Electromechanical changes of the myocardium after anthracycline chemotherapy

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background and objectives The most common side effects of chemotherapeutics in breast cancer is on the cardiovascular system. Global longitudinal strain (GLS) is the only parameter recommended for follow-up in current guidelines with limited evidence. Other strain imaging parameters and electrical changes after chemotherapy is not well studied. It is not known whether electrical or mechanical changes occur initially. The aim of this study is to evaluate repolarization parameters on ECG and mechanical changes together after chemotherapy in breast cancer patients. Subjects and method Consecutive patients who received chemotherapy due to breast cancer were included. Strain echocardiography and ECGs were performed pre-treatment (T0) and 3rd month after chemotherapy (T2). Additionally, just in three hours of first dose of chemotherapy (T1) another ECG was performed. QT and QT correction for heart rate (QTc), QT dispersion (QT disp) and QTc dispersion (QTc disp), T wave peak to end time (Tpe) and Tpe corrected for QT-QTc measurements were performed (figüre 1 and 2). GLS, longitudinal strain for myocardial layers, circumferential strain (CS), radial strain (RS) and torsion measurements were performed. All mechanical and electrical parameters from different time intervals were compared. Results Thirty-five consecutive patients (35 females, mean age 48.9 ± 11.8 years) who received chemotherapy (mean doxorubicin cumulative dose 415 ± 32 mg/m2) due to breast cancer were included. There was no significant change in mean GLS values before and after treatment (T0 -%18.8 ± 6.82, T1 18.6 ± 3.5 p = 0,863 respectively). However, there was a significant decrease in CS, RS and torsion (T0 -%17,2 ± 3,5, T1-%13 ± 2,84 p <0,001, T0 %45,1 ± 8,3, T1 %35,6 ±10 p <0,001 and T0 %12,1 ± 3.5, T1 %7.7 ± 2.1 p <0,001, respectively). QT, QTc, QTc disp and Tpe, Tpe/QTc parameters were prolonged just after chemotherapy and were still prolonged 3 months after ((QTc: T1 440.01 ± 27.63, T2 468.00 ± 38.98, T3 467.86 ± 35.09), (QTc disp T1 55.48 ± 20.22, T2 78.59 ± 16.15, T3 66.16 ± 14.62), (Tpe (QTc) T1 104 ± 18.52, T2 148.62 ± 19.16, T3 139.77 ± 21.63), (Tpe/QTc T1 0.213 ± 0.05, T2 0.281 ± 0.08, T3 0.258 ± 0.06). Conclusion Electrical and mechanical functions of the heart could be impaired together acutely even three months after doxorubicin chemotherapy. Cardio toxicity should be evaluated in terms of both electrically and mechanically. Abstract Figure. ECG repolarization parameters