One of the most commonly carried out tests in Cardiology is an electrocardiogram (commonly called an ECG). Expert interpretation of this relatively simple test can provide information about common conditions which the patient may have suffered from in the past such as a heart attack, conditions of which they are unaware, such as hypertension, as well as inherited disorders of the heart muscle or rhythm. An ECG may also identify patients with rare, but potentially life-threatening conditions that need further investigation and treatment by rapidly evolving techniques. Echocardiography is a versatile investigation that uses ultrasound to assess heart structure and function. Among its applications are to monitor the deterioration of leaky or narrow heart valves and to determine the timing and type of cardiac surgery. Echocardiography can also used to identify the causes of strokes, for screening patients before noncardiac procedures and to detect cardiac valve infections. The examination is usually carried out whilst the patient is at rest and semirecumbent with the probe on the front of the chest, but in some situations it may be necessary to get more information about the heart structures by passing a specialised probe down the gullet. Stress echocardiography is a modification of the examination with images taken whilst the heart is made to work harder, by the administration of drugs.

Another widely used investigation is Exercise testing. Treadmill ECG stress testing is used to help estimate the severity of coronary disease in patients with angina and can also be used to assess the effectiveness of treatment. The ECG trace, blood pressure response and the duration of exercise on the treadmill are amongst the features used by the specialist to make a diagnosis and suggest the best approach to further testing and treatment.

Longterm ECG recording is more often used to make a diagnosis in patients with significant palpitations, dizzy spells, faints and collapses. The ECG monitor is worn by the patient for at least a day. The results of the test can be used to define patients who will need specific drug therapy, pacemaker, ablation or in some patients all these means of treatment. The risk of life-threatening arrhythmias can also be predicted by combining the results of interpretation of the ECG during exercise testing and longterm monitoring. Ambulatory blood pressure monitoring also involves a series of recordings this time of the blood pressure over a 24 hour period. The results can be used to make or confirm a diagnosis of hypertension, identify the patients at highest risk of suffering complications as well as identifying subjects with erroneously high office readings whose blood pressure is normal on ambulatory monitoring and who can thus be reassured.

Many patients may need only one test, but patients with complex problems may need more than one test, to decide on the most appropriate treatment. The Cardiologist, Physiologists and Nurses work closely to arrange, supervise and report these tests. The Clockhouse provides excellent noninvasive cardiac diagnostic facilities to help clinicians treating patients with heart disease, still the single most common cause of death in the United Kingdom.