(FIT)-Module 2 Workshop 2: Entrainment and SVT Maneuvers-Stevenson Workshop 2

Stevenson Workshop 2

Pdf Summary

In this document, various cases of ventricular tachycardia (VT) and the use of entrainment and VT maneuvers are discussed. Entrainment is a technique used during catheter ablation procedures to identify the location of reentry circuits causing VT. VT circuits can be categorized as reentry circuit isthmus, outer loop, bystander, or remote from the VT circuit. Pacing is performed from the ablation catheter in the LV infarct region to determine the relation of the pacing site to the VT circuit. Tracings and maps are presented for each case.<br /><br />In Case 1, pacing from the ablation catheter in an apical LV infarct suggests a pacing site in the reentry circuit isthmus based on the termination of VT without producing a propagated response.<br /><br />Case 2 involves epicardial mapping in a patient with nonischemic dilated cardiomyopathy and recurrent VT. Pacing at site A is most likely the pacing site, which is an outer loop close to the exit. The entrainment with subtle fusion and no S-QRS delay is consistent with pacing outside the isthmus.<br /><br />Case 3 features pacing in a ventricular scar region during VT. The pacing site is determined to be remote from the VT circuit based on the long post-pacing interval (PPI) and S-QRS that does not match the electrogram to QRS.<br /><br />In Case 4, pacing from the ablation catheter in a ventricular scar region during VT suggests a pacing site in the circuit isthmus proximal to the exit based on the entrainment with concealed fusion and PPI matching the VT cycle length.<br /><br />Case 5 involves programmed stimulation in an anterior wall infarct scar to induce VT. The most likely location of the pacing site relative to the VT circuit is the entrance to the isthmus based on the short S-QRS, change in QRS morphology, and conduction block.<br /><br />Case 6 presents epicardial mapping in a patient with nonischemic dilated cardiomyopathy and recurrent VT. Pacing at site D is most likely the pacing site, which corresponds to an isthmus site 200 ms proximal to the exit.<br /><br />In Case 7, entrainment during LV mapping is performed in a patient with prior anterior wall myocardial infarction and incessant VT. The most reasonable next step is to reposition the catheter and continue mapping during the VT.<br /><br />Case 8 involves endocardial catheter mapping in a patient with prior myocardial infarction and recurrent VT. Pacing to entrain tachycardia at this site is most likely to reveal an indeterminant response to entrainment due to cycle length variability.<br /><br />In summary, entrainment and VT maneuvers are valuable tools in identifying the location and characteristics of VT circuits during catheter ablation procedures.

Keywords

ventricular tachycardia

VT maneuvers

entrainment

catheter ablation

reentry circuit isthmus

epicardial mapping

ventricular scar

post-pacing interval

nonischemic dilated cardiomyopathy

myocardial infarction