ECG Interpretation Flashcards

Which ECG finding is characteristic of atrial fibrillation?

Answer: Irregularly irregular rhythm with no P waves

Atrial fibrillation shows an irregularly irregular ventricular rhythm with fibrillatory baseline waves replacing organized P waves.

A prolonged QT interval increases the risk of:

Answer: Torsades de pointes

Prolonged QT interval can lead to torsades de pointes, a dangerous polymorphic ventricular tachycardia that can degenerate into ventricular fibrillation.

Which lead is best for identifying atrial activity?

Answer: Lead V1

Lead V1, positioned over the right sternal border, is closest to the atria and provides the best visualization of P waves and atrial activity.

What ECG change is seen with hyperkalemia?

Answer: Peaked T waves

Elevated potassium levels cause tall, peaked T waves as one of the earliest ECG manifestations, progressing to widened QRS and sine wave pattern if severe.

What does sinus rhythm mean on an ECG?

Answer: The heart rhythm originates from the SA node

Sinus rhythm means the electrical impulse originates from the sinoatrial node, the heart's natural pacemaker, producing a normal, regular rhythm with consistent P waves before each QRS.

What is the normal duration of the QRS complex?

Answer: 0.06 to 0.10 seconds

A normal QRS complex lasts 0.06-0.10 seconds (1.5-2.5 small boxes). A QRS wider than 0.12 seconds suggests a bundle branch block or ventricular origin.