The chapter discusses the investigation of heart failure, emphasizing the importance of clinical assessment and objective tests such as echocardiography. Key components of the investigation include: 1. **Chest X-ray**: Useful for detecting cardiac enlargement (cardiothoracic ratio >50%) and monitoring treatment response. Cardiomegaly can be absent in acute conditions like acute myocardial infarction. Echocardiography is necessary to distinguish between different causes of cardiac silhouette changes. 2. **12 Lead Electrocardiography**: Abnormalities are common in heart failure but can be normal in up to 10% of cases. Normal findings rule out heart failure secondary to left ventricular systolic dysfunction. Holter monitoring can detect arrhythmias and other abnormalities. 3. **Echocardiography**: The most useful non-invasive test for assessing left ventricular function. It provides objective data on cardiac structure and function, including left ventricular ejection fraction, regional wall motion abnormalities, and valvar disease. Transesophageal echocardiography is useful for detailed visualization in challenging cases. 4. **Haematology and Biochemistry**: Essential for excluding anemia and metabolic abnormalities. Renal function and electrolyte levels are crucial in severe heart failure, where hyponatremia and hypokalemia are common. 5. **Radionuclide Imaging**: Used when echocardiography is not feasible, assessing global ventricular function and myocardial perfusion. 6. **Angiography and Cardiac Catheterisation**: Considered for recurrent ischemic chest pain or severe reversible ischemia. Myocardial biopsy is valuable in difficult cases. 7. **Pulmonary Function Tests**: Useful for excluding respiratory causes of breathlessness, though often coexisting with cardiac disease. 8. **Stress Studies**: Assess myocardial reversibility in coronary artery disease patients. The chapter highlights the importance of a comprehensive approach to diagnosing heart failure, combining clinical assessment with objective tests to ensure accurate diagnosis and effective management.The chapter discusses the investigation of heart failure, emphasizing the importance of clinical assessment and objective tests such as echocardiography. Key components of the investigation include: 1. **Chest X-ray**: Useful for detecting cardiac enlargement (cardiothoracic ratio >50%) and monitoring treatment response. Cardiomegaly can be absent in acute conditions like acute myocardial infarction. Echocardiography is necessary to distinguish between different causes of cardiac silhouette changes. 2. **12 Lead Electrocardiography**: Abnormalities are common in heart failure but can be normal in up to 10% of cases. Normal findings rule out heart failure secondary to left ventricular systolic dysfunction. Holter monitoring can detect arrhythmias and other abnormalities. 3. **Echocardiography**: The most useful non-invasive test for assessing left ventricular function. It provides objective data on cardiac structure and function, including left ventricular ejection fraction, regional wall motion abnormalities, and valvar disease. Transesophageal echocardiography is useful for detailed visualization in challenging cases. 4. **Haematology and Biochemistry**: Essential for excluding anemia and metabolic abnormalities. Renal function and electrolyte levels are crucial in severe heart failure, where hyponatremia and hypokalemia are common. 5. **Radionuclide Imaging**: Used when echocardiography is not feasible, assessing global ventricular function and myocardial perfusion. 6. **Angiography and Cardiac Catheterisation**: Considered for recurrent ischemic chest pain or severe reversible ischemia. Myocardial biopsy is valuable in difficult cases. 7. **Pulmonary Function Tests**: Useful for excluding respiratory causes of breathlessness, though often coexisting with cardiac disease. 8. **Stress Studies**: Assess myocardial reversibility in coronary artery disease patients. The chapter highlights the importance of a comprehensive approach to diagnosing heart failure, combining clinical assessment with objective tests to ensure accurate diagnosis and effective management.