Papillary Muscle Ventricular Tachycardia Masquerading as Bidirectional Ventricular Tachycardia

Abstract

Introduction: Bidirectional ventricular tachycardia (VT) is a rare type of VT that appears in digoxin toxicity and young patients with catecholaminergic polymorphic VT (CPVT). The occurrence of bidirectional VT originating from the papillary muscle has not been reported in the literature. Case Presentation: A 38-year-old female presented with long standing palpitation lasting several months. Palpitation was begun after pregnancy. The patient's symptom was intensified with exercise and emotional stress. A 12-lead electrocardiography shows bidirectional VT. Conclusions: Bidirectional VT is a life-threatening VT characterized by right bundle branch morphology (common type) in V1 and beat to beat variation in QRS axis in the limb leads. This arrhythmia usually develops in a patient with digitalis toxicity or in patients with CPVT. Mechanism of the arrhythmia is not well-defined. Alternation of arrhythmia from bidirectional morphology to bigeminy premature ventricular contraction, successful ablation of the VT in territory of the posteromedial papillary muscle, and start-stop pattern show that the arrhythmia has focal origin.