Objectives. To present the anatomical basis and mechanism underlying the trigemino-cardiac reflex (TCR), and to indicate some potential clinical implications of the TCR.
Review. The TCR is a brain-stem reflex that has gained much attention in clinical medicine in recent years. The reflex is evoked by stimulation of any of the sensory branches of the trigeminal nerve, directly increasing parasympathetic impulsation transmitted via the vagal nerve. The picture predominating in the course of TCR is primary inhibiting of the automatism of the sinoatrial node, and a decrease in the ino-, chrono- and dromotropism of myocardiac cells caused by increasedparasympathetic vagal tone. As a result, a sudden development of hemodynamic instability such as cardiac dysrhythmia up to asystole, arterial hypotension and apnea are manifested.
Conclusions. Due to the long course of the trigeminal nerve at the skull base, the TCR may occur during surgery freąuently performed in this region. Therefore, the knowledge of the mechanism and clinical features of this reflex is essential to effectively prevent and reduce the risk of potential complications associated with the trigemino-cardiac reflex.