Brugada-type patterns are easily observed in high precordial lead ECGs in collegiate athletes

Background

Displacement of ECG leads can result in unwarranted findings. We assessed the frequency of Brugada-type patterns in athletes when precordial leads were purposely placed upward.

Methods

Four hundred ninety-one collegiate athletes underwent two ECGs: one with standard leads, one with V1 and V2 along the 2nd intercostal space. A positive Brugada-type pattern was defined as ST elevation in V1 or V2 consistent with a Type 1, 2, or 3 pattern in the high-lead ECG. A control group was comprised of 181 outpatients.

Results

No Type 1 patterns were seen. In 58 athletes (11.8%), a Brugada-type 2 or 3 pattern was observed. Those with Brugada-type 2 or 3 patterns were more likely male, taller, and heavier. In the control group, 18 (9.9%) had Brugada-type 2 or 3 patterns and were more likely male.

Conclusions

Proper lead positioning is essential to avoid unwarranted diagnosis of a Brugada-type ECG, especially in taller, heavier male athletes.     

Laboratory Diagnosis of Non-Tuberculous Mycobacterium Infections in Bronchiectasis Patients: Issues and Controversies

Non-tuberculous mycobacteria (NTM) are environmental microbes that can cause pulmonary infection and are especially problematic in bronchiectasis patients with or without cystic fibrosis (CF). Microbiological identification of NTM in these patients is difficult given the high microbial burden in the lungs and the need to differentiate between colonization and transient and true infection. Determining if and when to initiate antimicrobial treatment against this multi-drug-resistant group of organisms is also challenging. To address the changing landscape of care for these patients, the U.S. Cystic Fibrosis Foundation and the European Cystic Fibrosis Society convened an expert committee in 2016 and drafted new guidelines for the management of NTM in CF patients. These recommendations update the 2007 American Thoracic Society and Infectious Disease Society of America guidelines on the diagnosis and treatment of NTM pulmonary infections. Here, we provide data to support the new recommendations and discuss the advancements and ongoing challenges associated with NTM infections.     

Plasticity of skeletal muscle phenotype: mechanical consequences

Muscles are complex biological machines that perform a wide variety of mechanical activities. Over the past 30 to 40 years, a large amount of effort has been devoted to understanding cellular/molecular responses of skeletal muscle to various altered physiological states (e.g., altered loading state induced via immobilization/spaceflight, resistance training). Many cellular/molecular adaptations brought about by such interventions act on underlying processes that regulate activation, force and velocity of shortening/lengthening, and relaxation. In this context, measurements of mechanical properties (e.g., force-velocity relationship) are important, because they can provide insight into the physiological consequences of such adaptations. During the course of the past 10 to 15 years, a number of investigators have employed the work-loop technique to provide a more realistic approach toward understanding muscle function. Additionally, the work-loop technique provides a unique conceptual perspective that integrates: (1) the length-tension relationship, (2) activation kinetics, (3) the force-velocity relationship in the shortening domain, (4) relaxation kinetics, (5) the force-velocity relationship in the lengthening domain, and (6) the compliance of the passive elastic elements. A discussion of those factors (i.e., factors 2-5) that appear to be highly malleable forms the basis of this paper.     

A randomized, single blind comparative trial of norethindrone enanthate and depo-medroxyprogesterone acetate in Bangladesh

A randomized, single blind comparative trial of norethindrone enanthate (NET-ENT) and depo-medroxyprogesterone acetate (DMPA) was conducted in the Model Clinic, Decca, Bangladesh, to determine if there were differences in reported side effects, reasons for discontinuation and discontinuation rates of these two injectables. On all follow-up visits the proportion of women reporting no bleeding (amenorrhea) was higher for the DMPA clients compared to the NET-ENT clients. Concurrent with these findings, the proportion of women reporting irregular bleeding was consistently higher for the NET-ENT clients. Concurrent with these findings, the proportion of women reporting irregular bleeding was consistently higher for the NET-ENT clients compared to those receiving DMPA. By the fourth injection, less than 15% of the clients in both drug groups still reported having regular cyclic bleeding (4 of the 26 DMPA clients and 4 of the 28 NET-ENT clients). Five of the 133 women on DMPA and 6 of the 106 women on NET-ENT became pregnant while using the injectables. At the end of one year of follow-up, 14 of the 133 DMPA and 14 of the 106 NET-ENT clients were still continuing (came back for a fifth injection).     

Fetal tissue amino acid concentrations in argininosuccinic aciduria and in "maternal homocystinuria".

Free amino acid concentrations have been measured in the tissues of a fetus at risk for argininosuccinic aciduria and of an obligate heterozygous fetus in a mother homozygous for homocystinuria. Argininosuccinic acid was detected in all tissues studied of the homozygous affected fetus from the heterozygous mother. Abnormal concentrations of methionine and cystathionine were observed in the tissues of the fetus who was an obligate heterozygote for homocystinuria. These abnormal free amino acid concentrations occur early in fetal development and may be related to later brain dysfunction.