10 Must Know ECG Rhythms

What is the defining characteristic of a normal sinus rhythm on an ECG?

• Absence of P-waves

• Irregularly irregular ventricular rate

• Regular P-waves followed by a QRS complex

• Wide QRS complexes

A patient's ECG shows a regular sinus rhythm with a heart rate of 55 beats per minute. How would this be classified?

• Sinus Tachycardia

• Sinus Bradycardia

• Atrial Fibrillation

• Atrial Flutter

Which of the following is a characteristic ECG finding in atrial fibrillation?

• Consistent PR interval

• Regular P-waves

• Irregularly irregular ventricular rate

• Wide QRS complex

Atrial fibrillation typically arises from a combination of a susceptible substrate and a triggering event. Which of the following is a common example of a triggering event?

• Ventricular hypertrophy

• Ectopic electrical activity from pulmonary veins

• Bundle branch block

• Normal sinus node function

What distinctive ECG pattern is classically associated with atrial flutter, particularly in inferior leads?

• Tall, peaked T-waves

• Deep, wide S-waves

• "Sawtooth" appearance

• Absent P-waves

If a patient with atrial flutter has an atrial rate of approximately 300 BPM and an AV node conduction ratio of 2:1, what would be the approximate ventricular rate?

• 300 BPM

• 150 BPM

• 100 BPM

• 75 BPM

A premature ventricular contraction (PVC) on an ECG is characterized by which of the following?

• A narrow QRS complex

• Originating from the atria

• A compensatory pause

• Being preceded by a normal P-wave

What is a key feature distinguishing a premature atrial contraction (PAC) from a premature ventricular contraction (PVC) on an ECG?

• PACs have a wide QRS complex

• PACs originate from the His-Purkinje region

• PACs are followed by a narrow QRS complex

• PACs always lead to ventricular tachycardia

What is a common ECG feature shared by both Left and Right IVCDs?

• A narrow QRS complex

• A deep S-wave in V1

• A wide QRS complex

• An irregularly irregular rhythm

How do bundle branch blocks (aka IVCDs) affect the interpretation of ST segment changes on an ECG?

• They make ST segment changes easier to interpret.

• They have no effect on ST segment interpretation.

• They make ST segment changes challenging to interpret.

• They always cause ST elevation.