Abstract 13224: Cardiovascular Outcomes of Patients With Intraventricular Conduction Blocks: 16 Year Follow-Up in a Statewide Database
Objectives: In previous studies, apparently normal individuals with left axis deviation (LAD) associated with left bundle branch block (LBBB) or left anterior hemiblock (LAHB) had higher mortality compared to right bundle branch block (RBBB) and LBBB without LAD. The presence of LAHB alone or in combination with RBBB is associated with delay in depolarization of the posterobasal segment of the left ventricle with adverse consequences in overall LV function and mitral valve competency. We compared the occurrence of adverse outcomes of intraventricular blocks (IVB).
Methods: In a 16 year follow up using the Myocardial Infarction Data Acquisition System (MIDAS), a statewide database, we studied the occurrence of mitral regurgitation (MR), atrial fibrillation (AF), heart failure (HF), cardiovascular death and all cause death among patients with LAHB (n=3888), RBBB and LAHB (n=970), LBBB (n=6744) compared to RBBB (n=13454). We excluded patients with coronary artery and congenital heart disease. Patients with MR, AF, CAD, HF, pacemaker, CABG or PCI before the diagnosis of IVB were excluded.
Results: MR occurred more frequently only among patients with LBBB (adjusted HR 1.681 95% CI 1.469, 1.923, p<.0001). For AF, LAHB and LBBB were associated with significant excess risk (adjusted HR 1.147 95% CI 1.020, 1.291, p=.0223 and 1.341 95% CI 1.217, 1.478, p<.0001 respectively). HF was significantly higher in all three groups (p<.0001) compared to RBBB without LAD (HR 2.614 95% CI 1.891, 3.614, 2.396 95% CI 1.671, 3.436 and 3.770 95% CI 2.745, 5.179 respectively). CV death was higher in LAHB (HR 2.608 95% CI 1.683, 4.043; in RBBB with LAD HR 2.628 95% CI 1.645, 4.199) and LBBB (HR 2.696 95% CI 1.746, 4.162, for all p<.0001). For all cause death excess risk was (HR 1.593 95% CI 1.241, 2.045, p=.0003; 1.622 95% CI 1.238, 2.125, p=.0004; 1.477 95% CI 1.153, 1.892, p=.0020 respectively) for the 3 groups compared to RBBB. LBBB in the MIDAS database does not differentiate between LBBB with and without LAD to establish the percentage of LBBB with LAD.
Conclusions: The presence of LAHB alone or in combination with RBBB as well as LBBB imparts increased risk of AF, HF, CV mortality and all cause mortality. The risk appears higher for RBBB with LAHB compared to the other two groups.
- © 2012 by American Heart Association, Inc.