Perimitral flutter with a long epicardial bypass tract successfully treated by selective ethanol infusion to a branch of the vein of Marshall

We present a 83-year-old woman suffering from paroxysmal AT after three AF procedures including isolation of pulmonary veins (PVs) and posterior left atrium (LA), linear lines for the cavotricuspid isthmus and anterior LA. The activation map during left atrial appendage (LAA) pacing showed extensive scar in the posterior and anterior walls with activation appearing at the septal edge of the large anterior scar (Panel A). Although no EGMs were identified in this area and low-output pacing did not capture the LA, high-output did. The activation map of an induced clinical AT (cycle length = 409 ms) showed a centrifugal activation from the ridge between the left PVs and LAA. However, entrainment mapping diagnosed the AT as PMF using a long epicardial bypass tract on the anterior roof (Panel B). Endocardial radiofrequency applications along the origin of the centrifugal activation on the ridge (Panel B, yellow tag) failed to affect the AT. Because of a risk of the LAA being isolated with mitral isthmus block, the distal VOM branch (Panel C, blue dotted circle) corresponding to the level of the inferior ridge was selectively targeted under fluoroscopic guidance for ethanol infusion (Panel C). One millilitre ethanol infusion terminated the AT, and the selective lesion on the ridge without LAA isolation was achieved (Panel D).
Source: Europace - Category: Cardiology Source Type: research
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