Serial measurements of cardiac troponin I (cTnI) in dogs treated with doxorubicin.

The study aimed to evaluate whether cardiac troponin I (cTnI) and pulsed-wave tissue Doppler imaging (TDI) measurements can detect cardiac changes during doxorubicin therapy in dogs with various types of cancers compared to conventional echocardiography. Serial measurements of cTnI and conventional and pulsed-wave TDI echocardiography were performed in 12 dogs diagnosed with various types of cancers at day 0, weeks 3, 6, 9, and 12 prior to each doxorubicin injection. After treatment with doxorubicin, dogs had significantly increased cTnI levels at week 9 (p = 0.027) and 12 (p = 0.027) compared to normal untreated dogs. Dogs had increased cTnI levels during doxorubicin therapy (p = 0.004). Percent left ventricular ejection fraction (LVEF) and fractional shortening (FS) assessed by 2-dimensional and M-mode echocardiography significantly decreased at weeks 9 and 12. Pulsed-wave TDI derived myocardial performance index (MPI) increased significantly at weeks 9 and 12 compared to day 0 (p = 0.028 and 0.040, respectively). In conclusion, dogs treated with doxorubicin had increased cTnI levels. An increase in cTnI levels was detected before echocardiographic value changes. Serum cTnI can be a sensitive marker for detection of cardiotoxicity in dogs treated with doxorubicin.