tag:blogger.com,1999:blog-549949223388475481.post1914711908405541156..comments2024-03-28T14:02:08.119-05:00Comments on Dr. Smith's ECG Blog: Hyperkalemia in the setting of Left Bundle Branch BlockUnknownnoreply@blogger.comBlogger7125tag:blogger.com,1999:blog-549949223388475481.post-25448587615514802272019-08-07T22:51:28.419-05:002019-08-07T22:51:28.419-05:00i have a question ...in LBBB R wave always should ...i have a question ...in LBBB R wave always should be positive in 1 and v6 ? or it can be negative in V6 also ?Anonymoushttps://www.blogger.com/profile/13057528237109176348noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-80473570223100982152012-12-01T08:00:57.215-06:002012-12-01T08:00:57.215-06:00Thanks Dr. SmithThanks Dr. SmithAnonymoushttps://www.blogger.com/profile/10900423767859353173noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-86975220414477073912012-11-30T13:53:43.933-06:002012-11-30T13:53:43.933-06:00Pay attention to the QRS, not QTc. Calcium will s...Pay attention to the QRS, not QTc. Calcium will shorten the QRS only in hyperkalemia. Hypercalcemia does not result in a short QRS, only a short QT as a result of a short ST segment. If the QRS is shorted by calcium, it is not a bundle branch block.<br /><br />Steve SmithSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-55210976395109470442012-11-30T12:26:09.409-06:002012-11-30T12:26:09.409-06:00Dr. Smith
Lets say you have a patient that you th...Dr. Smith<br /><br />Lets say you have a patient that you think might have hyperkalemia, but on the ECG you're not 100% sure if it is a preexisting bundle branch block or if the widened QRS is from hyperkalemia. Let's also say you decide to go ahead and treat for hyperkalemia (for example CaCl 1 gram and 2 amps (90 meq) of sodium bicarbonate). <br /><br />With the treatment the QRS duration shortens from 169 ms to 149 ms, and the QTc shortens from 534 ms to 492 ms. (The HR decreases from 88 to 82). <br /><br />Do the results prove or strongly suggest hyperkalemia? Or can the treatments narrow the QRS of a BBB and shorten the QTc? (I suspect the CaCl would shorten the QTc regardless of the presence or absence of hyperkalemia). <br /><br />Thanks,<br />MikeAnonymoushttps://www.blogger.com/profile/10900423767859353173noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-23453673845265787172012-10-06T17:44:02.398-05:002012-10-06T17:44:02.398-05:00Mike,
Good point! Either way, 220 ms is too long...Mike,<br /><br />Good point! Either way, 220 ms is too long for RBBB, LBBB, or IVCD.<br /><br />Steve SmithSteve Smithhttps://www.blogger.com/profile/08027289511840815536noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-65587112002399573252012-10-06T17:03:43.050-05:002012-10-06T17:03:43.050-05:00Dr. Smith,
With the deep S wave in V6, would the ...Dr. Smith,<br /><br />With the deep S wave in V6, would the first ECG not be more accurately interpreted as a Nonspecific Intraventricular Conduction Delay? And therefore another factor leading one to consider hyperkalemia? <br /><br />In the second ECG the NIVCD has resolved and there is a typical LBBB pattern with fully upright broad R or RsR waves in both Leads I and V6.<br /><br />Mike SherriffAnonymoushttps://www.blogger.com/profile/10900423767859353173noreply@blogger.comtag:blogger.com,1999:blog-549949223388475481.post-85782956171024462492012-10-06T07:54:33.471-05:002012-10-06T07:54:33.471-05:00Hmmm.. Easy to assume the widened QRS is from the ...Hmmm.. Easy to assume the widened QRS is from the bundle branch block, rather than hyperkalaemia. Especially when a nurse flicks an ECG in front of your nose to sign, without any story that could suggest to you electrolyte disturbance.Anonymoushttps://www.blogger.com/profile/00135836224689876195noreply@blogger.com