Objective: To investigate the clinical value of heart rate deceleration capacity (DC) in predicting the risk of epirubicin-induced cardiotoxicity.
Methods: The CK-MB and cTnI levels and DC values of 86 patients were examined before chemotherapy and again after 2 and 4 cycles of chemotherapy. Patients were divided into low-risk group (LRG) (40 cases), medium-risk group (26 cases), and high-risk group (HRG) (20 cases) based on the calculated DC values.
Results: After 4 cycles of chemotherapy, HRG showed a significantly greater increase in serum CK-MB (17.1 ± 4.9 vs. 14.6 ± 3.7) and cTnI (1.28 ± 0.38 vs. 1.0 ± 0.29) concentrations over the prechemotherapy levels when compared with LRG. After 2 and 4 cycles of chemotherapy, HRG exhibited a significantly greater increase in mean heart rate (2 cycles: 79.6 ± 6.0 vs. 77.6 ± 6.7; 4 cycles: 88.2 ± 10.2 vs. 82.4 ± 6.2) and the supraventricular (2 cycles: 68.9 ± 19.3 vs. 57.2 ± 17.6; 4 cycles: 131.1 ± 29.5 vs. 91.7 ± 16.5) and ventricular arrhythmia counts (2 cycles: 179.0 ± 20.5 vs. 162.3 ± 16.3; 4 cycles: 228.6 ± 44.8 vs. 187.4 ± 22.6) over the prechemotherapy values compared with LRG. When the supraventricular and ventricular arrhythmia counts measured after 4 cycles of chemotherapy were compared with those obtained before chemotherapy, HRG (131.1 ± 29.5 and 228.6 ± 44.8, respectively) showed the largest differences, followed by medium-risk group (107.4 ± 31.9 and 202.0 ± 29.8, respectively) and then LRG (91.7 ± 16.5 and 187.4 ± 22.6, respectively) (P < 0.01). After 4 cycles of chemotherapy, the incidence rates of ventricular arrhythmia greater than Lown's grade 3 (30% vs. 2.5%), QTc (20% vs. 0) elongation, and ST-T (40% vs. 5%) changes in HRG were significantly higher than those observed in LRG (P < 0.05).
Conclusions: DC test was shown to be an effective predictor of the risk of epirubicin-induced cardiotoxicity.