This is a simple, painless and non-invasive test which records electrical signals of the heart, over a few seconds, using 10 electrodes on specific areas of the chest wall and limbs. An ECG provides important electrical information from the heart that can diagnose arrhythmia, such as atrial fibrillation, but also identify patterns consistent with heart muscle disease, such as cardiomyopathy and heart attacks.
Patients with suspected coronary artery disease or exertional symptoms may require ECG assessment during exercise, commonly using a treadmill, to identify abnormalities suggesting poor blood supply to the heart or arrhythmia. The test is a controlled walking test, starting slowly and progressing in stages to a brisk walk on an incline depending on the individual's fitness. The test is completed when either a target heart rate is achieved or ECG abnormalities are identified.
An echocardiogram is a painless, non-invasive heart scan performed by transmitting ultrasound waves through the chest to assess heart muscle and valve function. This test is important to diagnose many conditions including heart failure, cardiomyopathy, previous heart attacks, valve disease and holes in the heart. A transoesophageal echocardiogram (TOE) is sometimes required, particularly to further assess certain heart valve abnormalities. This is performed by passing a small tubed ultrasound probe into the food pipe (oesophagus) behind the heart under local anaesthetic and controlled sedation.
Symptoms such as palpitation, dizziness or blackouts may occur intermittently and without warning. A 12-lead electrocardiogram can evaluate heart rhythm at a given time but prolonged heart rhythm monitoring may be required to identify episodic problems. This type of test is called Holter ECG monitoring and can be carried out continuously for 24 hours up to 7 days or alternatively as a patient activated event recorder. These tests involve placing electrodes on the chest wall and connecting to a small recording device. The patient can continue with normal daily activities and are asked to complete a symptom diary to aid diagnosis.
Symptoms of palpitation or blackouts may be infrequent and difficult to capture despite Holter ECG monitoring. An implantable cardiac ECG event recorder can provide monitoring for up to 3 years if required. A small device is injected under the skin in the chest wall, through a small incision under local anaesthetic. The device can constantly monitor and record heart rhythm disorders and either manually or automatically send information wirelessly to a cardiac investigation department for further analysis and diagnosis. The device can be removed once a diagnosis is made or if no abnormality is found.
A diagnosis of hypertension is made after at least 3 elevated recordings taken on separate days and different times. There are occasions when a diagnosis of hypertension is not clear, either due to borderline readings or commonly 'white-coat syndrome' whereby the blood pressure is raised in a doctor's clinic due to stress and anxiety. In these situations, recording of the blood pressure over a 24-hour period at home can provide very useful information to make both an accurate diagnosis and assess response to treatment. The test is carried out by fitting a blood pressure cuff and monitor and taking regular automatic blood pressure recordings throughout the day and night.
A Cardiac MRI scan uses magnets and radiowaves to create detailed images of the heart muscle and related structures. An injection of gadolinium contrast can provide further information with regards to scar tissue within the heart, commonly related to previous heart attacks but also other conditions including cardiomyopathy, myocarditis and sarcoidosis. The test is non-invasive and low risk but does involve lying down in a tunnel for 45-60 minutes and may not be appropriate for patients suffering from claustrophobia.
Coronary angiography uses X-rays to examine blood flow to the heart, most commonly for patients experiencing angina. Depending on the risk profile and cardiac history of the patient, this test can be performed either non-invasively, using a cardiac CT scan, or invasively by a cardiologist. An invasive study is performed by inserting a thin tube, called a cardiac catheter, into an artery in the wrist or groin and advancing it to the coronary arteries. An injection of contrast dye allows the cardiologist to evaluate for any significant narrowing or blockages. The test is performed with the patient lying flat, using local anaesthetic, and usually takes around 20 minutes. The patient can generally mobilise soon after the test and go home the same day. It is important to be aware that all invasive tests carry a small risk and this should be discussed with you by your heart specialist.