Basic Electro Cardio Graphy (ECG) and Arrhythmia 2026

A comprehensive set of practice questions covering Basic ECG interpretation, various arrhythmias, diagnostic criteria for ischemia, and management protocols for heart rhythm disorders based on the lecture by Abdulrouf Yousef.

What does the acronym "ECG" stand for and what is its primary function?

ECG stands for “Electro-Cardio-Gram,” and it is a drawing that shows the electrical activity of the heart.

How many electrodes and leads are typically used to produce an ECG strip?

9 special electrodes are used to produce 12 different leads ("pictures") on the ECG strip.

Which ECG leads correspond to the Inferior Aspect of the heart?

Leads aVF, II, and III.

Which ECG leads correspond to the Anterior Aspect of the heart?

Leads V1, V2, V3, and V4.

Match the wave to its physiological event: P wave, QRS, T wave, and U wave.

P wave → Atrial depolarization; QRS → Ventricular depolarization; T wave → Repolarization of ventricle; U wave → Repolarization of papillary muscles.

What are the normal duration and height parameters for a P-wave?

Duration: $\le 3\,small\,squares$ ($\le 120\,ms$); Height: $\le 2.5\,small\,squares$ ($\le 0.25\,mV$).

What is "P-Pulmonale" and what are its common causes?

P-Pulmonale is characterized by a peaked, tall P-wave ("Himalayan P") with a height $> 2.5\,small\,squares$ in Lead II. Common causes include pulmonary hypertension, COPD, chronic lung disease, tricuspid disease, and PE.

What is "P-Mitrale" and what does it indicate?

P-Mitrale is an M-shaped (notched) P-wave in lead II with a duration $> 3\,small\,squares$. It indicates Left Atrial Enlargement, often due to Left atrial hypertrophy or Mitral valve disease (especially Mitral Stenosis or Mitral Regurgitation).

What is the normal duration range for the P–R interval?

3–5 small squares ($120–200\,ms$).

A short P–R interval ($< 3\,small\,squares$) suggests which syndromes?

Pre-excitation syndromes such as WPW Syndrome (marked by a Delta wave) and LGL Syndrome (no delta wave).

What ECG finding is highly suggestive of Acute Pericarditis regarding the PR segment?

P–R Segment Depression (usually seen in leads II, V5, V6 with PR elevation in aVR).

What is the interpretation difference between a narrow QRS and a wide QRS complex?

Narrow QRS ($< 120\,ms$) indicates a supraventricular origin (from AV node or above); Wide QRS ($> 120\,ms$) indicates a ventricular origin or conduction delay.

Which clinical condition is characterized by diffuse, concave ("smiling") ST elevation in most leads?

Acute Pericarditis.

What is the height threshold for a "Peaked T-wave" and what is its classic earliest cause?

Height $\ge 2\,large\,squares$ ($\ge 10\,mm$); Hyperkalemia is the classic earliest cause.

How is Dextrocardia detected on an ECG?

Lead I shows global inversion (inverted P, QRS, and T), and aVR shows positive P, QRS, and T (instead of negative).

How is the heart rate calculated for a regular rhythm on an ECG?

$\text{HR} = 300 \div \text{number of big squares between R-R}$.

Based on the quadrant method, what does a positive Lead I and negative Lead aVF indicate?

Left axis deviation.

What are the primary causes of Right Axis Deviation (RAD)?

Tall, thin individuals, Right Ventricular Hypertrophy (RVH), Right Bundle Branch Block (RBBB), chronic lung disease (COPD), pulmonary hypertension, WPW, and Atrial Septal Defect (Ostium Secundum).

What is the definition of Tachyarrhythmia?

Heart rate $> 100\,beats/min$ occurring at normal body core temperature.

What is the drug of choice for managing Hemodynamically Stable PSVT and what is the dosing regimen?

Adenosine; 1st dose: $6\,mg$ rapid IV push; 2nd dose: $12\,mg$; 3rd dose (optional): $12\,mg$.

What is the definitive treatment for recurrent WPW syndrome?

Radiofrequency Catheter Ablation (success rate $> 95\%$).

What are the three key ECG features of Atrial Fibrillation (AFib)?

1. No P-waves (fibrillatory f-waves instead); 2. Narrow QRS complexes (usually); 3. Irregularly irregular R–R interval.

What is the maximum score on the CHA₂DS₂-VASc system and what does a score of $\ge 2$ in males or $\ge 3$ in females indicate?

Maximum score is 9; these scores indicate that anticoagulation is mandatory.

Define Ventricular Tachycardia (VT) and name the first-line drug for a hemodynamically stable patient.

VT is a wide QRS complex ($> 120\,ms$) tachycardia with absent P-waves and a regular R-R interval. The first-line drug for stable patients is Amiodarone ($150\,mg$ IV over 10 minutes).

What is the first-line treatment for Polymorphic VT (Torsades de pointes)?

Magnesium sulfate ($4\,g$ IV over 1 hour, followed by $1\,g/hour$ for 24 hours).

Identify the "H's" (metabolic causes) of Pulseless Electrical Activity (PEA).

Hypovolemia, Hypoxia, Hypoglycemia, Hypothermia, and Hypo / Hyperkalemia.

Which anti-arrhythmic drugs belong to Class III?

Amiodarone (Potassium channel blockers).

Define Second-Degree AV Block, Mobitz Type I (Wenckebach).

Progressive prolongation of the PR interval until one P-wave is not conducted (dropped QRS), at which point the PR interval resets.

What is the Sokolow–Lyon Criteria formula for Left Ventricular Hypertrophy (LVH)?

$\text{R in V6} + \text{S in V1} > 35\,mm$ (35 small squares).

What are the ECG characteristics of Acute Pericarditis?

1. Diffuse ST-Segment Elevation (except aVR and V1); 2. Concave ("smiling") ST elevation; 3. PR-Segment Depression (most specific finding).