Sleepless nights, restless hearts: spotting the OSA-AF connection

Our patients are our best teachers. I remember one, let’s call him Mike, who first taught me the link between atrial fibrillation and obstructive sleep apnoea (OSA). He was a large guy, always smiley and jokey, in his 50s who presented with recurrent symptomatic paroxysmal atrial fibrillation. I was discussing possible triggers with him (‘Is it when you’re stressed Mike? Is it after a few drinks? etc) when Mike said to me, laughing, ‘I think my snoring triggers it’. My initial reaction was to laugh with him, but then it belatedly dawned on me that Mike was really on to something here. Sure enough, on appropriate but VERY belated questioning from me, he gave a great history corroborated by his wife of previously undiagnosed OSA. I checked a STOP-bang questionnaire and bango - he scored 7/8. Once he had had the diagnosis confirmed and was started CPAP then his AF then got a lot better, as well as his snoring!

The recently updated European Society of Cardiology guidelines on Atrial Fibrillation ESC, AF Guidelines 2024 stress the importance of recognising, and managing, the common co-morbidities in patients presenting with AF. There is an argument that with AF we have become so focussed on preventing stroke through anticoagulation (which of course remains of critical importance) that we have neglected the other co-morbidities that commonly accompany AF, one of the most important of which is OSA. A recent evidence review states that OSA is strongly associated with AF and yet it is highly under recognized and underdiagnosed. The pathophysiological mechanisms linking OSA to AF include intermittent hypoxia, nocturnal sympathetic activation and structural remodelling of the atria all of which collectively increase the risk of developing AF. Furthermore, trials show that treatment of OSA with continuous positive airways pressure (CPAP) can help to reduce recurrences of AF and to maintain sinus rhythm, as happened with my patient Mike.

The ESC, AF Guidelines 2024 stress that OSA is a highly prevalent condition in patients with AF and quote evidence that untreated patients with OSA and AF respond poorly to treatments for AF with an increased risk of recurrence after ablation or cardioversion. Patients who have OSA treated with CPAP, also reduce their risk of developing AF and there is some intriguing evidence that CPAP in these patients can reverse atrial remodelling. 

So, what are the clinical implications of these findings for us? Firstly, we need to think in a patient with AF, could they have underlying OSA? As per NICE guidance for OSA NICE, NG202 if we suspect the diagnosis we should check a Epworth sleepiness score and also do a STOP-bang questionnaire prior to referral. The ESC, AF Guidelines 2024 recommend not to rely on questionnaires in suspected cases and to refer all suspected cases for sleep studies and polysomnography,  but in the NHS this is not feasible without an initial screening score except in the highest risk patients (who should have a high STOP-bang score anyway). The second implication for us is that in a patient with established OSA, to keep checking that pulse because those irregular breaths can lead to irregular beats!

In conclusion, these guidelines remind us that these are two very common co-morbidities. See one, and we should think of the possibility of the other and look for it. And treating OSA is not just about symptom control, it will also have profound implications for the management of AF including reducing recurrence rates and improving cardiovascular outcomes. 

The new ESC, AF Guidelines 2024 are a great resource and packed with lots of important clinical updates. But they are 106 pages long (!) so for a concise summary of the most useful learning points to take away and use in primary care do come and join us on one of our Hot Topics GP Update courses over the next few months.