Antitachycardia pacing + AICD firing

A 75 yo pt with h/o ischemic cardiomyopathy, S/P AICD placement was admitted due mechanical fall.

Image 1

Patient converted to monomorphic ventricular tachycardia (VT).

Image 2

The 8 pacer artifacts indicate anti-tachycardia pacing (burst pacing). However, no termination was noted. Instead, it degenerated to ventricular flutter/ventricular fibrilation (VF). 

Ventricular Flutter and Fibrillation

Electrocardiographic Recognition (From Braunwald's Textbook of Cardiology)

"Ventricular flutter and ventricular fibrillation are arrhythmias that represent severe derangements of the heartbeat that can terminate fatally or produce significant brain damage within 3 to 5 minutes unless corrective measures are undertaken promptly. Ventricular flutter is manifested as a sine wave in appearance—regular large oscillations occurring at a rate of 150 to 300 beats/minute (usually about 200). Distinction between rapid VT and ventricular flutter can be difficult and is usually of academic interest only. Hemodynamic collapse is present with both. VF is recognized by the presence of irregular undulations of varying contour and amplitude . Distinct QRS complexes, ST segments, and T waves are absent. Fine-amplitude fibrillatory waves (0.2 mV) are present with prolonged VF. These fine waves identify patients with worse survival rates and are sometimes confused with asystole."

Image 3

A few second later, AICD fired terminating the tachycarrhythmia.

Image 4

Reference:

Bonnow et al. 2011. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th Edition. PA.Saunders 

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