Lidija Srkoč Majčica, Ivan Malčić
Introduction: We present a rare ventricular tachycardia of unknown origin (idiopathic) which originates near the posterior fascicle of the left bundle branch of His. The tachycardia has four basic features: wide QRS complex, RBBB morphology, left (superior) axis deviation and sensitivity to verapamil. Since 1981 (when sensitivity to verapamil was discovered by Belhassen et al.) it has frequently been called Belhassen’s tachycardia. Aim: The purpose of this case report was to remind that correct diagnosis of this potentially dangerous arrhythmia can be made with detailed and correct interpretation of 12-lead ECG. Case report: Until now healthy adolescent girl came to the ER because of palpitations, dyspnoea and presyncopal attack. The 12-lead ECG was done. It showed three of four basic features of posterior idiopathic fascicular left ventricular tachycardia. After the conversion of tachycardia to sinus rhythm by intravenous application of verapamil, the fourth feature was also shown and by that the diagnosis was confirmed. Because of the frequent recurrence of ventricular tachycardia with clinical symptoms associated with cardiovascular system (palpitations, precordial oppressions, dizziness, presyncopal crisis) despite ever increasing dosage of oral verapamil and with taking into consideration a positive family history of sudden death syndrome, the adolescent girl was referred to the electrophysiology study and treatment with radiofrequency ablation. Conclusion: Detailed and correct interpretation of 12-lead ECG can correctly diagnose the type of tachycardia, which is fundamental for efficient managing and treatment.