Electrophysiological efficacy of Epicor high-intensity focused ultrasound.

Objectives: Clinical success of atrial fibrillation (AF) ablation depends on persistent blocking of electrical conduction across the ablation lines. Epicor high-intensity focused ultrasound (HIFU) ablation has been credited with a variable clinical efficacy. The aim of this work is to ascertain the electrophysiological (EP) efficacy of such lesions, by assessing pulmonary vein isolation (PVI) after open chest HIFU ablation, in the clinical setting.

Bileaflet mechanical heart valve closing sounds: in vitro classification by phonocardiographic analysis.

Bileaflet mechanical heart valves, which exhibit hemodynamic performance fairly similar to that of native valves, can be investigated by the analysis of their closing sounds. Signal spectra calculated from the closing sounds are characterized by specific features that are suitable for the functional evaluation of the valves. Five commercial bileaflet mechanical heart valves were studied under different conditions that were simulated in vitro using a Sheffield pulse duplicator for the aortic position.

Application of wavelet analysis to the phonocardiographic signal of mechanical heart valve closing sounds.

Heart valve disorders, caused by congenital defects, rheumatic fever, calcification, myocardial infarction and other cardiovascular diseases, often require native valves to be replaced by bio-prosthetic devices or mechanical heart valves (MHVs). Among MHVs, bileaflet valves are usually preferred for their hemodynamic features, similar to physiological ones, and their durability, but they are prone to complications due to thromboembolic events. Due to the asynchronous closure of the leaflets, bileaflet MHVs are also known to produce closing sounds typically characterized by the presence of two peaks in the time domain.