Second Degree Heart Block Type I EKG Interpretation with Rhythm Strip

EKG Features

Rate: The underlying rate
Rhythm: Irregular but with progressively longer PR interval lengthening
P Wave: Normal
PR Interval: Progressively longer until a QRS complex is missed, then cycle repeats
QRS: Normal (0.06-0.10 sec)
A prolonging P-R interval from one cardiac complex to the next, until it reaches a point where the QRS complex is non-conducted (blocked or more simply missing). Then the pattern starts over again.
Second degree Heart Block Type I Wenckebach is a condition where the atrioventricular node conducts each successive impulse earlier and earlier. The PQ interval prolongs from beat to beat up until a drop-out of one QRS complex. The following impulse will then be conducted normally and the cycle to begin again. Thus, the presence of second-degree AV block is diagnosed when one or more (but not all) of the atrial impulses fail to conduct to the ventricles.
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Second Degree Heart Block Type I EKG Interpretation Example

ekg rhythm strip for reference guide



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Authors, Reviewers and Developers EKG rhythms classes: Thomas O'Brien.
EKG monitor simulation: Steve Collmann
12 Lead Lecture: Dr. Michael Mazzini, MD, Cardiologist.
Spanish EKG: Breena R. Taira, MD, MPH
Medical review: Dr. Jonathan Keroes, MD, Cardiologist,
Dr. Barbara Erickson, PhD, RN, CCRN.
EKG tracings review: Dr. Pedro Azevedo, MD, Cardiology
Last Update: 11/10/2022




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