The Influence of Radiotherapy on the Function of the Left and Right Ventricles in Relation to the Radiation Dose Administered to the Left Anterior Descending Coronary Artery—From a Cardiologist’s Point of View

SIMPLE SUMMARY: Radiotherapy is an established method of cancer treatment, improving patients’ survival; however, it is associated with possible life-limiting late complications, including cardiovascular diseases. The cardiotoxic effects depend on the doses of radiation delivered to the heart. Despite significant advances in radiotherapy techniques, resulting in reduced doses of ionising radiation, cardiac dysfunction remains a common problem after mediastinal irradiation. The present study emphasises the need to calculate the radiation doses delivered to several parts of the heart, revealing relationships between doses delivered to the left anterior descending artery (LAD) and the whole heart, along with echocardiographic markers of early systolic dysfunction of the left (LV) and right ventricles (RV). ABSTRACT: The aim of this study was to assess the effects of radiotherapy involving the heart on LV and RV function using modern speckle-tracking echocardiography (STE), and in relation to the radiation dose applied to the LAD. This retrospective, single-centre study included 12 patients after a median of 51 months after irradiation for mediastinal lymphoma, in whom we were able to delineate the LAD. Correlations between doses of ionising radiation and echocardiographic parameters reflecting the systolic function of the LV and RV were analysed. The median irradiation dose delivered to the whole heart was 16.4 Gy (0.5–36.2 Gy), and to the LAD it was 15.1 Gy (0.3–35.3 Gy). LV longitudinal strain (LS) was impaired in the anteroseptal and anterior walls. Parameters reflecting RV function were normal, with the exception of RV myocardial performance index (RIMP). Significant correlations were found between the median dose to the LAD and LV global LS (rho = 0.6468, p = 0.034), the maximum dose to the LAD and LV anterior LS (rho = 0.6046, p = 0.049), the median and the mean dose to the whole heart and LV anterior LS (R = 0.772, p = 0.009 and rho = 0.7676, p = 0.01, respectively), and the total irradiation dose and RIMP (rho = 0.5981, p = 0.04). The calculation of irradiation doses allows the identification of patients at risk of cardiac dysfunction detected by modern STE.