Study of LQT-1213 on QTc-induced Prolongation in Healthy Adult Subjects (Part1) and on Congenital Long QT in Patients Diagnosed With Type 2 or 3 Long QT Syndrome (Part 2).

Exclusion criteria

• ✕. On Day 1 at 3 hours postdose in Period 1 only, of the first cycle of dofetilide, the QTcF on the triplicate ECGs will be manually confirmed by cardiologist experienced in ECG interval measurements. The ECG measurements at baseline and at the 3-hour time points will be performed by the same technician and cardiologist. If the mean QTcF increase from baseline is \<25 ms on triplicate safety ECGs compared to the mean from baseline (all ECG QTcF measurements averaged), the subject will be disqualified from further study participation.
• ✕. Clinically significant gastrointestinal, renal, hepatic, neurologic, hematologic, endocrine, oncologic, pulmonary, immunologic, psychiatric, or cardiovascular disease or any other condition, which, in the opinion of the investigator, would jeopardize the safety of the subject or impact the validity of the study results. No history of myocardial infarction or angina or ischemic heart disease, nonsustained or sustained ventricular tachycardia, atrial fibrillation, stroke, transient ischemic attack, syncope, congestive heart failure, family history of LQTS, Torsades de Pointes, or sudden cardiac death.
• ✕. Female subjects must not be pregnant, lactating, or breastfeeding, and must not be planning to become pregnant.
• ✕. Female subjects of childbearing potential must have a negative result for the serum pregnancy test at Screening and Check-in.
• ✕. Clinically significant abnormal findings on the physical examination or medical history during Screening as deemed by the investigator.
• ✕. Participated in a previous clinical study in the previous 3 months before dosing.
• ✕. Donation of blood volume greater than 300 mL within 30 days before Screening and agree to avoid donation from Screening and throughout the study.
• ✕. At Screening and on Day -2, if the 12-lead ECG demonstrates any of the following: PR \>240 ms; QRS \>110 ms, or QTcF \<400 ms and \>440 ms; second- or third-degree atrioventricular block; bundle branch block, significant ST-T wave abnormalities or flat T waves that could interfere with QT analysis. If HR \<50 or \>85 bpm, then 2 more ECGs will be recorded, and the mean values will be used.