An electrocardiogram, usually shortened to ECG, is a simple test that records the electrical activity of the heart. Cardiologists use it to check how regularly the heart is beating and whether the electrical signals that control each heartbeat are working as they should.

An ECG is one of the most commonly used tests in cardiology. It helps investigate symptoms such as palpitations, chest pain, dizziness, or breathlessness, and it also plays an important role in routine heart checks and long term monitoring. We carry out ECGs every day for patients across Kent and East Sussex. Many people feel anxious before the test because they are unsure what it involves or what it might show.

How the Heart’s Electrical System Works

The heart beats because of electrical signals that travel through the heart muscle in a precise pattern. These signals start in a small group of cells known as the sinus node, often called the heart’s natural pacemaker. From there, the signal spreads through the upper chambers of the heart, then passes through to the lower chambers. This process causes the heart to contract in a coordinated way, allowing it to pump blood efficiently around the body. If this electrical system changes or becomes disrupted, the heart may beat too fast, too slow, or irregularly. An ECG records these electrical signals and helps identify when the rhythm is not normal.

What an Electrocardiogram Measures

An ECG measures the timing and strength of the heart’s electrical signals. The machine records these signals as a line tracing with peaks and dips. Each part of the tracing relates to a specific stage of the heartbeat. By studying this pattern, a cardiologist can see whether the heart rhythm is regular, whether signals travel through the heart normally, and whether there are signs of strain or previous damage to the heart muscle. The ECG does not involve electricity passing into your body. It simply detects the electrical activity that is already there.

Why an ECG Is Used

Doctors use ECGs for many reasons. Often, it is the first test carried out when someone presents with symptoms that may relate to the heart. An ECG can help investigate palpitations, irregular heartbeats, chest discomfort, breathlessness, fainting, or dizziness. It is also useful for monitoring known heart conditions or checking how medication affects the heart rhythm. Some people have an ECG as part of a general heart health assessment, especially if they have risk factors such as high blood pressure, diabetes, high cholesterol, or a family history of heart disease. In many cases, a normal ECG provides reassurance and helps rule out serious rhythm problems.

What Conditions Can an ECG Detect?

An ECG can identify a wide range of heart rhythm and electrical problems. These include atrial fibrillation, slow heart rhythms, fast heart rhythms, and conduction delays. It can also show signs of strain on the heart, which may occur with high blood pressure or heart muscle thickening. In some cases, the ECG shows patterns that suggest previous heart damage.However, an ECG does not detect every heart condition. Some problems only occur during exercise or happen intermittently. If symptoms continue despite a normal ECG, your cardiologist may recommend further tests.

The British Heart Foundation provides clear information about what ECGs can and cannot show.

Different Types of ECG

There is more than one type of ECG, and the choice depends on your symptoms and medical history. Your cardiologist will decide which option gives the most useful information in your case. Below are the most common 3 options.

A resting ECG records your heart rhythm while you lie still. This is the most common type and suits many people.

A 24 hour or longer ECG monitor records your heart rhythm over an extended period while you go about your normal daily routine. This approach helps capture rhythm changes that come and go.

An exercise ECG records the heart during physical activity. Doctors use it to assess how the heart responds to exertion and whether symptoms appear with exercise. This is also often referred to as a ‘stress test’.

What Happens During an ECG Test?

When you attend for an ECG, a clinician will explain the process clearly before starting. You will lie down on an examination couch. Small sticky electrodes are placed on your chest and sometimes on your arms and legs. These electrodes connect to the ECG machine. The machine records your heart’s electrical activity for a short period, usually just a few minutes. You do not feel anything during the recording. Once the test finishes, the electrodes are removed. You can return to normal activities straight away.If you are having longer term monitoring, the clinician will show you how to wear the device and explain what to do if you notice symptoms.

How to Prepare for an ECG

An ECG requires very little preparation. Wearing loose clothing helps make electrode placement easier. Avoid applying creams or lotions to your chest on the day of the test, as these can interfere with electrode contact. Try to arrive relaxed, as anxiety or recent exertion can temporarily affect heart rate. You should continue taking your usual medication unless your doctor advises otherwise.

What Happens After the ECG?

After the test, a cardiologist reviews the ECG tracing. Many people find their results are normal, which offers reassurance. If the ECG shows an abnormal rhythm or other changes, your cardiologist will explain what this means and discuss next steps. Further tests may be recommended to gain more detail.

At West Kent Cardiology Partnership, we make sure patients understand their results and feel confident about the plan moving forward. You can contact us here to arrange an ECG or discuss whether this test is right for you.

Why ECGs Play a Key Role in Heart Care

ECGs help detect heart rhythm problems early, sometimes before symptoms become obvious. Early detection allows monitoring or treatment that reduces the risk of complications. For conditions such as atrial fibrillation, they also play a vital role in reducing stroke risk through early diagnosis and appropriate management. ECGs also support people with known heart conditions by helping doctors track changes over time and adjust treatment when needed.

ECGs as Part of a Wider Assessment

An ECG often forms part of a broader heart assessment. Cardiologists may combine it with echocardiograms, blood tests, heart rhythm monitoring, or imaging scans. Each test provides different information. Together, they help build a complete picture of heart health and guide personalised care.

Who Should Consider an ECG?

Anyone experiencing palpitations, chest discomfort, dizziness, or breathlessness should consider an ECG. People with heart disease, high blood pressure, or a family history of heart problems may also benefit from testing. Some people choose to have an ECG simply for reassurance. This is especially common if anxiety about heart health is affecting daily life.

Conclusion

An electrocardiogram (ECG) is a quick, painless, and reliable test that records the heart’s electrical activity. It plays a central role in diagnosing heart rhythm problems, monitoring existing conditions, and providing reassurance. Whether you have symptoms or simply want to understand your heart health better, an ECG can offer valuable insight. We provide prompt ECG testing alongside clear explanations and personalised care for patients across Kent and East Sussex. If you would like to arrange an ECG or discuss your symptoms, you can call us on 01892 526726 to book an appointment as well.