Six Minutes of Multiform Ventricular Tachycardia

Report:

Atrial fibrillation with ventricular response 80 – 135/min

VEB

Ventricular tachycardia, multiform, sustained, 180 – 220/min

Atrial fibrillation with slow response 37 – 44/min following VT

Comment:

This was a repeat Holter study, concerned with control of the ventricular rate in (known) atrial fibrillation and persistent bradycardia (53/min) and hypotension (88 mmHg systolic). Ventricular tachycardia was an unexpected finding, a rare event in overused and boring-to-report ambulatory monitoring.

As is often the case, the multiform VT has monomorphic runs, most of which would be long enough to fill a standard 12-lead ECG. This means that the 12-lead ECG diagnosis of uniform, monomorphic VT is sometimes inaccurate.

The initiating VEB, with a coupling interval of 0.44” is not particularly early. The significance of early and late VEBs in initiating VT and VF remains uncertain. Similarly, no sinister changes in heart rate or ST segment position preceded the VT. It terminated spontaneously, leaving some myocardial depression (manifest as slow response to AF) in its wake. The patient, asleep, reported no symptoms.

A slow-speed (6.25 mm/sec) scanning record of the entire paroxysm is shown on the next two pages (Fig 111a) to familiarise the student with the format. The comments and many of the numbers generated by the computer must be disregarded, even more so with Holters than with 12-lead ECGs.

The patient may have been digoxin-toxic but, looking at her response to AF, this does not look likely. After the routine electrolyte disturbances are ruled out, there will be several choices in her therapy, should active therapy be contemplated: surgery, EPS and ablation, implanted cardioverter-defibrillator, and antiarrhythmic drugs. I would, at this stage, opt for oral magnesium and low-dose beta-blockers and leave it at that.

111a. Two summary pages illustrate the onset and the cessation of VT, with AF before and after. 112. 37 year old woman following posterior fossa craniotomy for acoustic neuroma.

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