MAMma-ablation ECG study

Sex differences in several baseline characteristics of electrocardiograms (ECG)
are well known, but the clinical significance often remains unclear. These
concern amplitudes and duration as well as repolarization patterns of the ECG.
Most important gender-disparities in baseline ECG recording concern a longer
QT-interval and a longer and more horizontal RS-T segment in women compared to
men. The etiology of this *gender-repolarization-gap* has been puzzling
cardiologists until now. It has been proposed that testosterone-levels are
related to a shorter QTc in adult men, while estrogens interfere with potassium
and calcium channels in females. However, no significant cyclic variation in
ECG patterns have been found in females and conflicting reports have been
published on the association between ECG changes with menopausal status or
hormone use.
Other important factors that affect gender-differences in ECG recordings are
related to their different thorax size and presence of adipose tissue. Breast
tissue in women, dependent on breast size and shape as well as adipose tissue
in obese patients lead to lower QRS and T-amplitudes with an increase of the
QRS complex after mastectomy. Breast tissue in women often leads to incorrect
positioning of the precordial leads that may affect the quality of ECG
recordings.
As primary clinical decision rules in acute and chronic settings of cardiology
are importantly based on interpretation of baseline ECG recordings,
misinterpretation of ECG*s frequently occur in females patients. This often
results in unnecessary further diagnostic testing, especially since advanced
non-invasive cardiac imaging techniques are available (CT scans, MRI imaging,
PET-CT). This has contributed to the giant raise in costs of healthcare over
the past decennia. Moreover, these advanced imaging techniques have reduced
technical skills of young doctors in ECG reading and interpretation, while the
ECG has remained the first important step in the diagnostic cardiology process.

To establish the role of breast tissue on ECG recordings in asymptomatic women,
without prior CVD, before and < 6 weeks after ablation of the left (or both)
breasts.

All patients scheduled for ablation of the left (or both) breasts will be
invited for an ECG recording before and < 6 weeks after elective surgery, as
has been developed by the department of Medical Physics at the UMC St Radboud.
Both ECG recordings will be analyzed so patients can be used as their own
reference. The ECG recorded will either be the standard 12 lead ECG and a Body
surface map (BSM). As this study will investigate the changes in the ECG due to
changes in body shape, the body surface needs to be measured accurately. For
this purpose a 3D camera will be used to create accurate 3D reconstructions of
the body surface during each ECG measurement with the ECG electrodes attached.
To be able to compare the individual ECG changes, the same electrode positions
should be used for all the ECG measurements on one patient. The first
reconstruction of the body surface will be used for this purpose. From these
scans the changes in body shape can be analyzed as well. The reconstructed body
surface can be used as a reference.

Before the initiation of this study, the Institutional Review Board of the UMC
St Radboud in Nijmegen will be asked permission. Patients will be informed
about the procedure of the ECG recordings before and after surgery.

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