The aim of this study was to investigate whether patients with hypertrophic cardiomyopathy (HC) and sleep disordered breathing (SDB) have a higher prevalence of atrial fibrillation (AF) compared to patients with HC without SDB. HC is associated with a high prevalence of AF that contributes to increased morbidity and mortality. SDB is strongly associated with a higher incidence, prevalence, and recurrence of AF in patients without HC. Whether this association also applies to patients with HC is not known. Overnight oximetry was prospectively performed on 91 consecutive patients with echocardiographically confirmed HC. The presence or absence of AF in this population was correlated with the oximetric findings. SDB was associated with a higher prevalence of AF (40% vs 11%, p = 0.005). In addition, SDB was accompanied by significantly increased left atrial volume index (58 +/- 19 vs 42 +/- 13 ml/m(2), p = 0.0002). Increasing severity of SDB was correlated with higher AF prevalence and with increase in left atrial volume index. These associations remained significant even after accounting for potential confounders in a multivariate analysis. In conclusion, these findings suggest that the presence and severity of SDB may influence left atrial volume index and the prevalence of AF in patients with HC. SDB may therefore be an important and potentially modifiable cause of morbidity and mortality in this population.
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