First-in-Patient Study for Sing le Dose of M201-A Hydrochloride Injection in Japanese Patients With Paroxysmal Atrial Fibrillation

Inclusion Criteria: * (1) Japanese (male, female) adult with symptomatic paroxysmal atrial fibrillation (AF) * Written informed consent must be obtained on a voluntary basis before any assessment is performed. (2) Age: 20 to less than 85 years of age (3) Weight: 40 kilograms(kg) or more BMI: 18.5 to less than 28.0 on screening examination(screening) (4) Past AF History: Event(s) as symptomatic AF with (at least) 2 hours or more AF lasting has (have) occurred at least once or more a half year (6 months) prior to the screening. (5) Occurrence time of the latest AF: Record(s) of the patient portable electrocardiograph shows evidence to support that the latest AF has occurred within 3 hours to less than 3 days (72 hours) prior to an administration of the investigational product. (6) The AF lasting prior to the administration: 12 lead electrocardiogram just prior to the administration shows that AF has not stopped. (7) Excluded medication: Based on propositions of a principal investigator or a co-investigator(s), a patient can consent for discontinuation of below antiarrhythmic agents (the Vaughan-Williams classification) for at least 7 days after administration since an advanced registration. Nonetheless, if a period between the advanced registration and the administration is less than 7 days, it should be confirmed those agent has unadministered during 7 days prior to the administration. \[Vaughan-Williams classification\] Antiarrhythmic drug group I Antiarrhythmic drug group III Antiarrhythmic drug group IV Bepridil (8) Excluded administration of amiodarone: It should be confirmed that amiodarone hydrochloride is not unadministered within one (1) year before the screening. Exclusion Criteria: * (1) Heart failure (NYHA II, III, IV). Excluding palpitations induced by atrial fibrillation (AF) (2) Any atrioventricular block of first, second or third degree at the time of sinus rhythm (3) Any risk factor leads to Torsades de Pointes (TdP) 1. \[0\]: 440 ms or more in standard 12-lead electrocardiogram at the time of sinus rhythm within 3 months prior to administration 2. Hypokalemia or suspected to be hypokalemia: One or more of serum potassium levels, obtained at any time during 6 months in advance of administration including pre-administration examination, has been 3.6 \[1\]/L or less. 3. Hypomagnesemia or suspected be hypomagnesemia: One or more of serum magnesium levels, obtained at any time during 6 months in advance of administration including pre-administration examination, has been 1.8 mg/dL or less. 4. T-wave abnormality of electrocardiogram at the time of sinus rhythm 5. Past medical history as fainting; syncope with unknown etiology or complicating illness. 6. Past own medical history or family medical history as long QT syndrome (4) Severe heart hypertrophy; Cardiomegaly: Septal Thickness of cardiac ultrasound has been exceeded over 15 mm. (5) Left atrial dimension (parasternal long-axis view) of cardiac ultrasound has been exceeded over 45 mm.