Unexpected bradycardia and cardiac arrest under spinal anesthesia: case reports and review of literature.

Spinal anesthesia has been regarded as safe and simple technique since its introduction into anesthesia practice. Bradycardia and hypotension under spinal anesthesia is a known phenomenon. However sudden unexpected bradycardia and cardiac arrest under spinal anesthesia is considered as rare and uncommon manifestation. On the contrary, as per current reviews, severe bradycardia and cardiac arrest under spinal anesthesia occurs more frequently in healthy, young and vagotonic patients. It is often associated with higher mortality. However, appropriate risk stratification, careful monitoring and structured management plan will have favorable outcome in these patients. We report successful management of two cases of unexpected cardiac arrest under spinal anesthesia and briefly reviewed the literature.