Indirect measurement of left ventricular end-diastolic pressure in congestive cardiomyopathy and constrictive pericarditis

Pulmonary artery diastolic and pulmonary capillary wedge mean pressures were measured in 30 patients with congestive cardiomyopathy and in 30 patients with constrictive pericarditis. These measurements were compared with left ventricular end-diastolic pressure (LVEDP) to assess their value as indirect measurements of left ventricular function. There was close correlation between the indirect measurements and LVEDP in both disorders: a better statistical correlation was achieved using a power curve than with linear regression, since pulmonary artery diastolic pressure increased disproportionately when LVEDP was high.S. Afr. Med. J., 48, 540 (1974)

Acebutolol in cardiac arrhythmiaa

Acebutolol (Sectral), a new beta-adrenoceptor antagonist, was used in 44 patients with cardiac arrhythmias (53 episodes). It was used intravenously (12,5 and 25 mg), orally (100 mg every 8 hours) or in combination with quinidine. Acebutolol was most effective in supraventricular tachyarrhythmias, to control the ventricular response when digital's was ineffective, as a synergist with quinidine to convert patients to sinus rhythm, or prophylactically to prevent relapse to atrial fibrillation. It also terminated ventricular tachycardia in two patients. Side-effects occurred in three ill patients.S. Afr. Med. J., 48, 821 (1974

The Structure and Construction of Formal Research Networks: a Policy Oriented Understanding of Stakeholder Engagement

ven the complexity of the modern research environment, funders (usually government agencies) are encouraging the formation of formal research networks (FRNs). FRNs have a predictable structure which includes primary and (whether acknowledged or not) secondary stakeholders as participants. Policy and program managers need to understand the larger structure, not just the internal operations, of the networks. We propose the use of actor-network theory to understand the strategy and construction of FRNs, and in particular to understand the specific problems surrounding FRNs for social science sand humanities research.   &nbsp

Diagnostic electrocardiographic patterns in Bantu myocardiopathy and constrictive pericarditis

The electrocardiogram was analysed in 28 adult Bantu patients with myocardiopathy and 33 with constrictive pericarditis. The over-all pattern was quite distinctive in the two groups. Patients with CP usually had sinus rhythm, notched P waves, low voltage QRS complexes in the standard and precordial leads, a normal QRS duration, no intraventricular conduction defects and a uniform and characteristic pattern of ST-T  wave change in most cases. In contrast, the ECG in MCO shows left ventricular hypertrophy, varying degrees of intraventricular conduction disturbance and patterns simulating myocardial infarction

Coronary blood flow measured by the Xenon-133 washout technique

Coronary blood flow was measured by the radioactive xenon (133Xe) washout technique in 13 subjects: 6 controls, 5 patients with coronary artery disease and 2 patients who had undergone aortocoronary saphenous vein bypass grafts. The method did not discriminate between normal subjects and patients with coronary artery disease, but may be useful to the study of blood flow in coronary bypass grafts. In 2 patients changes in coronary flow were associated with a change in the patient's clinical status.S. Afr. Med. J., 48, 175 (1974)

Hypertrophic cardiomyopathy in South African Blacks

Hypertrophic cardiomyopathy (HCM) has been considered rare among the Black population of southern Africa. We report 7 patients with the disease who presented during a 14-month period. Current concepts in the approach to the diagnosis and treatment of HCM are discussed. It is possible that with greater awareness of the occurrence of the condition in Blacks the diagnosis of HCM will be made in more members of this population group

Prox-regularity of rank constraint sets and implications for algorithms

We present an analysis of sets of matrices with rank less than or equal to a specified number $s$. We provide a simple formula for the normal cone to such sets, and use this to show that these sets are prox-regular at all points with rank exactly equal to $s$. The normal cone formula appears to be new. This allows for easy application of prior results guaranteeing local linear convergence of the fundamental alternating projection algorithm between sets, one of which is a rank constraint set. We apply this to show local linear convergence of another fundamental algorithm, approximate steepest descent. Our results apply not only to linear systems with rank constraints, as has been treated extensively in the literature, but also nonconvex systems with rank constraints.Comment: 12 pages, 24 references. Revised manuscript to appear in the Journal of Mathematical Imaging and Visio

Wound healing and hyper-hydration - a counter intuitive model

Winters seminal work in the 1960s relating to providing an optimal level of moisture to aid wound healing (granulation and re-epithelialisation) has been the single most effective advance in wound care over many decades. As such the development of advanced wound dressings that manage the fluidic wound environment have provided significant benefits in terms of healing to both patient and clinician. Although moist wound healing provides the guiding management principle confusion may arise between what is deemed to be an adequate level of tissue hydration and the risk of developing maceration. In addition, the counter-intuitive model ‘hyper-hydration’ of tissue appears to frustrate the moist wound healing approach and advocate a course of intervention whereby tissue is hydrated beyond what is a normally acceptable therapeutic level. This paper discusses tissue hydration, the cause and effect of maceration and distinguishes these from hyper-hydration of tissue. The rationale is to provide the clinician with a knowledge base that allows optimisation of treatment and outcomes and explains the reasoning behind wound healing using hyper-hydration

Gadoxetate-enhanced abbreviated MRI is highly accurate for hepatocellular carcinoma screening.

The primary objective was to compare the performance of 3 different abbreviated MRI (AMRI) sets extracted from a complete gadoxetate-enhanced MRI obtained for hepatocellular carcinoma (HCC) screening. Secondary objective was to perform a preliminary cost-effectiveness analysis, comparing each AMRI set to published ultrasound performance for HCC screening in the USA. This retrospective study included 237 consecutive patients (M/F, 146/91; mean age, 58 years) with chronic liver disease who underwent a complete gadoxetate-enhanced MRI for HCC screening in 2017 in a single institution. Two radiologists independently reviewed 3 AMRI sets extracted from the complete exam: non-contrast (NC-AMRI: T2-weighted imaging (T2wi)+diffusion-weighted imaging (DWI)), dynamic-AMRI (Dyn-AMRI: T2wi+DWI+dynamic T1wi), and hepatobiliary phase AMRI (HBP-AMRI: T2wi+DWI+T1wi during the HBP). Each patient was classified as HCC-positive/HCC-negative based on the reference standard, which consisted in all available patient data. Diagnostic performance for HCC detection was compared between sets. Estimated set characteristics, including historical ultrasound data, were incorporated into a microsimulation model for cost-effectiveness analysis. The reference standard identified 13/237 patients with HCC (prevalence, 5.5%; mean size, 33.7 ± 30 mm). Pooled sensitivities were 61.5% for NC-AMRI (95% confidence intervals, 34.4-83%), 84.6% for Dyn-AMRI (60.8-95.1%), and 80.8% for HBP-AMRI (53.6-93.9%), without difference between sets (p range, 0.06-0.16). Pooled specificities were 95.5% (92.4-97.4%), 99.8% (98.4-100%), and 94.9% (91.6-96.9%), respectively, with a significant difference between Dyn-AMRI and the other sets (p < 0.01). All AMRI methods were effective compared with ultrasound, with life-year gain of 3-12 months against incremental costs of US$ < 12,000. NC-AMRI has limited sensitivity for HCC detection, while HBP-AMRI and Dyn-AMRI showed excellent sensitivity and specificity, the latter being slightly higher for Dyn-AMRI. Cost-effectiveness estimates showed that AMRI is effective compared with ultrasound. • Comparison of different abbreviated MRI (AMRI) sets reconstructed from a complete gadoxetate MRI demonstrated that non-contrast AMRI has low sensitivity (61.5%) compared with contrast-enhanced AMRI (80.8% for hepatobiliary phase AMRI and 84.6% for dynamic AMRI), with all sets having high specificity. • Non-contrast and hepatobiliary phase AMRI can be performed in less than 14 min (including set-up time), while dynamic AMRI can be performed in less than 17 min. • All AMRI sets were cost-effective for HCC screening in at-risk population in comparison with ultrasound