We described the first ultrasound-guided erector spinae plane block that provided complete surgical anesthesia for a right-sided mastectomy and axillary dissection in a patient with high cardiovascular risk. The block targeted at T5, and 20 mL of 0.5% ropivacaine with epinephrine 1:200,000 and dexamethasone 8 mg was administered. Complete anesthesia was accomplished in 20 minutes, and the patient received propofol infusion for sedation. The patient reported no pain and remained hemodynamically stable throughout the 2.5-hour procedure. At the end of the surgery, patient received morphine 2 mg and dipyrone 2 g intravenously, and demanded no analgesic until 24 hours after the procedure.