A study of narrow QRS tachycardia with emphasis on the clinical features, ECG, electrophysiology/radiofrequency ablation.

Aim: Atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) are the most common forms of paroxysmal regular supraventricular tachycardias. Materials & methods: The clinical, ECG and electrophysiological findings of 121 patients with narrow QRS tachycardia were evaluated prospectively. Results: A total of 75 (62%) of the patients had AVNRT while 46 (38%) had AVRT. Pounding sensation in the neck (40 vs 15.2%; p = 0.004), presynope (26.7 vs 56.5%; p = 0.001) identifiable P wave after QRS complex (25.3 vs 73.9%; p = 0.001), pseudo r'/s waves (45.3 vs 4.3%; p = 0.001), limb leads ST-T changes (34.7 vs 60.9%; p = 0.004) were the significant changes observed. A total of 94.7% of AVNRT and 87% of AVRT could be diagnosed correctly considering both clinical and ECG criteria. Conclusion: Pounding sensation in the neck and presyncope along with ECG features like identifiable P wave after QRS complex, pseudo r'/s waves and limb lead ST-T changes very accurately differentiate AVNRT and AVRT.