Bradyarrhythmias and conduction disturbances are well-recognized complications of acute myocardial infarction (MI). They are induced by either autonomic imbalance or ischemia and necrosis of the conduction system. It is important to recognize which bradyarrhythmias are transient and which are likely to progress to irreversible and symptomatic high-degree block.
The major conduction abnormalities associated with acute MI will be reviewed here; tachyarrhythmias, the other major dysrhythmic complication of MI, are discussed separately. (See "Supraventricular arrhythmias after myocardial infarction" and "Clinical features and treatment of ventricular arrhythmias during acute myocardial infarction".)
Issues related to LBBB — There are two specific issues related to left bundle branch block (LBBB) in association with an acute MI:
●LBBB can complicate the electrocardiographic diagnosis of MI. (See "Electrocardiographic diagnosis of myocardial infarction in the presence of bundle branch block or a paced rhythm".)
●Patients with a new or presumably new LBBB are treated as if they have an ST elevation MI . (See "Overview of the acute management of ST elevation myocardial infarction".)