VECTORCARDIOGRAPHIC MONITORING OF PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION AND CHRONIC BUNDLE-BRANCH BLOCK

Aims This study was set up to describe vectorcardiographic patterns in patients with bundle-branch block and acute myocardial infarction. Me thods and Results Sixty-five patients admitted to the coronary care un it with bundle-branch block and suspected acute myocardial infarction were monitored by dynamic vectorcardiography with trend analysis. In 2 8 patients, a clinical diagnosis of acute myocardial infarction was ma de. In patients with left bundle-branch block and acute myocardial inf arction, the pattern of QRS vector-difference evolution was similar to that in patients with the narrow QRS complex, while ST vector-magnitu de changes increased over time. Using a cut-off value for QRS vector-d ifference at 12 h of more than 20 mu Vs and a specific trend curve pat tern, acute myocardial infarction in the presence of left bundle-branc h block could be diagnosed with an accuracy of 71%. For patients with right bundle branch block, using a maximum ST vector-magnitude of >200 mu V during the first 4 h, acute myocardial infarction could be diagn osed with a 78% accuracy. Conclusion Our results indicate that dynamic vectorcardiography is a valuable tool in diagnosing and monitoring ac ute myocardiai infarction in patients with bundle branch block.