QrV1 Fascicular Tachycardia

Report:

Ventricular tachycardia 180/min

Comment:

The QRS is only 0.10” long, qualifying this as a fascicular VT. Its ventricular source is easily detected in V1, where the broad Q wave slopes obligingly over the requisite 0.06” to its nadir. The gracile R wave is appended, making doubly sure nobody mistakes this complex for LBBB.

The admission ECG, taken before adenosine and verapamil, is shown below (Fig 27a). The rate is the same, 180/min, but the axis is –40o and there is no R wave in V1. The drugs appear to have normalised the VT axis. The overall QRS duration is below 0.10”. The most interesting feature are the dissociated P waves, at approximately 62/min. It makes one seek them in the index trace and, indeed, they are there, at the same rate.

Another sinus rhythm ECG, at 51/min, is shown in Fig 27b, with a QR of rapid descent in V1.

27a. Initial ECG showing LAD characteristic of fascicular VT. Dissociated sinus rhythm is easily recognised in V1. 27b. Sinus rhythm with 1o AVB, probably drug-induced. 28. 70 year old woman with recent inferolateral infarction.