Effect of Cardiac Resynchronization Therapy on Reverse Left Ventricular Remodeling in Patients with Functional Class II Heart Failure

Introduction. Implantation of a cardioverter-defibrillator reduces the risk of sudden cardiac death caused by the development of ventricular tachycardia (VT) and ventricular fibrillation (VF) of the heart, but implantation of this device does not improve the function of the left ventricle (LV). Modern implantable cardioverter-defibrillators (ICD) with endocardial electrodes allow for optimal treatment of cardiac arrhythmias in heart failure (HF) due to the function of electrical cardiac pacing. Cardiac resynchronization therapy (CRT) is aimed at synchronizing contractions of the opposite walls of the LV, which leads to an improvement in the inotropic function of the heart, and subsequently to reverse remodeling of the LV geometry. The obtained results of the study made it possible to determine whether there was an improvement in volume changes, cardiac function and shock rate when using CRT in combination with an ICD (CRT-D) in patients with HF accompanied by LV dysfunction and a wide QRS complex. Aim of Study. To assess whether CRT in combination with ICD has an effect on LV reverse remodeling in patients with functional class (FC) II HF. Material and Methods. A total of 35 patients with a wide QRS complex >130 ms were included in the study: 15 patients in the CRT-D group and 20 with ICD. The obtained results of the study were interpreted one year after the start of treatment in all patients. Changes in the volumes and contractility of the ventricles of the heart were analyzed in both groups. An assessment was made of the dependence of these changes on the results of treatment in subsequent years. Results. In patients in the CRT-D group, compared with the ICD group, there was an improvement in the LV end-diastolic volume index (-18.7 vs. 8.6 ml/m 2 ), LV end-systolic volume index (-22.5 vs. 5.2 ml/m 2 ), LV ejection fraction (13.2 vs. 0.4%), left atrial volume index (-16.8 vs. 2.7 ml/m 2 ), and pulmonary artery systolic pressure (-11.4 vs. 1.4 mmHg), p<0.05 for all parameters. The improvement in LV functional parameters 1 year after treatment was reflected in a decrease in mortality and recurrence of HF in these patients in the long-term period (13% in the CRT-D group vs. 50% in the ICD group, p><0.05). During the first year of observation, one to two shocks for VT/VF were administered in two patients with CRT-D and three patients with an implanted ICD. During the subsequent threeyear observation period, the defibrillation function was activated in two more patients in the CRT-D group and in two patients with an implanted ICD. CONCLUSION Cardiac resynchronization therapy combined with an implantable cardioverter -defibrillator improves cardiac performance in patients with class II heart failure. Our study demonstrated a decrease in end-diastolic volume, end-systolic volume, left atrial volume, an increase in left ventricular ejection fraction, and an improvement in right ventricular function in patients treated with combined cardiac resynchronization therapy and an implantable cardioverter -defibrillator compared with those treated with an implantable cardioverter -defibrillator alone. These results were consistent with improved outcomes, and outcomes at 1 year were directly related to the degree of improvement in ventricular volumes and function. Keywords: cardiac resynchronization therapy, left ventricular remodeling, heart failure> < 0.05 for all parameters. The improvement in LV functional parameters 1 year after treatment was reflected in a decrease in mortality and recurrence of HF in these patients in the long-term period (13% in the CRT-D group vs. 50% in the ICD group, p < 0.05). During the first year of observation, one to two shocks for VT/VF were administered in two patients with CRT-D and three patients with an implanted ICD. During the subsequent three-year observation period, the defibrillation function was activated in two more patients in the CRT-D group and in two patients with an implanted ICD. Conclusion. Cardiac resynchronization therapy combined with an implantable cardioverter -defibrillator improves cardiac performance in patients with class II heart failure. Our study demonstrated a decrease in end-diastolic volume, end-systolic volume, left atrial volume, an increase in left ventricular ejection fraction, and an improvement in right ventricular function in patients treated with combined cardiac resynchronization therapy and an implantable cardioverter -defibrillator compared with those treated with an implantable cardioverter-defibrillator alone. These results were consistent with improved outcomes, and outcomes at 1 year were directly related to the degree of improvement in ventricular volumes and function.