Atrial Arrhythmia Identification Flashcards

Which feature best distinguishes atrial tachycardia from sinus tachycardia on a 12-lead ECG?

Answer: Abnormal P wave axis or morphology differing from sinus P waves

Atrial tachycardia originates from an ectopic focus rather than the sinus node, producing P waves with an axis or morphology that differs from normal sinus P waves.

A patient in atrial flutter with 2:1 conduction is most likely to show a ventricular rate near which value?

Answer: 150 bpm

With typical atrial flutter at 300 bpm and 2:1 AV conduction, the ventricular rate is 300 divided by 2, equaling 150 bpm.

Wandering atrial pacemaker differs from multifocal atrial tachycardia primarily by which criterion?

Answer: Heart rate is less than 100 bpm in wandering atrial pacemaker

Wandering atrial pacemaker has three or more P wave morphologies and an irregular rhythm but a rate less than 100 bpm, while MAT is defined by a rate of 100 bpm or greater.

In a patient with Wolff-Parkinson-White syndrome who develops atrial fibrillation, which ECG feature poses the greatest danger?

Answer: Rapid conduction over the accessory pathway causing very fast ventricular rates

In WPW with atrial fibrillation, the accessory pathway bypasses the AV node rate-limiting function, allowing extremely rapid ventricular rates up to 300 bpm that can degenerate into ventricular fibrillation.

Which of the following best describes the P wave in AVNRT?

Answer: P waves are often buried within or immediately after the QRS complex

In AVNRT, retrograde P waves are typically buried within or occur just after the QRS due to near-simultaneous atrial and ventricular depolarization, appearing as pseudo-r in V1 or pseudo-S in inferior leads.

Which antiarrhythmic approach is considered first-line to terminate acute PSVT when vagal maneuvers have failed?

Answer: IV adenosine

IV adenosine (6 mg rapid IV push, repeat 12 mg if needed) is the first-line pharmacological treatment for PSVT, acting by transiently blocking AV nodal conduction to interrupt the reentrant circuit.