Alcohol is cardio-toxic, it is among the many side effects of drinking to excess, it damages the heart and may destabilise the conducting system, so it is is fortunate you have stopped. it is particularly unfortunate to drink heavily from an early age as it is pretty much bound to catch up with you if you don t stop. On the other side almost everyone has some extra beats or ectopics at some time and most are harmless. The fact that your tests so far are normal is very reassuring and your 24 hour monitor may also fail to show anything important is happening. Take this as a warning however and for your own sake try and either keep off the drink or drink sensibly for the rest of your life!