IN this final segment on heart testing, we will look at testing your heart to find out if you have an abnormal heart rhythm.

The tests may include:

* Electrocardiogram (ECG)

* Telemetry

* 24-48 Hour Holter

* Loop Recorder

* Electrophysiology Testing (EP Tests)

Your cardiologist may suspect you have an abnormal heart rhythm based on palpitations, fainting (syncope) or near-fainting (near-syncope). Diagnosing the definite cause for your symptoms may be extremely difficult, because it requires your cardiologist to capture a recording of your heart’s electrical activity at the very moment you are having your symptoms. These symptoms are usually very brief (lasting seconds to minutes), and by the time you get to your doctor or emergency room, they may have already stopped and your ECG may be perfectly normal. This does not necessarily mean that all is well. It just means nothing abnormal was happening to your heart rhythm when you had no symptoms. A longer recording of your heart’s electrical activity will, in most cases, help us to determine the cause of your symptoms and recommend appropriate treatment.

ECG

An ECG with expert interpretation is a standard test that you will need if you have palpitations or fainting. The automated interpretation provided by the ECG machine is not sufficient, and the ECG will need to be reread by a cardiologist or internist (specialist in Internal Medicine) who has a lot of experience and expertise in ECG interpretation. Paying particular attention to various conditions that may give subtle changes on an ECG, which in someone who has no symptoms, may not be significant, but in the case of someone with symptoms may mean abnormal electrical pathways, putting you at risk for abnormal heart rhythms which can be fatal.

TELEMETRY

If you require admission to hospital for observation after a fainting episode, telemetry is useful. Telemetry allows your heartbeat to be recorded for several days while in hospital. It uses electrodes similar to an ECG, but you may be mobile while wearing your telemetry pack, allowing your heartbeat to be monitored, usually by a nurse who is specifically trained. Any abnormality in your symptoms is usually recorded and matched with any abnormality on your ECG tracing.

24-48 HOUR HOLTER

A holter is a digital recording of your heartbeat for either a 24-hour or 48-hour period. For example, if the recorder is set up 10:00 am today, you will wear the recorder home until the next day, when you return to the office to remove it.

WHY WOULD YOUR DOCTOR ORDER A 24 HOUR HOLTER

The doctor may order this test if you have palpitations or fainting and a normal ECG during your office visit. This is in an attempt to capture your heartbeat during the time when you are having the palpitations.

IMPLANTABLE LOOP RECORDER

The loop recorder is similar to the holter, but extends the period of time that your heart rhythm is recorded. It is implanted beneath the skin, similar to a pacemaker, and records your heartbeat for three to six months.

WHY A LOOP RECORDER?

A loop recorder may be needed for people who have severe symptoms, such as repeated fainting episodes without a diagnosis, especially if these fainting episodes are accompanied by palpitations. In these cases, the doctor is suspicious of a severe or potentially fatal abnormal heart rhythm. It is particularly useful in people whose symptoms occur infrequently – this increases the chance of capturing the abnormal beating.

ELECTROPHYSIOLOGY STUDY (EPS)

Electrophysiology is the study of the electrical abnormalities of the heart. Cardiologists who specialise in this area undertake at least an additional year of training after general cardiology. The electrophysiology study is performed in the cardiac catheterization laboratory. Catheters are passed to the heart and specialised equipment is used to map the electrical pathways in the heart. During EPS, the cardiologist may use special techniques to trigger and diagnose abnormal rhythms which may not be apparent on an ECG or other recording methods. At the same time, the cardiologist has the opportunity to treat these abnormal rhythms using a procedure called ablation.

This test is currently not available in Jamaica on a routine basis and is extremely expensive to perform. In the past, we had visiting teams who offered this service to people in need. Now patients need to be referred abroad to obtain the test.

Dr Claudine Lewis is an adult cardiologist and medical director at Heart Smart Centre in Montego Bay. She is also a cardiologist at the Cornwall Regional Hospital and an associate lecturer with the University of the West Indies. Questions may be sent to questions@heartsmartcentre.com and for additional information call 684-9989 or visit the website www.heartsmartcentre.com