Dr Dave Richley’s ECG of the Month – October 2020 by SCST Council | Oct 8, 2020 | ECG Of The Month | 4 comments I don’t have any information about the patient, but can you provide a full description of the rhythm on this 3-lead recording? Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on WhatsApp (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to print (Opens in new window)Like this:Like Loading... 4 Comments Scott Walton on 15 October 2020 at 3:50 pm Sinus rhythm, first degree AV-block (PR ~220ms), with marked Q-waves in lead III (possible old inferior MI – deep inspiration please). Sinus P-wave rate is unchanged by ectopic beats, therefore we have no V-A conduction. I believe the short runs are deceptively broad, appearing narrow, but actually measure ~120ms in lead II. These short runs appear to be triggered by a distinctly different ventricular ectopic complex and could be caused by a Ventriculo-Hisian accessory pathway initiating a short self-limiting re-entrant arrhythmia. Reply Dave Richley on 20 October 2020 at 11:21 am As Scott says, this ECG seems to show sinus rhythm with 1st degree AV block and short runs of ventricular premature beats. I agree with him that the sinus rate is unchanged by the VPBs – I can make out dissociated sinus P waves throughout the ventricular ectopic activity. I also agree with Scott that although the premature complexes may appear narrow at first glance, they are actually 120 ms in duration when measured in lead II. Scott suggests that the ectopic runs may be reentrant in nature, initiated by the 1st VPB and involving a ventricular-Hisian accessory pathway. I must confess that this is beyond my level of knowledge – do any of SCST’s EP/arrhythmia experts have any comments to offer on this theory? One thing I disagree with Scott about is the usefulness of recording lead III on deep inspiration to determine whether or not the Q wave is pathological. I know this is standard practice in some departments but several studies back in the 1970s (1,2,3) failed to find any benefit in this manoeuvre and as far as I know there are no authoritative recommendations for it. I’m happy to be corrected though! If there is not a pathological Q wave in aVF (>25% of the R wave amplitude), then a Q wave in lead III can be ignored. References: 1. Shettiga UR, Hultgrenm HN, Pfeifer J, Lipton MJ (1974). Diagnostic value of Q-waves in inferior myocardial infarction. Am Heart J 88(3):170-175. https://doi.org/10.1016/0002-8703(74)90006-4 2. Bodenheimer MM, Banka VS, Helfant RH (1977). Determination of lead III Q waves significance. Utility of deep inspiration. Arch Intern Med 137(4):437-9. 3. Mimbs JW, deMello V, Roberts R (1977). The effect of respiration on normal and abnormal Q waves. An electrocardiographic and vectorcardiographic analysis. Am Heart J 94(5):579-84. Reply Scott Walton on 20 October 2020 at 10:02 pm If the lead III Q-wave confirms old MI then of course the ventricular runs may represent simple scar related re-entrant rhytms. Reply Buddhadeb Ganguly on 23 November 2020 at 3:43 pm Sir any chance of turn into nsvt Reply Submit a Comment Cancel replyYour email address will not be published. Required fields are marked *Comment Name * Email * Website Save my name, email, and website in this browser for the next time I comment.