A panic attack, or anxiety attack, is an effect caused by a patient's misapprehension that chest pain or a rapid heartbeat is a symptom of an impending heart attack. It was once believe that this was a form of mental illness, and the disorder was treated with anti-anxiety drugs. However, studies have recently shown that patients can be taught not to overreact to the initial symptoms by having them induce an attack at will, showing that their "heart attack" is actually their own reaction to their symptoms. It is therefore seen as a psychosomatic disorder.
In all cases, the patient misapprehends that a chest pain or rising heart rate is the sign of something serious. This worries the patient, and the worry raises the patient's heart rate. This cycle continues until the patient is dehabilitated by fear. However, panic attack patients are not more anxiety prone than anyone else, and their increasing distress is ironically due to their increasing distress.
A panic attack can easily be distinguished from a genuine heart attack by a medical professional as the patient's respiration remains more or less strong, the heart rhythm is strong and steady, and blood oxygen levels do not change. In heart attack patients, respiration rises rapidly and is irregular, the heart beats less regularly, and blood oxygenation starts to fall.