The results of a new study suggest that breast implants can impede ECG readings, and that doctors ought to be warned of false abnormalities.
The study, which was presented recently at the European Society of Cardiology meeting EHRA EUROPACE-CARDIOSTIM 2017, held in Vienna, Austria, is published in the Society's Europace journal.
An electrocardiogram (ECG) is a recording of the heart's electrical activity that is made using a machine attached to the skin of the chest, arms, and legs.
An ECG can reveal how fast the heart is beating, whether or not the rhythm of the beat is irregular, and the pattern of electrical pulses in each part of the heart.
They are used routinely in clinics, doctor's surgeries, and outpatient departments. Emergency departments also use them to investigate chest pains.
Implants can disrupt heart readings
Breast implants are used in breast augmentation to enlarge or restore breast size. They can also be used in mammoplasty or reshaping of the breast, as well as in breast reconstruction - following mastectomy, for instance. Most implants are of the saline or silicone-gel type.
In 2016, plastic surgeons carried out nearly 290,500 breast augmentations in the United States, 4 percent more than in 2015.
Dr. Sok-Sithikun Bun, lead author of the new study and a cardiologist at Princess Grace Hospital in Monaco, explains why they carried out their investigation.
"Our experience shows that breast implants make it difficult to see the heart with echocardiography because ultrasound cannot penetrate through the implant. We wanted to find out if implants also disrupt an ECG."
For the study, 28 women with breast implants and 20 control women of the same age without breast implants underwent ECGs. All the women were healthy and showed no evidence of structural heart disease.
Each ECG was analyzed by two electrophysiologists who were "blinded" about the subjects - that is, they were unaware of key characteristics such as the age and sex of each patient, whether they had breast implants, and whether they had heart disease.
One physiologist declared all the ECGs of the control group to be normal. The other said that one of them was abnormal.
'Be aware of potentially abnormal ECGs'
When they examined the ECGs of the group with breast implants, one physiologist said that 38 percent of them were abnormal, while the other said that 57 percent of them were abnormal.
Dr. Bun says that since "the main difference between the two groups of women was the breast implants," he and his colleagues concluded that the abnormal ECG recordings were due to the implants.
"Albeit echocardiography is difficult in women with implants, these measurements indicated that they had normal hearts and no structural heart disease, which suggests that there was no heart problem that could explain the abnormal ECGs," he adds.
Doctors look at various patterns in an ECG - such as "ST depression" and "T wave inversion" - to diagnose a heart attack.
Dr. Bun says that the pattern that came up the most often in the abnormal ECG recordings of the group with breast implants was "T wave inversion from leads V1 to V4, followed by ST depression."
"T wave inversion is an unspecific sign but can indicate the presence of coronary artery disease, while ST depression indicates that a patient may have a heart attack," he explains.
Dr. Bun advises patients to let doctors know if they have breast implants before they undergo an ECG. They should also consider having an ECG before receiving implants so that there is a pre-implant recording on file for comparison later. He concludes:
"Doctors should be aware that ECG interpretation can be misleading in patients with breast implants. In case of any doubts regarding the diagnosis, blood tests need to be performed depending on the symptoms."