Markov modeling of phase singularity interaction effects in human atrial and ventricular fibrillation.

Atrial and ventricular fibrillation (AF/VF) are characterized by the repetitive regeneration of topological defects known as phase singularities (PSs). The effect of PS interactions has not been previously studied in human AF and VF. We hypothesized that PS population size would influence the rate of PS formation and destruction in human AF and VF, due to increased inter-defect interaction.

The inspection paradox: An important consideration in the evaluation of rotor lifetimes in cardiac fibrillation.

Renewal theory is a statistical approach to model the formation and destruction of phase singularities (PS), which occur at the pivots of spiral waves. A common issue arising during observation of renewal processes is an inspection paradox, due to oversampling of longer events. The objective of this study was to characterise the effect of a potential inspection paradox on the perception of PS lifetimes in cardiac fibrillation.

Role of interatrial conduction in atrial fibrillation: Mechanistic insights from renewal theory-based fibrillatory dynamic analysis.

Background: Interatrial conduction has been postulated to play an important role in atrial fibrillation (AF). The pathways involved in interatrial conduction during AF remain incompletely defined.

Objective: We recently showed physiological assessment of fibrillatory dynamics could be performed using renewal theory, which determines rates of phase singularity formation (λ) and destruction (λ).

Understanding the origins of the basic equations of statistical fibrillatory dynamics.

The mechanisms governing cardiac fibrillation remain unclear; however, it most likely represents a form of spatiotemporal chaos with conservative system dynamics. Renewal theory has recently been suggested as a statistical formulation with governing equations to quantify the formation and destruction of wavelets and rotors in fibrillatory dynamics. In this perspective Review, we aim to explain the origin of the renewal theory paradigm in spatiotemporal chaos.

WITHDRAWN: Impact of Racial Differences on the Epidemiology and Clinical Outcomes of Atrial Fibrillation.

Unlabelled: Since the authors are not responding to the editor’s requests to fulfill the editorial requirement, therefore, the article has been withdrawn by the publisher. Bentham Science apologizes to the readers of the journal for any inconvenience this may have caused. The Bentham Editorial Policy on Article Withdrawal can be found at https://benthamscience.

Electrogram analysis to detect cathodal and anodal capture in left ventricular cardiac resynchronization pacing leads.

Aims: Our study analyzed cardiac electrograms (EGMs) to identify characteristics for detecting cathodal, anodal, or cathodal-anodal (simultaneous) capture in left ventricular (LV) quadripolar pacing leads of cardiac resynchronization therapy (CRT) patients. The relationship between these EGM characteristics and the electrocardiogram (ECG) was also examined.

Methods: We performed a retrospective analysis of 54 bipolar pacing configurations across nine patients with implanted CRT devices and quadripolar leads who had undergone a 12 lead ECG optimization.

Reconceptualising Atrial Fibrillation Using Renewal Theory: A Novel Approach to the Assessment of Atrial Fibrillation Dynamics.

Despite a century of research, the mechanisms of AF remain unresolved. A universal motif within AF research has been unstable re-entry, but this remains poorly characterised, with competing key conceptual paradigms of multiple wavelets and more driving rotors. Understanding the mechanisms of AF is clinically relevant, especially with regard to treatment and ablation of the more persistent forms of AF.

Relationship between coronary microvascular dysfunction and left ventricular diastolic function in patients with chest pain and unobstructed coronary arteries.

Backgroud: Diastolic dysfunction (DD) is reported to affect up to 35% of the adult general population. The consequence of progressive DD is heart failure with preserved ejection fraction (HFpEF). Coronary microvascular dysfunction (CMD) has been suggested as one of the pathologic mechanisms leading to HFpEF.

An Experimental Series Investigating the Effects of Hyperinsulinemic Euglycemia on Myocardial Blood Flow Reserve in Healthy Individuals and on Myocardial Perfusion Defect Size following ST-Segment Elevation Myocardial Infarction.

Background: Incomplete restoration of myocardial blood flow (MBF) is reported in up to 30% of ST-segment elevation myocardial infarction (STEMI) despite prompt mechanical revascularization. Experimental hyperinsulinemic euglycemia (HE) increases MBF reserve (MBFR). If fully exploited, this effect may also improve MBF to ischemic myocardium.

The Clinical Utility and Enduring Versatility of Stress Echocardiography.

Stress echocardiography is an established cardiac imaging modality for the detection and quantification of severity of coronary artery disease. In recent years, there has also been an increasing use of stress echocardiography in the assessment of non-ischaemic cardiac disease given its ability to assess functional capacity and haemodynamic changes with exercise which can help guide therapy and inform prognosis. The emerging use of strain, myocardial contrast and three-dimensional (3D) echocardiography further assists in improving diagnostic accuracy particularly in patients with coronary artery disease.

The management of the older adult patient with anomalous left coronary artery from the pulmonary artery syndrome: a presentation of two cases and review of the literature.

ALCAPA (anomalous left coronary artery from pulmonary artery) syndrome is a rare congenital abnormality that involves an anomalous insertion of the left coronary artery into the pulmonary artery. Ninety percent of patients present in the first year of life with signs and symptoms of heart failure or sudden cardiac death secondary to chronic myocardial ischemia. There have been an increasing number of reports of ALCAPA patients surviving to adulthood.