Anxiety Attack - also known as Panic Attack, is a psychological and physiological state of a person that is typically associated with symptoms like chest pain, shortness of breath, dizziness, headache, sweating, racing heart, feeling as if the mind has gone blank, feeling of being detached from the world etc...
Some of the causes of Anxiety Attack/Panic Attack are...

• Fight or Flight Response - Every person shows fight (defend himself) or flight (run away from the situation) response when he/she senses danger.
  It is an adaptive function placed in us for the sole purpose of self protection.
  Because of this response body chemicals will get activated and physical symptoms like rapid heartbeat, increase in blood pressure, etc will appear.
  Though the purpose of this response is to protect a person from danger (doing good thing), sometimes our brain misunderstands the situation and believes that there is danger when in reality there is not.
  This abnormal behavior of brain leads to anxiety.
  
• Heredity (Genetics) - Studies show that some times anxiety disorders will be inherited to next generation just like physical characteristics.
  That is if parents suffer from anxiety, there is greater chance the child will also suffer from anxiety.
  
• Chemical Imbalance in the Brain - Serotonin and Dopamine (neurotransmitters) are the two chemical messengers in the brain that regulates thoughts and feelings of a person.
  Due to chemical imbalance in the brain, functionality of these two chemical messengers will get affected.
  This changes the way person interprets the situation.
  He/She starts becoming anxious for unknown or not realistic reasons.
  
• Drug and Alcohol consumption may lead to development of Anxiety.
  
• Fearful Experiences - Unconscious conflicts that arise from past fearful experiences leads to anxiety.
  
• Environmental Factors - Situations such as abuse, the death of a loved one, violence, divorce, changing jobs or schools, poverty or stress leads to development of anxiety.
  

Here are some recommended natural remedies for Anxiety Attack/Panic Attack...

Practice Relaxation Techniques - Meditation and Yoga are proven to be effective natural remedies for anxiety.
It removes negative energy from the body, relaxes tensed muscles, and calms the mind, which in turn, effectively reduces irrational fear.

Bring Chemical Balance in the Brain - Eat food items having more omega 3, fatty acid, Vitamin B and Magnesium content.
This brings the chemical balance in the body.
Try to avoid alcohol and junk foods.

Think Positive - As anxiety is a "state of mind" problem, keeping a positive attitude can contribute greatly to recover from anxiety.
Avoid negative thinking as it creates fearful situations which make anxiety even worst.

Find the root of problem that causes anxiety - Note down the situations of getting anxiety symptoms.
Analyze such situations in realistic way and try to find the root of the problem.
Now work towards solving the problem.
This technique will gradually end anxiety in you.