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EKG05: Sinus Tachycardia

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Podcast Transcription

Hi guys, and welcome to the podcast. My name is Katie Cleaver and I’m your host and today we’re going to talk about sinus tachycardia. When your patient has sinus tachycardia, what does that look like on an EKG strip? It’s something that in kind of nurse slang and in report, “Hey, the patient’s tachy.” That’s kind of something we say a lot. Sinus tachycardia, which is also called tachy, is basically when the heart is beating more than 100 beats per minute and this is due to the rapid firing of the SA node. So when you’re looking at that EKG strip, all wave forms are present, so it makes this is a fast, but steady arrhythmia, okay? So, remember, when you’re looking at that strip, the P, QRS waveforms and everything is present and regular, it’s just faster than 100 beats per minute, okay?

So bradycardia or brady is less than 60, tachycardia is greater than 100. Pretty straightforward. If you want to check out a awesome PDF that has these all differentiated, because I’m explaining them, but it’s hard to explain them and not see them, so if you go to and you see on our top menu, the far right is “Cheat Sheets” and if you click that, one of the options is an EKG strips and you can download it for free and you get a great PDF. So, you can print it and do whatever you want with it. We also have a wonderful EKG course that dives much farther into depth than I’m going to in this podcast, but it explains everything so detailed and it’s wonderful. I don’t teach it, someone else does, but it’s, guys, it’s wonderful and you can pay a dollar and check it out for three days. It’s wonderful. All right, that is at Let me continue.

So what causes sinus tachycardia? Lots of things can cause that. Let’s go through a couple of them. Heart tissue damage, like a myocardial infarction, like a heart attack, or a heart failure. Maybe some abnormal vital signs, fever, hypertension, pain can cause someone to be tachycardic. Stress, anxiety, or fear can really do that. Alcohol, caffeine, or nicotine. Cocaine definitely does that. Electrolyte imbalances, hyperthyroidism, anemia, hemorrhage. Keep in mind, that list is not all inclusive. Those are just some top ones.

So what could happen to someone who’s in sinus tachycardia? So, think about this. If you had a higher heart rate, you’re going to have a decreased cardiac output because that heart is not going to be able to pump as much. It doesn’t have as much time to pump out the blood, all right guys? So, sinus tachycardia causes decreased cardiac output due to inadequate ventricular filling as well as an increased oxygen demand for the myocardial cells. I want to repeat that. That’s very important. Sinus tachycardia causes decreased cardiac output due to [inaccurate 00:03:17] ventricular filling as well as an increased oxygen demand for the myocardial cells. Translation: You’ve got pump, it doesn’t have enough time, those ventricles don’t have enough time to fill up with blood in between each of those beats, so that’s what results in that decreased cardiac output. Also, the heart itself has an increase in oxygen demand for those myocardial cells. It is working hard. So, those are two things, ventricular filling and the myocardial oxygen demand, all right?

So a patient with sinus tachycardia may have some signs and symptoms. You may have some people that have absolutely no clue they’re tachycardic. Sometimes that happens, but we also have patients that are very symptomatic. Some of those symptoms include dizziness, lightheadedness, syncope. Remember we have decreased cardiac output, would make sense if we’re having lightheaded, syncope, and dizziness. Chest pain. Some patients can actually feel, “Oh, I can feel my heart is racing, it’s just racing.” So they kind of feel this fast heart rate. They may feel, maybe they may call that palpitations, and they also may have shortness of breath. So those are some symptoms.

Let’s take a look at how we can treat tachycardia. So the treatment is really dependent upon the cause, so you can’t just say kind of like bradycardia, “Okay, I’m just going to give atropine because of their symptomatic bradycardia.” But sinus tachycardia is a little different. We’ve got to make sure we understand, not saying you don’t need to understand this with bradycardia, but the treatment relies heavily on the cause in tachycardia. So, for example, if a patient has a fever, you probably want to give Motrin or Tylenol. If the patient is having a high heart rate because they’re having an anxiety attack, let’s give them some Valium, let’s give them some Ativan, you know? Or let’s say if the patient has this narrow QRS complex, then we need to maybe treat them with a vagal maneuver, so having them bear down. Adenosine, beta blockers, calcium channel blockers, or they may even require a synchronized cardioversion. But if the patient has a wide QRS complex, then we may need to treat them with an anti-arrhythmic like amiodarone or something.

So, that’s a little information about sinus tachycardia. Go to and click “Cheat Sheets” and then check out that EKG cheat sheet. It looks wonderful. It’s really, really helpful. We also have a great blog post about interpreting EKG rhythms. If you just Google “How to interpret EKG rhythms like a boss,” it will be the first one that comes up. Both of those are free resources, and we also, again, have our EKG course, an entire course about EKGs, go way into depth on everything. So that you can access at