- [voiceover] supraventricular tachycardia also known as svt refers toan abnormally high heart rate. the prefix supra means above. so supraventricular meansabove the ventricles. this right here is the heart and right now in green i'moutlining the ventricles. so again supraventricularmeans above the ventricles. the term supraventricular, implies that the abnormalheart beat is starting from,
at or above, the av node which is that orange structurei circled right here. the av node is the key player and the heart's electricalconduction 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 100 beats per minute. typically, young healthy peoplehave a heart rate between
1,580 beats per minute. now the 100 beats per minutecutoff applies to somebody who is at rest. it can be totally normalfor someone's heart rate to go above a 100 dependingon the circumstance. let's say you're the average person and you sprint 200 meters. your muscles are moving andthey're requiring more oxygen. therefore your heart isgoing to increase its rate
in order to supply the rest of your body and those muscles with more oxygen. so it would not be unrealistic for your heart rate to goabove 100 in this case. it's even normal for astrong emotional response, like intense fear, to pushyour heart rate over 100. imagine being terribly afraid of heights and cresting the world'shighest roller coaster. you can imagine that atthe 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 unreasonablefor your heart rate to go above a 100. however, in supraventricular tachycardia someone's going to have
a heart rate greater than a100 beats per minute, at rest. they're not going to have just run and not in the setting of anintense emotional reaction. now what are the signsand symptoms of an svt? well some people might havean svt and not even know it. it might be what's called asymptomatic, meaning they're not showing any symptoms. people that do havesymptoms might complain of, the feeling of a heartbeating out of their chest.
this is known as palpitations, and again, this is the feeling that their heart's beatingout of their chest. they can feel it pounding. because the heart's beatingso fast and working overtime, people might also experience chest pain. so chest pain is a common complaint. when your heart beats fastsome people feel anxiety. so anxiety is another symptom of svt.
other people say thatthey 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 heartto the rest of the body. when the heart's atrest it fills with blood and when you feel your heart beat
that's when the heart ispumping blood from the heart to the rest of the body, tosupply oxygen to the tissues. if your heart's beating really fast it doesn't get the chanceto 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 svts this is apretty rare occurrence. however, it's not uncommonfor people to feel dizzy. now how is svt diagnosed? well, symptoms alone aren'tenough 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 thatrecords and reports
information on the heart'selectrical activity. it's also needed to diagnose an svt and can tell you what type ofsvt a person is experiencing. now it's important to note that svts and other abnormal heart rhythms 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 getto the doctor's office,
their heart might haveswitched out of the svt. in this case, their ekg may be normal. if a patient has a normal ekg but has been reporting symptoms of an ekg such as i've been feeling palpitations, with shortness of breath and dizzy and the healthcare provider hasa strong suspicion of an svt they can send the patienthome, with a portable ekg. now will monitor theirheart's rate and rhythm
over the next couple of days. if that monitor detects anystrange heart rate and rhythm, it's going to alert the clinician and will record the ekg. because there are several types of svts there are multiple svt risk factors. people can have inheritedgenetic mutations that affect the heart cells, all the way down to the cellular level.
also, structural abnormalities that occur over alifetime of wear and tear can increase someone'srisk factor for an svt. another risk factor iscoronary artery disease. the coronary arteries are blood vessels that supply the heartwith oxygenated blood. over years the insideof the coronary arteries can get clogged and this inhibits the flowof 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 and 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 chronicobstructive pulmonary disease
have a higher risk of an svt. copd is typically found in people who have a longstanding 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 makestoo much thyroid hormone;
and pathologically highlevels of certain medications such as theophylline and digitalis.
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