The effect of ventricular unloading on the T-wave

The electrocardiogram (ECG) is the most important diagnostic tool in
cardiology, measuring electrical activity in the heart. T-wave abnormalities
are associated with e.g. ischemia, repolarization disorders and arrhythmias
which may lead to sudden cardiac death. The (patho)physiological background of
the T-wave and its alterations however, is not beyond debate. Many studies have
been conducted to examine the exact genesis of the T-wave. Notwithstanding that
multiple factors may affect the morphology of the T-wave, the majority of these
studies are solely focused on the dispersion in repolarization of the action
potential. The heart however, is a contracting and relaxing muscle which
suggests that, beside electrical factors, mechanical factors may be of
importance as well. Examination of the effect of cardiomechanics on the
morphology of the T-wave may contribute to a better understanding of T-wave
genesis and consequently an improvement of the diagnostics of repolarization
disorders and the associated risk for arrhythmias. In order to elucidate the
effect of cardiomechanics on the ECG in the in vivo human heart, we selected a
moment in which an abrupt change in ventricular work load occurs, and
structural remodelling is absent. In the catheterisation lab, acute unloading
of the heart takes place during impella guided percutaneous coronary
interventions. Therefore we selected this moment to make body surface maps
(BSMs; multiple lead ECGs) recordings in order to assess whether any changes
occur, and whether mechanoelectrical feedback plays a role in vivo

The main objective in this study is to determine whether there is an effect of
acute unloading of the left ventricle on the ECG, in particular the T-wave.

Observational

The PCI procedure will be extended with 15-20 minutes extra time (10 minutes
for preparation and application of electrodes, plus 5-10 minutes for the BSM
measurements). This includes one extra stepwise increase in pump settings and
one stepwise decrease. This all is not accompanied by extra risks for the
patient. In some cases shaving of the thorax is necessary to obtain good
contact of electrodes with the skin. The electrodes of the BSM system might
cause skin reactions such as irritation and itching. There will be no extra
fluoroscopy time due to measurements. The BSM electrode strips are
radio-translucent and do not influence the PCI procedure.