Tarryn’s monitor strip captured by the ambulance shows a broad complex tachycardia. Given she was dizzy at the time and her presenting history, it should definitely be treated as Ventricular Tachycardia (VT) . VT is a potentially life threatening arrhythmia.
Ventricular tachycardia occurs when there is an abnormal firing of electrical signals in the ventricle of the heart. They interfere with electrical signals coming from the Sino-atrial node. The rapid heartbeat does not allow enough time for the heart to fill before it contracts so blood flow to the rest of the body is compromised which may lead to symptoms of dizziness, lightheadedness, unconsciousness, and cardiac arrest.
See animation of Ventricular Tachycardia HERE
The rhythm is monomorphic in character
A good rule of thumb is that any regular broad complex tachycardia such as Tarryn’s should be treated as VT unless proven otherwise.