I don't know that worrying will help. So, no, don't worry. Instead, if you're the least bit interested, start reading about atrial and ventricular hypertrophy, tachyarrhythmias and their treatment. The better prepared you are to absorb, and to question, information caregivers and experts who want to put you through diagnostics and treatments ask of you, the more likely you are to feel empowered and on top of things....at least to the extent any patient can feel on top of a new and unpleasant diagnosis.

The only truly dangerous arrhythmia needing a call to 911 is ventricular fibrillation, and it's unlikely you'll ever make that call yourself. Someone will be standing over you and dialing. All the others, ventricular and atrial tachycardia, SVT, atrial fibrillation, etc, can all be dealt with initially at an ER, but you can drive there or be driven there...you don't need an ambulance and EMTs to keep you alive. Of course, if you are feeling very faint, generally unwell, out of breath, then it might be best to call an ambulance.

Again, this is naturally worrying, but you don't have to get yourself worked up while waiting for the cardiologist's appointment. Believe me, I've been 'there', with you, as have millions of others. I have been on my back for hours in an ER, all hooked up, blood drawn, and within five-eight hours my heart reverts to NSR and I slink home. Three weeks later, same thing, same atrial fibrillation, same outcome. I hate it, but it hasn't killed me, and the forumites at afibbers.org have told me plenty of times....most arrhythmias are not emergencies, and most will not kill you. They'll just make you miserable if you're symptomatic while it's happening.

General rule to follow: if any device or trained person records a heart rate of yours that runs 100 BPM or more, and that lasts up to 24 hours, then get to emerg soonest and get looked after. And good for you if you manage to tough it out that long...I never could. Yes, I'm a wimp.

At some point you may be referred to, or advised to seek the services of, an electrophysiologist. An EP is a heart specialist looking into electrical disorders, which an arrhythmia is. I would strongly counsel you to see one for at least an initial look a you and a consultation to determine what, if anything, should be done by such a specialist. You may find that they can help you a great deal.