thanks Doc, i appreciate it. i will definitely bring all these up at my next cardiologist visit! my doc did mention an accessory pathway but he said ultimately he would only know with catheterization- and to provoke the heart to see what happens when it goes to 150- but i am way too scared to do that. i dont want to end up with a pacemaker.
PAC's are irregular beats that originate from the upper chamber of the heart (atrium), but not the sinus node (the normal pacemaker of the heart). However, it would be very unusual for PAC's to be the cause of periods of a very high heart rate (especially into the 140-150's). There are a number of different arrhythmias that can be responsible for a rapid heart rate that occur episodically (atrial fibrillation with a rapid ventricular response, atrial flutter with 2:1 conduction, AVNRT, atrial tachycardia, inappropriate sinus tachycardia, etc). A holter monitor is usually the best study to have done (in combination with a good history and physical, basic lab work, an ECG, and possibly an echocardiogram). If your original holter did not catch any events, you might try having one for an extended period. Additionally, having a short PR interval with your symptoms, you should be ruled out for having an accessory pathway (pre-excitation syndrome such as Wolf Parkinson White).