Narrow irregular QRS tachycardia with AV dissociation: what is the mechanism?
Jesús Castillo Castillo1, Pablo Peñafiel Verdú, Juan Martínez Sánchez
1Electrophysiology Unit, Department of Cardiology, Virgen de la Arrixaca University Hospital, Murcia, Spain. jesus_kastillo@hotmail.com
Abstract:
A 39-year-old woman with no structural heart disease and frequent episodes of sudden onset palpitations was referred for the electrophysiological study. During the study, a slightly irregular narrow QRS tachycardia with AV dissociation was repeatedly induced and spontaneously terminated. Apparently, irregular cycles and termination of the tachycardia were related to the dissociated sinus rhythm: atrial depolarizations timed when the AV junction was refractory were able to reset the tachycardia, while early atrial depolarizations caused its termination. This observation was enough to diagnose the tachycardia mechanism in our case.
Related Concept Videos
Dysrhythmias IV: Characteristics of Bradyarrhythmias
Disturbances in Heart Rhythm
Arrhythmias are categorized by their speed, rhythm, and origin. A slow heart...
Mechanism of Cardiac Arrhythmias
Dysrhythmias III: Characteristics of Dysrhythmias
Dysrhythmias II: Classification of Tachyarrhythmias
ECG Interpretation of Arrhythmias II: Atrial, Junctional and Ventricular Arrhythmias

