Getting down to the core
WHEN people think about magnetic resonance imaging scans, they usually think of brain scans. But the cardiac MRI – an MRI scan for the heart – has been in clinical use in Malaysia for nearly 12 years now.
The use of this technology has gained popularity over the past few years, but there are still a limited number of centres that perform cardiac MRIs in the country, explains Dr Chua Seng Keong, a consultant cardiologist at Ara Damansara Medical Centre.
Cardiac MRIs are considered the gold standard of non-invasive tests used to assess right and left heart function and are commonly used to ascertain in detail the tissue health of heart muscles and provide information to the cardiologist or surgeon on whether or not an invasive procedure (angioplasty or bypass surgery) is required when dealing with coronary artery disease.
Nowadays, cardiac MRIs are used in a multitude of ways:
• Assess left and right heart structure and pump function
• Assess heart valve function, especially leaky valves
• Assess large blood vessels of the heart A HEART attack is a serious thing that requires immediate medical intervention. Not only is it important to know the signs of heart attack, everyone should also know where to go during such an emergency.
Hospital emergency rooms (ERs) are usually equipped to deal with all kinds of emergencies, including those related to the heart.
An ER physician in Malaysia will see trauma cases – where there has been injury to the heart, such as when a person is stabbed in the chest – and medical emergency cases such as heart attacks or acute pulmonary oedema (accumulation of fluid in the lungs) leading to a cardiac arrest.
“Most of the time, when patients come into the ER with chest pains, it does turn out to be a heart attack, or something like an unstable angina, which is one step away from becoming a full-blown heart attack,” says Dr Abdullah Asad Siddiqui, emergency physician and head of the Emergency Department at Ara Damansara Medical Centre.
When a patient comes into the ER with chest pains, it is taken very seriously, says Dr Asad. He explains that the doctors and nurses
• Determine the presence of heart muscle scarring, primary heart muscle diseases and extent of damage caused by heart attacks in patients with weakened hearts
• As a cardiac stress test to determine if there is significant coronary artery disease
• To detect excess iron deposition in the heart (especially useful in Thalassemia patients requiring regular blood transfusions)
Cardiologists turn to cardiac MRIs when one of the more basic tests or scans, such as an echocardiogram or a treadmill stress test (an ultrasound of the heart) is unsuitable or do not provide adequate answers.
“Cardiac MRIs become indispensible when monitoring adults with congenital heart diseases because tests on them immediately start to diagnose whether or not the patient is having a cardiac event or one is imminent using a few methods:
Electrocardiogram – this machine records the heart’s electrical activity and will pick up any unusual activity, allowing doctors to determine if the patient is experiencing a heart attack
Blood examination – this tests the enzymes in the blood and takes a few minutes need to be repeated serially and the MRI does not carry any risk of radiation.” says Dr Chua.
Pros and cons
Compared to other tests, MRIs have a significant number of advantages: • No radiation risk • Non invasive • Best non-invasive test available to determine heart function
• The adenosine stress perfusion cardiac MRI used to detect significant coronary artery disease is superior to the equivalent nuclear perfusion study that involves radiation and has a lower resolution
There are, of course, a few disadvantages:
• Cost – it is the most expensive non-invasive test
• Confined space - the space in which the patient lies in the MRI scanner is small, typically 60-70cm in diameter
• Long scan time – patients may have to lie in the scanner for an hour or more
• Limited availability – there are limited cardiac MRI-enabled equipment, software and trained personnel in Malaysia
“MRIs are not for everyone and are indeed a luxury, but now that this technology is available we have a robust alternative should other initial imaging modalities fail to provide answers.
“Hopefully, with more trained cardiologists and radiologists this service will become more affordable and easily available to the heart patients that need it,” says Dr Chua.