What is a steam pop and what risks does it pose during RF ablation?

• A. Rapid tissue heating and vaporization during RF causing a steam pop; risk of perforation, char formation, and thromboembolism.
• B. A benign thermal event with no risk.
• C. A type of contrast-induced reaction.
• D. An imaging artifact with no clinical consequence.

Answer: (A)

Steam pops happen when RF energy heats tissue so rapidly that water inside the tissue boils and forms a steam bubble. The sudden bubble expansion or collapse can mechanically disrupt the tissue, potentially perforating the heart wall and causing pericardial effusion or tamponade. The event can also leave behind char or thrombus, increasing the risk of thromboembolism. This is a dangerous, real complication, not a benign thermal event, a contrast reaction, or an imaging artifact.