The chest X-ray and ECG

The clinical encounter between the physician and the patient begins with the taking of a detailed history and continues with the physical examination. At this stage, in most instances, a clinical diagnosis should have been firmly made (or at least suspected).

The third and final stage is then embarked upon and this is the performance of a series of special investigations which should begin with the simplest (and hence least costly) and should be designed to confirm the clinical diagnosis.

Effective utilisation of special investigations requires a knowledge of the relevant clinical features as this allows the most accurate interpretation of the test results.

In recent years, a wide variety of relatively new and sophisticated cardiac investigations have become available in Jamaica, and the fact that many members of the public may not be aware of what cardiac tests (investigations) are available locally forms the rationale for this series of articles.

Thus, a review of all relevant cardiac investigations available in Jamaica will be provided emphasising their clinical utility, the specifics of local availability, and their approximate cost.

(1) THE CHEST X-RAY (CXR)

The plain chest X-ray is done by directing a beam of X-rays through the chest of the patient on to a radiosensitive X-ray plate thus producing a static image of all the structures within the chest, especially the heart and the lungs.

This investigation is of use in determining the size and shape of the heart, the status of the major blood vessels within the chest, and the normality or otherwise of the lungs.

While there are many more sophisticated investigations to assess the heart and lungs, the chest X-ray remains extremely useful in the basic investigation of cardiovascular disease.

AVAILABILITY

Widely available in the public and private health sectors throughout Jamaica.

COST CODE .....

2) THE RESTING ELECTROCARDIOGRAM (ECG/EKG)

This simple investigation was introduced to Jamaica in the early 1950s at both the Kingston Public Hospital and the University Hospital of the West Indies. Its rationale is predicated on the fact that cardiac function is controlled by weak electrical currents. These currents emanate from specialised cardiac tissue in the upper part of the heart (the sino-atrial node) and are then conducted first to the collecting chambers (atria) and then to the pumping chambers (ventricles) by other special cardiac tissues. These events result in the contraction of the cardiac muscle and hence the pumping of the blood which is the primary function of the heart.

The basic electrocardiograph (ECG machine) records these weak electrical currents and produces a graphic display which provides the cardiologist/internist with a wealth of information with respect to the patient's cardiac structure and function.

Such information includes the normality (or otherwise) of the cardiac rhythm, the presence of acute cardiac injury or scarring, the presence of enlargement of the atria or ventricles, and the normality (or otherwise) of the passage of the electrical impulses through the heart.

This investigation constitutes a 'bread and butter' investigation in modern cardiology.

AVAILABILITY

Widely available in the public and private sectors in Jamaica.

COST CODE ...

Charles E. Denbow is Professor of Medicine and consultant cardiologist at the University of the West Indies (Mona).

This week's special guest columnist is Professor Charles E. Denbow. He will present a four-part series on various tests used to investigate problems in the heart. He is Professor of Medicine at the University of the West Indies, Mona, and has been a consultant cardiologist at that institution since 1979, and at Cardiotechnics Limited in Kingston since 1986. He is the holder of fellow-ships in the American College of Cardiology (1984), the American College of Physicians (1985), the Royal College of Physicians of London (1987) and the Royal College of Physicians of Edinburgh (2005). Professor Denbow was certified by the American Board of Internal Medicine (1979), and in cardiovascular disease (1981). Over the years, he was intimately involved in introducing here, several of the cardiac investigations described in this series.