[The importance of the autonomic nervous system for sinus and atrioventricular node function in patients with sick...

Autonomous nervous system (ANS) influence on sinus (SN) and atrioventricular (A-V N) nodes is still under investigation, especially in pathological states. We analysed role of ANS for SN and A-VN function in patients with different forms of sick sinus syndrome (SSS). From 310 patients (pts) after electrophysiological examinations before and after pharmacological denervation of the heart we selected 206 pts with SSS (group S) for further investigation. In group S were 124 men and 82 women from 17 years old (mean 46 +/- 16). Coronary heart disease was present in 102 pts (myocardial infarction in 7), mitral valve prolapse in 10, hypertrophic cardiomyopathy in 2. SSS was the only pathological finding in 75 pts. In 92 cases pacemaker was implanted (45%) of whole group S. Only sinus bradycardia was observed in 118 cases, tachycardia-bradycardia syndrome in 34 and sinus arrest or/and sinoatrial block in 53 cases. Electrophysiological examinations were performed using transesophageal stimulation of the left atrium before and after denervation of the heart. Pharmacological denervation of the heart was obtained by propranolol (i.v. 0.2 mg/kg body weight) and than atropine (i.v. 0.04 mg/kg body weight). We analysed sinus cycle length in basic state, after propranolol injection and after full denervation, maximal sinus nodes recovery time, maximal corrected sinus node recovery time, secondary pause, sino-atrial conduction time, Wenckebach point before and after full denervation. The whole group with SSS (group S) was divided: pts with normal (S1) and abnormal (S2) intrinsic properties of SN (104 and 102 pts respectively).(ABSTRACT TRUNCATED AT 250 WORDS)