what is it? PAC and irregular rhythm

hey guys, my names Joey and im 22 years old. my doc has always told me I have tachycardia so he had me on metoprolol 50mg for a couple of years. then all of a sudden, about a couple of months ago i was completely relaxed and out of nowhere, my heart skips a few big long beats and then my BPM sky rockets and goes to 150 from 65. i get tunnel vision, about to pass out, nausea and a HUGE sense of impending doom, but without hyperventilation since then iv been getting these episodes more often. out of no where i get a huge surge of "nervousness" throughout my whole body- think im going to die- and within seconds my heart pounds out of my chest and goes to 155 bpm. I have been on a halter monitor, it hasn't caught an episode like that, but it has caught some irregularity and when i sleep my heart rate goes from 40 to 140 although i never wake up from it. my Doc read the halter and said its most likely PAC's and hes pretty sure the beats are coming from the right place, and most people shouldn't feel them. i severely doubt this is anxiety because theres no trigger and no hyperventilating (and i dont have anything really to be anxious about). anyone else have this? i also have a short PR interval on my EKG that read A-FIB but the doc didn't agree with it. anyone got some info? thanks for listening to me ramble

[CCF HeartMD6]

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).

[batmanjoey]

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.