title: Concealed antidromic re-entrance during rapid atrial pacing in the Wolff-Parkinson-White syndrome.
abstract: In a patient with Wolff-Parkinson-White syndrome, rapid atrial pacing up to rates of 140/min resulted in A-H prolongation; increases in rate up to 200/min, however, failed to lengthen A-H further. The delta-H interval increased as rate rose to 120/min, but remained stable thereafter. These and other findings suggest retrograde activation of the His bundle via the accessory pathway at rates greater than 140/min. Such a phenomenon: 1) prevents initiation of PSVT with atrial pacing; 2) prevents one from determining the anterograde block rate of the AV node; 3) represents concealed antidromic re-entrance, which may theoretically lead to antidromic re-entrant PSVT.
mesh_terms: D001281:Atrial Fibrillation / Q000150:complications; D002036:Bundle of His / Q000503:physiopathology; D002304:Cardiac Pacing, Artificial; D003331:Coronary Vessels / Q000503:physiopathology; D004562:Electrocardiography; D005071:Evoked Potentials; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D012849:Sinoatrial Node / Q000502:physiology; D013614:Tachycardia, Paroxysmal / Q000150:complications / Q000209:etiology / Q000503:physiopathology; D014927:Wolff-Parkinson-White Syndrome / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*