Risks of cardiac ablation. Just like any other medical procedure, cardiac ablation comes with its drawbacks. The risks of this procedure include infection, bleeding, and vessel damage at the site of the catheter insertion and throughout the vessel. Cardiac ablation also carries the risks of a heart puncture, heart valve damage, and too much damage to the electrical pathways of the heart that may mandate a pacemaker to resolve it. Additionally, just like with many other surgical procedures, leg or lung blood clots, heart attack, stroke, and pulmonary vein stenosis can occur, however these complications are very uncommon.