Sand should be part of the topdressing used to topdress your field after aerating and before overseeding. However, this section on sand is for a different use of sand. Sanding the baseball field turf, especially the infield, is a good practice.and should be part of the topdressing used to topdress your field after aerating and before overseeding. However, this section on sand is for a different use of sand. Sanding the baseball field turf, especially the infield, is a good practice.
Atrioventricular (AV) Block. A slow heart rate can be due to many causes, including the earlier described sick sinus syndrome (SSS). Another cause, atrioventricular block (AV block), is due to abnormally slowed electrical conduction of the sinus impulse through the AV node.
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.