Lesions at the cerebellopontine angle (CP angle) are associated with various brain-heart interactions, which can include those from stimulation of the fifth cranial nerve along the scalp incision in a retrosigmoid suboccipital surgical approach. A 27-year-old male patient with recently diagnosed hypertension (on calcium channel blocker) underwent left CP angle lesion decompression. Transient episodes of bradycardia, hypotension, and bradypnea were observed from the skin incision onward, exacerbated during tumor manipulation. Most episodes subsided with cessation of the surgical stimulus while some required intervention. Postoperatively, blood pressure decreased below the pre-operative levels. Thus, trigeminocardiac reflex can occur as early as the skin incision even in a retrosigmoid approach due to stimulation of the mandibular division, when specific risk factors exist. Such episodes may serve as early warning signs for subsequent intraoperative occurrences. Brainstem compression can be a possible etiology of hypertension in young patients. It underscores the importance of considering brain-heart interactions in surgical interventions involving the CP angle.