Look at the rhythm strip at the bottom of the EKG…
–If a) every P/QRS/T grouping looks the same, AND b) the spacing between groupings is the same throughout, the rhythm is ‘regular.’
–If either a) or b) fails to hold, the rhythm is ‘irregular.’
Once you’ve determined that the rhythm is irregular…
–If the same pattern (however weird it may be) occurs over and over again, the rhythm is ‘regularly irregular.’
–If there is no discernible repeating pattern, the rhythm is ‘irregularly irregular.’
I am going to go and look back at the heart blocks. This makes sense for a 2nd degree mobitz type 1, but I am not sure if it will be like that for 3rd degree, or a couple others I have been told are defined as “regular.”[/quote]
Mobitz I is the standard example of a ‘regularly irregular’ rhythm, which is why it can be described with respect to its p:qrs ratio (eg, 5:4). OTOH, Mobitz II is irregularly irregular, as there is no repeating relationship between the number of p waves and qrs complexes.
3rd degree block is a classic ‘irregularly irregular’ rhythm, as there is a complete decoupling between the occurrence of p waves and that of qrs complexes. The p waves march along at one rate (usually dictated by the SA node), while the qrs complexes march along at another (usually much slower) rate. Because these two rates are independent of one another, there is no coordination between them; hence the overall (ie, p + qrs/t) rhythm is irregularly irregular. [/quote]
Thanks man. Is there any other examples of stuff that can show up as a regular irregular? Also, what is the difference between idiojunctional and idioventricular rhythm? Doesn’t idiojunctional lack the inverted P wave? It looks the same to me. Maybe it is a wider QRS?[/quote]
I can’t imagine they’d give you anything besides an obvious Mobitz I as an example of a regular-irregular rhythm.
There are two main differences between junctional- and ventricular-paced EKGs:
- The rate. Junctional pacing will be at ~40-60 BPM, whereas ventricular pacing will be 20-40.
- The width of the qrs complexes. Because junctional pacing originates ‘above’ the normal ventricular conduction pathways (ie, the bundle branches), the ventricles will be ‘fired’ in the usual and customary fashion. Because of this, the qrs complex will be normal (ie, narrow) in appearance. OTOH, ventricular pacing does NOT propagate in a normal anterograde manner along the bundle branches; rather, depolarization ‘crawls’ around the ventricles from muscle cell to muscle cell. Thus, it takes much longer for the entire ventricle(s) to receive the ‘contract’ order, and contraction therefore occurs in ‘slow motion’ (relatively speaking of course). Because of this, the qrs complexes in ventricular pacing are very wide (they look like PVC complexes).