Practical Clinical Electrophysiology, 2e by Unknown

Author:Unknown
Language: eng
Format: epub

If all three criteria are met, there is a high likelihood that ablation at that site (±1 cm) will terminate the VT and prevent its reinitiation. However, there are limitations to this and other mapping techniques. They include stimulating and recording far field, poor contact, inability to define the local EGM, production of conduction delays due to too rapid pacing thereby exceeding PPI tolerance, terminating or accelerating the VT during pacing, or pacing-induced changing VT morphologies. Too large an isthmus, endocardial clot or epicardial fat, and intramural location are factors preventing a successful ablation even when entrainment mapping appears to have identified a reasonable site.

FIGURE 10-12. Schema of an area of scar, which generates a circuit for ventricular tachycardia (VT). The center is a protected region, which represents an isthmus for the VT circuit. Pacing from this area with entrainment of the tachycardia, which produces an exact 12-lead morphology as the clinical VT, is called concealed entrainment and identifies an excellent site for ablation. The exit site results in the surface QRS morphology. (Modified from William Stevenson, MD, with permission.)

FIGURE 10-13. A 12-lead electrocardiogram (ECG) demonstrating entrainment (first six beats) with a complete match of the clinical ventricular tachycardia (VT) morphology.

FIGURE 10-14. Demonstration of all three criteria for an excellent ablation site in the same ventricular tachycardia (VT) shown in Figure 10-13.

Substrate mapping has been suggested as an alternative approach for ablating VT, particularly for VT which is not hemodynamically tolerated. This technique involves mapping the ventricle of interest during sinus rhythm. Areas of low voltage indicating scar are identified. Lesions are then created between areas of scar and anatomic barriers (e.g., mitral valve annulus).

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.