Hello n welcome to HCM....
as per ur history, its possible that u got VT also, some time we get ECG look like SVT
any how whenever ur heart rate
will be more than 160-180 or so (depends upon the setting/ programming of ur Defibrillator) it will discharge SHOCK
very rarely some time it can sense the external contraction/movement of the muscle, then also it senses wrong/high heart rate, then it will shock u.
but in ur case it looks VT/SVT, that means ur machine has given a right shock.
now ur cardiologist has to see for REPROGRAMMING and high doze of BETA BLOCKER
to be prescribed.
some time ur doze of beta blocker will settle the problem..
so, dont worry and Meet ur CARDIOLOGIST and describe all event in Detail.
wish u a STRONG HEART ...