Use of Cardiac Troponin I and T for Detection of Cardiac Chamber Dilatation in Horses

Background
Cardiac troponin i (ctni) is routinely used in equine clinical practice for detection of myocardial damage. However, many ctni assay varieties exist and assay availability is currently decreasing. in contrast, troponin t (ctnt) assays are widely available and the number of different assays is limited. unfortunately, ctnt is poorly studied in horses. for both troponins, usefulness in case of cardiac dilatation remains unknown. the aim was to compare ctni and ctnt concentration in healthy horses and horses with cardiac dilatation caused by structural heart disease.

Material and methods
Blood samples were collected from 20 healthy horses (body weight 572±54kg, age 7.9±4.3 years) and 24 horses with atrial or ventricular dilatation due to valvular regurgitation (body weight 570±115kg, age 11.6±7.3 years). Samples were centrifuged within 1 one hour after collection and serum was stored at -20°C. troponin i and t were determined using an acces accu-ctni assay (Beckman Coulter inc. fullerton, Ca; detection limit: 0.03ng/mL) and a Cobas E immunoassay (roche Diagnostics, Belgium; detection limit: 0.01ng/mL), respectively .

Results
The median ctni and ctnt concentration in healthy horses was ≤0.03ng/mL (range: ≤0.03-0.04) and ≤0.01ng/mL, respectively. Ctni concentration (median: 0.07ng/mL) was significantly higher in horses with chamber dilatation (p<0.001; range: ≤0.03-30.92), while no significant difference in ctnt concentration was found between healthy horses and horses with chamber dilatation (p=0.183). the median ctnt level in horses with chamber dilatation was ≤0.01 ng/mL (range: ≤0.01-0.57)

Conclusion
Cardiac troponin i can detect atrial or ventricular dilatation. the currently used ctnt test did not perform well. other, especially high sensitive, ctnt assays should be studied.