Gas embolism is a known complication of minimal access procedures in which carbon dioxide insufflation is used. We report a case of significant venous and right heart gas embolization, which occurred during performance of routine minimally invasive vein harvesting. This was manifest by hemodynamic deterioration secondary to transmission by a patent foramen ovale into the left heart and coronary circulation. Techniques to predict, diagnose, and prevent this rare but potentially fatal complication of minimally invasive vein harvesting are suggested.