1094 Exercise syncope as initial symptom of constrictive pericarditis in a young patient

Introduction

Constrictive pericarditis is a form of diastolic heart failure that arises because an inelastic pericardium inhibits cardiac filling. Syncope is a rare initial symptom of constrictive pericarditis.

Clinical case

A 22-year-old man with previous medical history of viral meningitis when he was 3 months-old but without any family history of cardiac disease or sudden cardiac death, was admitted to the Emergency Department for syncope. During the last year, he had suffered several episodes of intense exercise-related syncope. The patient denied having prodromes, chest pain, palpitations or any other symptoms. The physical exam of the patient was normal with stable vital signs. Normal S1 and S2 heart sounds were present, no murmurs or gallop. There were no signs of heart failure, only a minimal jugular ingurgitation. An electrocardiogram (ECG) revealed sinus rhythm, signs of bi-atrial enlargement (prominent P-wave with P mitral morphology in DI-II leads, with enhanced negative deflection in V1), and negative asymmetric T-waves in inferior (DII-III-aVF) and V6 leads. Chest X-ray showed minimal calcium density in the inferior pericardial silhouette. The patient was admitted in the Cardiology Department for aetiological study. A transthoracic echocardiogram revealed a marked protodiastolic cleft in the interventricular septum, with 40% variations of the transmitral flow with the respiratory changes and dilation of the cava vein, with absent respiratory collapse. A marked thickening and calcification of the inferoposterior pericardium was also seen. Considering these results, the diagnosis of constrictive pericarditis was suggested (Fig. A, B, C). Blood tests for autoimmune disease screening, as well as infectious diseases, including Quantiferon test, HIV, HVC, HVB and other viral serologies were done, with negative results. A cardiac magnetic resonance was requested, which confirmed the echocardiographic findings, with bi-atrial enlargement and markedly thickened pericardium with loss of signal, suggestive of calcification. Left and right ventricle had normal dimensions and contractility. The CT coronary angiography revealed normal coronary anatomy. Extensive calcification and pericardial thickening were shown, with myocardial infiltration in the lateral-basal area (Fig D). It was considered important to rule out any additional arrhythmic aetiology of the exercise syncope. Therefore, a stress test and, an electrophysiologic study were done, both with normal results. The patient remained asymptomatic and a pericardiectomy was indicated given the severe thickening and calcification of the pericardium and frequent syncopal episodes that our patient suffered.

Conclusions

Syncope as the initial symptom in the absence of significant right heart failure signs is a very unusual form of presentation of idiopathic constrictive pericarditis given the severe thickening and calcification of the pericardium of our patient.

Abstract 1094 Figure.

A broad analysis of resistance development in the malaria parasite

Microbial resistance to chemotherapy has caused countless deaths where malaria is endemic. Chemotherapy may fail either due to pre-existing resistance or evolution of drug-resistant parasites. Here we use a diverse set of antimalarial compounds to investigate the acquisition of drug resistance and the degree of cross-resistance against common resistance alleles. We assess cross-resistance using a set of 15 parasite lines carrying resistance-conferring alleles in pfatp4, cytochrome bc₁, pfcarl, pfdhod, pfcrt, pfmdr, pfdhfr, cytoplasmic prolyl t-RNA synthetase or hsp90. Subsequently, we assess whether resistant parasites can be obtained after several rounds of drug selection. Twenty-three of the 48 in vitro selections result in resistant parasites, with time to resistance onset ranging from 15 to 300 days. Our data indicate that pre-existing resistance may not be a major hurdle for novel-target antimalarial candidates, and focusing our attention on fast-killing compounds may result in a slower onset of clinical resistance.

It is unclear whether new antimalarial compounds may rapidly lose effectiveness in the field because of parasite resistance. Here, Corey et al. investigate the acquisition of drug resistance and the extent to which common resistance mechanisms decrease susceptibility to a diverse set of 50 antimalarial compounds.

Case Study of Small Molecules As Antimalarials: 2-Amino-1-phenylethanol (APE) Derivatives

Antiparasitic oral drugs have been associated to lipophilic molecules due to their intrinsic permeability. However, these kind of molecules are associated to numerous adverse effects, which have been extensively studied. Within the Tres Cantos Antimalarial Set (TCAMS) we have identified two small, soluble and simple hits that even presenting antiplasmodial activities in the range of 0.4-0.5 μM are able to show in vivo activity.

A Divergent SAR Study Allows Optimization of a Potent 5-HT2c Inhibitor to a Promising Antimalarial Scaffold

From the 13 533 chemical structures published by GlaxoSmithKline in 2010, we identified 47 quality starting points for lead optimization. One of the most promising hits was the TCMDC-139046, a molecule presenting an indoline core, which is well-known for its anxiolytic properties by interacting with serotonin antagonist receptors 5-HT2. The inhibition of this target will complicate the clinical development of these compounds as antimalarials. Herein, we present the antimalarial profile of this series and our efforts to avoid interaction with this receptor, while maintaining a good antiparasitic potency. By using a double-divergent structure-activity relationship analysis, we have obtained a novel lead compound harboring an indoline core.

[Changes in the norms governing practices for the manufacture of pharmaceutical products: implications for the MERCOSUR]

It is done a comparative study between the "Recommended rules for drug products manufacturing and inspection", approved in 1975 by the World Health Organization (and still in force in the MERCOSUR); and the standards published in 1992 by the WHO Expert Committee on Specifications for Pharmaceutical Preparations 32nd Report, named "Good Manufacturing Practices for pharmaceutical products". The correspondence between the regulation in force in the MERCOSUR and the Good Manufacturing Practices Inspection Guide for pharmaceutical industry, used by Health Authorities in the Common Market Member States, is analysed. It is noticed a disagreement between the rule in force and the instrument for verifying its fulfillment. The proposal of this article is the adoption by the Common Market Group, of the rules published by the WHO in 1992, and the establishment of an inspection guide which absolute agrees with it.