at UHCW, said it was hoped that by closely monitoring the hearts of their patients, they would be able to observe abnormal heart rhythms in a way that wouldn’t otherwise happen.  

“We know that the pick-up rate for AF in patients with OSA is traditionally very low, but with this trial we’re planning to get, for the very first time in the world that I am aware of, an accurate idea of exactly what the prevalence rate is,” he said.  

“We hope that by the end of the trial to know what the true rate of atrial fibrillation and other arrhythmias is in these patients and be able to prove that this is something that is happening to people with OSA but isn’t always discovered. 

“This would mean that heart monitoring could become more routine for those at risk who present with OSA with the very real potential to save lives.” 

The patients taking part in the trial, all living in the Coventry and Warwickshire area, have been chosen because they have obstructive sleep apnoea but at the start of the trial at least, do not have any known heart rhythm problems.   

Keen to help researchers

One of the patients taking part in the trial is Leo Smith from Nuneaton in Warwickshire. Leo, 70, said he has had OSA for as long as he can remember – although he only had it officially diagnosed recently.  

Leo, who lives with his wife Angela, said that although the condition itself didn’t really impact his life at all, he was keen to help the researchers find out what the longer-term implications could be on hearts.  

“I fall asleep, I stop breathing, then I start breathing again and I wake up and I have no idea anything has happened,” he said.  

“But I don’t know what it does to my heart and this is the reason why I have had a loop recorder implanted under my skin”. 

Leo, who has health issues not related to OSA or his heart including a collapsed spine, only discovered he had sleep apnoea when he was in hospital for other treatment and the clinical staff panicked when he stopped breathing under general anaesthetic.  

“I realise I had forgotten to tell them!” he said. “But joking aside, one of the reasons I was happy to be part of the trial is because in the long term it might help save someone’s life – it's as simple as that. 

“Although I myself have a strong heart, I do have a lot of other health problems so I am the sort of person that never says no to anything the medical professionals want to do to me.” 

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