Sinus bradycardia is established as a heart rate less than 60 bpm. This can be normal in young, healthy adults or in patients taking blocking agents. It is considered pathological if it produces a decrease in cardiac output and presents symptoms. The conduction abnormality can occur at the level of the sinus node, atrioventricular node tissue, or the specialized His-Purkinje conduction system. 68-year-old female patient diagnosed with L2-L3 adjacent segment disease; L3-L4, who is scheduled to undergo a surgical procedure for transforaminal decompression and removal of instrumentation material under total intravenous general anesthesia in prone surgical position, with neurophysiological monitoring. During the decompression of the canal, sudden loss of motor and sensory evoked potentials is reported; followed by abrupt sinus bradycardia with a value of 23 beats per minute under a baseline of 50 bpm; With immediate recovery of evoked potentials and restoration of heart rate after a dose of 1mg intravenous atropine. It was decided to interrupt the surgical procedure and continue with the cardiovascular study protocol and surveillance in the intensive care unit. The objective of this case report is to describe the possible causes that led to the total loss of evoked potentials during surgery in correlation with drastically presented hemodynamic changes.
