Cardiac toxicity associated with chronic administration of anthracycline antibiotics (e.g. daunorubicin, doxorubicin) represents a serious complication of their use in anticancer chemotherapy, but can also serve as a useful experimental model of cardiomyopathy and congestive heart failure. In this study, the relation between left ventricular (LV) contractility and cardiac troponin T (cTnT) plasma concentrations was studied, using a model of repeated daunorubicin administration to chinchilla male rabbits. Two groups of animals were used: control group (n = 10) received i.v. saline, experimental group (n=11) received daunorubicin (3 mg/kg, i.v.). Substances were administered once weekly for 10 weeks. 5 – 7 days after the last administration, dP/dtmax (i.e. the maximal rate of the pressure rise in the isovolumic phase of the systole) was invasively measured as the index of the left ventricular contractility under pentobarbital anaesthesia (30 mg/kg i.v.). Immediately after the LV contractility determination, arterial blood had been sampled for the cTnT determination and all the animals were humanely killed. The cTnT concentrations in heparinized plasma samples were measured using an Elecsys Troponin T STAT Immunoassay on the Elecsys 2010 immunoassay analyser (Roche, Switzerland). Four animals (i.e. 36%) from the experimental group died or were moribund and had to be killed prematurely. In the control group no premature deaths occurred. The cardiac contractility (dP/dtmax) was in 7 surviving daunorubicin-receiving animals significantly lower than in control group (745.7±69.3 vs. 1245.1±86.2 kPa/s; P〈0.001), while the cTnT plasma concentrations were significantly increased (0.262±0.034 vs. 0.007±0.003 nmol/mL; P〈0.001). When the dP/dTmax values were plotted against the cTnT plasma concentrations, a linear correlation (R=0.91; P〈0.005; Regression equation: dP/dtmax= -1861*cTnT+1234) was found in daunorubicin-receiving group of animals. This study shows that pathologically increased plasma cTnT concentrations closely correlate with the decreased LV contractility as measured with the use of invasive haemodynamic measurements. The cTnT plasma concentration determination, which is simple and inexpensive, can thus be used for LV systolic function assessment and contractility estimation. However, further studies are necessary to evaluate this finding in different experimental and clinical conditions.