Percutaneous coronary angioplasty (PCA) is sometimes complicated by bradyarrhythmias necessitating emergency temporary cardiac pacing. This is usually performed by the classical transvenous endocardial approach. This experimental study investigated the possibility of using the metallic guide wire used during PCA as a monopolar electrode. Systematic electrical stimulation at different levels of the coronary arteries in 6 anaesthetised pigs showed threshold levels in the distal segments of 3 to 15 mA, close to the values observed in the right ventricule. Short periods of pacing were well tolerated. On the other hand, prolonged pacing (2 to 5 days) invariably led to the formation of a thrombus in the coronary segment occupied by the metallic guide wire and so should be avoided. This study shows that the metallic guide wire can be used as an emergency pacing electrode during PCA but this should be limited to a short period. This technique could replace the systematic introduction of classical transvenous pacing catheters.