Hello. Thank you for your question and welcome to HCM. I understand your concern. First, this one paroxysm of atrial fibrillation is not very worrisome, but there are medical remedies that should be taken, to prevent another bout of this supraventricular arrhythmia. The proper drugs for this aim, which slow down the electrical impulse conduction throw the atrio-ventricular node, are beta-blockers, verapamil and diltiazem from the calcium channel blockers, and digitalis (digoxin or digitoxin). Before going back to vigorous physical activity, as far as this problem is concerned, an echo cardiogram should be done to assess the size of atria, and evaluate if this phenomenon, with highest probability, is a one-time thing or there is a predilection that it can happen again. In the latter case, no such vigorous activities should be performed. As for the stent implantation part, they are widely used to treat and cure coronary artery disease. The only problem that should be taken into account, as far as this issue is concerned, is the punction site in the groin. After it is healed, you are clear to go . No problems can come from stent placement, regarding this, except for the inherent probability of within-stent narrowing, which is the same for all people that undergo this procedure. You can exercise without problems now, it is only the paroxysm of atrial fibrillation that warrants further evaluation. I hope I have been of help. My best regards, Dr. Meriton