Echocardiography in patients with cardiomegaly identified on chest X-Ray at an academic hospital in Zambia

Abstract

Introduction: Cardiomegaly is a sign that there is an underlying cardiovascular disease. It is a medical indication in which the heart is enlarged. This indication is strongly associated with high blood pressure or coronary heart disease. When enlarged, the heart may pump blood ineffectively, and this can lead to congestive heart failure. Common underlying causes of cardiomegaly are heart failure, heart muscle disease (cardiomyopathy), coronary heart disease, high blood pressure (hypertension), congenital heart disease, heart valve disease, thyroid disease, and obesity. Cardiovascular diseases are very often accompanied by an enlarged heart and these diseases are the world’s leading cause of death. Early detection of cardiovascular diseases in cardiomegaly patients is particularly important for the prevention of fatalities as cardiovascular diseases are the number one cause of diseases worldwide. Although the chest X-ray (CXR) is the number one imaging modality for cardiomegaly, echocardiography (ECHO), a dynamic ultrasound imaging modality of the heart can also be used to assess the functioning of the heart. In Zambia, no documented study has been done to establish the association between cardiomegaly identified on a chest x-ray and the results of the echocardiography reports of the same patients. The aim of this research study, therefore, was to establish whether there is an association between cardiomegaly identified on the CXR and the ECHO reports of the same patients. Methodology: This retrospective cross-sectional study involved the retrieving of data from 124 patients who had cardiomegaly identified on the CXR and had undergone an ECHO examination. The study was performed at Levy Mwanawasa General Hospital (LMGH) in Lusaka, Zambia. Findings: Cardiomegaly was detected in 124 patients (n = 124) on the CXR using the cardio-thoracic-ratio. Cardiomegaly was more prevalent in females (67.7% of participants were female) compared to males (32.3% of participants were male). All age groups were affected, however the prevalence increased with age; 60% of the patients were aged 60-80 years. More than 50% of the patients had severe cardiomegaly. There was no significant difference between males and females with severe cardiomegaly. The ECHO findings showed left ventricular diastolic dysfunction as the most common condition (presented in 71% of the patients) followed by left atrium dilation (presented in 29.1% of the patients) and left ventricular systolic dysfunction (presented in 29% of the patients). Doppler ultrasound was used to detect abnormal blood flow patterns within the heart. It revealed a significant correlation between severe cardiomegaly and severely increased blood flow patterns (p=0.004); and between cardiomegaly (minimal, moderate, and severe) and increased blood flow patterns (p=0.002, p=0.000 and p=0.04 respectively). Other abnormal ECHO findings included: ejection fraction (presented in 36.3% of the patients), fractional shortening (presented in 31.5% of the patients) left atrial dilation (presented in 28.2% of the patients), tricuspid valve regurgitation (presented in 25.8% of the patients), right atrium dilation (presented in 24.2% of the patients), posterior wall thickness (presented in 23.4% of the patients), inter-ventricular septal thickness (presented in 22.5% of the patients), pericardial effusion (presented in 21% of the patients), left ventricular dilation (presented in 20.2% of the patients ), right ventricular outflow tract (presented in 16.9% of the patients), mitral valve regurgitation (presented in 15.5% of the patients), aortic root dilation (presented in 8.8% of the patients) and pleural effusion (presented in 8.1% of the patients). There was a strong positive association between severely increased blood pressure and cardiomyopathy (p=0.023), inter-ventricular hypertrophy (p=0.017), left atrial dilation (p=0.007) left ventricular diastolic dysfunction (p=0.045), left ventricular dilation (p=0.003), left ventricular hypertrophy (p=0.028), left ventricular systolic dysfunction (p=0. 048) and pericardial effusion (p=0.001). Conclusion: Cardiomegaly detected on the plain CXR of patients was found to be a helpful marker for cardiac diseases, as well as an index of its severity. While 7.2% and 4.8% of patients with minimal and moderate cardiomegaly had normal ECHO findings respectively, all patients with severe cardiomegaly were identified with cardiovascular diseases. Hence, the ECHO made an important contribution to the diagnosis of specific cardiac anomalies in patients identified with severe cardiomegaly. ECHO may be considered a useful screening tool for patients identified with cardiomegaly on the CXR in adults.