Thank you for your question! Regarding your concern I would like to explain to you that first if QTc prolongation is confirmed by a specialist that you have to be graded for your future risk of QT prolongation-induced arrhythmia: is it more that 500 ms? Or are you diagnosed with any congenital long QT syndromes? Have you a family history of sudden cardiac death, or have you experience any life-threatening arrhythmia in the past? So to cut it clear it should be ascertained whether QT prolongation is totally acquired or it is congenital; in the first case we can impede any future risks by avoiding factors (including drugs) that influence QT prolongation. It is true that methadone by blocking potassium channels predispose to QT prolongation, for this treatment you should discuss with your prescribing doctor to find any other option of pain therapy. If congenital QT prolongation is suspected, then even genetic analysis couldhelp together with clinical background. If you are confirmed in high risk for future arrhythmia ( that is QTc 500 ms, or you have a personal or family history of arrhythmia or sudden death, or a congenital long QT syndrome is evident, genetic screening etc) first you should avoid the list of drugs that aggravate the situation; then there are some options of treatment like: beta-blocker drugs; implantation of pacemakers-ICD, or even stellectomy (surgically). So discusswith your cardiologist to quatify your future risk and to decide the ongoing strategy. Feel free to ask again for specifications. Hope to have been helpful to you. Greetings from Dr. Iliri