The nurse needs further education and training when she describes Mobitz Type I Block as:

An unstable rhythm that is usually caused by an infranodal conduction disturbance.
First-degree atrioventricular block.
The most severe form of heart block that carries a bad prognosis.


• Second-degree AV block is a problem with the electrical conduction system in the heart between the atria and the ventricles

• Mobitz type I heart block involves prolonged PR intervals followed by blocked P waves (this is a 'dropped' QRS complex). Then the cycle repeats. This is usually benign and no treatment is indicated

• Mobitz type I is the mildest form of second-degree heart block and carries a better prognosis compared to type II

• Mobitz type I is a stable rhythm that usually does not result in clinical manifestations because the ventricular rate is adequate

• Mobitz type I is also known as the Wenckebach phenomenon in which the QRS complexes are typically "grouped" into twos, threes, fours, and so on

• Mobitz type I is a form of second-degree heart block

• Mobitz type I is caused by a block in the AV node

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