New research from Harvard Medical School has shown that the results of treatment of paroxysmal and persistent atrial fibrillation (AF) by catheter ablation are much better when co-existent sleep apnoea (OSA) is treated (JACC July 23 2013).
Obstructive sleep apnoea is now recognised to be a major trigger for atrial fibrillation. Treatment of AF with drugs or electrical cardioversion has a high short term success rate but the long term results are often disappointing.
Catheter ablation procedures use high frequency electrical energy or intense cold (cryotherapy) to electrically insulate areas of the left atrium which can lead to AF. The procedure (pulmonary vein isolation or PVI) is time consuming, expensive and may have to be repeated but cure rates of over 70% can be achieved when AF is intermittent (paroxysmal or persistent) but much it is less effective when AF is chronic.
In previous studies, the results of PVI were much worse in patients with AF who also had OSA. There have been reports that results of PVI may be better if OSA is treated with CPAP. In this study of patients having PVI for paroxysmal or persistent AF at the Beth Israel Hospital in Boston, those with previously diagnosed OSA were compared with the remainder who were not known to have OSA. The effect of self- reported CPAP treatment on the results of PVI was compared with untreated OSA patients, non-OSA patients having PVI and non-OSA patients treated with drug treatment alone.
The failure rate of PVI in OSA patients was doubled when it was untreated but those treated with CPAP did just as well as the rest of the PVI group. Untreated OSA patients did just as poorly as those who were treated with drug treatment alone.
The authors concluded there was little value in PVI procedures for atrial fibrillation unless OSA is treated in those who have it. More research is needed but clearly a case can be made for testing patients with AF for sleep apnoea.