Page 1736 - Saunders Comprehensive Review For NCLEX-RN

▪ For accuracy, timing should begin on the P wave or the QRS complex and end
exactly at 30 large blocks later.

FIG. 52-7 Atrial dysrhythmias—atrial fibrillation.

FIG. 52-8 Ventricular dysrhythmias—normal sinus rhythm with multifocal premature
ventricular contractions (PVCs; one negative and the other positive).

Box 52-4

Premature Ventricular Contractions

Bigeminy: Premature ventricular contraction (PVC) every other heartbeat
Trigeminy: PVC every third heartbeat
Quadrigeminy: PVC every fourth heartbeat
Couplet or pair: Two sequential PVCs
Unifocal: Uniform upward or downward deflection, arising from the same
ectopic focus
Multifocal: Different shapes, with the impulse generation from different sites
R-on-T phenomenon: PVC falls on the T wave of the preceding beat; may
precipitate ventricular fibrillation

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