Windows Movie Maker is a fun and easy to use video editing program that allows you to make home movies, automated photo albums and business presentations. It is included as part of the Windows XP operating system. Version Version 2.1 of Windows Movie Maker can be downloaded for free, to upgrade your existing version.
1 When the natural pacemaker is defective, the heartbeat may be too fast, too slow or irregular. 2  Rhythm problems also can occur because of a blockage of your heart's electrical pathways. 3  The artificial pacemaker's pulse generator sends electrical impulses to the heart to help it pump properly. Your heartbeat is sometimes normal and sometimes too fast or too slow. 2  The sinoatrial (SA) node or sinus node is the heart's natural pacemaker. 3  It's a small mass of specialized cells in the top of the right atrium (upper chamber of the heart).
If the heart can't get enough blood pumping through the body, the body -- and especially the brain -- suffers from lack of oxygen. An artificial pacemaker sends out electrical impulses to mimic the heart's natural pacemaker, the sinoatrial node (SA node), located in the right atrium.hen the SA node sends out an electrical impulse, the first place it goes is to the AV node. While the SA node sets the rhythm of your pulse, the AV node sets the rhythm of your heart contractions. It delays the signal on its way to the ventricle, giving the atrium time to contract first.