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.
When your heartbeat speeds up for no apparent reason, however, that may be a sign of an abnormally rapid heartbeat â a condition called tachycardia (tachy means fast; cardia refers to the heart). Tachycardia can cause the heart to beat faster than 100 beats per minute, in some cases racing up to 400 beats per minute.Most Dangerous Rapid Heart Rhythms. Sudden rapid heartbeats originating in the ventricles are the most dangerous arrhythmias.ate If the heart rate is rapid, or greater than 100 beats a minute, it is considered a tachycardia. Alternatively, a slow heart rate, below 60 beats a minute, is known as a bradycardia.