This is footage of a fatal ventricular fibrillation due to a cocaine overdose. This is a tine-lapsed video (15 min minutes in total)
The heart rate progresses from an average of 72 beats per minute (bpm) to a ventricular flutter (>250 bpm) followed by a ventricular fibrillation (>350 bpm)
This is the last step before the heart flatlines and proceeds into cardiac arrest, when it stops pumping all together.
Cocaine prevents the cleanup of stress chemicals in the brain. The heart becomes quick and inefficient, reducing blood flow, and dies due to a lack of oxygen.