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Video transcript

super ventricular tachycardia also known as s B T refers to an abnormally high heart rate the prefix Supra means above so super ventricular means above the ventricles this right here is the heart and right now in green I'm outlining the ventricles so again super ventricular means above the ventricles the term super ventricular implies that the abnormal heartbeat is starting from at or above the a B node which is at orange structure I circled right here the AV node is a key player and the heart's electrical conduction system now tachycardia refers to a heart rate greater than 100 beats per minute at rest a person's heart rate should be under a hundred beats per minute typically young healthy people have a heart rate between 50 and 80 beats per minute now the hundred beats per minute cutoff applies to somebody who is at rest it can be totally normal for someone's heart rate to go above 100 depending on the circumstance let's see the average person and you sprint 200 meters your muscles are moving and they're requiring more oxygen therefore your heart is going to increase its rate north to supply the rest of your body and those muscles with more oxygen so it would not be unrealistic for your heart rate to go above 100 in this case it's even normal for a strong emotional response like intense fear to push your heart rate over 100 imagine being terribly afraid of heights in cresting the world's highest rollercoaster you can imagine that at the top of that crest your heart would be beating pretty fast that's because in times of intense fear the body sends out chemical signals to increase your heart rate this is another scenario where it wouldn't be unreasonable for your heart rate to go above 100 however in super ventricular tachycardia someone's going to have a heart rate greater than 100 beats per minute at rest they're not going to just run and not in the setting of an intense emotional reaction now what are the signs and symptoms of an SVT well some people might have an SVT and not even know it there might be what's called asymptomatic me they're not showing any symptoms people that do have symptoms might complain of the feeling of a heart beating out their chest this is known as palpitations and again this is the feeling that their heart's beating out of their chest they can feel it pounding because the heart's beating so fast and working overtime people might also experience chest pain so chest pain is a common complaint when your heart beats fast some people feel anxiety so anxiety is another symptom of SVT other people say that they feel short of breath sometimes people say they feel dizzy or that they're going to pass out now why do people feel dizzy well let's remember the heart serves as a pump to pump blood from the heart to the rest of the body when the heart's at rest it fills with blood and when you feel your heartbeat that's when the heart is pumping blood from the heart to the rest of the body to supply oxygen to the tissues if your heart's beating really fast it doesn't get the chance to fill with as much blood therefore the circulation of the blood to the rest of the body including the head can be compromised that's why sometimes people feel dizzy rarely people might even pass out but with svt's this is a pretty rare occurrence however it's not uncommon for people to feel dizzy now how is SVT diagnosed well symptoms alone aren't enough to diagnose an SVT however they can give a practitioner clues that someone might be experiencing an SVT if a healthcare provider suspects an SVT they're going to order an EKG an EKG is a device that records reports information on the heart electrical activity it's also needed to diagnose an SVT and can tell you what type of SVT a person is experiencing now it's important to note that SVT's and other abnormal heart rhythm can be here one second and gone the next that means a person might be experiencing symptoms of an SVT when they're at home but by the time they get to the doctor's office their heart might have switched out of the SVT in this case their EKG may be normal if a patient has a normal EKG but it's been reporting symptoms of an EKG such as I've been feeling palpitations with shortness of breath and dizzy and the healthcare provider has a strong suspicion of an SVT they can send the patient home with a portable EKG that will monitor their hearts rate and rhythm over the next couple days if that monitor detects any strange heart rate and rhythm is going to alert the clinician and will record the EKG because there are several types of SVG's there are multiple SVT risk factors people can have inherited genetic mutations that affect the heart cells all the way down to the cellular level also structural abnormalities that occur over a lifetime of wear and tear can increase someone's risk factor for an SVT another risk factor is coronary artery disease the coronary arteries are blood vessels that supply the heart with oxygenated blood over here is the inside of the coronary arteries can get clogged and this inhibits the flow of blood to the heart years of coronary artery disease leads to chronic heart failure which is a condition where the heart has a diminished pump function they can't pump blood from the heart to the rest of the body as well there are also risk factors outside of the heart such as the lungs people with COPD or chronic obstructive pulmonary disease have a higher risk of an SVT COPD is typically found in people who have a long-standing smoking history also a blood clot in the lung known as a pulmonary embolus will increase your risk of an SVT other non cardiac risk factors are years of alcohol abuse hyperthyroidism which is a condition where the thyroid gland makes too much thyroid hormone and pathologically high levels of certain medications such as theophylline and digitalis