23 Sep, 2021

Our young researcher, Cristina Pérez, has been the winner of the Young Researcher Award (YIA) at the STAFF congress held in Sirolo (Italy), from Septembre 1 to 4, for her work entitled “Characterization of impaired ventricular repolarization by quantification of QT delay after heart rate changes in stress test”

Cristina Pérez explains in her research work, how increased spatio-temporal heterogeneity in ventricular repolarization is related to cardiac instabilities. Slowed adaptation of the QT interval to sudden abrupt changes in heart rate (HR), measured by the time constant of a first-order-like step response, has been identified as a marker of arrhythmic risk. Theoretically, the ramp-response  of  a  first order  system  is  characterized  by  a  delay corresponding  to  the  same  time  constant  as  the  one  of  the step-response.

Since abrupt HR changes are difficult to induce in patients, ramp-like HR variations observed in exercise stress test are considered. So, the first-order-system time constant is estimated as the delay between the QT series response and the series of memoryless expected QT series from the instantaneous HR in this work, separately in the exercise and recovery phases. We applied this procedure to a subset of 251 patients with different risk levels for Coronary Artery Disease (CAD). The time constant values ranged from 20s to 49s, which are comparable with the time lags reported in other studies in response to step-like HR changes. The delays in exercise and recovery phases and the difference between these delays are markers with capacity for CAD risk stratification.

Alba Martín also participated in the congress, presenting a work about “QT adaptation to heart rate changes in AF patients”.