Abstract 12696: What is the ECG significance of Myocardial Septal Late Gadolinium Enhancement Patterns by Cardiac MRI?
Background: Interventricular conduction delay is a progressive problem and in patients with congestive heart failure it portents a very poor prognosis, especially in those with LBBB. However, the myopathological etiology of IVCD remains poorly understood. Cardiac MRI (CMR) is a very sensitive method to delineate myocardial tissue abnormalities due to inflammation, ischemia, infarction or infiltration, and the relationship of the presence of any abnormal septal delayed hyperenhancement (DHE) to the conduction system may be important.
Hypothesis: We hypothesize that patients with conduction disorders on ECG will have abnormal myocardial septal DHE by CMR.
Methods: A retrospective study of 215 consecutive patients with DHE CMRI performed in the last 18 months and their most proximate ECG was analyzed for QRS duration, LBBB, RBBB and interventricular conduction delay (IVCD) pattern. The DHE image was analyzed for the presence (+) or absence (−) of any basal anterior or anteroseptal enhancement.
Results: Of the 215 patients, 175 ECG's were available within 1 month. Of those, 71 (40%) had a conduction defect on ECG: 19 patients (11%) had LBBB, 25 (14%) had RBBB and 27 (15%) had IVCD. Of those, 11% of the DHE+ patients had LBBB, as did 11% of the DHE- patients (p=NS). Similarly, 13% of DHE+ patients had RBBB while 16% of DHE- patients had RBBB (p=NS). Likewise, 20% of DHE+ patients had IVCD while 11% of DHE- patients had IVCD (p=NS). Fully 50/86 (58%) of DHE+ patients showed some type of ECG abnormality (RBBB, LBBB or IVCD), along with 64/89 (72%) of DHE- also revealing some level of conduction abnormality (χ2=3.07, 1 df, p=.08).
Conclusion: Counterintuitively, despite the high resolution capabilities of CMR, the presence or absence of DHE signal does not influence the ECG conduction pattern, suggesting that abnormal DHE patterns affect mechanical but not electrical properties within the heart. Surprisingly, the conduction system appears to be relatively ‘immune’ to disorders typically depicted by highly-resolved DHE imaging. We show for the first time that abnormal septal DHE patterns presence or absence does not routinely materially predict presence, absence or even type of conduction disorder.
- © 2010 by American Heart Association, Inc.