Key Words: Heart Rate Variability; Statistical Analysis; Atrial Fibrillation; Premature Ventricular Contraction; Normal Sinus Rhythm; Orthogonal Transforms.
Abstract. Cardiovascular diseases are among the first causes of death. The main cardiovascular diseases are myocardial ischemia, various types of arrhythmias, reduced ability to contract the left ventricle. Cardiac testing is performed non-invasively by electrocardiograph or Holter monitoring. The paper examines, through the application of orthogonal transforms, the continuous holter recordings of individuals with Atrial Fibrillation, Premature Ventricular Contraction and Normal Sinus Rhythm. The mathematical analysis is performed in the time domain. The results show characteristic differences between patients with both types of arrhythmias and in healthy individuals. The presented results can be of benefit to cardiology practice in Bulgaria and worldwide.