Autonomic Nervous System Activity and Oculocardiac Reflex.

Pulling the eyeball during ophthalmic surgery provokes decrease in heart rate. This phenomenon is called oculocardiac reflex. In some patients asystole may occur. Other cardiac features of this reflex include hypotension, dysrhythmias, atrioventricular block. These cardiovascular disturbances may lead to decreased perfusion and ischemia of vital organs. Patients with existing cardiovascular disease are in risk of complications. Cardiovascular system is mainly innervated with autonomic nervous system (ANS). Sympathetic/parasympathetic activity may be determined by Heart Rate Variability (HRV). HRV analysis based on short 5 minutes electrocardiography has been found useful for prediction of hypotension and bradycardia during induction of general anaesthesia and during spinal block. The aim of this study is to verify whether it is possible to predict oculocardiac reflex with the use of HRV analysis for ANS activity assessment, measured prior to the ophthalmic surgery.