[Predictors of Electrical Myocardial Instability in Men With Arterial Hypertension and Obstructive Sleep Apnea-Hypopnea Syndrome].

OBJECTIVE: To access the detectability of corrected QT interval (QTc) prolongation ( more or equal 450 ms) and increased QT dispersion (QTd more or equal 60 ms) in men with obstructive sleep apnea-hypopnea syndrome (OSAS) and newly diagnosed arterial hypertension (AH).

MATERIAL AND METHODS: We included in this study 138 men (mean age 40.5+/-6.9 years, body mass index 34.5+/-4.7 kg/m2, all with more or equal 3 risk factors of AH development, 34% with subclinical target organs damage). According to office systolic and diastolic blood pressure level (SBP and DBP), AH of 1st degree was diagnosed in 103 (74.6%), 2nd - in 26 (18.9%) and 3rd - in 9 (6.5%) patients. All patients underwent 24-h multifunctional monitoring. According to the apnea-hypopnea index (AHI) patients were divided into 4 groups: I (control, n=34) with AHI less than 5/h, II (n=36) with AHI 5-14/h, III (n=32) with AHI 15-29/h, IV (n=36) with AHI more or equal 30/h.

RESULTS: There were no significant intergroup differences in age, body mass index, sleep duration, mean daytime SBP, QT and JT dispersion in the diurnal, daytime and nighttime periods. However, in group IV values of mean heart rate (in normal range), daytime DBP, nighttime SBP and DBP, QTc and JTc intervals were higher than in other groups. Portions of patients with prolonged QTc and increased QTd were 38.2 and 35.3%, 44.4 and 33.3%, 34.4 and 40.6%; 50.0 and 38.9% in groups I, II, III, IV, respectively. Multiple regression analysis revealed associations between mean diurnal QTc interval prolongation and reduction of mean oxygen saturation (SpO2) during sleep, and between mean diurnal JTc interval prolongation and increase of AHI.

CONCLUSIONS: Rates of detection of QTc interval prolongation and QTd increase in men with newly diagnosed AH and OSAS of different severity were almost similar. However, there was a trend to higher detectability of QTc interval prolongation (50.0%) among patients with AHI more or equal 30/h. Reduction of mean SpO2 and AHI increase during sleep were found to be predictors of diurnal QTc and JTc intervals prolongation, respectively.