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Study objective Methadone is associated with QT interval prolongation and torsades de pointes. Expert panel recommendations advocate a pre-methadone electrocardiogram (ECG) and another ECG at 30 days of therapy in patients with risk factors. Some guidelines recommend a pre-methadone ECG and routine ECG monitoring in all methadone patients, but this is controversial due to the resources required. Availability of a convenient, less resource-intensive method of ECG monitoring for patients taking methadone is desirable. The objective of this study was to assess the accuracy of a handheld smartphone ECG (iECG) for QT measurement in patients on maintenance methadone therapy in an urban opioid treatment program. Design Prospective study. Setting Urban opioid treatment program. Patients n = 115 patients in normal sinus rhythm who were on steady-state maintenance methadone therapy INTERVENTION: Patients (n = 115) underwent a simultaneous 12-lead ECG and a single-lead iECG. Measurements and main results The first three QT and RR intervals from lead II of the 12-lead ECG and simulated lead I from the iECG were compared using the Bland-Altman analysis of measurement agreement. Mean [± standard deviation) age was 34 ± 11 years; 71% were female, 75% were white. Compared to the 12-lead ECG, the iECG was associated with a QTc bias of - 0.14 ms (SD = 12 ms, 95% CI = -2.4 to 2.1 ms). The absolute mean difference in QTc between the two methods was 9.5 ± 7.1 ms. For identification of patients with methadone-associated QTc prolongation, the iECG performed moderately well [c-statistic 0.97 (95% CI 0.91-0.99); sensitivity and specificity 75% (95% CI 43-95%) and 99% (95% CI 94-99%), respectively]. The positive and negative likelihood ratios of the iECG for identifying patients with methadone-associated QTc prolongation were 77.25 (95% CI 10.69 to 558.18) and 0.25 (95% CI 0.09 to 0.67), respectively, while the positive and negative predictive values were 90% (95% CI 56-99%) and 97% (95% CI 92-99%), respectively. The accuracy of the iECG for identifying patients with QTc prolongation was 97% (95% CI 91-99%). Conclusion A handheld smartphone ECG is accurate for QT interval measurement in patients taking maintenance methadone therapy, and its performance is moderately good for identifying patients with methadone-associated QTc prolongation.

We have previously reported that transdermal testosterone attenuates drug-induced QT interval lengthening in older men. However, it is unknown whether this is due to modulation of early ventricular repolarization, late repolarization, or both. In a secondary analysis of a prospective, randomized, double-blind, placebo-controlled three-way crossover study, we determined if transdermal testosterone and oral progesterone attenuate drug-induced lengthening of early and late ventricular repolarization, represented by the electrocardiographic measurements J- T(peak)c and. T(peak)-T(end’) respectively, as well as T(peak)-T(end)/QT, a measure of transmural dispersion of repolarization. Male volunteers ≥ 65 years of age [Formula: see text] were randomized to receive transdermal testosterone 100mg, oral progesterone 400mg, or matching transdermal/oral placebo daily for 7 days. On the morning following the seventh day, subjects received intravenous ibutilide 0.003mg/kg, after which electrocardiograms were performed serially. One subject was excluded due to difficulty in T-wave interpretation. Pre-ibutilide J-T(peak)c was lower during the testosterone phase than during progesterone and placebo (216 ± 23 vs. 227 ± 28 vs. 227 ± 21 ms, [Formula: see text]). Maximum post-ibutilide J-T(peak)c was also lower during the testosterone phase (233 ± 22 vs. 246 ± 29 vs. 248 ± 23 ms, [Formula: see text]). Pre-ibutilide T(peak)-T(end) was not significantly different during the three phases, but maximum post-ibutilide T(peak)- T(end) was lower during the testosterone phase (80 ± 12 vs. 89 ± 18 vs. 86 ± 15 ms, [Formula: see text]). Maximum T(peak) T(end)/QT was also lower during the testosterone phase (0.199 ± 0.023 vs. 0.216 ± 0.035 vs. 0.209 ± 0.031, [Formula: see text]). Progesterone exerted minimal effect on drug-induced lengthening of J-T(peak)c, and no effect on T(peak)-T(end) or T(peak)- T(end)/QT. Transdermal testosterone attenuates drug-induced lengthening of both early and late ventricular repolarization in older men.

Introduction: Methadone, a racemic mixture of S - and R -enantiomers, prolongs the QT interval and causes torsades de pointes. Methadone has been shown to lengthen late ventricular repolarization, represented by the T peak-Tend interval, which is modulated primarily by I Kr and I Ks . However, it is unknown whether methadone prolongs early ventricular repolarization, represented by the heart rate-corrected J-T peak (J-T peak c) interval, which is regulated primarily by L-type calcium and late sodium currents. In addition, the relationship between stereospecific serum methadone and metabolite concentrations and effects on J-T peak c and T peak -T end intervals are unknown. Hypothesis: 1) Methadone lengthens both J-T peak c and T peak -T end , and 2) Methadone effects on J-T peak c and T peak -T end correlate with serum S - and R -methadone and S - and R -metabolite [ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP)] concentrations. Methods: Patients (n=81) on steady state maintenance methadone therapy at an urban narcotic treatment center who had undergone a pre-methadone 12-lead ECG within the previous 6 months were identified and asked to return for a followup ECG during steady-state methadone therapy. In a subset (n=41), blood was obtained to determine serum S - and R -methadone and S - and R -EDDP concentrations. Results: Compared to baseline, methadone lengthened mean ± SD J-T peak c (225 ± 26 vs 232 ± 28 ms, p=0.02) as well as T peak - T end (80 ±14 vs 90 ± 16 ms, pS -methadone correlated with J-T peak c [R 2 = 0.41 (95% CI 0.11-0.65), p=0.007]. Serum R -methadone concentrations also correlated with J-T peak c [R 2 = 0.47 (0.17-0.68), p=0.002]. In addition, serum concentrations of S - and R -EDDP correlated with J-T peak c [R 2 = 0.39 (0.09-0.63), p=0.01] and [R 2 = 0.38 (0.07-0.62), p=0.02], respectively. There were no significant correlations between serum S - and R -methadone or S- and R-EDDP concentrations with T peak - T end intervals. Conclusions: Methadone lengthens both early and late ventricular repolarization, suggesting that methadone’s ion channel effects may extend beyond inhibition of I Kr . Serum S - and R -methadone and S -and R -EDDP concentrations are associated with effects on J-T peak c intervals.

STUDY OBJECTIVE Methadone is associated with QT interval prolongation and torsades de pointes. The objective of this study was to (a) determine the incidence of QT interval prolongation among patients on maintenance methadone therapy in an urban opioid treatment program (OTP), (b) compare characteristics of patients who developed methadone-associated QT prolongation with those who did not develop QT prolongation, and (c) investigate the relationship between QT interval prolongation and stereospecific serum methadone and metabolite [2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP)] concentrations. DESIGN Prospective study. SETTING Urban opioid treatment program (OTP). PATIENTS n = 93 patients on maintenance methadone therapy in an urban OTP. INTERVENTION Patients underwent a 12-lead electrocardiogram (ECG) prior to initiating methadone and again during steady-state maintenance methadone therapy. In a subset (n = 43), blood was obtained to determine serum (S)- and (R)-methadone and (S)- and (R)-EDDP concentrations, which were compared in patients who developed Bazett's-corrected QT (QTc) prolongation [≥470 ms (men) or ≥480 ms (women) and/or ≥60 ms lengthening from pretreatment value] with those who did not have QTc prolongation. MEASUREMENTS AND MAIN RESULTS Mean [± standard deviation (SD)] age was 36 ± 12 years; 73% were female, and 74% were white. QTc prolongation occurred in 14 (15.1%) patients. Patients who developed QTc prolongation were older (41 ± 13 vs. 35 ± 9 years, p = 0.03) and had a longer pre-methadone QTc compared with those who did not have QTc prolongation (429 ± 11 vs. 420 ± 20 ms, respectively, p = 0.02). Serum (S)-methadone concentrations were higher in patients with QTc prolongation compared to patients without prolongation (199 ± 81 vs. 128 ± 68 ng/ml, respectively, p = 0.01), whereas the difference in serum (R)-methadone concentrations between the groups did not reach significance (189 ± 68 vs. 125 ± 60 ng/ml, respectively, p = 0.08). Serum (R)-methadone concentrations correlated with QTc intervals [R2 = 0.15 (95% confidence interval (CI) 0.11-0.62, p = 0.0009)]. The correlation between serum (S)-methadone concentrations and QTc did not reach significance [R2 = 0.08 (95% CI -0.01 to 0.54, p = 0.06)]. Serum (S)-and (R)-EDDP concentrations were not significantly different between the groups and did not significantly correlate with QTc intervals. CONCLUSIONS Approximately 15% of patients taking maintenance methadone therapy developed QT interval prolongation. Both serum (S)- and (R)-methadone concentrations, but not (S)- or (R)-EDDP, contribute to methadone-associated QT prolongation.

Background Patients with heart failure (HF) with reduced ejection fraction demonstrate enhanced response to drug-induced QT interval lengthening and are at increased risk for torsades de pointes. The influence of HF with preserved ejection fraction (HFpEF) on response to drug-induced QT lengthening is unknown. Methods and Results We administered intravenous ibutilide 0.003 mg/kg to 10 patients with HFpEF and 10 age- and sex-matched control subjects without HF. Serial 12-lead electrocardiograms were obtained for determination of QT intervals. Demographics, maximum serum ibutilide concentrations, area under the serum ibutilide concentration vs time curves, and baseline Fridericia-corrected QT (QTF) (417 ± 14 vs 413 ± 15 ms, P = .54) were similar in the HFpEF and control groups. Area under the effect (QTFvs time) curve (AUEC) from 0 to 1.17 hours during and following the ibutilide infusion was greater in the HFpEF group (519 ± 19 vs 497 ± 18 ms·h, P= .04), as was AUEC from 0 to 8.17 hours (3576 ± 125 vs 3428 ± 161 ms·h, P = .03) indicating greater QTF interval exposure. Maximum QTF (454 ± 15 vs 443 ± 22 ms, P = .18) and maximum percent increase in QTF from baseline (8.2 ± 2.1 vs 6.7 ± 1.9%, P = .10) in the 2 groups were not significantly different. Conclusions HFpEF is associated with enhanced response to drug-induced QT interval lengthening.

Prolongation of the heart rate-corrected QT (QTc) interval increases the risk for torsade de pointes (TdP), a potentially fatal arrhythmia. The likelihood of TdP is higher in patients with risk factors that include female sex, older age, heart failure with reduced ejection fraction, hypokalemia, hypomagnesemia, concomitant administration of two or more QTc interval-prolonging medications, among others. Assessment and quantification of risk factors may facilitate prediction of patients at highest risk for developing QTc interval prolongation and TdP. Investigators have utilized the field of predictive analytics, which generates predictions using techniques including data mining, modeling, machine learning, and others, to develop methods of risk quantification and prediction of QTc interval prolongation. Predictive analytics have also been incorporated into clinical decision support (CDS) tools to alert clinicians regarding patients at increased risk of developing QTc interval prolongation. The objectives of this article are to assess the effectiveness of predictive analytics for identification of patients at risk of drug-induced QTc interval prolongation and to discuss the efficacy of incorporation of predictive analytics into CDS tools in clinical practice. A systematic review of English-language articles (human subjects only) was performed, yielding 57 articles, with an additional 4 articles identified from other sources; a total of 10 articles were included in this review. Risk scores for QTc interval prolongation have been developed in various patient populations including those in cardiac intensive care units (ICUs) and in broader populations of hospitalized or health system patients. One group developed a risk score that includes information regarding genetic polymorphisms; this score significantly predicted TdP. Development of QTc interval prolongation risk prediction models and incorporation of these models into CDS tools reduce the risk of QTc interval prolongation in cardiac ICUs and identify health system patients at increased risk for mortality. The impact of these QTc interval prolongation predictive analytics on overall patient safety outcomes, such as TdP and sudden cardiac death relative to the cost of development and implementation, requires further study.

Background: Because of the increasing demand for drugs addressing life-threatening and rare diseases, regulatory agencies have developed a variety of accelerated regulatory pathways. These programs are aimed at prioritizing the most promising drug candidates for diseases lacking satisfactory treatments. The most prominent accelerated programs introduced have been Breakthrough-Therapy Designation (BTD) in the United States, Priority Medicine (PRIME) in the European Union and Sakigake in Japan. This article reviews these designations and looks at differences in how they are granted across the 3 jurisdictions focusing on neuroscience and oncology. Methods: Our objective was to analyze BTD, PRIME, and Sakigake approvals between 2012 and 2019 with a focus on numerical disparities of designations granted between the 2 therapeutic areas. A search of public sources pertaining to topics of BTD, PRIME, and Sakigake was undertaken. Results: This analysis revealed that 48% of BTD were granted in oncology, while neuroscience received 8% of these designations, for PRIME designations were 27% received by oncology and 15% by neuroscience and in Japan, 50% of Sakigake were granted to oncology and 22% to neuroscience products. Conclusion: Given the global nature of drug development and relative similarity of these regulatory mechanisms, there is an apparent disparity between the US granting special status at 6:1 (oncology: neuroscience) and both the EU and Japan granting at 2:1. This disproportionate ratio is likely impacted by multifactorial issues; however, this difference is worth further investigation.