KOLOMYTSEVA, I. M.; VOLKOV, D. E.; LOPIN, D. A.; YABLUCHANSKY, M. I. FUNCTIONAL CLASS OF CHRONIC HEART FAILURE AND CLINICAL FEATURES OF PATIENTS WITH PERMANENT PACEMAKERS. The Journal of V. N. Karazin Kharkiv National University, series "Medicine", n. 27, p. 5-9, 5 Jul. 2015.