Ranolazine, originally introduced as an antianginal agent for the treatment of chronic stable angina, is now being recognized as an antiarrhythmic agent as well. It has been included in the class Id of the Modernized Classification of Cardiac Antiarrhythmic Drugs . Class Id is by virtue of its inhibition of late Na+ current (INaL).
It has been included among the drugs for treatment of ventricular arrhythmias in the 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death . Ranolazine reduces early after depolarization (EAD) induced triggered activity.
Ranolazine has a half life of 7 hours. The extended release preparation of ranolazine can be used in a twice daily schedule. Though ranolazine can slightly prolong the QTc, the chance of inducing torsades des pointes is very low . The only case report with probable association  had other confounding factors including treatment with fluoxetine, amiodarone and diuretics causing hypokalemia and hypomagnesemia which are well known to cause torsade de pointes.
Ming Lei, Lin Wu, Derek A Terrar, Christopher L-H Huang. Modernized Classification of Cardiac Antiarrhythmic Drugs. Circulation. 2018 Oct 23;138(17):1879-1896.
Sana M Al-Khatib, William G Stevenson, Michael J Ackerman, William J Bryant, David J Callans, Anne B Curtis, Barbara J Deal, Timm Dickfeld, Michael E Field, Gregg C Fonarow, Anne M Gillis, Christopher B Granger, Stephen C Hammill, Mark A Hlatky, José A Joglar, G Neal Kay, Daniel D Matlock, Robert J Myerburg, Richard L Page. 2017 AHA/ACC/HRS Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol. 2018 Oct 2;72(14):e91-e220.