| Abstract [eng] |
Heart diseases are one of the most common causes of death worldwide. Every year, around 3.8 million people in Europe die from heart disease. Chronic cardiovascular diseases are a significant economic issue for patients and their family members, so it is important to detect the diseases as early as possible and start treatment in time. In search of parameters sensitive to changes in the cardiovascular system, the proposed parameter of heart rhythm fragmentation was recently calculated based on electrocardiogram (ECG) signal analysis. Although the ECG is considered a key clinical tool in the diagnostic process of heart disease, electrodes are required to record this signal, which restricts patient movement and causes discomfort. Contact gel is used to ensure good contact between the electrodes and the skin, which can cause skin allergies or dry out over time. An alternative method to record pulse rate is photoplethysmography (FPG). FPG is a convenient and relatively simple method. The patient only needs to wear a bracelet. The aim of this work is to implement and investigate the parameters of heart rate fragmentation recorded by photoplethysmography. 3 databases were used for the study, which were registered: in healthy young subjects, during vagus nerve stimulation experiment and in patients with cardiovascular autonomic neuropathy. The evaluation of fragmentation parameters showed that the fragmentation parameters calculated from the FPG signal were close to the parameters calculated from the ECG signal. Fragmentation parameters have been found to be sensitive to changes in the balance of the autonomic nervous system. Increasing parasympathetic nervous system activity decreases fragmentation parameters, but fragmentation parameters were less sensitive to changes in sympathetic nervous system activity. Fragmentation parameters did not show a significant statistical difference between the vagus nerve stimulation and placebo phases, but they reliably assigned patients with type 1 diabetes with undiagnosed cardiovascular autonomic neuropathy to patients already diagnosed with cardiovascular autonomic neuropathy. Because photoplethysmography signals are sensitive to movement noise, it is recommended that heart rate fragmentation parameters be assessed during static tests or during sleep. Comparison of the fragmentation parameters with the classical time-domain heart rate variability parameters showed significant differences, so it can be argued that the fragmentation parameters provide additional diagnostic information. |
