The problem is not torsade, because torsade is a self-limiting episode of tachycardia...the problem is that it can degenerate to VF.
It is caused by a long-short cycle, the "long" bit occurring because of a VPB that causes a pause.
In the long QT syndrome, patients have slow hearts with a propensity to ectopics from after-depolarizations...therefore get a loooong pause. So, the treatment is to speed up their heart.
NB: "early after depolarizations are depolarizations that interrupt phases 2 and 3. They occur because too many calcium or sodium channels are still open. Delayed AD's are depols that interrupt phase 4 and are due to too much calcium being in the cell cytosol in phase 4.
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