Low-flow, low-gradient severe aortic stenosis despite normal ejection fraction is associated with severe left ventricular dysfunction as assessed by speckle-tracking echocardiography: a multicenter study.

Background: Low-flow low-gradient (LFLG) is sometimes observed in severe aortic stenosis (AS) despite normal ejection fraction, but its frequency and mechanisms are still debated. We aimed to describe the characteristics of patients with LFLG AS and assess the presence of longitudinal left ventricular dysfunction in these patients.

Methods And Results: In a multicenter prospective study, 340 consecutive patients with severe AS and normal ejection fraction were studied.

Lineage-specific partitions in archaeal transcription.

The phylogenetic distribution of the components comprising the transcriptional machinery in the crenarchaeal and euryarchaeal lineages of the Archaea was analyzed in a systematic manner by genome-wide profiling of transcription complements in fifteen complete archaeal genome sequences. Initially, a reference set of transcription-associated proteins (TAPs) consisting of sequences functioning in all aspects of the transcriptional process, and originating from the three domains of life, was used to query the genomes. TAP-families were detected by sequence clustering of the TAPs and their archaeal homologues, and through extensive database searching, these families were assigned a function.