['This study was conducted to (1) compare the recovery times from rocuronium-induced muscle relaxation after reversal with sugammadex between young and elderly patients undergoing electroconvulsive therapy (ECT), and (2) to examine the existence of a correlation between cardiac index and reversibility of rocuronium-induced neuromuscular block with sugammadex after ECT.', 'Seventeen patients (young group, 50 years or younger, n = 8; elderly group, 70 years or older, n = 9) who were scheduled to undergo ECT were studied. Anesthesia was induced using propofol (1.0 mg/kg) followed by rocuronium (0.6 mg/kg). Assisted mask ventilation was initiated with 100% oxygen. Cardiac index was monitored noninvasively throughout the procedure. After the first twitch of the train of four (TOF) was assessed as being zero by neuromuscular monitoring, an electroshock stimulus was applied bilaterally. Immediately after the seizure stopped, patients were given 8-mg/kg sugammadex intravenously to reverse the muscle relaxation. Neuromuscular monitoring was continued until recovery of the TOF ratio to 0.9 at the tibial nerve in the leg. The time to recovery of the TOF to 0.1 and 0.9 was compared in both groups.', 'Although no significant difference in return to a TOF of 0.1 was found between the groups, there were significant differences in both recovery to a TOF of 0.9 and the time interval to the first spontaneous breath between groups (time to recovery to a TOF of 0.9, young group, 403 ± 37 seconds; elderly group, 443 ± 36 seconds; P < 0.05). In contrast, there was no relationship between cardiac index after ECT and recovery time to TOF of 0.9.'] Is recovery time after sugammadex reversal of rocuronium-induced muscle relaxation for electroconvulsive therapy independent of cardiac output in both young and elderly patients?