Effects of exercise-based cardiac rehabilitation in patients with cardiac resynchronization therapy
cardiac rehabilitation, cardiac resynchronization therapy; exercise
Background. Cardiac resynchronization therapy (CRT) is indicated for patients with severe ventricular dysfunction, advanced stages of HF and refractory to conventional treatment. It is an artificial cardiac pacing modality that aims to correct electromechanical dysfunctions of the heart, which reduce morbidity and mortality in individuals with HF and has been widely used in recent years to improve symptoms, exercise capacity and function. ventricular Central adaptations derived from CRT are accepted as beneficial in the treatment of HF with severe ventricular dysfunction. However, it is known that the cause of exercise intolerance in heart failure (HF) is multifactorial, and central alterations, with low cardiac reserve, peripheral alteration with skeletal muscle dysfunction and low pulmonary reserve contribute to low exercise capacity. Objectives. To evaluate and compare the effects of a cardiac rehabilitation program on HF patients with CRT. Methods. The patients were referred to the cardiac rehabilitation by the cardiologist and included in the research those who had a diagnosis of HF confirmed by clinical examination and echocardiography, cardiac resynchronizer implantation for at least three months, with functional class I, II and III, according to New York Heart Association (NYHA) and with reduced and preserved EF and composed the HF + CRT group. The study included a retrospective analysis of patients with heart failure without cardiac resynchronizer or any type of pacemaker who underwent cardiac rehabilitation from October 2014 to February 2018 in the HF group. All patients underwent clinical, anthropometric and spirometric evaluation. In a second moment they performed the cardiopulmonary exercise test (CPET) using a conventional treadmill. In all tests, ventilatory measures (VE, VE/VO2, VE/VCO2-, RER) and metabolic (VO2) measurements were taken of breath-by-breath with Cortex-Biophysik-Metamax3B system, as well as effort perception variables (fatigue and dyspnea) – Borg 6-20 ), HR max and systolic and diastolic blood pressures. Cardiac rehabilitation sessions were performed three times a week for 12 weeks as a prescription for individualized exercise. A new CPET was performed after 12 weeks of training. SPSS software version 20.0 was used for statistical analysis and a value of 5% was assigned to test the hypotheses. Preliminary Results. Eighteen patients with HF with CRT were eligible for the study and 8 were excluded because they did not participate in all stages of the study, totaling 10 individuals analyzed. For the HF group 69 patients were eligible, however 47 were excluded, totaling 22 patients analyzed. The patients had a mean age of 52 ± 13 years, with male prevalence (68.7%), with mean EF of 34 ± 5% and 46.8% of ischemic etiology. The HF + CRT group presented statistically higher functional class of NYHA (2.2 ± 0.6) than the patients of the HF group (1.6 ± 0.5; p = 0.02). After cardiac rehabilitation the mean increase in test time was 136.9 seconds in the HF group and 142.8 seconds in the HF + CRT group. After cardiac rehabilitation, patients in the HF group had a mean increase of 4.9 mL / kg / min in peak VO2 and patients in the HF + CRT group an increase of 2.19 mL / kg / min and average predicted percentage of VO2 peak increase from 61 to 76% and from 57 to 67%, respectively. In addition, patients in the HF group showed an increase in peak VO2 in AT (15.7 ± 5 to 18 ± 5.5 mL / kg / min) and in AT time (252 ± 92 to 366 ± 102 seconds). Additionally, this group showed improvement in ventilatory efficiency, reflected by the values of VE/VCO2 and VE/VCO2 slope (35.4 ± 6 to 32 ± 5.7).