STARS Patient Information
If you experience symptoms of recurrent loss of consciousness, palpitations, lightheadedness or dizziness, your doctor might advise that you require heart rhythm monitoring. A heart rhythm monitor is a diagnostic test in which the electrical activity of your heart is recorded in order to identify an irregular heart rhythm. Your heart rhythm can be recorded in a number of ways:
- ECG (Electrocardiogram)
- 24 hour/ 7 days Holter Monitor
- Implantable Cardiac Monitor (ICM)
- Implantable Loop Recorder (ILR)
Every patient presenting with an unexplained blackout should be given a 12-lead ECG. An ECG is a simple test in which the electrical activity of your heart is recorded. Electrodes that are attached to your body send impulses to a machine that prints out a graphic picture of your heart’s activity. An ECG is usually done in your doctor’s office. An ECG may identify a heart rhythm disorder, it normally will not provide a definite diagnosis of the cause of your faint. An ECG produces a record of your heart during your doctors appointment.
A Holter monitor is a portable ECG. Holter monitoring is used in patients who experience frequent fainting episodes (one or more a week). Electrodes attached to your chest are connected to a small box that records your heart activity as you go about your day activities. It is automatic, so you do not need anything. The Holter monitor provides your doctor with either a 24 hour or seven day record of your heart activity. The difficulty with an abnormal heart rhythm is that they occur at unpredictable times. A holter monitor can be useful for diagnosing the disturbances in your heart’s rhythm that may occur at unpredictable times.
Whilst you are wearing your Holter monitor the doctor will ask you to record your activities and any experiences you have had. Using the information from the monitor and your activity log over several days may allow your doctor to identify the activities and causes which may have triggered your faint.
If a doctor is unable to diagnose the cause of your symptoms with simple recording methods such as an ECG or a 24 hour monitor, they may consider an implantable cardiac monitor (ICM).
Traditionally doctors would have implanted an insertable loop recorder (ILR) (which is the size of a USB stick) under the skin on the left side of a patient’s chest in order to capture a recording of the heart rate and rhythm at the time of an episode of loss of consciousness. The device records on a continuous loop for up to three years. If you experienced a blackout, you would use a separate device to freeze the recording and document the episode which would then be assessed by a heart rhythm specialist.
The ICM is a diagnostic tool that will monitor the heart’s electrical activity that helps a heart rhythm specialist identify the cause of your symptoms. This device offers the same benefits as a traditional ILR but is a tenth of the size. Virtually invisible to the naked eye, it is more comfortable and much less noticeable under the skin.
Your doctor may be unable to determine the cause of your symptoms with external ECGs and 24hr/ 7 day holter monitoring. Inserting an ILR that monitors your heart rhythm over a longer period of time may enable your doctor to identify what is causing your symptoms and to prescribe appropriate treatment if required.
An implantable loop recorder is a small thin device that is inserted under the skin to record the activity of your heart and can be performed as a day case in hospital. The ILR monitors and records your hearts’ electrical activity in order to identify an irregular heart rhythm. The device can remain in place for up to 4 years. However the device may be removed sooner depending on when you experience symptoms, such as a faint and your doctor has made a diagnosis.
Dr Nick Linker, Consultant cardiologist,James Cook University Hospital, discusses the use, implant procedure and aftercare of implantable loop recorders.