Ventricular Tachycardia

Report:

Atrial tachycardia 130/min

First degree AV block

Second degree AV block

Shifting pacemaker (bottom)

VEBs, multiform

Ventricular tachycardia 260/min (top)

Spontaneous termination

Multiform ventricular tachycardia 310/min

Ventricular fibrillation (not shown)

Comment:

This patient was given only 0.5 mg digoxin IV during an episode of AF that followed the arrest. The arrhythmias shown are presumably due to acute infarction rather than digoxin.

The multiform tachycardia in the middle strip could, morphologically, “pass” for a torsade de pointes but the lack of background QT prolongation, bradycardia and an appropriate cause are against it.

Some authorities would regard this rhythm as VF ab initio. Others, more honestly (which of course includes me) do not know what to call it46. The rates are often very fast (300/min, like here), and some are self-terminating. To my mind, the spontaneous termination is diagnostically decisive: if it goes on, it’s VF; if it stops sua sponte, it’s a VT! There are exceptions to that, even in this Library44 , but it generally holds true.

The loss of blood pressure in the bottom strip can only be attributed to myocardial depression in the wake of ischæmic arrest and electrical countershock (at maximum DC output).

Shifting atrial pacemaker (bottom strip) is not what this diagnosis usually implies: slow or normal atrial rates with sinus-atrial-junctional rhythms. Nevertheless, atrial waves’ morphology definitely changes from left to right. PAT with block need not have a uniform rate or P’ morphology. Note how the autonomous focus of the PAT survived the defibrillation.