Supraventricular tachycardia (SVT) | ACLS-Algorithms.com

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    • Jeff with admin. says

      It can be difficult to identify p-waves when a patient has SVT. Most of the time they will be buried in the QRS complex. The easiest way to ensure that the patient has p-waves is to slow the heart rate down so that the p-wave can be visualized. If the rate is regular most likely there is a p-wave that is buried, and if the rhythm is irregular there is a high likelihood that the pt. has atrial fibrillation. In the case of atrial fibrillation that has a rapid ventricular rate, they will not have p-waves before the QRS complexes.

      Simply put if the rate is regular there is most likely a p-wave in there. If it is irregular there is a high likelihood of no p-wave present.
      Best option is to slow the heart rate down and see what is going on.

      Kind regards,
      Jeff

  1. kim says

    Just wondering if and at what rate to convert a stable sinus tachycardia. I think I must have missed that.
    Thanks for your great work and sharing it with us!
    Kim (PA-C)

    • Jeff with admin. says

      Sinus Tachycardia is not considered an arrhythmia and would have some underlying cause that would need to be treated. For example, the following things cause stable sinus tachycardia: fever, dehydration (hypovolemia), medications, and exercise. For stable sinus tachycardia, your main action should be to reverse whatever conditions exist that are making the heart beat more rapidly.
      Kind regards,
      Jeff

  2. Bob says

    Jeff:
    Started reviewing ACLS materials and see Re-entry SVT showing on AHA practice strips. Can you give some overview on this rhythm identification, characteristics, etc. Also, do you not have algorithm information and review on Acute Coronary Syndrome? Thanks for all the great information!

    • Jeff with admin. says

      Thanks for contacting me. RSVT is the most common form of SVT. More specifically it is called AV nodal reentrant tachycardia. Stimulation of the atria occurs at the same time as stimulation of the ventricles. As a result, the p waves may not be seen (buried in the QRS complexes), and at times the p waves may be seen after the QRS waves. What is commonly seen as SVT is (RSVT OR AVNRT). This is the most common form of regular SVT. The main symptom is palpitation. The Review of SVT above essentially covers this type of SVT.
      Atrioventricular nodal reentry tachycardia (AVNRT) is the most common type of reentrant supraventricular tachycardia (SVT). The substrate for AVNRT is the presence of dual AV nodal pathways.
      I have not yet developed an algorithm AHA ACS Syndrome at the site. Here is a link to the AHA diagram.

  3. Omaril6113 says

    Hello Jeff,
    thank you very much for your amazing website. It helps me with my preparation for my first ACLS. I am ashamed to ask, but please, could you explain to me the different between STABLE and UNSTABLE tachycardia? I have learned how to treat VF,VT,but still I am confused of this. Sorry for my English, it is not my mother language.
    Thank you and wish you the best.

    • Jeff with admin. says

      The difference between stable and unstable tachycardia is unstable tachycardia has progressed to the point at which blood perfusion to the vital organs is being affected and the patient is have signs and symptoms that indicate instability. Hypotension (systolic BP less than 90); changes in level of consciousness, and chest pain to name a few.
      Stable tachycardia has not yet progressed to the point at which perfusion to the vital organs is being affected.
      Kind regards,
      Jeff

  4. Sandra says

    Heard a doctor say once, that they have the patient try and blow the plunger out of a 5-10 mL syringe.
    First he show’s the patient how easy it is to move the plunger by puling it back and forth in within the syringe and then he has the patient do it. Reasoning: It is usually a more “dignified” vagal maneuver, because the patient is less apt to be incontinent of stool. In which case, is the patient is concerned about embarrassing themselves in this situation and they may not bare down as forcefully as they should, as compared to blowing really hard trying to push the plunger out of the syringe. I have not seen this I action, but it sounds like a good idea.

    • Kevin says

      Interesting variation on the valsalva Sandra.. I’ve always liked pressing into the pts abd while they contract and resist pressing into their abd. Obviously most of the time it is something that only younger, healthier individuals can easily perform. Same concept is any vagal maneuver is that you are attempting to increase intraabdominal and intrathoracic pressure and stimulating the vagus nerve elliciting a parasympathetic response.

      • nora says

        what about cold water splash (mammalian reflex ) I used this many times and it was effective , either splashing cold water to the face of the patient or putting iced bag on the forehead of anesthetized patient during surgery .
        thanks

      • herb_wms says

        Sounds cool, pun totally intended, but you can also get a big dose of adrenaline.
        I think increased vagal tone without the adrenaline is safer. Have never read this anywhere, just my thoughts.

        I like the syringe idea.

        Herb

  5. Raman says

    Inverted p waves are seen in VTach because the conduction is retrograde but why in SVT?Please clarify?

    • Jeff with admin. says

      You would not normally see p-waves in VT. In SVT, the most common type being AVNRT (Atrioventricular nodal reentrant tachycardia). P waves if visible exhibit retrograde conduction with P-wave inversion.
      P waves may be buried in the QRS complex, visible after the QRS complex, or very rarely visible before the QRS complex.
      Here is a detailed article from AHA on the subject.

    • Jeff with admin. says

      Stable SVT would be a supraventricular tachycardia in which the patient is having no symptoms that classified as unstable (hypotension SBP<90, changes in level of consciousness, chest pain). For instance, some time ago I took care of a 50 something female with SVT (HR 160's). Here only symptom was having the feeling that her heart was racing. No chest pain, no hypotension, etc. She was stable. I hope this makes sense. Kind Regards, Jeff

      • Vicki Behrens says

        I am one of those 50-something females who have AV nodal re-entrant tachycardia with no other symptoms. Only tachycardia …and a feeling like a 10# weight is whirling about in my chest. This started in August for me. I am excited to be scheduled for an ablation on the 16th of this month. As a B.S.N, appreciate the site also!

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