What spikes up a heart rate, i was out and it was normal one second and then my heart rate shot up real fast, pounding...

Anxiety?: Other than stimulants like amphetamines and cocaine, some prescription drugs, caffeine, decongestants, fight or flight response with epinephrine surge from fear or anxiety, it could be tachyarrhythmia. Please see your primary care physician who can refer you to a cardiologist if necessary. You may need a 24 Holter monitor or 2 week event monitor if this continues. Mitral valve prolapse also.