Oculo cardiac reflex : An unique neural link between the eyes and Heart
Heart by development originates from near the same spot , where the brain develop (Neuralcrest) .Hence there is no surprise though a richly a vascular organ, heart retains many neural connections with brain .Eyeballs with it’s extensive neural connections can be considered direct extension of brain.
Occulo cardiac reflex .
When the eyeballs or the ocular muscles are manipulated or massaged slowing of heart rate can occur .This is due to a reflex called Occulo cardiac reflex mediated by vagal stimulation .This phenomenon is also referred to as Aschner phenomenon
The circuit
Afferent _Trigeminal branch of opthalmic nerve
Center- Medulla : Trigeminal neural signal spill over signals to Vagal nucleus
Efferent- Vagus -SA node
Biochemical mediator -Acetyl choline
Prevention
Adequate local anesthesia
Retro bulbar block of ciliary ganglion
Prompt Atropine injection
Courtesy :Indian journal of Ophthalmology
Clinical scenarios
Opthalmic surgery : Serious bradycardia even asystole can occur as a rare complication especially in elderly and very young (Cataract /Squint surgery) .
Cardiac events and strokes are clustered around opthalmic surgery in many elderly for some unknown reason ( OCR triggered ?)
OCR can unmask hidden sinus node dysfunction in elderly.Routine cardiac evaluation before eye surgery may be recommended .
Orbital fracture especially Medial orbit can elicit dangerous bradycardia (BMJ Case Rep. 2014 Apr 15;2014.)
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Source: Dr.S.Venkatesan MD - Category: Cardiology Authors: dr s venkatesan Tags: Neuro cardiology circuits for occulo cardiac reflex diver's reflex eye ball massage trigemianl vagal reflex Source Type: blogs
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