Measurements of stroke volume and cardiac output (CO) are important parameters in the management of pregnant women who have or develop serious cardiorespiratory or renal complications, Measurement by thermodilution utilising a pulmonary artery flotation catheter has numerous limitations. This study evaluates the measurement of CO in normal pregnant women by non-invasive, thoracic electrical bio-impedance. The study design was cross-sectional, involving all trimesters of pregnancy and the postpartum period. One hundred and one normal pregnant women were studied. The procedure for measurement of CO entailed 15 minutes of rest followed by 3 measurements at 5-minute intervals. The results demonstrate a coefficient of repeatability of 22 % for CO measurement as defined by the protocol in this study. The cross-sectional CO data analysis was not able to detect the expected trend in CO changes during normal pregnancy. The limitations of CO measurement by thoracic electrical bio-impedance and thermodilution method are discussed, and refinements in methods are suggested to achieve acceptable repeatability of these measurements.
The effects of acute myocardial ischaemia and reperfusion were studied on regional myocardial function in 10 pigs subjected to fentanyl-pentobarbital anaesthesia. Regional function was defined by pressure-length characteristics in the myocardium supplied by the left anterior descending coronary (LAD) artery and left circumflex coronary (LX) artery. The LAD artery was occluded for 15 minutes and reperfused for 120 minutes thereafter. Acute ischaemia shifted the pressure-length loop to the right and reduced regional systolic shortening while post-systolic shortening (diastolic dysfunction) occurred. Reperfusion was associated with arrhythmias that required lignocaine and direct defibrillation in all the animals. During reperfusion the end-systolic pressurelength relationship was similar to that registered during the control period (before ischaemia) but was left shifted as gauged by a decrease in the extrapolated length intercept at zero ventricular pressure. Decreased regional systolic shortening and post-systolic shortening persisted during reperfusion. Results indicated that myocardial stunning is associated with progressive stiffening of the reperfused myocardium, reduced systolic function and significant diastolic dysfunction.
In a recent descriptionption of changes in disease patterns in the Western Pacific region, particular attention was paid to changes in cardiovascular diseases and associated risk factors. Prevalences ranged from near absence in some regions, where populations live traditionally, to excessive, exceeding those in Western populations, as is the case in the Maori and Aborigines. The relevance of these findings to the future health/ill-health of South African populations, particularly blacks, is discussed, bearing in mind restrictions in health spending, widening socio-economic disparities and the general reluctance of populations to alter lifestyles.
Acute rheumatic fever (ARF) is still a major health problem in South Africa. In this retrospective, descriptionptive study, 100 patients with ARF were analysed to establish whether the clinical profile has changed. Carditis was found in 94% of patients and was therefore the most common of the major criteria found at presentation. The two most common early complications were congestive cardiac failure (CCF) in 16% and infective endocarditis (IE) in 5 % of patients. Late complications were CCF in 35% with IE contributing to CCF in 10% of patients. A further 15% developed IE. In conclusion, the profile of ARF as descriptionbed in the literature has changed, with carditis now being the most common manifestation.