Spatial QRS-T angle in patients with newly diagnosed obstructive sleep apnea syndrome

The aim of the study was to assess the spatial QRS-T angle (QRS-TA) in a group of newly diagnosed and untreated adult patients with obstructive sleep apnea syndrome (OSAS) and to identify potential factors affecting this parameter.

The study group (PSG-confirmed OSAS) included 62 individuals, aged 51.7±10.3 years. The control group consisted of 25 individuals, aged 46.6±16.6 years with no sleep-disordered breathing. The diagnosis of OSAS and assessment of its severity was based on unattended all-night screening polysomnography. The spatial QRS-TA was reconstructed from 12-lead ECG using Kors' regression method.

Significant differences of spatial QRS-TA values were found between patients with severe OSAS (36.9±18.9°) and the controls (20.3±13.4°; p<0.01) and between patients with mild or moderate OSAS (32.3±20.1°) and the controls (p=0.01). Statistically significant correlations were found between spatial QRS-TA and polysomnographic indices (i.e. AHI, AI, RDT and RDTI).

Spatial QRS-TA values are significantly higher in patients with OSAS than in controls, thus indicating increased heterogeneity of myocardial action potential. Further long-term prospective studies evaluating the prognostic value of spatial QRS-TA in OSAS patients are needed.