ECG signal

Dr Diana R Holdright

Consultant Cardiologist

Dr Diana Holdright

Cardiac Investigations - ECG and Holter Monitoring

ECG (Electrocardiogram)

An ECG is a tracing of the electrical activity of the heart. The test is completely painless and takes only a few minutes; it involves sticking several small patches (electrodes) to the arms, legs and chest, which are connected by leads to an ECG machine that records the electrical impulses generated by each heartbeat. The ECG is a very useful and simple baseline test that can help to identify many different heart problems, including changes in heart rate and rhythm, a propensity to certain rhythm disturbances, abnormalities of the heart muscle and damage to the heart from a prior heart attack.

Holter Monitoring (24 hour, 48 hour and 7 day)

A Holter monitor is essentially a device that records the ECG for a prolonged period, typically 24 hours or longer. Recording the electrical activity of the heart over a longer period of time than a standard ECG can help to identify the heart rhythm at times of symptoms such as palpitations or dizziness, which may not occur all the time. As with a standard ECG, small patches (electrodes) are stuck to the chest, then attached to wires leading to a small portable recorder worn on a belt around the waist. Once the system has been set up the patient can go about all daily activities as usual, but should avoid swimming, bathing and showering until the monitoring period has come to an end. The patient will also be asked to keep a diary of any symptoms experienced during the time the monitor is worn, so that the doctor can pay special attention to the recordings made at those times and determine whether the symptoms in question are related to the heart.

Cardiomemo/Event Recorder

Some symptoms do not occur as frequently as every day, and in such cases a longer period of external monitoring may be worthwhile. Following discussion with a doctor, the patient will decide whether to extend the period monitoring for up to 7 days with a Holter monitor, or whether to elect for an event recorder such as a  cardiomemo, which is a freestanding device activated by the patient only at the time of symptoms. This type of monitor is a small hand-held device that the patient simply carries around with them; at the time of symptoms the patient presses the metal feet of the monitor to the chest and holds down a button to begin the recording, which lasts for a minute at a time. Once a few recordings have been made, the data will be downloaded and analysed to see if there is any correlation between symptoms and the heart rate and rhythm.

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Cardiac Investigations - ECG and Holter MonitoringCardiac Investigations - ECG and Holter Monitoring