Dual Ventricular Response or 1 : 2 Atrioventricular Conduction in Dual Atrioventricular Nodal Physiology

Abstract

Dual ventricular response to a single supraventricular impulse is an interesting possibility in the presence of dual atrioventricular nodal physiology. Double His bundle and ventricular responses to a single atrial impulse caused by a simultaneous fast and slow pathway conduction is the hallmark of this condition. One of the earliest descriptions of simultaneous conduction through both atrioventricular (AV) nodal pathways was by Csapo G1, who described various electrocardiographic patterns due to simultaneous conduction through dual AV nodal pathways. Activation through triple AV nodal pathways has also been described2,3. In one case2 an atrial impulse evoked double ventricular response due to simultaneous activation of the slow and fast pathway. The next impulse activated the ventricles through the intermediate pathway, The net result was a narrow QRS tachycardia with irregular RR intervals. In another case3 an incessant form of complex supraventricular tachycardia was noted, with simultaneous conduction over multiple AV nodal pathways. The tachycardia was successfully treated by ablation of intermediate and slow pathways. Over 20 cases non-reentrant supraventricular tachycardia with 1:2 AV conduction during sinus rhythm has been described in literature so far4-19

Keywords

• Dual ventricular response
• 1:2 atrioventricular conduction
• dual atrioventricular nodal physiology.