Influence of a Complete Vegetative Block on a Cardiac Rhythm Rate at the Graves Disease
Aim of investigation is a study of the sympathetic and parasympathetic system isolated influence on a cardiac rhythm rate in patients with a thyrotoxicosis.
Materials and Methods. A complete vegetative block according to the A. Jose and D. Collison (1970) method to 10 patients at the background of a thyrotoxicosis and 5 volunteers was made.
Results. The initial cardiac contraction rate (CCR) in patients was 91 beats/min, in a control group — 65 beats/min (p<0.001). The CCR alteration was at the 11th [4; 18] beat/min at the background of a propranolol infusion, in a control group — at the 8th [6; 17] beat/min; the statistically significant differences in the CCR were conserved — 79 and 59 beats/min (p=0.008). The CCR growth at a subsequent atropine infusion in patients was 22 [12; 29] beats/min, in a control group — 42 [22; 43] beats/min, and the differences in the CCR in the investigated groups were leveled — 99 and 92 beats/min (p=0.679). A real cardiac rhythm in two patients was exceeding the admissible rated meanings. It can be concluded on a basis of received data that a decrease of a parasympathetic nervous system tonus plays a defining role in a tachycardia development at the background of a thyrotoxicosis. A sympathetic system influence is insignificant. A direct influence of the thyroid hormones on the sinus node functional activity cannot be excluded.
