P1: SBT
0521779407-05 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 20:49
210 AV Reentrant Tachycardia (AVRT)➣12-lead ECG:
➣Delta waves with short PR interval (<100 ms, depends on degree
of pre-excitation) from antegrade ventricular pre-excitation.
➣ECG with full pre-excitation, Rs in lead V1: left-sided accessory
pathways.
➣rS to Rs transition > lead V2: reight-sided accessory pathways.
➣Positive delta wave and QRS in lead V1: LV accessory pathway.
➣Negative delta wave and QRS in V1: RV accessory pathway.
➣No delta wave: concealed accessory pathway; ventriculo-atrial
conduction.
➣Antidromic AVRT: Wide QRS complex SVT using the accessory
pathway as the antegrade limb and the AVN as the retrograde
limb of the reentrant circuit.
➣Orthodromic AVRT: Narrow QRS tachycardia with antegrade
conduction over the AVN and retrograde conduction over the
accessory pathway.
➣Retrograde P waves during AVRT follow QRS (short RP tachycar-
dia).
■Specific Diagnostic Test:
➣Electrophysiology study to characterize and map the location of
the pathway (usually performed in conjunction with RF abla-
tion).Differential Diagnosis
■Sinus tachycardia, atrial flutter, and atrial tachycardia. Diagnostic
electrophysiology study often required.management
What to Do First
■Vital signs to assess hemodynamic response.
■12 lead ECG to rule out atrial fibrillation and flutter with pre-
excitation during AVRT.General Measures
■In adult, no treatment or diagnostic electrophysiology study if delta
wave only but no history of tachyarrhythmias.
■Avoid caffeine and alcohol, if correlated with SVT occurrence
specific therapy
Restore NSR
Acute