Glossary

Sinus Tachycardia (ST) is a normal variation in heart rate. Sometimes it is normal to have an increased heart rate. For example, during exercise, with a high fever, under stress, or even just breathing in and out. This fluctuation in the heart rate, called sinus tachycardia is a normal response to these stressors and is usually not considered a medical problem.

Supraventricular Tachycardia (SVT) is an abnormal fast heart rhythm that starts in the upper chambers, or the atria, of the heart.  Supraventricular means above the ventricles, “tachy” means fast, and “cardia” means heart.
SVT is often an umbrella term for any arrhythmia that originates above the ventricles.  There are many types of arrythmia that may be called SVT.

Normally, the heart’s electrical system precisely controls the rhythm and rate at which the heart beats.  In supraventricular tachycardia, abnormal electrical connections (or abnormal firing of the connections) cause the heart to beat too fast.  Typically, during SVT episodes, the heart beats faster than 100 beats per minute.  Sometimes the heart beats as fast as 300 beats per minute.  Usually, the heart returns to a normal rate (60 to 100 beats per minute) on its own or after treatment.

Paroxysmal supraventricular tachycardia (PSVT) and paroxysmal atrial tachycardia (PAT) are both types of SVT.

Loss of consciousness caused by lack of blood flow to the brain.  Symptoms just prior to syncope may include feeling dizzy or lightheaded.  Syncope in and of itself is not an indicator of a serious problem, as many things can cause syncope.  However, episodes of syncope should be investigated by a medical professional to determine the cause and course of treatment, if needed.

(Pronounced SIS-tuh-lee) Systole is the contraction phase of the cardiac cycle.  The word comes from the Greek systolē, from systellein to contract, and is usually associated with ventricular contraction, not atrial contraction.

When your blood pressure is being taken, your systolic pressure (the first number) is the measure of the pressure in your arteries when it is at it’s highest point, just after your heart’s ventricles have contracted, pushing blood around your body.