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(A) Diagrammatic representation of atrioventricular re-entrant tachycardia. This macro re-entrant circuit (gray arrows) uses the AV node and an accessory
pathway (AP), in this case a right lateral pathway. In orthodromic AVRT, antegrade conduction occurs over the AV node and retrograde conduction occurs
over the AP. Because of the conduction delay from the His-Purkinje system through the ventricular myocardium to reach the AP, retrograde P waves are
discernible after the QRS complexes (arrow). In antidromic AVRT, the re-entrant circuit is reversed and surface ECG shows P waves that closely precede
the QRS complexes. CS = coronary sinus; IVC = inferior vena cava; RA = right atrium; RV = right ventricle; SVC = superior vena cava; TV = tricuspid
valve. (B) Intracardiac recording of atrioventricular re-entrant tachycardia with termination of eccentric conduction over the accessory pathway during RF
Source: Chapter 57. Interventional Therapy for Atrial and Ventricular Arrhythmias, Cardiac Surgery in the Adult, 4e
ablation. The tracing at 50-mm-per-second speed shows four surface leads (VI, II, I, and aVF) and intracardiac recording from catheters:ablation (ABL);
Citation:
Cohn LH.asCardiac
in the Adult,
4e;(RVA).
2012 Available
at: http://mhmedical.com/
May 10,
2017
His distal, mid,
and proximal;
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show evidence
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conduction over an
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accessory pathway: short PR segment and delta wave. With onset of RF energy (RF On) from the ablation catheter positioned in the region of shortest AV
conduction, conduction becomes normal within two beats, with normalization of the PR segment and loss of the delta wave.