The Role of Cardiac Repolarization Index for Sudden Cardiac Death Risk in Patients with Obstructive Sleep Apnea Syndrome without any Systemic Disesae

Introduction: Obstructive sleep apnea syndrome (OSAS) is associated with sudden cardiac death (SCD). In this study we aimed to evaluate the ventricular recovery time in OSAS patients without chronic systemic diseases, such as hypertension, diabetes, thyroid dysfunction, electrolyte imbalance, cardiac disease and the relationship of OSAS with SCD. Materials and Methods: In the study, between January 2008-January 2010, we analyzed 170 patientswith a mean age of 44.45±10.1 (21-75) years, who were clinically suspected of having OSAS. Following overnight polysomnography (PSG), 12 lead surface electrocardiogram (ECG), recordings were perforned and QT minimum, QT maximum and QT dispersion were computed from ECG. Results: The patients were divided into to the following 4 groups; AHI (apnea-hypopnea index) ≤5, 5< AHI ≤15, 15< AHI <30, and AHI ≥30. The mean QTD was 3.8±2 (0.40-9.7) msn in all patients and 3.5±1.8 (0.6-8.9) msn in normal group (AHI ≤5), and 4.5±1.9 (0.4-9.7) msn in severe group (AHI ≥30). It is shown that QTD increases significanty when AHI rises. Discussion: We showed that the patients with OSAS without chronic systemic disorder have higher SCD risks due to increased QT dispersion