Relação entre escore cardíaco e o condicionamento físico de eqüinos da raça Mangalarga Relationship between heart score and physical conditioning in Mangalarga horses

Heart size, by definition, determines the animal’s maximal cardiac and aerobic performance, and due to the possibility in obtaining this measure through electrocardiography, the relationship between heart score and physical conditioning in Mangalarga horses was verified. Seventy horses ranging from 11 month to 10 years old were examined, divided into three groups: G1 (control), with 30 adult sedentary horses (10 males and 20 females); G2 (conditioned), with 30 adult horses (15 males and 15 females) submitted to a regular training schedule for at least 12 months, and G3, with 10 fillies beginning training. After the derivations registers were obtained, the heart score was calculated by the average of the QRS complexes duration in the bipolar derivations (I, II and III), considering five complexes in each one, with the result in milliseconds (ms). The mean heart score in G1 (97.10 ± 12.37 ms) was significantly smaller than G2 (129.07 ± 9.28 ms), P 0.05) to G1 and smaller (P 0.05) between sexes in G2, with a mean female heart score 127.27 ± 7.98 ms, whereas the male heart score was 130.9 ± 10.4 ms. In group G1 (sedentary animals) the females had a mean heart score of