Highway to the danger zone...

Supraventricular Arrythmias, Atrio-ventricular reentrant tachycardia

During an accessory pathway EP study we induce an atrial fibrillation.

History of the patient

A 45 y.o. patient had episodes of palpitations at rest with dizziness. His clinical exam and echocardiography were normal. His 12 lead electrocardiogram revealed a pre-exitation at rest. During stress test, it slowly disappears... He is refered for an electrophysiological study.


Baseline ECG is preexited. An postero-septal accessory pathway is suspected. We usually perform, as recommended, an anterograde EP followed by atrial fibrillation induction to assess AP malignancy.

Despite a smooth manipulation, a lot of mechanical ectopy arise from the CS catheter. Some induced first a orthodromic tachycardia starting without a jump. A PVC stopped the tachy and proved that ventricle is part of the circuit. Then a sustained atrial fibrillation is induced. During AF, very short VV interval can be mesured (< 220 ms). This is a clear ablation indication. We had to cardiovert our patient.

Ablation was perfomed in the postero-septal area. The ventricle insertion of the AP was targeted the best site were defined by a clear AV fusion, an early V EGM,  a sharp unipolar electrogram without R wave (despite low voltage and fragmentation).

We waited 30 minutes and finally infused adenosine to confirm the ablation of this AP.