Monitoring of chronic heart failure using transthoracic impedance and heart rate variability sensor in patients with cardioverter defibrillator

Objective. To evaluate the role of transthoracic impedance (TTI) and heart rate variability (HRV) in control of HF deterioration in patients with implanted ICD. Material and methods. The study included 48 patients with HF class II-III, LVEF<35% and indications for primary prevention of SCD. They received optimal therapy of HF for more than three months. The patients were implanted with CHARISMA TM EL ICD Boston Scientific, and then they were followed-up for 6 months. We evaluated the indicators of TTI and HRV sensors during ICD intervention, the number of shocks, clinical and laboratory dynamics of HF and quality of life, as well as the need for diuretic therapy. Results. Mean age of patients was 56.4±13.6 years, male patients predominated. Coronary artery disease, dilated cardiomyopathy and hypertension were the main causes of HF. We identified patients (n=17) with clinical deterioration of HF defined as the presence of at least one of the following signs: increased HF class, decreased 6MWT distance and higher need for diuretic therapy. At ICD interrogation, this group demonstrated lower TTI and HRV values, higher NT-proBNP and decreased 6MWT distance. Conclusion. TTI and HRV in patients with CVD can serve as an accurate indicator for predicting and detecting deterioration of CHF.