Electrocardiogram (ECG) and Its Diagnostic Value in Cardiovascular Diseases

Part 1. Normal Electrocardiogram (ECG)

An electrocardiogram (ECG or EKG) is a non-invasive medical procedure used to record the electrical activity of the heart.

By attaching electrodes to the skin, the ECG measures voltage changes during different phases of the cardiac cycle.

These electrical signals are displayed as waveforms on a graph, allowing physicians to detect abnormalities in cardiac function and make accurate diagnoses of heart conditions.

Specialist Doctor Chu Van Dien (Chu Duc, Doctor Chu) guides students in ECG interpretation through an online practical training course.

An ECG can help detect various cardiac problems, including arrhythmias, myocardial infarction, myocarditis, and other cardiovascular disorders.

The ECG is one of the most important and accurate diagnostic tools in modern medicine — easy to perform, reliable, and cost-effective.

Who Should Have an ECG Test?

An electrocardiogram is essential not only for patients with heart disease symptoms but also for individuals at high risk of cardiovascular disease.

Groups recommended to undergo ECG testing include:

1. Individuals with cardiac symptoms

If you experience chest pain, shortness of breath, palpitations, or irregular heartbeats, an ECG is necessary to identify the underlying cause.

2. Patients with a history of heart disease

Those with previous cardiovascular conditions — such as myocardial infarction, myocarditis, or valvular heart disease — should have periodic ECGs to monitor heart health.

3. Individuals with cardiovascular risk factors

People with hypertension, diabetes, obesity, or a family history of heart disease — particularly those over 40 years old — should undergo regular ECG screenings for early detection.

4. Preoperative patients

Before major surgery, an ECG may be required to ensure the heart is strong enough to tolerate the procedure.

5. Athletes or people performing high-intensity exercise

For those engaged in frequent or professional sports, ECG testing helps assess heart function and detect hidden abnormalities without obvious symptoms.

🔗 Read more: Top 5 ECG Machines in Vietnam Today.

Diagnostic Value of the ECG

The electrocardiogram provides crucial diagnostic insights for many cardiovascular conditions:

1. Detecting Arrhythmias

ECG can identify various rhythm disturbances, such as tachycardia, bradycardia, or complex arrhythmias like atrial fibrillation.
This helps determine whether immediate treatment is required.

2. Diagnosing Myocardial Infarction (MI) on Electrocardiogram (ECG)

One of ECG’s most critical applications is detecting signs of myocardial infarction.
Abnormal ECG patterns may reveal infarction even before clinical symptoms become apparent.

3. Assessing Myocardial Function

ECG can help detect myocarditis, cardiac hypertrophy, or heart failure.
Characteristic waveform changes indicate cardiac function and guide appropriate treatment.

4. Detecting Valvular Heart Abnormalities

ECG findings can reflect conditions like valvular stenosis or regurgitation, based on characteristic electrical changes in the tracing.

5. Evaluating Treatment Effectiveness

After cardiac treatment, ECG monitoring helps assess the heart’s recovery and treatment response.

Part 2. Normal ECG Exercises

Exercise 1

Practice analyzing the waveforms in the ECG tracing below:
🩺 “Guide to Reading a Normal ECG” – by Doctor Chu.

Exercise 2

Identify the ST segment in the ECG sample:

• Is it elevated or depressed, and in which leads?

• What does this ST change indicate in the clinical case?

💬 Register as a member on Doctor Chu’s Blog and comment your ECG interpretation below each post.

Conclusion: The Role of Electrocardiogram (ECG) in Modern Medicine

The ECG remains one of the most valuable tools in diagnosing and monitoring cardiovascular diseases.

Since 2015, Doctor Chu has shared ECG knowledge through the “Online Medical Education” fanpage, helping thousands of learners improve their clinical skills.

To make ECG learning more systematic and accessible, he established the “Practical ECG Section” — guiding learners step-by-step through:

• Educational blog posts

• Real-world instructional videos

• Practice exercises after each lesson

• Personalized feedback via comments on the blog

Full Content (text, mind map, AI Test, Video & Podcast) at: ECG notebook – Doctor Chu

🔹 Next article: Guide to the P Wave in ECG Interpretation

Your Doctor,
Blog Author: Doctor Chu – The Doctor for the Poor
Head of Diagnostic Imaging, Functional Testing & Rehabilitation Department
Military Hospital 110, Bac Ninh, Vietnam

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