Check out my post titled - "Marijuana Panic Arrhythmia" for some important facts. Also, the skip a beat or hesitate for a second.....that's an arrhythmic symptom not a fast heart rate usually associated with panic attacks. However, it is very unsettling to have ANYTHING abnormal occur with your heart. It's the center of your life and an organ that is actually deeply connected to your emotional life. Many people can be arrhythmic prone and only have occasional events. Some may go their entire life and never really notice. Yet others, like me, have to be on medication to keep the heart in good rhythm. Caffine, (even decaff) Alcohol, cigarettes, energy drinks (even non-caffine versions) all can push the heart out of rhythm, sometimes momentarily, sometimes for an extended time. Never allow the heart to be out of rhythm for more than a few hours before going to the ER. The most common danger is that you can throw a blood clot and have a stroke if the condition persists for a long time. The ER can put your heart back into rhythm. There are different severities of arrhythmia but all are impacted negatively by stimulants. If you try marijuana, be sure to use Indica strains only (they are less of a stimulant), and don't take a huge hit, take a very small puff and let it take affect for at least 20 minutes before you try to take more. Also, holding in your hit will not retain more THC....once your lungs have fully inhaled, they're done metabolizing the THC and you will only retain the smoke contaminants. peace.
I'm no doctor, but from what you are saying it sounds like PVC's. You might want to do some research on them, and try not to worry, they are actually quite common and in the vast majority of cases- benign. Your drinking and smoking could in fact be making them worse, as will caffeine (even soda with caffeine or chocolate) I would avoid that if you could and try to see a doctor that can set your mind at ease. :) Good luck to you!!!