Prognostic Assessment of Right Ventricular Systolic Dysfunction on Post-Transcatheter Aortic Valve Replacement Short-Term Outcomes: Systematic Review and Meta-Analysis.

Background Right ventricular systolic dysfunction (RVSD) is a known risk factor for adverse outcome in surgical aortic valve replacement. Transcatheter aortic valve replacement (TAVR), on the other hand, has been shown to be either beneficial or have no effect on right ventricular systolic function. However, the prognostic significance of RVSD on TAVR has not been clearly determined. We conducted a systematic review and meta-analysis to define the impact of RVSD on outcomes in terms of 1-year mortality in patients with severe aortic stenosis undergoing TAVR. Methods and Results An extensive literature review was performed, with an aim to identify clinical studies that focused on the prognosis and short-term mortality of patients with severe symptomatic aortic stenosis who underwent TAVR. A total of 3166 patients from 8 selected studies were included. RVSD, as assessed with tricuspid annular plane systolic excursion, fractional area change or ejection fraction, was found to be a predictor of adverse procedural outcome after TAVR (hazard ratio, 1.31; 95% CI, 1.1-1.55; P=0.002). Overall, we found that RVSD did affect post-TAVR prognosis in 1-year mortality rate. Conclusions Patients with severe, symptomatic aortic stenosis and concomitant severe RVSD have a poor 1-year post-TAVR prognosis when compared with patients without RVSD. Right ventricular dilation and severe tricuspid regurgitation were associated with increased 1-year morality post-TAVR and should be considered as independent risk factors. Further evaluations of long-term morbidity, mortality, as well as sustained improvement in functional class and symptoms need to be conducted to determine the long-term effects.

Recurrent Cardiac Arrest With Negative Stress Test: An Unusual Presentation of Catecholaminergic Polymorphic Ventricular Tachycardia.

Catecholaminergic polymorphic ventricular tachycardia is a genetic disorder that causes ventricular tachyarrhythmias via increased release of intracellular calcium. The standard diagnostic measure is an exercise stress test that reveals ventricular ectopy. We present an extraordinary case marked by a normal stress test and no relation to exertion. (Level of Difficulty: Intermediate.).

Cyanobacterial neurotoxin BMAA and brain pathology in stranded dolphins.

Dolphin stranding events occur frequently in Florida and Massachusetts. Dolphins are an excellent sentinel species for toxin exposures in the marine environment. In this report we examine whether cyanobacterial neurotoxin, ß-methylamino-L-alanine (BMAA), is present in stranded dolphins. BMAA has been shown to bioaccumulate in the marine food web, including in the muscles and fins of sharks. Dietary exposure to BMAA is associated with the occurrence of neurofibrillary tangles and ß-amyloid plaques in nonhuman primates. The findings of protein-bound BMAA in brain tissues from patients with Alzheimer's disease has advanced the hypothesis that BMAA may be linked to dementia. Since dolphins are apex predators and consume prey containing high amounts of BMAA, we examined necropsy specimens to determine if dietary and environmental exposures may result in the accumulation of BMAA in the brains of dolphins. To test this hypothesis, we measured BMAA in a series of brains collected from dolphins stranded in Florida and Massachusetts using two orthogonal analytical methods: 1) high performance liquid chromatography, and 2) ultra-performance liquid chromatography with tandem mass spectrometry. We detected high levels of BMAA (20-748 µg/g) in the brains of 13 of 14 dolphins. To correlate neuropathological changes with toxin exposure, gross and microscopic examinations were performed on cortical brain regions responsible for acoustico-motor navigation. We observed increased numbers of ß-amyloid+ plaques and dystrophic neurites in the auditory cortex compared to the visual cortex and brainstem. The presence of BMAA and neuropathological changes in the stranded dolphin brain may help to further our understanding of cyanotoxin exposure and its potential impact on human health.