Pressure or tension that results from a demanding situation. A panic attack is a sudden episode of intense fear that triggers severe physical reactions when there is no real danger or apparent cause. A panic attack is the abrupt onset of intense fear or discomfort that reaches a peak within minutes and includes at least four of the following symptoms: Palpitations, pounding heart, or accelerated heart rate. Panic attacks come on suddenly and involve intense and often overwhelming fear. A panic attack is an intense wave of fear characterized by its unexpectedness and debilitating, immobilizing intensity.