PECULIARITIES OF MYOCARDIAL BIOELECTRIC ACTIVITY IN PATIENTS WITH PROGRESSIVE MYLTIPLE MYELOMA RECEIVING BORTEZOMIB-CONTAINING CHEMOTHERAPY SCHEMES

Abstract

Introduction. New approaches to the oncohematology management that also include multiple myeloma treatment, makes higher level of hematological remission and improve survival rates. But novel cytostatic drugs have higher incidence of cardiotoxicity. According to the modern multiple myeloma management guidelines, patients, who have no indications for bone morrow transplantation, should be treated by VRd chemotherapy scheme as a first line therapy. The VRd scheme includes: bortezomib, lenalidomid and dexamethasone.
 Both early cytostatic-induced cardiovascular toxicity risk factor indication and cardiovascular toxicity detection have high prognostic value due to influence on individual management strategy that include chemotherapy and supportive care. This, in turn, decreases level of late and remote cytostatic-induced myocardial injury.
 The aim of this study is to investigate changes of myocardial bioelectric activity in patients with progression of multiple myeloma during bortezomib-containing chemotherapy scheme.
 Materials and methods. 20 patients who had multiple myeloma and no concomitant cardiovascular disease were examined. All patients obtain bortezomib-containing chemotherapy scheme. The patients underwent the examination three times: before the chemotherapy, in 84th day and in 140th day. General and biochemical blood count findings were analyzed. Some points of Holter electrocardiography monitoring and standard 12-leads ECG were evaluated, including heart rate, PQ interval, and corrected QT interval.
 Results: multiple myeloma progression was associated with the development of anaemia in 19 (95%) of the patients and was characterized by the 1.3-fold decrease in the haemoglobin and red blood cells level compared to healthy individuals (p<0,05). Rate of conductivity disorder was in 1.4 times higher than rate of rhythm disorder in the patients with multiple myeloma. The following findings were obtained by Holter monitoring and standard 12-leads electrocardiography: rhythm disorder was found in 5 (25%) patients, while conductivity disorder was detected in 7 (35%) patients. Sinus bradycardia and premature ventricular contractions were found in 2 (10%) patients following the 4 course of chemotherapy that is 2,5 times lower than in case of multiple myeloma progression. The incidence of conductivity disorder during the specific treatment were higher in 1.1 (RR=1.1; 95% СІ 0.51-2.55) (p>0,05) times and includes first degree atrioventricular block detected in 5 (25%) patients, left anterior fascicular block found in 3 (15%) patients and incomplete right bundle branch block found in 1 (5%) patient.
 Conclusion. The use of bortezomib-containing chemotherapy scheme in multiple myeloma patients with low cardiovascular risk lead to the decrease on the incidence of heart rate disorders simultaneously with increasing incidence of heart conductivity disorder.