Bigeminal Ventricular Tachycardia

Report:

Atrial fibrillation

Incomplete left bundle branch block

Probable acute lateral infarction

Ventricular tachycardia 204/min[!xe "Ventricular tachycardia:bigeminal" \t "See alternating cycle length"!]

Alternating cycle length

Comment:

The diagnosis of atrial fibrillation with LBBB and lateral MI is, perhaps, difficult to make from the initial few beats available before the onset of VT. It is more obvious in the ECG taken after two 50 mg boluses of Xylocaine85 which abolished the (ventricular, at least) tachycardia (below, 87a).

The bigeminal grouping of the VT beats is due to a 3:2 Wenckebach exit block from the ectopic focus or to an alternating reentry pathway. The QRS complexes are slightly different in shape: this VT may be a cousin of the better-known bidirectional VT usually due to digitalis toxicity.

This patient’s digoxin level was in the therapeutic range at 1.2 ng/cc [0.6 - 1.4 ng/cc]. That, the presence of acute infarction and the ease of cardioversion with Xylocaine, is against digoxin toxicity.

Next (Fig 87b) is his ECG 6 weeks later, on readmission following VF arrest at home. The lateral MI has changed the axis to the right, but is no longer obvious as a lateral MI. There is a diffuse and sinister ST segment depression, still visible during the AIVR on the following page Fig 87c). This AIVR is quite similar, morphologically, to the original VT. He died, with a massive pneumoperitoneum from the CPR.

Reader, our lives should not end like this. These tracings are sad, and not only because … mentem mortalia tangunt. The recording of our heartbeat need not be made, if we are dying.