Have fast heartbeat then slows down sometimes skips a beat?

Need further evaluat. I would recommend you get an electrocardiogram(ekg) which measures the electrical activity of your heart. You could possibly be having something known as atrial fibrillation or an irregular type of heartbeat. You may also consider something called holter monitoring or an event recorder(these measure the electrical activity of the heart over a period of time i.e. 24 hours or more).