Early detection of cardiac dysfunction using shear wave imaging: insights into reduced cardiorespiratory fitness in childhood cancer survivors

Abstract Background Diastolic dysfunction is thought to be the earliest cardiotoxic sequel after cancer therapy among childhood cancer survivors. Despite many survivors do exhibit reduced cardiorespiratory fitness (CRF) potentially due to cardiotoxicity, current echocardiographic parameters fail to detect hidden diastolic dysfunction early after therapy (1). High frame rate (HFR) shear wave imaging (SWI) is a novel tool that could give insights about myocardial stiffness, which is a key determining factor of diastolic function. Purpose We aimed at testing the ability of SWI to detect early alterations in myocardial stiffness among childhood cancer survivors and its relation with the reduced CRF. Methods Fifty childhood cancer survivors (mean 20 ±3 years) who received chemo-and/or- radiotherapy (mean time after treatment: 4 ±3 years) and thirty-two matched healthy volunteers (HV) were recruited. Conventional as well as HFR echocardiographic images (ca. 1200 frames/second) were acquired at rest using a modified commercial echocardiography machine. All participants underwent an incremental, symptom-limited cardiopulmonary exercise test on a treadmill measuring peak oxygen consumption (VO2 peak). HFR data were analysed offline. An anatomical M mode was drawn along the ventricular septum, and tissue Doppler acceleration maps were extracted to measure SW velocities after mitral valve closure (MVC) (Figure 1). Results Among cancer survivors, left ventricular ejection fraction (LVEF) and global longitudinal strain were significantly lower compared to HV (56 % ±4 vs 59 % ±4, and 17.6 % ±1.6 vs 19.1 % ±1.2, respectively; p 0.05). The mean SW velocities were significantly higher in cancer survivors compared to HV (3.9 ±0.6 m/s vs 3.2 ±0.3 m/s respectively; p