Heart rate during a defined exercise test in horses with heart and lung diseases

During a gradually increasing exercise test heart rates were determined in healthy animals and in 2 groups of sick horse. These included 31 animals with a chronic pulmonary disorder and 5 with chronic heart disease. The alteration in heart rate was correlated with the clinical signs exhibited. In the horses with lung disease there was a close correlation between the stage of the diseases and the heart rate during the exercise test. In 3 animals with heart valve disease there was no apparent difference in heart rate compared with healthy horses. On the other hand the exercising heart rate of horses with atrial fibrillation showed a significant increase. The recovery rate of pulse and respiration after a 20 min trot did not show any correlation with the stage of disease or the pulse and respiration after a 20 min trot did not show any correlation with the stage of disease or the results of gradually stepping up the exercise in horses with lung disease.