General 3-Lead ECG Basics and Rate and Rhythm Interpretation

What is the primary purpose of a 3-lead ECG?

• Detailed analysis of myocardial ischemia

• Continuous cardiac rhythm monitoring

• Diagnosing bundle branch blocks

• Assessing axis deviation

Which lead in a 3-lead ECG is most commonly used for rhythm analysis?

• Lead I

• Lead II

• Lead III

• Lead aVR

In a normal sinus rhythm on a 3-lead ECG, the P wave should be:

• Upright in Lead II

• Inverted in Lead II

• Absent

• Biphasic in Lead II

What is the paper speed typically used for ECG interpretation?

• 10 mm/sec

• 25 mm/sec

• 50 mm/sec

• 100 mm/sec

What is the normal heart rate range for sinus rhythm?

• 40–60 bpm

• 60–100 bpm

• 100–150 bpm

• Over 150 bpm

Which rhythm is characterized by a regularly irregular pattern?

• Sinus rhythm

• Atrial fibrillation

• Sinus arrhythmia

• Ventricular tachycardia

In atrial fibrillation, P waves are typically:

• Upright and uniform

• Absent, replaced by fibrillatory waves

• Biphasic

• Regular and inverted

What rhythm is characterized by a "sawtooth" pattern in Lead II?

• Atrial fibrillation

• Atrial flutter

• Sinus bradycardia

• Junctional rhythm

What is the key feature of ventricular tachycardia on a 3-lead ECG?

• Narrow QRS complexes

• Wide, regular QRS complexes

• Fibrillatory baseline

• Irregularly irregular rhythm

A heart rate below 60 bpm with upright P waves in Lead II is called:

• Sinus tachycardia

• Sinus bradycardia

• Junctional rhythm

• Atrial fibrillation