Electrocardiogram abnormalities in patients with hematological malignancies before and after high dose chemotherapy and autologous hematopoietic stem cell transplantation

Abstract

Rationale: Electrocardiography (ECG) is an objective and widely available method for the diagnosis of cardiovascular disorders recommended for identification of abnormalities, including those in patients with malignancies. A few studies have been published on the assessment of changes in ECG over time in patients with hemoblastoses under high-dose chemotherapy (HDCT) with subsequent transplantation of autologous hematopoietic stem cells (autoHSCT). Aim: To study ECG abnormalities before HDCT with autoHSCT and after treatment and their association with cardiac dysfunction in patients with hematological malignancies. Materials and methods: This prospective cohort observational study included 71 patients with confirmed hemoblastoses. Before HDCT with autoHSCT and at the average of 20 weeks thereafter, a 12-lead standard ECG, echocardiography, and measurement of cardiac biomarkers (troponin T [TnT] and N-terminal pro-peptide of brain natriuretic peptide (NT-proBNP) were performed. We assessed P wave abnormalities, PQ duration, QRS, ST segment, and T wave. The following cut-off values were considered abnormal: duration of P wave above 110 ms, of PQ interval above 210 ms, of QRS above 110 ms. The QTc intervals were calculated according to Bazett and Fridericia. QTc above 450 ms in men and above 460 in women was considered as prolonged. Results: After HDCT with autoHSCT, increased left ventricular myocardial mass index (LVMMI) was more commonly found in the patients with prolonged P wave ( 110 ms) at baseline (χ2 = 7.214; odds ratio (OR) 4.179; 95% confidence interval [CI] 1.425–12.250; p = 0.015), and increased left atrial volume index (LAVI) was more common for those with initially two-humped P wave (χ2 = 11.169; OR 19.231; 95% CI 2.064–179.212; p = 0.004). Before HDCT with autoHSCT, flattened T wave was present in 14 (19.7%) of the study patients. After the treatment, 8 (11.3%) of the patients demonstrated a new T wave abnormalities, associated with more frequent new TnT increase ( 14 pg/mL) (χ2 = 7.945; p = 0.025), as well as with increased LAVI (p = 0.018) and LVMMI (p = 0.018). Before HDCT with autoHSCT, 10 (14.1%) of the study patients had a prolonged QTc interval, which correlated to the increased NT-proBNP level ( 125 pg/mL) (r = 0.247; p = 0.038). The assessment of the QTc length after HDCT with autoHSCT showed, that the increase of NT-proBNP levels by 1 pg/mL was associated with an increase of the QTc duration by 0.003 mc(p = 0.027). Conclusion: In patients with hematological malignancies, baseline P wave abnormalities are the risk factor for increased LVMMI and LAVI after HDCT with autoHSCT. New T wave abnormalities and QTc prolongation after HDCT with autoHSCT are associated with the signs of myocadial injury and dysfunction.