GENERAL MEDICINE

Investigations

All patients suspected of cardiac disease should have a thorough history and physical examination which will often establish the diagnosis. Commonly required investigations include:

• CXR This will identify cardiac enlargement and in some instances the cardiac chamber involved and any associated pulmonary congestion or pulmonary oedema.
• ECG This can confirm ischaemic heart disease showing ischaemia at rest or myocardial infarction. However a normal ECG does not exclude IHD and an exercise ECG, under medical supervision, is useful in the assessment of the patient with suspected angina. The ECG is also essential in the diagnosis of cardiac arrhythmias and conduction abnormalities. Characteristic abnormalities may occur in LVH, mitral stenosis, pulmonary embolism, pericarditis, ventricular aneurysm and hypothermia.
• Echocardiography 2-dimensional scans have largely replaced the M-mode echo and allow, visualization of all four chambers, their wall thickness and valves in the heart. Combined with Doppler studies the flow of blood across valves or septal defects can be determined and quantities.
• Angiography This can be used to outline the coronary circulation and is essential in the assessment of coronary atheromatous disease in those who would be candidates for coronary surgery or angiography. Cardiac cathetherization with contrast studies, pressure measurement and O₂ saturation allows/accurate assessment of ventricular size and function, valvular heart disease or intracardiac shunts.
• Isotope scans These can be used in the assessment of ventricular function, myocardial ischaemia and myocardial infarction. Pulmonary perfusion scans are commonly used in the diagnosis of pulmonary embolism.