Search results for "Arrhythmia"
showing 10 items of 210 documents
Spiral wave induced numerically using electrical stimulation and comparison with experimental results.
2010
Experiments in vitro on a Microelectrode Array (MEA) platform show that electrical stimulation can provoke the generation of spiral waves in cardiac tissue. Nevertheless, the conditions leading to this artificial fibrillation state remain unclear. In order to have a better understanding of this phenomenon, a numerical simulation study has been conducted. The results obtained with a two-dimensional FitzHugh-Nagumo model proved that it is possible to create spiral waves by adding a stimulation current under certain conditions, which are made explicit.
Electrocardiographic Abnormalities and Mortality in Epilepsy Patients
2021
Background and Objectives: People with epilepsy (PWE) have a 2–3 times higher mortality rate than the general population. Sudden unexpected death in epilepsy (SUDEP) comprises a significant proportion of premature deaths, whereas sudden cardiac death (SCD) is among the leading causes of sudden death in the general population. Cardiac pathologies are significantly more prevalent in PWE. Whether electrocardiographic (ECG) parameters are associated with remote death in PWE has yet to be elucidated. The study objective was to assess whether interictal ECG parameters are associated with mortality in the long-term. Materials and Methods: The study involved 471 epilepsy patients who were hospitali…
Management of Direct Oral Anticoagulants in Patients with Atrial Fibrillation Undergoing Cardioversion
2019
Atrial fibrillation the most common cardiac arrhythmia. Its incidence rises steadily with each decade, becoming a real “epidemic phenomenon”. Cardioversion is defined as a rhythm control strategy which, if successful, restores normal sinus rhythm. This, whether obtained with synchronized shock or with drugs, involves a periprocedural risk of stroke and systemic embolism which is reduced by adequate anticoagulant therapy in the weeks before or by the exclusion of left atrial thrombi. Direct oral anticoagulants are safe, manageable, and provide rapid onset of oral anticoagulation; they are an important alternative to heparin/warfarin from all points of view, with a considerable reduction in b…
Crystal structure of vinorine synthase, the first representative of the BAHD superfamily.
2005
Vinorine synthase is an acetyltransferase that occupies a central role in the biosynthesis of the antiarrhythmic monoterpenoid indole alkaloid ajmaline in the plant Rauvolfia. Vinorine synthase belongs to the benzylalcohol acetyl-, anthocyanin-O-hydroxy-cinnamoyl-, anthranilate-N-hydroxy-cinnamoyl/benzoyl-, deacetylvindoline acetyltransferase (BAHD) enzyme superfamily, members of which are involved in the biosynthesis of several important drugs, such as morphine, Taxol, or vindoline, a precursor of the anti-cancer drugs vincaleucoblastine and vincristine. The x-ray structure of vinorine synthase is described at 2.6-angstrom resolution. Despite low sequence identity, the two-domain structure…
Myocardial bridge pathology and preventable accidents during physical activity of healthy subjects: A case report and a literature review.
2020
Myocardial bridging is a congenital coronary pathology described as a segment of coronary artery which courses through the myocardial wall under the muscle bridge. Although the prognosis of myocardial bridging is benign, sports medicine recognises myocardial bridging as a leading cause of sudden death among young basketball, football and soccer players. The authors report a case of a 42-year-old man who collapsed while playing football. He died notwithstanding prompt medical assistance and cardiopulmonary resuscitation. At autopsy, gross examination of the heart revealed the intramural course of the left anterior descending coronary artery to be 2 cm from its coronary ostial origin. Histol…
A Newly-Detected Reductase fromRauvolfiaCloses a Gap in the Biosynthesis of the Antiarrhythmic Alkaloid Ajmaline
2002
A new enzyme, 1,2-dihydrovomilenine reductase (E.C. 1.3.1), has been detected in Rauvolfia cell suspension cultures. The enzyme specifically converts 2beta( R)-1,2-dihydrovomilenine through an NADPH-dependent reaction into 17-O-acetylnorajmaline, a close biosynthetic precursor of the antiarrhythmic alkaloid ajmaline from Rauvolfia. A five-step purification procedure using SOURCE 30Q chromatography, hydroxyapatite chromatography, 2',5'-ADP Sepharose 4B affinity chromatography and ion exchange chromatography on DEAE Sepharose and Mono Q delivered an approximately 200-fold enriched enzyme in a yield of approximately 6%. SDS-PAGE showed an M r for the enzyme of approximately 48 kDa. Optimum pH …
Recommendations of the European Cardiac Arrhythmia Society Committee on Device Failures and Complications
2006
Recommendations of the European Cardiac Arrhythmia Society Committee on Device Failures and Complications MASSIMO SANTINI,* JOHANNES BRACHMANN,† RICCARDO CAPPATO,‡ WYN DAVIES,§ JERONIMO FARRE,‖ SAMUEL LEVY,¶ AURELIO QUESADA,# RENATO P. RICCI,** EDWARD ROWLAND,†† NEIL SULKE‡‡ From *San Filipo Neri Hospital, Rome, Italy, †Klinikum Coburg, Germany, ‡Policlinico S. Donato, Milan, Italy, §St. Mary Hospital, London, UK, ‖Fundacion Jimenez Diaz, Madrid, Spain, ¶Hopital Nord des Bourrellys, Marseille, France, #Hospital General University of Valencia, Spain, **San Filippo Neri Hospital, ††St. George Medical School, London, UK, ‡‡Eastbourne General Hospital, Sussex, UK
Sudden death in water: Diagnostic challenges
2016
Abstract The authors report a case of sudden death in a breath-holding diver and highlight the forensic diagnostic difficulties in opining the cause of sudden death in water. The autopsy showed increased thickness of the left ventricular wall with a distinct pattern of concentric hypertrophy, evident particularly in the subaortic interventricular septum. Histological examination revealed diffuse interstitial fibrosis and associated findings of multifocal myocyte disarray especially evident in the subaortic interventricular septum. The analysis and discussion of this case made it possible to attribute sudden death to a lethal arrhythmia following myocyte disarray and hypoxia caused by breath…
Machine Learning Identification of Pro-arrhythmic Structures in Cardiac Fibrosis
2021
Cardiac fibrosis and other scarring of the heart, arising from conditions ranging from myocardial infarction to ageing, promotes dangerous arrhythmias by blocking the healthy propagation of cardiac excitation. Owing to the complexity of the dynamics of electrical signalling in the heart, however, the connection between different arrangements of blockage and various arrhythmic consequences remains poorly understood. Where a mechanism defies traditional understanding, machine learning can be invaluable for enabling accurate prediction of quantities of interest (measures of arrhythmic risk) in terms of predictor variables (such as the arrangement or pattern of obstructive scarring). In this st…
Reduction of ICD Shock Burden by Eliminating Back-Up Pacing Induced Ventricular Tachyarrhythmias
2014
ICD Shock Reduction by Subthreshold Pacing Introduction Implantable cardioverter defibrillators (ICD) may have the capacity to provoke or worsen ventricular tachyarrhythmias (VT). It has been reported that ICD shocks by itself can increase mortality. This study aimed to determine the role of back-up pacing-induced VT (PIT) in the overall ICD shock burden by avoiding pause-related ventricular back-up pacing. Methods and Results A population of 550 single-chamber ICD patients was studied. Of them, 17 (3%, 69 ± 16 years, 14 male) patients had documented episodes of PIT. A total of 431 VT episodes were documented including 89 (21%) due to PIT. In 3 patients, VT events were exclusively PITs. Aft…