Medical Term:
vulnerable period
Definition: a brief time during the cardiac cycle when stimuli are particularly likely to induce repetitive activity like tachycardia, flutter, or fibrillation which persists after the stimulus has ceased; for the ventricle, it occurs during the latter part of systole, during the relative refractory period coincident with the inscription of the latter half of the T wave of the electrocardiogram.
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Examples: glitazone, GI cocktail, etc.
