[A case of WPW syndrome with slow Kent documented by ATP injection]

A 46-year-old woman with chest tightness and palpitation at exercise was admitted to Sapporo Medical College Hospital for the evaluation of the ST-T changes on stress electrocardiogram. In this patient, PQ time was 0.14 second and pre-exitation was not clearly documented on electrocardiogram at rest. Bolus injection of 10 mg of adenosine-5'-triphosphate (ATP) demonstrated deltawave through the elongation of antegrade conduction of atrio-ventricular (AV) node. Electrophysiological study also showed left lateral accessory pathway with slow antegrade conduction, slow Kent. Stress 201-T1 myocardial scintigraphy using bicycle ergometer did not show the existence of ischemic region in spite of the ST-T changes on electrocardiogram. In this case, it seemed that a false positive ST-T changes might be caused by ventricular pre-exitation through slow Kent fiber. From these findings, it was suggested that the transient interruption on conduction through AV node by ATP bolus injection may be a useful diagnostic method in borderline pre-exitation syndrome.