Short communication Application of low dose rate pulsed fluoroscopy in cardiac pacing and electrophysiology: patient dose and image quality implications

The performance of a low dose rate pulsed fluoroscopy option and its successful application to cardiac pacing and electrophysiology is reported. Low dose rate 6.25 frames per second pulsed fluoroscopy was made available in two catheter laboratories at a specialist cardiac centre in February 2003, and was adopted as the standard imaging technique for cardiac pacing procedures. The image quality was found to be considerably poorer than conventional modern units, being very similar to that which would have been accepted as adequate performance 20 years ago, but at less than one-tenth of the dose rate. No problems with the clinical acceptance of this imaging mode for cardiac pacing and electrophysiology have been reported. The already low median patient dose-area product for pacing at this cardiac centre was further reduced by 50% with the introduction of this fluoroscopy option. It is a requirement of the Ionising Radiation (Medical Exposure) Regulations 2000 (1) that radiation doses to patients undergoing radiological procedures ''are kept as low as reasonably practicable consistent with the intended purpose''. This philosophy of optimization has been widely accepted for many years. It is, however, relatively rare in general radiology that an examination protocol is selected that intentionally sacrifices image quality in order to reduce patient dose. Clearly, the types of examination where this strategy is acceptable are limited to those where the requirement is only to adequately distinguish high contrast features. Procedures which could be considered to be in this category are cardiac pacing and electrophysio- logy. In these procedures pacing or electrophysiology wires are inserted via an artery or vein and guided into the heart using fluoroscopy and electrocardiographic monitoring.