Acute Left Ventricular Outflow Tract Research Articles

Transcatheter mitral valve implantation using a novel system: preclinical results.

BackgroundThis preclinical study in sheep sought to demonstrate the initial safety and feasibility of a novel transcatheter mitral valve system (Mi-thos valve) composed of a self-expanding frame and a bovine pericardial tissue bioprosthesis.MethodsThe valve was implanted in 26 sheep using a transapical approach for short- and long-term evaluation. The technical feasibility, safety, durability, and valve function were evaluated during and 6 months after the procedure using intracardiac and transthoracic echocardiography, multisliced computed tomography, histological analysis, and electron microscopy.ResultsThe success rate of valve implantation was 100%, and the immediate survival rate after surgery was 84%. Five animals died within 90 min after the development of the prosthetic valve due to an acute left ventricular outflow tract obstruction (n = 2) and sudden intraoperative ventricular fibrillation (n = 3). Twelve animals died within 1 month due to acute left heart dysfunction. Mild (n = 5) and moderate (n = 2) paravalvular leakage occurred in seven animals, and two moderate PVL animals died of chronic heart failure within three months. Multimodality imaging studies of the remaining seven animals showed excellent function and alignment of the valves, with no coronary artery obstruction, no left ventricular outflow tract obstruction, no severe transvalvular gradients and no paravalvular leakage. Macroscopic evaluation demonstrated stable, secure positioning of the valve, with full endothelialization of the valve leaflets without injury to the ventricular or atrial walls. Histological and electron microscopic examinations at six months showed no obvious macro- or microcalcification in the leaflets.ConclusionsPreclinical studies indicate that transcatheter implantation of the Mi-thos valve is technically safe and feasible. The durability, functionality, and lack of leaflet calcification were all verified in animal experiments. The information from these preclinical studies will be applied to patient selection criteria and the first-in-human studies.

Acute Left Ventricular Outflow Tract Obstruction in Non - Mitral Cardiovascular Surgery: A Case Series Analysis

Acute Left Ventricular Outflow Tract Obstruction in Non - Mitral Cardiovascular Surgery: A Case Series Analysis

McConnell's sign — An insight into the pathogenesis of Takotsubo syndrome?

Takotsubo syndrome (TTS), also known as stress-induced cardiomyopathy, is an acute cardiac syndrome. The unique characteristics of TTS are that one or more circumferential cardiac segments are stunned out of contraction in the absence of an explanatory coronary lesion [1]. Although the peculiar myocardial akinesia can affect any part of the ventricular wall, two common patterns of TTS are apical akinesis (the typical TTS) and basal akinesis (the inverted pattern) [2]. The pathogenesis underlying Takotsubo syndrome is incompletely understood. Several mechanisms have been proposed for the development of TTS, including overstimulation of the β2-adrenoceptor-Gi pathway [3], acute coronary microvascular and endothelial dysfunction [4], aborted myocardial infarction with spontaneous recanalisation [5], acute metabolic stunning [6], lipotoxicity [1,7], acute left ventricular outflow tract obstruction (LVOTO) and abnormal ventriculo-arterial coupling [8]. One critical shortcoming of some of these proposed mechanisms is that they are not able to elucidate why myocardial akinesia in TTS is usually segmental and circumferential. Although the gradient distribution of β-adrenoceptors or sympathetic nerves in the heart may explain why catecholamine-induced myocardial akinesia can be apical or basal, such physiological properties, including genetic profiles, currently fail to

Successful negative inotropic treatment of acute left ventricular outflow tract obstruction by elongated mitral valve leaflet

Elongated anterior mitral valve leaflet (EAMVL) has not been reported to cause left ventricular outflow tract obstruction (LVOTO) in the absence of left ventricular hypertrophy. We report the case of an elderly male patient who presented with acute heart failure and severe mitral regurgitation in the setting of dehydration. Echocardiography revealed acute LVOTO secondary to EAMVL. The patient was ineligible for surgery and was treated with negative inotropic agents, which ensured resolution of heart failure and marked improvement in the degree of LVOTO. This case demonstrates that, under certain circumstances, EAMVL without associated left ventricular hypertrophy may produce hemodynamic compromise that can be successfully treated medically.