Clinical cardiac assessment
Each assessment will begin by recording details of symptoms, dietary habits, smoking history, family history, exercise frequency and the results of any prior testing. A brief cardiovascular examination can sometimes help identify signs of heart disease, but specialised cardiac and blood testing offers far greater accuracy.
Cardiac testing
Echocardiogram
This is an ultrasound of the heart which shows the structure and function of the four heart valves and can identify any prior damage to the heart muscle which pumps blood around the body. An “echo” cannot directly evaluate the coronary arteries for plaque build-up.
Stress-test / Stress-echo
This is an exercise test typically done on a treadmill which can detect a severe limitation to flow in the coronary arteries due to plaque buildup. It can not detect minor plaque and its accuracy for severe plaque detection is somewhat limited. Nevertheless it remains one of the more cost-effective and harmless means of coronary assessment. A patient who has a positive stress test will often be referred for coronary angiography as this test can accurately confirm the presence and extent of coronary disease as well as the severity of each blockage.
24-Hour Holter ECG monitoring
Patients suspected of having an arrhythmia will often need prolonged rhythm monitoring. The most common way this is done is by attaching ECG wires and strapping on a portable device which the patient takes home and wears through the night for a full 24-hour period. The data stored on the device is then analysed by the cardiologist and the minimum, maximum and average heart rates, as well as the occurrence and duration of any arrhythmia, are reported.
24-Hour Blood-Pressure monitoring
A blood pressure cuff and portable device are worn by the patient through the night for a 24-hour period and a graph of systolic and diastolic blood pressures and heart rates is generated. This device is helpful for patients with possible “white coat” hypertension who have high blood pressures only when visiting their physician because it allows accurate assessment of blood pressure at home. Furthermore the many readings throughout the period can be averaged to determine overall control. It is the only test which can detect nocturnal hypertension — elevated blood pressure during sleep — which is associated with an elevated risk of stroke.
Coronary Calcium Score
This is a quick low radiation CT scan of the heart which does not require placement of an intravenous access or contrast administration (“dye”). It shows calcium deposits in the coronary artery wall — plaque deposits in the artery wall become calcified over time, so the extent of coronary calcification correlates with the the amount of long-standing coronary atherosclerosis. Patients with a high calcium score typically have a higher risk of a coronary event than those of similar age with a lower score.
CT Coronary Angiography
This CT scan of the heart involves more radiation than the calcium score and requires intravenous contrast administration. However it is more accurate as it can show non-calcified (“younger”) plaque and can also grade the severity of plaque deposits. It is not as accurate as a the more invasive conventional form of coronary angiography, which may still have to be done if there is a plan to “fix” a blocked artery with angioplasty and stenting or with coronary artery by-pass surgery.
Basic Lab Testing
CBC — complete blood count — most important are the haemoglobin (blood count), white cell count (can indicate infection) and platelets (affect bleeding).
RFT — kidney function — impaired kidney function is associated with a significantly elevated risk of heart disease; many medications have to be dose-adjusted or avoided; elevated uric acid is strongly correlated with hypertension and cardiovascular disease.
LFT — liver function — all medications are typically excreted by either the kidneys or the liver. This test can identify issues with liver function. Some patients can develop liver issues while taking a type of cholesterol-lowering medication called statins so monitoring is important.
CPK — creatine phosphokinase — Some patients have muscle issues when taking statin cholesterol-lowering medications. Those with more serious issues have elevations in CPK.
HbA1C — glycated haemoglobin — This gives a good estimate of the average blood sugar over the prior 3 months and is now a preferred means of identifying pre-diabetes and diabetes.
TFT — thyroid function — Over-active thyroid can be associated with palpitations and heart failure while under-active thyroid is associated with very slow heart rate, elevated cholesterol and atherosclerotic heart disease.
Urine Analysis — Identifying protein in the urine can indicate early kidney damage and correlates with endothelial damage and an elevated risk of atherosclerosis.
Advanced Testing
See RISK ASSESSMENT for details of these more specialised tests.