Posterior fascicular tachycardia

A young male presents with palpitation.

A 28 year-old man presents with tachycardia with the rate of 185 bpm. There is no history of structural heart disease. His blood pressure was 117/82 mm Hg in ED. He stated that he had these complaints 2 or 3 times a year for 3 years.

This ECG shows;

• Wide complex tachycardia but QRS complexes that are relatively narrow (0.12 sec)
• 2. Right bundle branch morphology in V1 (RR’ in V1 ) but S>r in V6
• 3. The frontal plane QRS axis is extremely leftward (negative QRS complexes in leads II, III, and aVF)
• 4. R waves are also narrow in V3-6 and inferior leads representing fast initial forces of QRS because of ventricular activation through the his purkinje network.

These are typical features of posterior fascicular tachycardia. This tachycardia is localized to the inferior apical left ventricular septum.