Cardiac Dysrhythmias and Arrhythmias Flashcards

Which finding on an ECG strip indicates third-degree (complete) AV block?

Answer: P waves and QRS complexes firing independently with no association

In third-degree AV block, atria and ventricles beat independently — P waves and QRS complexes have no consistent relationship.

Ventricular fibrillation on a monitor appears as:

Answer: Chaotic, irregular waveforms with no identifiable QRS complexes

Ventricular fibrillation produces chaotic, irregular undulations with no discernible QRS complexes, representing disorganized ventricular electrical activity.

A patient develops a regular wide-complex tachycardia at 180 bpm. The most dangerous assumption to make is that this is:

Answer: SVT with aberrant conduction

Assuming a wide-complex tachycardia is SVT with aberrancy is dangerous because the majority are ventricular tachycardia, requiring prompt intervention.

What is the escape rate of a junctional (AV nodal) escape rhythm?

Answer: 40-60 bpm

The AV node has an inherent pacemaker rate of 40-60 bpm and will generate escape beats when higher pacemakers fail.

Which arrhythmia is defined as three or more consecutive PVCs at a rate greater than 100 bpm?

Answer: Ventricular tachycardia

Ventricular tachycardia is defined as three or more consecutive ventricular beats at a rate exceeding 100 bpm.

On a monitor strip, which feature most reliably distinguishes sinus bradycardia from a junctional rhythm?

Answer: Presence and polarity of P waves in lead II

Sinus bradycardia has upright P waves before each QRS in lead II, while junctional rhythms show inverted, absent, or retrograde P waves.

PVCs occurring on every other beat are called:

Answer: PVC bigeminy

Bigeminy refers to a repeating pattern of one normal sinus beat alternating with one PVC.