Abstract 1739: Alcohol Septal Ablation of Hypertrophic Cardiomyopathy Produces a Distinctive ECG Pattern
Alcohol septal ablation (ASA) of patients with hypertrophic cardiomyopathy (HCM) produces necrosis limited to the base of the interventricular septum. Atherothrombotic occlusion of the left anterior descending coronary artery proximal to the first septal perforator (pLAD) may infarct the same area together with adjacent left ventricle free wall. The ECG of the latter is said to be identified by new RBBB, ST elevation in V1 >2.5mm, or ST depression in aVF. This study was designed to uncover differences from this pattern that might be peculiar to the effect of ASE because the alcohol-induced necrosis is confined to the basal septum. 84 consecutive pts underwent ASA for HCM. ECGs recorded immediately prior to and after the ASA were reviewed. 20 pts with pacing prior to ASA and 6 in whom no preprocedure ECG was available were excluded. The ECG’s of the remaining 58 pts were examined with attention to the patterns previously attributed to pLAD occlusion. A comparison cohort of 58 consecutive pts with anterior ST-elevation myocardial infarction was identified from the CCU database. All had acute angiography. LAD occlusion was proximal to the first septal branch (pLAD) in 25 and more distally (dLAD), in 33. New RBBB appeared in 29 (50.0%) ASA pts and 3 (12.0%) pts with pLAD occlusion (p=0.001). Pacing was required in 8 (13.7%) ASA and 1 pLAD pts (p<0.05). ST in V1 exceeded 2.5 mm in 6 (10.9%) ASA pts and 4 (16%) pLAD pts (p=ns). The table compares the frequency of ST segment deviation (≥1mm) in pertinent leads in the 55 pts in whom an unpaced post-procedure ECG was available to the frequency in the same leads in 58 pts with LAD occlusion.
Conclusions: The post ASA ECG may be distinguished from that of occlusion of the LAD by a greater frequency of new RBBB or advanced heart block, a greater frequency of a rightward and superiorly directed ST segment, and by greater ST elevation in V1 than in V2.