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Background and Objective: Methadone is a synthetic opioid which is used in opium addiction therapy and relief of acute and chronic pain. Side effects of Methadone were reported on heart and induction of Torsade De Pointes disease and increase QTc interval in electrocardiogram. This study was conducted to determine the effect of Methadone therapy on QTc interval in electrocardiogram and its relationship with dosage and duration of Methadone therapy. Method: This cohort study was conducted on 60 opium addicted patients (57 males, 3 females) whom referred to “Methadone Therapy Clinic” in 5 Azar teaching hospital in Gorgan, northern Iran during 2009-10. Patients were divided to three groups based on the dosage of methadone: 0-35 mg (27 cases), 35-55 mg (27 cases) and 55-120 mg (26 cases) per day. QTc interval in electrocardiogram was measured at the beginning of study, one month and 5 months afterward. Results: The mean±SD of QTc interval in patients at the beginning, one month and 5 months afterward of study was 0.42±0.027, 0.43±0.029 and 0.43±0.041 seconds, respectively. There was a significant increase in QTc interval after one month of methadone therapy, compared to the beginning of study. There was no significant difference in QTc interval between 1 month and 5 months following methadone therapy. There was no significant difference between QTc interval and different dosage of methadone. Conclusion: Methadone therapy increase QTc interval but there is not any relationship between dosage and duration of methadone therapy and QTc interval.

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Background and Objective: ECG is one of the most common diagnostic procedures. Errors related to incorrect placement of electrodes and/or inaccurate connection of them in their standard anatomical location will cause some changes in the ECG waves. These errors may cause therapeutic or diagnostic mismanagements. This study was done to determine the common errors in connection or placement of leads in standard electrocardiograms.
Methods: This descriptive-analytical study was performed on 315 patients admitted to an educational and therapeutic hospital in Gorgan, Iran during 2014. The recorded variables included the distance between the positions of the V1, V2, V5 and V6 leads from the standard location, the displacement of the left and right electrodes in bipolar limb lead I and the incorrect right and left connectivity of V1 and V2, the admission section, the urgency of ECGs and the patient's gender. The gender of ECG operator, the standard ECG voltage, staff shift, the average number of ECGs taken by the personnel, and the precise bonding of wires were observed. In the precordial leads, the distance of more than 2 centimetres from the standard leads location was considered as error threshold.
Results: The misplacement errors were observed in 149 cases (47.3%). In 20 cases (13.42%) of ECGs, the standard voltage was not observed. The highest number of misplacement errors was observed in the V5 (30.2%). Misplacement errors showed a significant differences (P<0.05) for the patient gender (61.77%), the type of department (emergency department 61.67%), the non-urgent application (68.12%), and the average number of ECGs taken by personnel of 5 or less in each shift (11.67%).
Conclusion: Patient's gender and emergency department are the most important factors in misplacement of precordial leads.