1. Thanks this is very helpful. This remains a diagnostic dilemma particularly in the population who are at risk of both VF and SVT. I shall use this rubric for my residents when they want to know how to differentiate. Thanks again…

  2. Excellent teaching module, very brief, precise and to the point. Thank you and keep up the good work !

  3. Thank you!
    You have put it simple the differences between VT & SVT with aberrancy. I now fully understand and that I will teach the same to the Residents and Medical students.
    A very useful site!

  4. Great EKG’s and commentary, it also makes it easier when you consider the patient’s status -- if they are unstable it’s makes the management choice a lot easier given it’s the same. Shock’em!

  5. First, I would like to compliment everyone involved with LITFL for such an amazing and needed website. I refer my ECG students to it frequently (I teach advanced electrocardiography here in Houston, Texas). I do have a bit of input, however, regarding your rhythm strip selection illustrating a capture beat. The “capture beat” shown is unquestionably a supraventricular impulse that has indeed “captured” the ventricles, but it really isn’t a “capture beat.” A capture beat must be early. By appearing early, it has proved two and perhaps three things: 1) the AV node and bundle branches are quite capable of conducting normal narrow beats at a rate as fast or faster than the wide complex rhythm thus disproving a rate-related bundle branch block, 2) that there is no pre-existing permanent bundle branch block and 3) that if the wide complex tachycardia persists, then it is very unlikely to be an antidromic AVRT (WPW) because the appearance of the AV-conducted beat would have interrupted the re-entry cycle and terminated the dysrhythmia. While the captured beat shown certainly proves that there is no pre-existing permanent bundle branch block, it appears at an interval that is much longer than the R-R intervals of the wide rhythm, so conceivably, the pause could have given the bundle branches time to refresh and conduct a normal appearing QRS complex. In that case, a rate-related bundle branch block due to an SVT really hasn’t been ruled out. I hope this information is useful and again, thank you for maintaining this much-needed site.

  6. An excellent description and explanation. Thank you very much . I will refer residents to this site.

  7. Capture beat, though not part of Brugada, Miller’s or Josephson criteria is a very strong criteria. If present, it confirms the diagnosis of VT.

    • A capture beat implies AV dissociation which is indeed part of the Brugada criteria. Actually, while AV dissociation is a good indication of VT it is still possible for a wide complex tachycardia with AV dissociation to be supraventricular. Marriott published an ECG in which a junctional tachycardia developed in a patient with a preexisting LBBB, resulting in AV dissociation.

  8. Standard limb lead negative concordance is yet another sign diagnostic for VT.If leads 1,2,3 show QS complexes without any R wave at all is diagnostic of VT(paper published in
    chest journal by G.V.Reddy


  1. […] tachycardia (VT),  supraventricular tachycardia (SVT) with aberrancy and pacemaker rhythms.For more on WCT from the LITFL ECG Library, click hereQ2. What clinical features help differentiate VT from SVT? Answer and […]