ECG Interpretation & Analysis Flashcards

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

Answer: Delta wave with short PR interval

WPW is characterized by a delta wave (slurred QRS upstroke) and a short PR interval (<120 ms) due to an accessory pathway bypassing the AV node.

A patient's ECG shows an RSR' pattern in V1 and a wide S wave in lead I. This pattern is consistent with:

Answer: Right bundle branch block

Right bundle branch block (RBBB) produces an RSR' (rabbit ears) pattern in V1 and a wide S wave in leads I and V6.

On a 12-lead ECG, ST elevation in leads II, III, and aVF with reciprocal depression in I and aVL suggests:

Answer: Inferior STEMI

Leads II, III, and aVF are inferior leads; ST elevation there with reciprocal changes in high lateral leads (I, aVL) localizes the infarct to the inferior wall.

Torsades de pointes is most closely associated with which underlying ECG abnormality?

Answer: Prolonged QT interval

Torsades de pointes is a polymorphic ventricular tachycardia that arises in the setting of a prolonged QT interval, creating dispersion of repolarization.

Which lead provides the best view for identifying P waves in a patient with a rapid heart rate?

Answer: Lead V1

Lead V1 is positioned over the right atrium and clearly shows P wave morphology, making it ideal for identifying atrial activity at fast heart rates.

A QRS axis of -60° is best described as:

Answer: Left axis deviation

Left axis deviation is defined as a QRS axis more negative than -30°; an axis of -60° falls within this range.

Which of the following ECG changes is consistent with hyperkalemia?

Answer: Peaked (tall, narrow) T waves

Hyperkalemia causes tall, narrow, peaked (tented) T waves as an early sign due to increased resting membrane potential.