I was one of the first patients to get ablation treatment for WPW or Wolfe-Parkinson-White syndrome.
5 catheters into my heart... and I drifted in and out while they did it. They had to seal off like 7 extra AV nodes... got 6 but had to give up on the seventh.
Since I was a teenager I have had episodes of tachycardia 300+ BPM and almost no blood pressure (60/40). At first I treated it with a pill (beta blocker)... but those quit working in the early 1990s and I would go to the ER... once for the paddles, and a few times for an intravenous drug called "endocard" or maybe "Indocard". This reboots your heart... kills you for a few seconds. I describe it like it was an elephant sitting on your chest. Then your heart rate is converted to normal.
The only problem with the ER visits is that a) the admitting nurse would never believe me when I told them my likely heart rate and BP... and then, once they checked for themselves... they would rush me into a bed and treat me for shock while calling for the on-call doctor. Treating me for shock involved sticking a large IV bag with a big needle (saline solution) into your arm... and opening it up to dump a LOT of saline into your veins... all of which has to go someplace in 30 min after. Dragging the IV cart to the bathroom to pee is never fun, but I refused to use the bedpan.
Anyway, 25 years later and no more episodes... although my heart often gives me that "skipped beat" pre-arrhythmia feeling.
Knock on wood. I was lucky to have the doctor that pioneered the microwave tip ablation surgery from inside the heart...
He told me it would likely be good for 20 years. So I guess I'm living on borrowed time now.