Complete the following ECG criteria for third-degree AV block:

Question

Rhythm ________________________________________
Rate ________________________________________
P waves ________________________________________
PR interval ________________________________________
QRS duration ________________________________________

Fill in the blanks with correct word

Answer 1

Rhythm Ventricular regular; atrial regular (Ps plot through); no relationship between the atrial and ventricular rhythms (i.e., AV dissociation is present).
Rate The ventricular rate is determined by the origin of the escape rhythm; the atrial rate is greater than (and independent of) the ventricular rate; ventricular rate is determined by the origin of the escape rhythm.
P waves Normal in size and shape; some P waves are not followed by a QRS complex (i.e., more Ps than QRSs).
PR interval None. The atria and the ventricles beat independently of each other; therefore there is no true PR interval.
QRS duration Narrow or wide, depending on the location of the escape pacemaker and the condition of the intraventricular conduction system.