Cardiac Investigation
ECG — Electrocardiogram
A painless, rapid recording of the heart's electrical activity — often the essential first step in evaluating any cardiac symptom, from palpitations and chest pain to breathlessness and dizziness.
The Test
What Is an Electrocardiogram?
An ECG (electrocardiogram) is a recording of the electrical impulses that travel through the heart with every heartbeat. A network of twelve electrodes placed on the chest, arms, and legs picks up these signals from twelve different angles simultaneously, producing a trace that reflects the heart's rhythm, conduction system, and muscle health.
The test is entirely painless, takes less than five minutes, and carries no risks — there is no electrical current passed through the body. It is performed at rest and provides an immediate snapshot of cardiac electrical activity at that moment in time.
Dr Nijjer personally reviews every ECG in the context of your symptoms and clinical history. The trace alone rarely tells the whole story — expert interpretation, combining the electrical findings with the clinical picture, is what makes the ECG a powerful diagnostic tool.
Diagnostic Value
What an ECG Can Reveal
A 12-lead ECG provides a remarkable amount of information from a few seconds of recording. The findings below represent the most clinically important abnormalities — each with a characteristic electrical signature that an experienced cardiologist can identify at a glance.
A normal ECG is itself diagnostically useful — it provides reassurance and a baseline for future comparison. Documenting normal conduction in a symptom-free patient is important context.
The most common sustained arrhythmia. AF produces a chaotic baseline with no identifiable P waves and completely irregular R-R intervals. Prompt detection is critical given the associated stroke risk.
ST elevation indicates an acute STEMI requiring emergency treatment. Q waves and T-wave changes can reveal a previous heart attack the patient may not have been aware of, prompting further investigation.
LVH is a marker of long-standing hypertension or aortic valve disease. Its ECG voltage criteria, combined with strain changes, signal that the heart muscle has thickened in response to pressure overload — an important finding requiring echocardiographic confirmation.
Left bundle branch block (LBBB) can indicate underlying structural heart disease and alters the interpretation of other ECG findings. New LBBB in the context of chest pain must be treated with the same urgency as STEMI.
A prolonged QT interval — corrected for heart rate — increases the risk of life-threatening ventricular arrhythmias including Torsades de Pointes. It may be inherited (congenital long QT) or drug-induced, and requires specialist evaluation.
What to Expect
The ECG Procedure
Preparation
You will be asked to remove your outer clothing to expose the chest. If necessary, a small area of chest hair may be clipped to ensure the electrodes make firm contact with the skin.
Electrode Placement
Ten sticky electrode pads are attached: six across the chest, and one each on both wrists and ankles. These are connected by thin leads to the ECG console. There is no discomfort at this stage.
The Recording
You will be asked to lie still, breathe normally, and avoid moving or talking for approximately 10 seconds while the trace is recorded. Movement artefact can obscure the trace, so stillness is important.
Review and Discussion
Dr Nijjer reviews the tracing immediately, contextualising the findings against your symptoms and history. The results are explained to you in plain English, and any further investigations are discussed.
Important Context
Understanding the Limitations
The ECG's greatest strength — its speed and simplicity — is also its key limitation. It records only the moment at which it is taken. If you experience palpitations twice a month, the chance of one occurring during a ten-second ECG recording is very small. A normal ECG does not rule out an intermittent arrhythmia.
Similarly, a resting ECG will not detect angina or ischaemia that only appears under the stress of exercise. It cannot assess the heart's mechanical function (structure and pumping — that requires echocardiography) and cannot image the coronary arteries (that requires CT or invasive angiography).
When a resting ECG is not enough
If your symptoms are intermittent, an ambulatory ECG monitor worn during daily life will capture any rhythm disturbance at the time it occurs. If ischaemia during exercise is suspected, an exercise stress test or stress echocardiogram is more appropriate. If structural heart disease is the concern, echocardiography is the primary imaging test.
Further Investigation
If Further Tests Are Needed
Concerned About Your Heart Rhythm?
Let Us Investigate.
An ECG is a simple first step. Dr Nijjer will interpret your recording personally and advise clearly on whether further tests are needed.