what is limited first degree heart block
First Degree Heart Block Overview. What is a first degree heart block? A person with first degree heart block has a delay in the electrical impulse that travels through the heart. An electrical impulse stimulates the muscle fibers in the heart to contract. The impulse spreads through the heart in a very organized manner, so that the atria contract first, followed by the ventricles.
Background. First-degree atrioventricular (AV) block, or first-degree heart block, is defined as prolongation of the PR interval on an electrocardiogram (ECG) to more than 200 msec.V block is more common in the setting of inferior MI. In the Thrombolysis in Myocardial Infarction (TIMI) II study, high-degree (second-or third-degree) AV block occurred in 6.3% of patients at the time of presentation and in 5.7% in the first 24 hours after thrombolytic therapy.