Determination of Standard Reference Cardiothoracic Ratio and the Relationship with Body Parameters as A Patients Health Indicator for Clinical Application

Abstract

The heart is a muscular organ about the size of a closed fist that function by pumping blood throughout the body making the body size extremely important in its performance. Hence, the work done by the heart depend largely on the total body size of the individual, measurements of which depends on the weight and height to estimate BMI, BSA and BSI. The aim of the study was to establish Ghanaian based standard reference values of cardiothoracic ratio and determine the relationship with body parameters for clinical application. The maximum transverse diameter of the heart was obtained by adding the widest distance of the right heart border from the midline and the left heart border to the midline (cardiac diameter). This value was then divided by the maximum transverse diameter of the thorax (the thoracic diameter) to give the cardiothoracic ratio (CTR). Which is described as a ratio of the cardiac width as against thoracic width. The measured CTR was approximately 15: 33 (cm) and is therefore within the normal limit of 50%. This is because a CTR of greater than fifty percent is abnormal, in terms of Posterior - Anterior (PA) or an Anterior - Posterior (AP) view. In addition, the height and weight were measured to estimate the BMI, BSA and BSI and the relationship of these parameters with the measured cardiothoracic ratio. The result shows that BSI better correlate with the cardiothoracic ratio than any other body parameter with 92.53% accuracy rate. The determination of the CTR which represent the size of the normal heart is of the greatest importance to cardiologists. This is because the heart size enlargement is better assess by determining the ratio of size of the heart (cardiac diameter) as against the size of the chest wall (the thoracic diameter). This is use for initial assessment of heart condition by cardiologist, with a standard adult heart having a CTR value of 0.5. The study shows that a normal size is so variable and depends so greatly on the sex, age and body parameters of the study population. In conclusion, the study will serve as basis of the relationship between body parameter and the CTR. It also established that a deviation of heart size with BSI may reveal an underlying pathologic condition, and called for further studies to be conducted for clinical decision.