Prevalence of steep disordered breathing in paroxysmal and persistent atrial fibrillation patients with normal left ventricular function

Aims Recent studies have suggested an emerging link between steep apnoea and atrial fibrillation (AF). These studies included patients with reduced left ventricular (LV) function which may cause both AF and steep disordered breathing (SDB). We examined the prevalence of SIDE, in a population of patients with AF and normal LV function. Methods and results Ninety patients with paroxysmal or persistent AF and 45 controls were prospectively enrolled and matched 2:1 for age (AF 56 +/- 12 years; controls 54 +/- 11 years) and sex. All patients had normal LV function. SDB was diagnosed using all-night portable potysomnography. Apnoea-hypopnoea index (AHI) in AF patients was higher than in controls (23.19 +/- 19.26 vs. 14.66 +/- 12.43, P = 0.01). The proportion with significant SDB (AHI > 15) was also greater in AF patients (62 vs. 38%, P = 0.01). After adjustment for relevant covariates, the odds ratio for the association between AF and SDB (AHl > 15) was 3.04 (95% CI 1.24-7.46, P = 0.02). The paroxysmal AF group was classified as either 'low-frequency AF (<= 6) or 'high-frequency AF (>6) episodes in the past year. High-frequency AF was associated with a higher prevalence (75 vs. 43%, P = 0.012) and severity (mean AHI 28.08 +/- 22.94 vs. 16.69 +/- 15.06, P = 0.028) of SDB when compared with those with tow-frequency AF. Conclusion A high prevalence of SDB is found in relatively young patients with both paroxysmal and persistent AF with normal LV function. This AF population warrants careful consideration for the presence of SDB.