Purpose: Obstructive sleep apnea (OSA) and myocardial fibrosis are associated with cardiac arrhythmia. The purpose of this study was to explore the relationship between OSA and myocardial fibrosis, as well as their impact on cardiac arrhythmia in hypertrophic obstructive cardiomyopathy (HOCM) patients.
Methods: We prospectively studied 151 consecutive patients with a confirmed diagnosis of HOCM at the Fuwai Hospital between September 2017 and 2018. Polysomnography, Holter electrocardiography, and cardiac magnetic resonance imaging were performed on all patients. Myocardial fibrosis was reflected by late gadolinium enhancement (LGE), detected using cardiac magnetic resonance imaging.
Results: Myocardial fibrosis, measured using LGE%, was found to increase with increasing OSA severity [6.8% (3.6– 12.9%), 6.1% (3.4– 10.0%), 9.6% (5.5– 14.5%), and 15.5% (9.3– 20.0%) for no-OSA, mild OSA, moderate OSA, and severe OSA, respectively; p=0.003]. LGE% correlated with the New York Heart Association functional classifications (p=0.018), septal thickness (p=0.026), and apnea-hypopnea index (AHI) (p< 0.001). The prevalence of isolated premature ventricular contraction (PVC) (p=0.028), paired PVC (p=0.036), ventricular bigeminy (p=0.005)/trigeminy (p< 0.001), non-sustained ventricular tachycardia (NSVT) (p=0.001), isolated premature atrial contraction (PAC) (p=0.032), and supraventricular tachycardia (p=0.029) was significantly higher in patients with OSA. Additionally, LGE% and AHI were independent risk factors for isolated PVC (OR: 1.04, p=0.001 and OR: 1.07, p=0.039, respectively), ventricular bigeminy (OR: 1.04, p=0.003 and OR: 1.26, p=0.002, respectively)/trigeminy (OR: 1.07, p=0.040 and OR: 1.06, p=0.001, respectively), and NSVT (OR: 1.17, p< 0.001 and OR: 1.08, p< 0.001, respectively) after adjustment for age, sex, and other parameters.
Conclusion: Both OSA and LGE% were associated with a greater likelihood and increased frequency of ventricular arrhythmias (including NSVT) in patients with HOCM. Thus, the severity of OSA was independently associated with more severe myocardial fibrosis in patients with HOCM.
Keywords: hypertrophic obstructive cardiomyopathy, obstructive sleep apnea, cardiac arrhythmia