Wagner_Marriot's Practical Electrocardiography, 12e

V 1

F I G U R E 2 2 . 1 7 .

A lead V1 rhythm strip from a patient with chronic congestive heart failure.

There is a lack of increase in the PR interval when a decrease occurs in the RP interval.

Figure 22.17 presents another example of type II block. Note that the PR intervals re- main unchanged despite longer and shorter RP intervals (i.e., there is no RP/PR reciproc- ity). The recording illustrates the two sources of variation in RP intervals: a change in the AV conduction ratio (from 1:1 to 2:1) and the presence of a ventricular premature beat.

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SECTION III: Abnormal Rhythms