Title What is baseballâs âmodern eraâ? The start of the 20th century might not seem particularly modernâafter all, there were only 45 states in the Union, hardly anyone owned a car (the Model T didnât debut until 1908) and William McKinley, a Civil War vet, occupied the White House.
Sinus tachycardia is a normal increase in the heart rate. How it happens. The sinoatrial (SA) node --- the heart's natural pacemaker-sends out electrical signals faster than usual. The heart rate is fast, but the heart beats properly.inus tachycardia is a normal increase in the heart rate. How it happens. The sinoatrial (SA) node --- the heart's natural pacemaker-sends out electrical signals faster than usual. The heart rate is fast, but the heart beats properly.
This is another type of fast heartbeat. It's caused by there being an extra pathway through a part of the heart called the AV node. It can cause heart palpitations, fainting, or heart failure. In some cases, you can stop it simply by breathing in and bearing down. Some drugs can also stop this heart rhythm.ecause the heart is beating too fast, it can't fill up with enough blood. This can be a serious arrhythmia -- especially in people with heart disease -- and it may be linked to other symptoms. Ventricular fibrillation. This happens when the heart's lower chambers quiver and can't contract or pump blood to the body.