We thank Dr. Bart for pointing out the inherent methodological limitations of our guideline. We acknowledge that the number and types of studies available regarding methadone cardiotoxicity are limited and do not lend themselves to critical appraisal criteria, meta-analytic techniques, or other quantitative quality assessments. Despite these inherent limitations, we adopted a validated clinical tool (5) to determine with certainty the link between methadone and torsade de pointes as a prerequisite to asserting the need for a risk mitigation strategy. Safeguarding patients from potentially fatal drug-induced arrhythmia creates a very different contextual framework than grading evidence for screening and treatment decision algorithms, such as the USPSTF guidelines that Dr. Bart alludes to. It is therefore no surprise that we found no evidence-based guideline recommendations from the USPSTF regarding mitigation of drug-induced torsade de pointes on review of the scientific literature (PubMed, accessed 10 May 2009). We are also unaware of any “effectiveness” evaluations of risk mitigation strategies that require ECG screening for drugs independently associated with torsade de pointes (6), including the methadone derivative levacetylmethadol (7). Finally, no scientific objections were raised to our recommendations during any of the cardiac expert panel meetings convened by the Center for Substance Abuse Treatment. Nonetheless, we respect the autonomy of clinicians to either change their views or decline acknowledgment. This in no way calls into question the integrity of the research process, the clinical science behind our guideline, or the editorial judgment in publishing it.