Acute Infarct Pattern in Ventricular Tachycardia

Report:

Ventricular tachycardia 120/min

Spontaneous termination & onset in the (subsequent) rhythm strip

Sinus escape beat

Probable anterior infarction

Comment:

There is little doubt about the acute anterior infarction, despite the bizarre complexes. This is probably another fascicular VT, originating from the anterior fascicle (and resembling, therefore, left posterior hemiblock). It also resembles LBBB + RAD, a combination not so far described with aberrant conduction of any supraventricular rhythm. In fact, the RAD with LBBB-like morphology has been specifically proposed as criterion for VT32. In V1, the differentiating feature (from LBBB) is the slurred, slow descent of the S wave, with rapid upstroke - opposite of true LBBB.

The sinus rhythm is suppressed by the retrograde conduction of the VT; retrograde P waves can be seen distorting the ST segments in several leads, best, perhaps, in V1. In Lead 2, there is a good example of their deceptive polarity – they appear positive as they “cut” into the ST segment before the T wave.

The ectopic QRS looks of normal duration in leads 1 and V6, as its initial vector is isoelectric; the onset of the complex can be determined from the complexes recorded on other simultaneous channels.

Below (Fig 31a), the same ectopic complexes can be seen in bigeminy, with dissociated sinus P waves preceding them.

31a. The P waves are too close to the bigeminal VEBs for any fusion to take place. 32. Recurrent broad complex tachycardia in a 60 year old man with ischæmic cardiomyopathy, hypoxic prior to intubation.