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Chest Percussion Therapy


What on earth?  Looks bad, doesn't it?  But look at the bottom lead: the R-R interval is regular at 0.39 seconds, giving a rate of 154, the QT interval is 0.22 seconds, a little short of normal for this lead, and the P-R interval is 0.14 seconds.  This is a simple supraventricular tachycardia.   What about the other leads?  Look at AVF: the regular QRS complexes can be seen pretty well, with something superimposed: it has to be an artifact of some kind.  In AVL and AVR, all that can be seen is the artifact.
Are we certain this is an artifact?  Consider: the interval between the major deflections in AVL is 0.16 seconds, which gives a rate of 375.   Human hearts don't beat that fast!  This must be an artifact, and it is: the patient is undergoing chest percussion.  This strip illustrates two important principles: look for the real, concealed within the unreal; and look for the impossible - and rule it out!