INTRODUCTION
Chronic Obstructive Pulmonary Disease (COPD), which is characterized by persistent airflow restriction and respiratory symptoms, is one of the most common causes of death globally 1. Previous studies have demonstrated that COPD patients are at increased risk of cardiovascular morbidity and mortality 2–4. Cardiac arrhythmias and sudden cardiac death (SCD) are very common in these patients 3,5. The underlying mechanism of the relationships among COPD, cardiac arrhythmias, and SCD has not been clearly elucidated yet. Nevertheless, hypoxemia, autonomic dysfunction and acid-base disturbances can causes the improving of cardiac arrhythmias and SCD by altering myocardial repolarization in these patients 6.
Alteration in myocardial repolarization has a crucial role in improving cardiac arrhythmias and SCD 7,8. Frontal QRS-T angle, which is a novel marker of the heterogeneity in myocardial depolarization and repolarization, is described as the absolute difference between myocardial depolarization (QRS- axis) and repolarization (T axis) 9. It can easily be measured by using the 12-lead surface electrocardiography (ECG), and its abnormality reflects the electrical instability of the myocardium10. The frontal QRS-T angle has been shown to be valuable in predicting many cardiac and non-cardiac diseases11.
To our knowledge, there is no research that investigated the relationship between the frontal QRS-T angle and the severity of COPD. Our objective in this study is to evaluate the relationship between the frontal QRS-T angle and the severity of recently diagnosed COPD.