The tests that are recommended for a patient depends upon what the doctor thinks that the patient has. Before sending you for testing, your doctor would take your detailed health history and examine your body thoroughly. Based on the suspicion, your doctor may refer to one or more tests.

Investigations not only help to detect a disease, they also help to check for presence of possible disease complications and to find out how is the treatment affecting your health.

Blood tests:

1. Complete blood count (CBC): A complete blood count helps to detect infection, anaemia and other blood disorders. Anaemia is a common finding in heart failure, plus it also contributes to worsening of heart failure. A low platelet count may be caused by medications such as diuretics or heparin.
   
   
2. Cardiac troponins (cTn1, cTnT, high sensitivity troponins): It is an important biomarker present in the blood which is very useful for the detection and prognosis of acute myocardial infarction. Cardiac troponins may also be high in other heart related conditions like acute myocarditis, coronary vasospasm and non-cardiac conditions (e.g. sepsis, chronic kidney disease).
   
   
3. Electrolytes, urea and creatinine: Levels of these help to find out your kidney function. Abnormal levels of electrolytes like potassium can increase the risk of arrhythmias Low levels of sodium is very common in heart failure. High levels of urea and creatinine indicate kidney failure which could be a possible complication of heart disease or its medications.
   
   
4. Liver function tests: Certain drugs such as statins and amiodarone, which are commonly prescribed for patient with heart disease, can trigger liver failure. Liver failure could also be a consequence of heart failure.
   
   
5. Thyroid function test: Medication for heart disease like amiodarone may cause hyper or hypo thyroidism. Altered thyroid hormone can also cause heart dysfunction.
   
   
6. Brain Natriuretic Peptides (BNP or N-terminal pro BNP): BNP is a useful tool to differentiate between cardiac and non-cardiac causes of shortness of breath especially when echocardiography is not available. High levels of BNP and N terminal pro BNP is associated with increased severity of heart disease and greater risk of hospitalisation.

Electrocardiography(ECG):

This test detects and records the electrical activity of the heart. This is a simple, non-invasive test which is very useful to determine abnormalities in the heart rate, rhythm and to identify risk of damaged heart muscle or other structural changes in the heart. This test detects the presence of arrhythmias and coronary artery disease.

Exercise stress testing:

Exercise makes your heart work harder. Exercise stress testing is done either on a treadmill or cycle ergometry with the patient connected to an ECG. Exercise stress testing may identify myocardial ischaemia, haemodynamic/ electrical instability, or other exertion-related signs or symptoms. When an individual is not able to exercise, medications are given to stress the heart and the response is evaluated.

Chest X-ray:

Chest X ray is very useful to differentiate whether shortness of breath is due to a respiratory disease or heart disease. It can also help in detecting complications of heart failure such as cardiomegaly, interstitial oedema, pulmonary oedema and pleural effusions.

Coronary angiography:

Coronary angiography is useful to determine the health of the coronary arteries. In this test, a catheter is inserted into the coronary arteries and a dye is injected to produce clear X ray images of the coronary arteries. This helps to find out the presence, location and extent of vessel narrowing. The results also help to decide what type of treatment would be most appropriate.

Echocardiography:

This test gives an ultrasound image of the heart. Echocardiography can provide information about the size and shape of heart chambers, blood flow velocities, heart muscle function when they contract and relax, abnormalities of the movement of the heart wall, valve function, and presence of thrombus (blood clot) in the heart.

Stress echocardiography helps in detecting decreased blood flow to heart during exertion. In this test, echocardiography is done immediately post stress. The stress can be exercise or induced by medications.

Myocardial perfusion scanning (MPS):

MPS is a non-invasive test which helps to determine how well blood flows through your heart muscles. In this test, a small amount of a radioactive substance is injected into the blood. The test evaluates the severity of coronary artery disease and provides guidance regarding the need for invasive procedures like angiography or coronary artery revascularisation.

Cardiac Computerised Tomography (CT):

Cardiac CT provides detailed images of the heart. This helps to identify structural abnormalities in the heart and blood vessels such as aneurysms, valve dysfunction and damage to the pulmonary vasculature. Cardiac CT also provides information about patency of grafts following coronary artery bypass graft.

Cardiac Magnetic Resonance Imaging (MRI):

Cardiac MRI uses strong magnetic fields and radiofrequency to provide detailed 3D images of the heart and surrounding structures. The image provides accurate information about cardiac volumes, muscle mass, contractility, and how efficiently the heart is pumping. Like cardiac CT, cardiac MRI also helps to provide information about patency of grafts following coronary artery bypass graft.