How would you describe a panic attack?

Panic attacks are: Sudden, intense, usually brief anxiety attacks & may be mistaken for a heart attack or other life-threatening condition. If they reoccur unpredictably, they can be called panic disorder. Avoiding certain types of places associated with an attack is called agoraphobia. Anxiety can be milder, more predictable or more general, including chronic worry. Panic & anxiety attacks are often synonymous.

Intense fear...: A panic attack is a sudden episode of intense fear that triggers severe physical reactions when there is no real danger or apparent cause. Panic attacks can be very frightening. When panic attacks occur, you might think you're losing control, having a heart attack or even dying. Panic attacks were once dismissed as nerves or stress, but they're now recognized as a real medical condition.