SHANINA, I. V.; VOLKOV, D. E.; LOPIN, D. A.; YABLUCHANSKY, N. I. QRS COMPLEX DURATION AND CLINICAL FEATURES OF PATIENTS WITH PERMANENT PACEMAKERS. The Journal of V. N. Karazin Kharkiv National University, series "Medicine", n. 25, p. 42-46, 5 Jul. 2015.