I was a little sleepy last night regarding the pacemakers of the heart, the SA node is at top of heart & is normal pacer at 60-80/minute. AV node (at border of atria & vents.) is in center and acts as delay for transmission between the chambers.
When we experimented with AED''s some time ago I believe the units we used were from Heartsine (first models) and they were well made and pretty sturdy. We are really hard on equipment and didn''t break any. We always say if you put a fireman in a padded room with 2 bowling balls he''ll break 1 and lose the other. T