Radiographic cardiac indices, cardiothoracic ratio and their correlation with age and body weight of apparently healthy German shepherd dogs

The study was conducted to establish the reference values of the various radiographic cardio-thoracic parameters in six apparently healthy German shepherd dogs (Group I) and three dogs with cardiac affections (Group II). Mean±SE values of body weight and age were 26.80±1.26 kg and 55.00±3.62 months in group I, and 36±1.53 kg and 68±4.00 months in group II, respectively. A significant negative correlation was seen in the cardiac height, tracheal diameter and tracheal diameter/length of 4^th thoracic vertebra (T₄) with the age and body weight. A significant positive correlation was observed between cardiac inclination angle and body weight. Cardiosternal contact, cardiophrenic contact, tracheal angle, cardiac width/T₃-T₅, cardiophrenic contact/cardiac height were positively correlated with the age and body weight. Cardiac width, thoracic height, length of thoracic vertebrae T₃-T₅ distance between 3^rd and 6^th rib (R₃-R₆), length of 4^th thoracic vertebra (T₄), cardiac height/thoracic height, cardiac width/ thoracic height, cardiac height/T₃-T₅ cardiac height/R₃-R₆, cardiac height and cardiac width/R₃-R₆ and cardiac height and cardiac width/thoracic height were negatively correlated with age and body weight. Cardiac width/R₃-R₆ and cardiac height and cardiac width/T₃-T₅ were negatively correlated with age but positively correlated with the body weight. These cardiothoracic indices can be used as a normal reference for evaluating the cardio-thoracic diseases in German shepherd dogs.