Paroxysmal supraventricular tachycardia

Palpitations
Chest pain
Shortness of breath
Fainting
Lightheadedness
Sweating
Fatigue
Visit a Cardiologist for proper diagnosis and treatment if you have any of these symptoms

Structural heart disease
Heart attack
Inflammation of the heart muscles
Increased activity of the thyroid gland
Medications (ex: Digoxin, Verapamil, Salbutamol)
Drug abuse (Cocaine, Methamphetamine)
Increased caffeine intake
Alcohol
Anxiety

Physical examination and reviewing the medications used by the patient help in the diagnosis.

Electrocardiogram (a simple test to examine the rhythm and electrical activity of the heart using skin-attached sensors to detect the electrical signals produced by the heart during each beat). This may be done at the doctor’s clinic, or he may ask you to use a portable one for monitoring throughout the day.
Echocardiogram (a type of ultrasound scan that is used to examine the heart valves and how it pumps blood to the body).
Laboratory tests (a blood sample is used for routine blood tests and examining the thyroid function).

Vagal manoeuvers: Certain techniques are done by the Cardiologist to treat fast heartbeats.
Cardioversion: A procedure in which patches on the chest are used to give the heart an electric shock to restore normal heartbeat rhythm.
Catheter ablation: A procedure in which a catheter is used to remove the small parts in the heart tissues that cause extra electric signals and beats.
Medications: Intravenous Adenosine, Carvedilol, Bisoprolol, and Metoprolol succinate may be used according to the case.