© 2019 by The Heart Partners.

Non-Invasive Tests //

After seeing a doctor, the most likely next step is for several tests to be performed to help understand the exact underlying state of the heart. The intial tests are usually non-invasive, that is they don't involve anything to be put inside the body (other than perhaps a small cannula in the arm). Most non-invasive tests are performed at Spire Bushey Hospital, and often at the same sitting as your clinic appointment. Others, such as a cardiac MRI scan, will require another appointment which will normally be within a few days. Results are usually available within a day or two.

ELECTROCARDIOGRAM (ECG)

This is the simplest of cardiac tests and gives an electric representation of the heart.  Four electrodes are attached with either suction cups or self adhesive pads to the extremities of the four limbs and a further six in a pre-determined pattern across the chest.  The machine then computes what we call a “12 lead” ECG showing 12 different representations of the heartbeat and prints it out for us.  The test is useful in showing the rhythm of the heart and can also show us disturbances in the conduction of electricity through the heart as well as alerting us to other conditions such as coronary artery issues and heart attacks and cardiomyopathies.   Many of the changes are non specific and just give a clue which then requires further investigation.

CHEST X-RAY (CXR)

The chest x-ray can be useful to show the size of the heart (extremely approximate), any abnormal calcium or shadows over the heart and in particular for showing us the state of the lungs which can be congested due to cardiac failure. Non-cardiac causes of breathlessness may also be detected.

CARDIAC RHYTHM MONITORING (24 / 48 / 72 Hour Tapes)

 

In patients complaining of palpitations and suspected of having cardiac rhythm disturbances (arrhythmias) long term monitoring is often the only way to capture the ECG during a patient’s symptoms.  The simplest way is with a 24 hour ECG monitor (which used to be performed with a small box with a cassette tape) that is connected to three or four monitoring electrodes on the patient’s chest. The recorder is now a smaller solid state device. This can be done for one or more days (typically 1, 2, 5 or 7) and is useful in looking at the background of the rhythm of the heart and also trying to pick up specific rhythm disturbances but is only useful if the patient is having their arrhythmia fairly frequently. 

Variations on this theme include a loop recorder which is a similar device again used with electrodes stuck to the chest in which the cardiac rhythm is constantly being recorded and over-written on a solid state device and if the patient gets an abnormal rhythm they can press a button on the device which will store not only the ECG at the time when the button is pressed but the ECG a few minutes before.  This may require fairly long term use of the device which is quite irksome for the patient and this device is not used very much.

The alivecor device

CARDIAC EVENT RECORDERS

 

There are two main types of event recorders. 

Our first option is the Kardia (by AliveCor) smartphone ECG recorder. This attaches to the back of your smartphone and allows immediate recording of a simple ECG which is sufficient for diagnosis of some rhythm abnomalities and palipitations. Many patients find it the most cost-effective and reliable way of capturing the all-important tracing of the heart rhythm whilst symptoms are occuring.

An alternative is a device called the Omron 801 Home ECG machine.  This is made by Omron, who make most of the home blood pressure monitors, and can be bought new on the Internet for just over £200 (sources vary and a search is always worthwhile). These devices are high quality event recorders that patients can buy for themselves and it is often useful not only in the initial diagnosis of the arrhythmia but the follow up of treatment, correlating symptoms with the ECG.  The devices can send in the ECGs online so we can report formally on these ECGs if required.

There is another type of event recorder that can be loaned to the patient for a week or two. This is useful if the patient is getting their symptoms long enough to be able to get the device out of their pocket or bag, place the monitor on their chest and press a button and record an ECG at the time.  This doesn’t usually show us the start and the end of the arrhythmia, so has some limitation, but can be very useful. 

Finally, there are longer-term, implantable event recorders, such as the Reveal Device. For many patients, these are the only way of diagnosing infrequent but severe arrhythmias. These are covered in the Invasive Procedures section.

The alivecor device

CARDIAC EVENT RECORDERS

 

There are two main types of event recorders. 

Our first option is the Kardia (by AliveCor) smartphone ECG recorder. This attaches to the back of your smartphone and allows immediate recording of a simple ECG which is sufficient for diagnosis of some rhythm abnomalities and palipitations. Many patients find it the most cost-effective and reliable way of capturing the all-important tracing of the heart rhythm whilst symptoms are occuring.

An alternative is a device called the Omron 801 Home ECG machine.  This is made by Omron, who make most of the home blood pressure monitors, and can be bought new on the Internet for just over £200 (sources vary and a search is always worthwhile). These devices are high quality event recorders that patients can buy for themselves and it is often useful not only in the initial diagnosis of the arrhythmia but the follow up of treatment, correlating symptoms with the ECG.  The devices can send in the ECGs online so we can report formally on these ECGs if required.

There is another type of event recorder that can be loaned to the patient for a week or two. This is useful if the patient is getting their symptoms long enough to be able to get the device out of their pocket or bag, place the monitor on their chest and press a button and record an ECG at the time.  This doesn’t usually show us the start and the end of the arrhythmia, so has some limitation, but can be very useful. 

Finally, there are longer-term, implantable event recorders, such as the Reveal Device. For many patients, these are the only way of diagnosing infrequent but severe arrhythmias. These are covered in the Invasive Procedures section.

The alivecor device
EXERCISE ECG

This is a 12 lead ECG that is recorded whilst the patient exercises.  It used to be used as a screen for coronary artery disease but has been shown to be fairly non specific and can significantly over-read and give us a “false positive” when there is nothing actually wrong with the patient.  It is still used from time to time for screening or for follow up and also for evaluating a patient’s exercise tolerance and for looking at exercise induced arrhythmias (rhythm disturbances).  The test is usually performed on a treadmill with the patient walking and then running. In the standard protocol (Bruce) the treadmill gets a little faster every three minutes and a little steeper.  Most patients exercise for between 6 and 12 minutes – the full test will run to stage 7 for 21 minutes.