<unk>  rhythm at a rate above the upper limit of normal
In adults, usually >100 bpm
In pediatric patients it varies by age until age 8 or 9 (see pediatric vital signs)
Usually seen as a secondary response to a primary medical condition
In adults, usually >100 bpm
In pediatric patients it varies by age until age 8 or 9 (see pediatric vital signs)
Emotional or psychiatric causes
Pain, anger, or anxiety
Response to fever (about 10 bpm per degree C > 37.0)
SIRS (from infection or other causes)
Dehydration/hypovolemia
Anemia
Drug/alcohol intoxication (particularly sympathomimetic or anticholinergic drugs, but may also be seen in aspirin, theophylline, or other ingestions)
Drug/alcohol withdrawal
Anion gap acidosis
Hyperthyroidism
PE
CHF
Cardiac tamponade
Myocardial contusion
Cardiac valvular disease
Hyper or hypoglycemia
Myocardial infarction
Pheochromocytoma
Pain, anger, or anxiety
Sinus tachycardia
Regular
Wide-complex tachycardia
AV Node Independent
Junctional tachycardia
Narrow-complex tachycardia
Atrial tachycardia 
Ventricular tachycardia