Common investigations in cardiovascular disease

1 Common investigations in cardiovascular disease clinical findings or ECG changes. Serial troponins are Blood tests frequently done to determine the peak troponin post Full Blood Count (FBC) MI, which has prognostic value. Cardiac troponins may be elevated in the presence of inflammatory Cardiac troponins (cTn1, cTnT, high conditions ( acute myocarditis), structural heart sensitivity troponins) disease , coronary vasospasm and non-cardiac Electrolytes, urea and creatinine conditions ( sepsis, chronic kidney disease ). Liver Function Tests (LFTs) Electrolytes, urea and creatinine Thyroid Function Tests (TFTs) Electrolytes, urea and creatinine tests identify electrolyte disturbances and define renal function. Brain Natriuretic Peptides (BNP or N-terminal pro BNP) Abnormal potassium (hyper- or hypo-kalaemia). may be secondary to renal impairment, potassium Electrocardiography (ECG).

2 Sparing medications and excessive diuresis and may Chest X-Ray (CXR) contribute to cardiac arrhythmias. Coronary angiography Hyponatraemia (low blood sodium) is Common in Echocardiography heart failure and is usually the result of fluid retention in excess of sodium stores. Myocardial perfusion scan (MPS) (sestamibi scan/ thallium scan) Elevated serum creatinine suggests renal impairment and in cardiac disease may be secondary to Cardiac computerised tomography (CT) medications; angiography (dye related), and Cardiac Magnetic Resonance Imaging (MRI) progression of heart failure. Liver Function Tests (LFTs). Blood tests Liver function tests identify abnormal liver function. Medications such as amiodorone and statins may Full Blood Count (FBC). provoke liver dysfunction. Chronic poor cardiac A full blood count can identify presence of infection, output may also disrupt liver function.

3 Anaemia and other blood disorders. Mild anaemia Congestive hepatomegaly may contribute to cardiac is Common in heart failure and if left untreated cirrhosis and subsequent hypoalbuminaemia, may contribute to worsening of the condition hypoglycaemia and increased prothrombin time and to a poorer prognosis. In cardiac disease , in heart failure. thrombocytopaenia (low platelet count) may be caused by medications such as diuretics or heparin. Thyroid Function Tests (TFTs). Cardiac troponin (cTn1, cTnT, high sensitivity TFTs identify hyper- or hypo-thyroidism. Although troponins) rare, thyroid dysfunction may cause or precipitate heart failure or precipitate atrial fibrillation. Cardiac troponin is a serum biomarker used for Amiodorone may cause hypo- or hyper-thyroidism. the diagnosis of acute myocardial infarction (MI).

4 And prognosis. Diagnosis of acute MI is dependent upon rise and fall of the biomarker, in addition to Source: Reviewed 11/2014 1. Common investigations in cardiovascular disease Brain Natriuretic Peptides (BNP or N-terminal Chest X-Ray (CXR). pro BNP). A chest x-ray aides in the differentiation between BNP assists in the differentiation between cardiac respiratory and cardiac causes of dyspnoea. In and non-cardiac causes of dyspnoea especially those with heart failure, Common findings include when echocardiography is not available. A BNP cardiomegaly, interstitial oedema, pulmonary oedema or N-terminal proBNP level < 100pg/ml makes and pleural effusions. Evidence of surgery (eg CABG, diagnosis of heart failure unlikely. Elevated (>600 valve repair, ICD implantation) is also detected pg/ml) BNP or N-terminal proBNP indicates heart on CXR.

5 Failure decompensation is likely and is associated with severity of disease , risk of hospitalisation and survival. Coronary angiography The tests are more useful in detecting heart failure Coronary angiography investigates integrity of with reduced ejection fractions (HFREF) rather than coronary arteries by insertion of a catheter into heart failure with preserved ejection fraction (HFPEF). the coronary vasculature and the use of dye to produce the image. The presence, location and Electrocardiography (ECG) extent of vessel narrowing is identified on the image ECG records the electrical activity of the heart. It is and likely sources of symptoms ( culprit lesions ). a simple test that identifies heart rate, conduction may be identified. The results guide treatment disturbances, myocardial ischaemia and possible such as revascularisation (PCI, CABG) or medical structural defects.

6 Management. As changes may be transient, comparison with Echocardiography (echo). previous ECGs is always valuable. ECG aids in the diagnosis of underlying causes of heart disease such An echocardiogram provides an ultrasound image as coronary artery disease or arrhythmias. of the cardiac anatomy . Echocardiography may be conducted using a transducer (probe) external to the ST segment elevation or depression may represent chest wall as is the case with transthoracic echo (TTE). ischaemia or infarction. Large voltage QRS A transoesophageal echo (TOE) is more invasive but complexes, downward sloping ST segments and T provides more detailed information and involves the wave inversion may represent chamber hypertrophy. (ultrasound transducer being passed into the patient's Rhythm disturbances such as atrial arrhythmias, heart oesophagus.)

7 Block and intraventricular septal conduction delays Echocardiography can provide information about are Common in heart failure secondary to cardiac chamber size and shape, blood flow velocities, remodelling and may also exacerbate heart failure. systolic and diastolic function, contractility, wall Exercise Stress Testing motion abnormalities and ejection fraction, valve function, and presence of chamber thrombus. The cardiac stress test is done with heart stimulation, either by exercise on a treadmill, cycle ergometry NB. Echocardiography is the gold standard with the patient connected to an ECG. Exercise investigation for diagnosis of heart failure and should stress testing may identify myocardial ischaemia, be re-assessed on completion of medication titration haemodynamic/ electrical instability, or other and at least every 2 years thereafter.

8 Echo can identify: exertion-related signs or symptoms. Note that cardiac Type of heart failure. Ejection fraction can stress may also be induced using medications, determine whether the type of heart failure, when an individual is unable to perform the exercise Heart Failure with Reduced Ejection Fraction . test as required. HFREF (EF < 45%). Source: Reviewed 11/2014 2. Common investigations in cardiovascular disease H. eart Failure with Preserved Ejection Fraction Cardiac Computerised Tomography (CT). HFPEF (normal EF however impaired diastolic Cardiac CT uses CT technology to provide detailed function). images of the heart. This may include identification of Regional wall motion abnormalities (RWMA) anatomical abnormalities such as aneurysms or valve and wall dyssynchrony (HF patients with wall dysfunction, as well as providing information about dyssynchrony may be eligible for biventricular pulmonary vein anatomy which may be implicated pacing).

9 In AF. Cardiac CT also provides information about Valve sclerosis, stenosis or regurgitation. (Valve patency of grafts following CABG. dysfunction may cause or exacerbate HF and CT angiography uses the addition of a contrast dye may be amenable to repair or replacement). to prove more detailed information about CAD. Stress echocardiography Calcium scoring may be undertaken with CT to Stress echo assesses patients with suspected or known investigate the presence, location and extent of myocardial ischaemia. Exercise or medication is used calcified plaque in the coronary vasculature. The to stress the heart. Cardiac function is then evaluated test has prognostic value and may guide further using echocardiography pre and immediately post investigations and management. stress. Myocardial response may be described as hypokinetic (decreased), dyskinetic (impaired) or Cardiac Magnetic Resonance Imaging akinetic (absent).

10 (MRI). This test is valuable in assessment of viable/ischaemic Cardiac MRI uses high intensity magnetic fields and myocardium in known CVD being considered for radiofrequency to produce 3D images with high revascularisation. resolution. The image provides accurate information about cardiac volumes, muscle mass, contractility, Myocardial perfusion scan (MPS) tissue scarring and ejection fraction. Location and (sestamibi scan/ thallium scan) size of myocardial infarction can be described with precision and may provide useful information MPS is a non invasive nuclear medicine scan regarding patency of bypass grafts. that examines myocardial perfusion both at rest and under stress using a small amount of The image can identify regional wall motion a radioactive substance, called a radionuclide abnormalities (RWMA) and wall dyssynchrony, (radiopharmaceutical or radioactive tracer).