Hypoxia affects myocardial oxygen supply resulting in subclinical cardiac dysfunction in obstructive sleep apnea (OSA) patients, with cardiovascular complications being associated with increased oxidative burst (OB). The aims of our study were to assess left ventricular (LV) dynamic myocardial deformation and diastolic reserve at rest and upon exercise, along with OB determination in this patients subset. Conventional echocardiography, Doppler myocardial imaging and LV 2D speckle tracking echocardiography were performed in 55 OSA patients with preserved LV ejection fraction (EF) and 35 age and sex-comparable healthy controls. Peripheral OB levels were evaluated by flow cytometry. Despite comparable LVEF, LV global longitudinal strain (GLS) was significantly reduced in OSA at rest (− 13.4 ± 3.8 vs − 18.4 ± 3.3 in controls, P < 0.001) and at peak exercise (− 15.8 ± 2.6 vs − 23.4 ± 4.3, P < 0.001). Systolic pulmonary artery pressure (sPAP) and E/E′ ratios increase during effort were higher in OSA than in controls (ΔsPAP 44.3% ± 6.4 vs 32.3% ± 5.5, P < 0.0001, and ΔE/E’ 87.5% ± 3.5 vs 25.4% ± 3.3, P < 0.0001, respectively). The best correlate of E/E′ at peak stress was peak exertion capacity (r = − 0.50, P < 0.001). OB was also increased in OSA patients (P = 0.001) but, unlike OSA severity, was not associated with LV diastolic dysfunction. Evaluation of diastolic function and myocardial deformation during exercise is feasible through stress echocardiography. OSA patients with preserved LVEF show subclinical LV systolic dysfunction, impaired LV systolic and diastolic reserve, reduced exercise tolerance, and increased peripheral levels of OB. Therapy aimed at increasing LV diastolic function reserve might improve the quality of life and exercise tolerability in OSA patients.

中文翻译：

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阻塞性睡眠呼吸暂停并保留左心室射血分数的动态左心室收缩和舒张功能的亚临床损害

低氧影响心肌供氧，导致阻塞性睡眠呼吸暂停（OSA）患者出现亚临床心脏功能障碍，心血管并发症与氧化爆发（OB）增加有关。我们研究的目的是评估该患者亚组在休息和运动时左心室（LV）动态心肌变形和舒张储备，以及OB测定。在55例左室射血分数（EF）保持不变的OSA患者以及35例年龄和性别可比的健康对照者中，进行了常规超声心动图，多普勒心肌成像和LV 2D斑点追踪超声心动图。通过流式细胞术评估外周OB水平。尽管LVEF相当，但静止时OSA的LV总体纵向应变（GLS）显着降低（对照组为− 13.4±3.8与对照组的− 18.4±3.3，P <0。001）和运动高峰期（− 15.8±2.6 vs − 23.4±4.3，P <0.001）。在OSA中，努力过程中的收缩期肺动脉压力（sPAP）和E / E'比增加高于对照组（ΔsPAP44.3％±6.4对32.3％±5.5，P <0.0001，ΔE/ E'87.5％±3.5对25.4 ％±3.3，分别P <0.0001）。E / E'在峰值应力下的最佳相关性是峰值施加能力（r =-0.50，P <0.001）。OSA患者的OB也增加（P = 0.001），但与OSA严重程度不同，它与左室舒张功能障碍无关。通过应力超声心动图可以评估运动过程中的舒张功能和心肌变形。LVEF保留的OSA患者表现为亚临床LV收缩功能障碍，LV收缩和舒张储备受损，运动耐量降低以及外周OB水平升高。