Clinical Use of the Duke Criteria in Patients With Suspected Infective Endocarditis and Negative Transesophageal Echocardiograms

2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

This executive summary of the valvular heart disease guideline provides recommendations for clinicians to diagnose and manage valvular heart disease as well as supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from January 1, 2010, to March 1, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, Cochrane, Agency for Healthcare Research and Quality Reports, and other selected database relevant to this guideline. Structure: Many recommendations from the earlier valvular heart disease guidelines have been updated with new evidence and provides newer options for diagnosis and treatment of valvular heart disease. This summary includes only the recommendations from the full guideline which focus on diagnostic work-up, the timing and choice of surgical and catheter interventions, and recommendations for medical therapy. The reader is referred to the full guideline for graphical flow charts, text, and tables with additional details about the rationale for and implementation of each recommendation, and the evidence tables detailing the data considered in developing these guidelines.

Clinical Analysis of 161 Cases of Surgical Treatment of Infective Endocarditis

Objective: To evaluate the diagnostic criteria, surgical indications, and prognostic factors in the surgical treatment of infective endocarditis (IE). Methods: A total of 161 cases of post-operative IE treated at our hospital from January 2007 to December 2016 were included. The IE was diagnosed by the modified Duke criteria. Echocardiography and standard blood cultures were performed. These cases were divided into severe and non-severe adverse event groups. The association between prognostic factors and severe versus non-severe outcomes was examined using logistic regression. Results: Thirty patients (20.1%) with post-operative IE had positive pre-operative blood cultures, and 130 patients (80.7%) had valve vegetations. Four patients (2.5%) died within 30 days post-operatively. Twenty-two patients experienced severe adverse events. There were significant differences between the two groups regarding their serum albumin and creatinine concentrations, ejection fraction, and hospitalization, cardiopulmonary bypass, aortic cross-clamp, intensive care unit (ICU), and ventilation times (all p < 0.05). The bypass time, aortic cross-clamp time, and ICU time were identified as prognostic factors for severe adverse events. Conclusion: Echocardiography is an important diagnostic method for IE, and repeated tests might improve the sensitivity of diagnosis. Cardiac surgery seems to be an effective treatment for IE. Patient screening and reducing the operative time may improve the prognosis for patients who undergo surgical treatment for IE.

Effect of electrical stimulus parameters on the development and propagation of action potentials in short excitable fibres

Intracellular action potentials (IAPs) produced by short fibres in response to their electrical stimulation were analysed. IAPs were calculated on the basis of the Hodgkin-Huxley (1952) model by the method described by Joyner et al. (1978). Principal differences were found in processes of activation of short (semilength L less than 5 lambda) and long fibres under near-threshold stimulation. The shorter the fibre, the lower was the threshold value (Ithr). Dependence of the latency on the stimulus strength (Ist) was substantially non-linear and was affected by the fibre length. Both fibre length and stimulus strength influenced the IAP amplitude, the instantaneous propagation velocity (IPV) and the site of the first origin of the IAP (and, consequently, excitability of the short fibre membrane). With L less than or equal to 2 lambda and Ithr less than or equal to Ist less than or equal to 1.1Ithr, IPV could reach either very high values (so that all the fibre membrane fired practically simultaneously) or even negative values. The latter corresponded to the first origin of the propagated IAP, not at the site of stimulation but at the fibre termination or at a midpoint. The characters of all the above dependencies were unchanged irrespective of the manner of approaching threshold (variation of stimulus duration or its strength). Reasons for differences in processes of activation of short and long fibres are discussed in terms of electrical load and latency. Applications of the results to explain an increased jitter, velocity recovery function and velocity-diameter relationship are also discussed.