Abstract 9955: Suboptimal Diagnosis and Interventional Treatment of Patients with Bundle Branch Block and Acute Myocardial Infarction
Several studies have shown the benefit of rapid revascularization in patients with presumed new-onset bundle branch block myocardial infarction (BBBMI). It is a major challenge to determine the age of the bundle branch block (BBB) and triage accordingly in the acute setting.
Methods Prehospital ECGs, final diagnosis and mortality were assessed in 4905 consecutive patients with suspected AMI. BBB was defined as QRS duration >120 ms in the absence of pace-rhythm, AV-block or ventricular rhythm. Mortality and angiography data were obtained from the Danish Cause of Death Registry and the Western Denmark Heart Registry. Final diagnosis of AMI and the onset of BBB were determined by expert consensus. Patients were divided into 4 groups +/-AMI and +/- BBB. Mortality was evaluated by Kaplan-Meier plots using Log rank statistics.
Results AMI was diagnosed in 954 patients, of whom 118 had BBBMI. In the 3951 patients without AMI, 436 had BBB. Coronary angiography (CAG) was performed in significantly fewer patients with BBBMI compared to patients with AMI without BBB (41% vs. 68%, p<0.001). In patients undergoing CAG, revascularization was more frequent in AMI patients without BBB (59% vs. 79%, p=0.002). BBBMI was categorized as new-onset in 43 patients. Significantly more patients with new-onset BBB underwent CAG compared to patients with established BBB (67% vs. 26%, p<0.001). Among those undergoing CAG, there was no difference frequency of revascularization between the groups (59% vs. 58%, p=0.99). Among patients with an adjudicated diagnosis of new-onset BBBMI 2/43=5% were triaged for acute angioplasty. Patients with BBBMI had the highest mortality of all groups (Log-rank p<0.001) (Figure).
Conclusions: Patients with new-onset BBBMI seem to be difficult to diagnose based on ECG and symptoms, leading to low rates of invasive procedures despite high mortality. To improve outcome we recommend a more aggressive approach to diagnosing and triaging patients with BBB and chest pain.
- © 2012 by American Heart Association, Inc.