CHANGES IN HEART RATE., HEART RATE VARIABILITY AND QT INTERVAL IN WOMEN WITH RHEUMATOID ARTHRITIS DURING RITUXIMAB TREATMENT
Rheumatoid arthritis (RA) is a proven high cardiovascular risk disease. High heart rate (HR), lower heart rate variability (HRV), and increased QT interval are considered as predictors of cardiovascular events in patients with coronary heart disease, chronic heart failure, and diabetes mellitus. In RA., there is a pronounced rise in HR, a reduction in HRV, and an increase in QT interval mainly due to the factors reflecting the severity of the disease. Rituximab (RTM) is successfully used to treat patients with high RA activity. At the same time there are only a few pieces of evidence for the effect of the drug on the cardiovascular system. Objective: to study changes in HR, HRV, and QT interval values obtained during electrocardiography (ECG) Holter monitoring (ECG HM) in RTM-treated women during a 6-month follow-up. Subjects and methods: The investigation enrolled 55 women (mean age 50 years) with a definite diagnosis of RA and its high activity. The patients were examined 6 months after administration of RTM. The latter was infused intravenously twice (500 and 1000 mg in 22% and 78% of the patients, respectively) during therapy with disease-modifying antirheumatic and non-steroidal anti-inflammatory drugs and glucocorticoids. The RA patients were divided into two groups: 1) a satisfactory/good effect of RTM according to the EULAR criteria (n = 41); 2) no effect (n = 14). Analysis of 24-hour ECG HM yielded the values of HR and mean duration of corrected QT interval (QTc). The timing HRV values obtained at ECG HM were standardized from age and mean HR (SDNNn, RMSSDn, and pNN50n). Results. The baseline HRmin and HRmean values were higher and SDNNn was lower in the RA patients in Group 1 than those in Group 2 (p < 0.05). In Group 1, RTM therapy was accompanied by a reduction in HRmean and HRmin by 8% and by an increase in SDNNn by 3%, RMSSDn by 26%, and pNN50n by 33% whereas no significant changes in HR and HRV were found in Group 2. The RTM therapy-induced HRmean decrease was associated with the reductions of C-reactive protein concentration and HAQ disability index (p < 0.01), the increases of rMSSDn and pNN50n associated with lower HAQ index, ERS, and DAS28 (p < 0.01). There were no differences in QTc in Groups 1 and 2 during 6 months after RTM therapy. Thus, effective RTM therapy is attended by reduced HR and improved HRV values.