Mechanistic implications of altered protein expression in rheumatic heart disease

Heart Failure Reviews - Rheumatic heart disease (RHD) is a major cause of cardiovascular morbidity and mortality in low- and middle-income countries, where living conditions promote spread of group...     

Native T1-mapping detects the location,extent and patterns of acute myocarditis without the need for gadolinium contrast agents

Background

Acute myocarditis can be diagnosed on cardiovascular magnetic resonance (CMR) using multiple techniques, including late gadolinium enhancement (LGE) imaging, which requires contrast administration. Native T1-mapping is significantly more sensitive than LGE and conventional T2-weighted (T2W) imaging in detecting myocarditis. The aims of this study were to demonstrate how to display the non-ischemic patterns of injury and to quantify myocardial involvement in acute myocarditis without the need for contrast agents, using topographic T1-maps and incremental T1 thresholds.

Methods

We studied 60 patients with suspected acute myocarditis (median 3 days from presentation) and 50 controls using CMR (1.5 T), including: (1) dark-blood T2W imaging; >(2) native T1-mapping (ShMOLLI); (3) LGE. Analysis included: (1) global myocardial T2 signal intensity (SI) ratio compared to skeletal muscle; (2) myocardial T1 times; (3) areas of injury by T2W, T1-mapping and LGE.

Results

Compared to controls, patients had more edema (global myocardial T2 SI ratio 1.71 ± 0.27 vs.1.56 ± 0.15), higher mean myocardial T1 (1011 ± 64 ms vs. 946 ± 23 ms) and more areas of injury as detected by T2W (median 5% vs. 0%), T1 (median 32% vs. 0.7%) and LGE (median 11% vs. 0%); all p < 0.001. A threshold of T1 > 990 ms (sensitivity 90%, specificity 88%) detected significantly larger areas of involvement than T2W and LGE imaging in patients, and additional areas of injury when T2W and LGE were negative. T1-mapping significantly improved the diagnostic confidence in an additional 30% of cases when at least one of the conventional methods (T2W, LGE) failed to identify any areas of abnormality. Using incremental thresholds, T1-mapping can display the non-ischemic patterns of injury typical of myocarditis.

Conclusion

Native T1-mapping can display the typical non-ischemic patterns in acute myocarditis, similar to LGE imaging but without the need for contrast agents. In addition, T1-mapping offers significant incremental diagnostic value, detecting additional areas of myocardial involvement beyond T2W and LGE imaging and identified extra cases when these conventional methods failed to identify abnormalities. In the future, it may be possible to perform gadolinium-free CMR using cine and T1-mapping for tissue characterization and may be particularly useful for patients in whom gadolinium contrast is contraindicated.     

Health practitioners' state of knowledge and challenges to effective management of hypertension at primary level

Background

Patient- and physician-related factors impact on the management and control of hypertension.

Objectives

To systematically examine: (1) South African primary care doctors’ state of knowledge on the management of hypertension; (2) primary health practitioners’ knowledge on the South African hypertension guidelines; (3) current approaches to management of hypertensive patients; and (4) challenges to effective management of hypertension at primary level.

Methods

A cross-sectional, observational study using a semi-structured questionnaire was carried out in two large community health centres (CHCs) in the Cape Town metropole. All 16 doctors employed at both CHCs were voluntarily enrolled, seven (43.7%) of whom were female, with 14 (87.5%) younger than 40 years of age. The majority (81.2%) of the doctors surveyed had been practicing for less than 10 years.

Results

Ten (62.5%) of the doctors surveyed aimed to treat hypertension to target, and recommendations on lifestyle modifications were reportedly poorly done. While 11 (68.8%) of the doctors were aware of the South African hypertension guidelines, were (81.8%) of them were not conversant with the contents thereof. Doctors estimated that only 35% of their patients are treated to target. Poor patient adherence to prescribed treatment, language difficulty, heavy patient load, medical staff shortages, and patient loss to follow up were identified by the doctors as significant impediments to the effective management of hypertension at the primary level of care.

Conclusion

Primary healthcare practitioners’ knowledge regarding hypertension and the South African hypertension guidelines is poor. Management of hypertension by these doctors is sub-optimal. There are significant challenges to effective management of hypertension at this level of care.     

Progressive human immunodeficiency virus-associated vasculopathy: time to revise antiretroviral therapy guidelines?

Cardiovascular abnormalities were appreciated early in the epidemic of the acquired immunodeficiency syndrome (AIDS), even before the aetiological agent, human immunodeficiency virus (HIV) was isolated and characterised. The aetiology and pathogenesis of cardiovascular disease in HIV infection is still the subject of intense speculation, and is likely multi-factorial. HIV affects every aspect of the cardiac axis, causing pericarditis, myocarditis, cardiomyopathy, coronary artery disease and microvascular dysfunction, valvular heart disease, pulmonary vascular disease and pulmonary hypertension, stroke and peripheral vascular disease. HIV-associated vasculopathy is an increasingly recognised clinical entity, causing high morbidity and increasing mortality in southern Africa, particularly from stroke and cardiovascular disease. HIV causes disease of the vascular tree, either by a direct effect on vascular or perivascular tissue, or indirectly via immune complex-mediated mechanisms, associated opportunistic infections and malignancies. As a result, highly active antiretroviral therapy (HAART) may have an important role in controlling disease progression. We report a case of histologically defined primary HIV vasculopathy in which the chance to start HAART was initially missed and in which the patient progressed to require bilateral amputations, but obtained disease quiescence upon commencement of HAART.     

Guideline for the optimal use of blood cultures

The incidence of sepsis is increasing globally, with high morbidity and mortality. Prompt, accurate detection of bacteraemia and fungaemia is imperative for improving patient care, yet health care professionals lack training in correct blood culture techniques. These guidelines discuss the clinical importance of blood cultures, the indications for their use and the correct technique for optimal yield of pathogenic micro-organisms that cause sepsis.