This week Consumer Reports released news that arsenic was found in brown rice, white rice, rice breakfast cereals, organic rice baby cereal, and other rice productsââmany at worrisome levelsââin tests they performed.
First-degree heart block. First-degree AV block is defined as a PR interval longer than 0.2 seconds. Each atrial activation leads to a ventricular activation with a 1:1 correspondence.
The PR interval will vary in second-degree AV block type I (Wenkebach). Note that the PR interval can be altered by changing sympathetic and parasympathetic tone. Because of this, medications such as beta-blockers can lengthen the PR interval and result in a first-degree AV block.