PROCEDURE

Eighty-three consecutive HIV infected subjects, divided into 2 groups of pre- AIDS and AIDS were recruited into the study from the wards, Emergency room and POP between the months of May and December 2004. Similarly, 83 uninfected controls, matched for age and sex, were also recruited simultaneously from the Community Health outpatient and Well Baby clinics as well as apparently healthy children attending other clinics at the

Paediatric Outpatient (POP) department. Informed consent (Appendix II) was obtained from either parent(s) or caregiver(s) before enrollment into the study.

The HIV status of the subjects was already known before recruitment into the study. This is determined by a mandatory HIV screening test for all children attending the Special clinic. Each subject was categorized into a stage using the revised CDC classification system currently in use at the Department of Paediatrics, LUTH. ⁸²

A child was classified infected with HIV if he/she showed a positive Enzyme Immunoassay (EIA) screening and Western-Blot electrophoresis tests. Some of them also had their CD4+ lymphocyte cell count and viral load measured. These were however, done in only 16 (19.3%) subjects because of the cost.

All sera from potential controls were subjected to HIV testing using the Capillus^© HIV testing kit. Prior to this, a verbal consent was obtained from either the parent(s) or caregiver(s). Only those that tested negative were recruited for the study.

All enrolled children had detailed medical, family, and social histories obtained and this information was entered into the study proforma by the investigator. A thorough physical examination was also performed on each child. The height and weight measurements of each child were obtained using an AVERY^ stadiometer and weighing scale. They had all their clothes (except their underwear) removed before these measurements were taken.

After checking for zero error, each child was made to stand on the footboard of the scale in an erect position, feet together and facing forward. The weight measurements were then recorded from the scale in kilogrammes. Attached to the weighing scale is a stadiometer. With the child still in the erect position on the footboard and his/her back

against the calibrated height bar, a flat surfaced headboard was then slid down along the bar until it touches the child’s head and the value was read off the height bar. For children less than two years, their recumbent length was measured using an Infa-length^ infantometer. This was done with an assistant who secured the child’s head to the fixed end within the trough of the infantometer, while the investigator straightened the lower limbs of the child. The footboard was then moved up until it touches the sole of the feet of the child. The length was indicated on the metric scale by the pointer on the slide. The height/length measurements were recorded in centimeters.

Systolic and diastolic blood pressure measurements were obtained using an Aneroid sphygmomanometer with an appropriate sized cuff, covering at least two-third of the child’s upper arm, after the child had rested for at least 5 minutes. The average of two readings taken 10 minutes apart was entered into the proforma.

The measurements and physical examinations were done at the same time of the electrocardiogram and echocardiogram.

Electrocardiographic technique and measurements

A 12-lead electrocardiogram was performed on every child using a commercially available Cardioline Delta 1 plus Version Base machine. With the child lying in the supine position, the chest leads were applied to the anterior chest wall and the limb leads were applied to the limbs. Aqua gel was used to ensure adequate contact of the leads to the appropriate skin surfaces. The recording speed of the paper was set at 25mm per second.

The ECG parameters measured included the rhythm, heart rate, P wave amplitude and duration, PR interval, P, QRS, and T axes, T wave amplitude, ST segment and R/S wave ratios in V1, V2 and V6. The values obtained for each child were compared with normal reference values.⁸³

Echocardiographic technique and measurements

A Two-Dimensional derived M-Mode echocardiography was performed on each child at the Cardiology laboratory of LUTH, using a Hewlett-Packard SONOS 500 machine and transducer with a frequency of 5 MHz. For each examination, the child laid in the supine or left lateral decubitus position. The younger subjects who were not cooperative in the presence of their parents or caregiver were pacified with toys. Aqua sonic gel was used to ensure effective contact of the transducer with the chest wall.

The parasternal long axis view was obtained by placing the transducer at the left sternal border, orienting the plane along the major axis of the heart from the left hip to the right shoulder. The beam was directed posteriorly to obtain a slice of cardiac structure at the mitral valve, which was the reference point. ⁸⁴ The cursor passed through the main body of the left ventricle and its chamber sizes namely the End Diastolic diameter (EDD), End Systolic diameter (ESD), and the posterior wall thickness along with the interventricular septal thickness were measured. The measurements were made using the American Society of Echocardiography (ASE) guidelines of the leading edge methodology. ⁸⁵ The average of the measurements obtained during three cardiac cycles was recorded.

Echocardiographic parameters measured in centimeters included the following⁸⁶:

1. Aortic root diameter (AO): this is the vertical distance taken from the leading edge of the anterior aortic root to the leading edge of the posterior aortic root at end-diastole.

2. Left atrial diameter (LA): this is the vertical distance at end-systole between the leading edge of the posterior wall of the aorta and the leading edge of the left atrial wall.

3. Left ventricular End Diastolic Dimension (EDD): this is the vertical distance measured from the trailing edge of the endocardial echoes of the interventricular septum to the leading edge of the posterior left ventricular endocardial echoes.

4. Left ventricular End Systolic Dimension (ESD): this is the vertical distance measured from the endocardium to the left side of the septum.

5. Interventricular septum (IVS): this is the vertical distance between the right and left septal surfaces at end-diastole.

6. Left ventricular posterior wall thickness (LVPW): this is the vertical distance measured from the epicardium of the posterior wall to the endocardium in end-diastole.

Other measurements derived from the left ventricular measurements were 1. Fractional Shortening (FS) %: EDD – ESD X 100

EDD

(EDD)³

3. Left ventricular mass (LVM): (EDD + IVS+ LVPW)³ – (EDD)³

For quality control, some of the measurements were correlated with that of the consultant paediatric cardiologist and there was a 98% concordance in the observed values.