Rhythm Analysis: Atrial/Junctional Flashcards

What ECG characteristics are used to identify atrial flutter with 2:1 conduction?

Answer: Sawtooth flutter waves at approximately 300 bpm with a regular ventricular rate of approximately 150 bpm

Atrial flutter typically has an atrial rate of 250-350 bpm (classic: ~300 bpm) producing sawtooth flutter waves. With 2:1 conduction, every other flutter wave conducts to the ventricles, giving a ventricular rate of approximately 150 bpm.

Which ECG finding is pathognomonic for Wolff-Parkinson-White (WPW) syndrome during sinus rhythm?

Answer: Short PR interval (< 0.12 sec) plus a delta wave (slurred QRS onset) plus wide QRS

The ECG triad of WPW syndrome during sinus rhythm is: short PR interval (<0.12 sec), delta wave (slurred initial QRS deflection from pre-excitation), and widened QRS complex — all resulting from early ventricular activation through the accessory pathway.

Multifocal atrial tachycardia (MAT) is most commonly associated with which underlying condition?

Answer: Chronic obstructive pulmonary disease (COPD) and other severe pulmonary conditions

MAT is strongly associated with severe pulmonary disease — particularly COPD — and is also seen in critically ill patients with hypoxia, hypercapnia, and theophylline toxicity.

On the ECG, a junctional escape rhythm typically presents with which rate and P wave pattern?

Answer: Rate 40-60 bpm; P waves absent, inverted (retrograde) before or after QRS, or hidden within the QRS, with narrow QRS morphology

The AV junction (His bundle area) has an intrinsic escape rate of 40-60 bpm. Junctional beats conduct to the ventricles normally via the His-Purkinje system (narrow QRS), but P waves are absent or retrograde (inverted in II, III, aVF).

What is the key ECG difference between a premature atrial contraction (PAC) with aberrant conduction and a premature ventricular contraction (PVC)?

Answer: A PAC with aberrancy has a preceding (often abnormal) P wave and typically shows RBBB morphology; a PVC has no preceding P wave and has a different QRS morphology with a full compensatory pause

The presence of an abnormal P wave before the wide QRS (or a 'no P wave' for PVCs) and the morphology pattern (PAC with aberrancy is usually RBBB; PVCs vary) are the key distinguishing features.

Atrial fibrillation (AFib) with a rapid ventricular response typically presents with a ventricular rate in which range?

Answer: 100-170 bpm (can be higher), irregular rhythm with absent discrete P waves, replaced by fibrillatory f waves

Uncontrolled (untreated) AFib typically conducts to the ventricles at rates of 100-170 bpm or higher, producing the characteristic irregularly irregular rhythm without identifiable discrete P waves.