tag:blogger.com,1999:blog-549949223388475481.post4211370010261832407..comments2024-03-28T14:02:08.119-05:00Comments on Dr. Smith's ECG Blog: A very fast narrow complex tachycardia in an InfantUnknownnoreply@blogger.comBlogger2125tag:blogger.com,1999:blog-549949223388475481.post-34005536262774690872017-01-22T14:43:05.027-06:002017-01-22T14:43:05.027-06:00thank you
thank you<br />Anonymoushttps://www.blogger.com/profile/07052330051789958982noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-2631392228510774542017-01-22T13:51:52.317-06:002017-01-22T13:51:52.317-06:00Most of us (assuming no pediatric cardiologists ar...Most of us (assuming no pediatric cardiologists are listening) do not see a large number of pediatric arrhythmias (certainly far less than we’ve all seen in adults). As a result — level of comfort in both diagnosis and management tends to be less than that attained with adult arrhythmias. As wonderfully emphasized by Dr. Smith by the 2 pediatric arrhythmia examples shown here — accurate determination of rate is CRITICAL in the assessment of pediatric arrhythmias. For this determination — I have found use of the “Every-other-Beat” (or sometimes, “Every-third-Beat”) method a user-friendly way to rapidly and accurate determine heart rate for any regular fast rhythm. While most of us recall, “300- 150 - 100 - 75 - 60 - 50” as the answers for rate calculation when the R-R interval of a regular tachycardia is 1, 2, 3, 4, 5 or 6 large boxes, respectively — this becomes problematic with very fast rates. That’s because small differences in measurements may translate into significant under- or over-estimates of rate when rounding off dimensions of the R-R interval. But IF you instead only look at every-OTHER beat — you’ll find it a MUCH more accurate way for determining HALF the rate — which you then just double to accurately determine the actual rate.<br /><br />START by selecting a part of the QRS complex that begins or ends on a heavy line. For example — the 3rd S wave in lead 1 of the 1st ECG here begins right on a heavy line (it begins on the 4th heavy line that we see). Now count over 2 beats. You should see that 2 beats over (ie, the 5th beat in lead I) shows the S wave point to be just in front of the 7th heavy line). This means that 2 beats have occurred in just UNDER 3 large boxes. This means that HALF the rate is just a little bit faster than 100/minute, or~110/minute. Since HALF the rate ~110/minute — if we double this, we get 220/minute as an accurate estimate of the rate.<br /><br />Knowing that infants and young children may have sinus tachycardia rates of 200-220/minute then tells us NOT to worry about the rate of 220/minute seen here in which there are clear sinus P waves. The slight right axis and incomplete RBBB pattern we see here are also not of concern.<br /><br />The rate in the 2nd example here is easier to determine — because the R-R interval is approximately 1 large box in duration — which we know corresponds to a heart rate of ~300/minute. One might also think of AFlutter with 1:1 conduction in the differential — though prompt resolution with adenosine confirmed reentry SVT in this case. (Of note — AFlutter is a highly unusual rhythm in otherwise healthy children — but when it occurs, the rate of the atria with pediatric flutter may actually be much faster than the 250-350/minute range typically seen for flutter in adults). THANKS for presenting these insightful examples Steve!ECG Interpretationhttps://www.blogger.com/profile/02309020028961384995noreply@blogger.com