Electrocardiography Procedures & Interpretation Flashcards

Which ECG finding is most characteristic of Wolff-Parkinson-White (WPW) syndrome?

Answer: Delta wave with short PR interval

WPW syndrome is characterized by a delta wave (slurred upstroke of the QRS) and a short PR interval due to an accessory pathway bypassing the AV node.

A patient's ECG shows ST elevation in leads II, III, and aVF. Which coronary artery is most likely occluded?

Answer: Right coronary artery

ST elevation in leads II, III, and aVF indicates an inferior STEMI, most commonly caused by occlusion of the right coronary artery.

What does a QTc interval greater than 500 ms indicate?

Answer: Significantly increased risk of torsades de pointes

A QTc >500 ms represents a clinically significant prolongation that markedly increases the risk of the potentially fatal arrhythmia torsades de pointes.

Which artifact on an ECG is most commonly caused by patient movement or muscle tremor?

Answer: Somatic muscle artifact

Somatic muscle artifact produces irregular, high-frequency deflections on the ECG tracing and results from involuntary or voluntary skeletal muscle activity.

In a 12-lead ECG, which lead is considered the best for identifying P-wave morphology?

Answer: Lead II

Lead II is oriented closely along the axis of normal atrial depolarization, making P waves most prominent and upright, which is ideal for rhythm analysis.

A CCT records an ECG showing a heart rate of 40 bpm with narrow QRS complexes and no identifiable P waves. What rhythm is most likely?

Answer: Junctional escape rhythm

A junctional escape rhythm typically produces a rate of 40–60 bpm with narrow QRS complexes and absent, retrograde, or buried P waves.

What is the primary purpose of applying conductive gel or electrode paste during ECG electrode placement?

Answer: To reduce skin-electrode impedance and improve signal quality

Conductive gel lowers the electrical impedance between the skin and the electrode, ensuring a clean, low-noise ECG signal.