The “Short-Coupled” Variant of Right Ventricular Outflow Ventricular Tachycardia: A Not-So-Benign Form of Benign Ventricular Tachycardia? (original) (raw)

2005, Journal of Cardiovascular Electrophysiology

originating from the right ventricular outflow tract (RVOT-VT) and idiopathic RVOT-extrasystoles are generally considered benign arrhythmias. We described three cases who originally presented with typical "benign looking" RVOT-extrasystoles or RVOT-VT but developed malignant polymorphic VT during follow-up. The unusual aspect of their RVOT-extrasystoles was their coupling interval, which appears to be intermediate between the ultra-short coupling interval of idiopathic VF and the long coupling interval seen in the truly benign RVOT-VT. (J Cardiovasc Electrophysiol, Vol. 16, pp. 912-916, August 2005) ventricular tachycardia, ventricular fibrillation, right ventricular outflow tract Ventricular tachycardias (VTs) occurring in patients without organic heart disease are conventionally categorized as "idiopathic monomorphic" or "idiopathic polymorphic" VTs. 1 The right ventricular outflow tract (RVOT) area is the site of origin of the most common type of idiopathic monomorphic VT 1 ; this RVOT-VT has a distinctive morphology (QRS complexes with left bundle branch block pattern and tall R waves in the inferior leads) and, in general, does not lead to hemodynamic decompensation. Therefore, recording of ventricular extrasystoles that appear to originate from the RVOT, in patients presenting with palpitations, is reassuring. This follows the assumption that any sustained arrhythmia originating from the RVOT-if it ever occurs-will be well tolerated. Recently, Haissaguerre et al. called our attention to the fact that the RVOT area may also be the site of origin of malignant polymorphic arrhythmias. 2,3 Indeed, ventricular fibrillation (VF) originating from the RVOT has been described in patients with Brugada syndrome 2 and idiopathic VF. 3 Nevertheless, distinguishing patients with benign idiopathic monomorphic RVOT-VT from those with these malignant polymorphic forms has not been a clinical problem. This is because the former group generally presents with palpitations that have been present for months to years and have frequent RVOT-extrasystoles with a long coupling interval. In contrast, patients in the latter group present with syncope or cardiac arrest and have rare extrasystoles with a uniquely short coupling interval. 2-5 This coupling interval is so short that idiopathic VF has also been referred to as the "shortcoupled variant of torsade de pointes." 5 We now present patients who-based on their clinical presentation and frequent RVOT-extrasystoles-were initially given the diagnosis of