The ECG tracing in<unk>  demonstrates a polymorphic ventricular tachycardia with a characteristic illusion of a twisting of the QRS complex around the isoelectric baseline (peaks, which are at first pointing up, appear to be pointing down for subsequent "beats" when looking at ECG traces of the "heartbeat"). It is hemodynamically unstable and causes a sudden drop in arterial blood pressure, leading to dizziness and fainting. Depending on their cause, most individual episodes of<unk>  revert to normal sinus rhythm within a few seconds; however, episodes may also persist and possibly degenerate into ventricular fibrillation, leading to sudden death in the absence of prompt medical intervention.<unk>  is associated with long QT syndrome, a condition whereby prolonged QT intervals are visible on an ECG. Long QT intervals predispose the patient to an , wherein the R-wave, representing ventricular depolarization, occurs during the relative refractory period at the end of repolarization (represented by the latter half of the T-wave). An R-on-T can initiate<unk> . Sometimes, pathologic T-U waves may be seen in the ECG before the initiation of<unk> . A "short-coupled variant of<unk> ", which presents without long QT syndrome, was also described in 1994 as having the following characteristics: * Drastic rotation of the heart's electrical axis * Prolonged QT interval (LQTS) - may not be present in the short-coupled variant of<unk>  * Preceded by long and short RR-intervals - not present in the short-coupled variant of<unk>  * Triggered by a premature ventricular contraction (R-on-T PVC)
Torsades de pointes
Ventricular fibrillation
Pre-excitation syndrome
Brugada syndrome
Pacemaker syndrome
Takotsubo cardiomyopathy
Sudden arrhythmic death syndrome
Unstable angina