A typical diagnosis starts from a physical examination and assessment of the patient and the patient’s family medical history. Based on the findings of the assessment, the doctor may request for selected cardiac diagnostic tests to be performed for the patient. Cardiac diagnostic tests are essential in the diagnosis of heart diseases such as coronary heart disease and arrhythmias (abnormal heart rhythms), and are usually carried out in a cardiac laboratory. Additional tests such as cardiac computed tomography (CT) scans may sometimes be carried out to detect the presence of narrowing in heart arteries in some patients.

The cardiac laboratory in NHCS provides a wide range of diagnostic tests and services that are designed to identify abnormalities in the function of one’s cardiac system. It is a full-fledged facility providing services to inpatients, outpatients as well as patients undergoing surgery in the operating theatre. The cardiac laboratory performs close to 45,000 echocardiograms (Echo) and 78,000 electrocardiograms (ECG) a year. The cardiac technologists are trained on-thejob at NHCS and accredited with allied health professional certification from American Registry of Diagnostic Medical Sonographers (Echo) and International Board of Heart Rhythm Examiners (Device Therapy/ Electrophysiology). They perform the non-invasive tests and generate preliminary reports for the cardiologists to decide on further invasive treatment.

Advancing Cardiac Diagnostic Tests’ Capability

Echocardiogram is a diagnostic procedure using high frequency sound waves (ultrasound) to take moving pictures of the heart and its related structures such as valves. The pictures or images appearing on the screen may be in black and white or colour. 

From the pictures, the cardiologist can measure the size and function of heart chambers, study the motion of heart valves, and assess the efficacy of the contraction of heart muscles and the blood flow pattern across the valves and within the heart chambers. This allows the cardiologist to have better assessment on how well the heart is working and whether there are any abnormalities. 

The upright tilt test is used to detect recurrent syncope (fainting) of unknown origin. A common form of syncope is called a vasovagal syncope, also refers to fainting due to abnormally sensitive reflexes in the cardiovascular system during prolonged standing or when subjected to unpleasant stimuli. Though this form of faints may appear alarming, they are rarely life-threatening. The test requires the patient to be tilted (70 degrees) in a standing position to simulate a situation of prolonged standing and he or she will be closely monitored for any symptoms of fainting. 

The Ambulatory ECG - Holter Monitoring is a test where the ECG is continuously monitored for 24 or 48 hours and the signals are simultaneously recorded onto a special recorder worn by the patient, either at his or her own home or work environment. It allows any abnormal rhythms or ECG abnormalities to be captured during the monitoring period.

This test is useful for detecting transient rhythm disorders of the heart, which sometimes can be hard to detect. It is suitable for patients with palpitations, giddiness or fainting spells. By quantifying the amount and type of ECG abnormalities, it will be able to provide quantitative and qualitative information on the effect of the drug therapy.

The test can also help post-procedural patients, especially those who have undergone the electrophysiological studies, to determine if the procedure was successful.