Went to hospital having a rapid heartbeat and feeling faint.

That would be the rate of the ventricles. The atrium might flutter at 300 BPM, but the lower number is the beats of the ventricles.

Flutter is quite easily treated via a catheter ablation. You should be referred to an electrophysiologist and see about an ablation if the flutter is not otherwise controllable. You had a successful cardioversion, and that's great. If the flutter returns, especially in the next few weeks, another cardioversion might still work....probably will. However, the frequency may rise, in which case you will need an ablation. Day surgery, no big deal, and it is 95% successful in the right hands.

Thanks! Good to know!

LucyLucinda

@lucylucinda If you have a download of the EKG or other clinical notes, then look for a notation of "RVR" which is Rapid Ventricular Rhythm.

RVR would definitely be at play if the ECG shows a rate much above 100. Some people have fibrillation at rates as low as 75-80, as shown by the ECG graphic. This means the ventricles are only getting their usual signal. When a person knows they are fibrillating or in SVT, but their assessed HR is between about 105-200, it's a distinct sign that 'rapid ventricular response' is happening, and that's not good long term. No more than 24 hours, and if it goes that long, get to an ER for help.
https://www.webmd.com/heart-disease/atrial-fibrillation/afib-rapid-response

@gloaming Thanks for the correction on RVR. Rapid Ventricular Response rather than Rhythm. I had an episode of rapid heartbeat and then Afib I had a few months ago and the clinical notes stated that I was experiencing RVR. Diltiazem IV lowered the heartrate and with it the RVR and the return to sinus rhythm. Since that episode I have found that I can put myself into and out of Afib almost at will. Eating something that has a high level of sugar content can kick me into Afib. Sitting and doing deep breathing exercises for about 10 minutes and back to sinus rhythm. Some modes of exercise such as heavy lifting (stacking hay bales) can kick me into Afib. Sitting and resting and again deep breathing exercises and back to sinus rhythm. Afib never lasts for more than 10 minutes or so. Contemplating a return to the electrocardiologist for another round of PFA. Or possibly a catheterization procedure to see if a blockage may be causing low blood flow which can trigger Afib.

@suerte The body has two regulatory systems, the sympathetic and the parasympathetic. First is the one that gets us up 'n goin' in the morning with elevated cortisol and blood glucose as we awaken. It's also responsible for the fight-or-flight mechanism. Either way, adrenalin plays a role, and sometimes a person's heart becomes sensitive to adrenaline and it can begin to fibrillate or to develop ectopy like PACs. So, drugs like metoprolol, a 'beta-adrenergic' drug, actually block the receptors of adrenaline and make the heart less responsive by being slower to beat but also beating less strenuously. Each contraction is easier on the heart.

The other system, parasympathetic, involves the amygdala and the Vagus nerve. The former is our 'fear response' part of the brain, and the Vagus nerve controls how much we relax, how often we breath, helps regulate blood pressure (along with the kidneys which play a very important role in blood pressure), and so on. Vagal tone is a known thing, and there is such a syndrome as 'dysautonomia', or a disorder of the Vagus nerve's purpose.

I think it sounds more like you have an adrenergic sensitivity, but it could still be 'Vagal tonality' that is at play here. Both need to be ruled out. Otherwise, yes, more meds, higher doses, or try new ones, or ask for a second ablation...it happens. I had to have two before my EP found the gap he'd missed in his scarring 'dams' he made around my pulmonary veins the first time. He found that small gap when burning around my third pulmonary vein. Suddenly my heart went into happy and steady NSR, and he felt he'd found the gap through which enough signal was getting to cause my AF.

@suerte Very interesting and helpful! So far no more episodes for me, but it's good to have your experiences in the back of my mind!