2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS.

Peer reviewe

Computer simulation of a novel technique for Radio-Frequency Ablation of ventricular arrhythmias

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 169-175).Ventricular Tachycardia (VT) is a rapid arrhythmia, most commonly due to reentrant electrical activity in the heart. A common treatment for VT is Radio-Frequency Ablation (RFA), which is minimally invasive, but requires maintenance of VT until the target site for ablation is determined. Most patients with VT cannot tolerate this maintenance phase due to hemodynamic instability and for those who are hemodynamically stable, the RFA procedure is successful in permanently terminating the VT in only approximately half of the cases. Therefore, the need for an RFA procedure that accurately localizes the site for ablation, or exit site of the reentry circuit, and is safe for unstable patients is evident. We believe utilization of the Single Equivalent Moving Dipole model and inverse problem in cardiology will prove to be efficient in localizing the exit site of the reentry circuit and guiding the ablation catheter to that localized site during the RFA procedure. In principle, our RFA technique only requires a single beat of VT to localize the exit site of the reentry circuit. The objective of this thesis is to determine in a simulation model if one can guide a catheter to the exit site of the reentry circuit using body surface potentials in order to ablate that site with radio-frequency energy.(cont.) In our new approach to RFA, we sought to design a finite element model to simulate VT due to reentry, develop an algorithm to localize the exit site of the reentry circuit through analysis of body surface potentials, localize the ablation catheter in both slow and fast VT, and advance the ablation catheter to the localized exit site of the reentry circuit. The proposed new RFA procedure promises to provide a new rapid and effective means for treatment of VT.by Tamara S. Rosbury.Ph.D

Cardiac Arrhythmias

The most intimate mechanisms of cardiac arrhythmias are still quite unknown to scientists. Genetic studies on ionic alterations, the electrocardiographic features of cardiac rhythm and an arsenal of diagnostic tests have done more in the last five years than in all the history of cardiology. Similarly, therapy to prevent or cure such diseases is growing rapidly day by day. In this book the reader will be able to see with brighter light some of these intimate mechanisms of production, as well as cutting-edge therapies to date. Genetic studies, electrophysiological and electrocardiographyc features, ion channel alterations, heart diseases still unknown , and even the relationship between the psychic sphere and the heart have been exposed in this book. It deserves to be read

The contact electrogram and its architectural determinants in atrial fibrillation

The electrogram is the sine qua non of excitable tissues, yet classification in atrial fibrillation (AF) remains poorly related to substrate factors. The objective of this thesis was to establish the relationship between electrograms and two commonly implicated substrate factors, connexin 43 and fibrosis in AF. The substrates and methods chosen to achieve this ranged from human acutely induced AF using open chest surgical mapping (Chapter 6), ex vivo whole heart Langendorff (Chapter 7) with in vivo telemetry confirming spontaneous AF in a new species of rat, the Brown Norway and finally isolated atrial preparations from an older cohort of rats using orthogonal pacing and novel co-localisation methods at sub-millimetre resolution and in some atria, optical mapping (Chapter 8). In rodents, electrode size and spacing was varied (Chapters 5, 10) to study its effects on structure function correlations (Chapter 9). Novel indices of AF organisation and automated electrogram morphology were used to quantify function (Chapter 4). Key results include the discoveries that humans without any history of prior AF have sinus rhythm electrograms with high spectral frequency content, that wavefront propagation velocities correlated with fibrosis and connexin phosphorylation ratios, that AF heterogeneity of conduction correlates to fibrosis and that orthogonal pacing in heavily fibrosed atria causes anisotropy in electrogram-fibrosis correlations. Furthermore, fibrosis and connexin 43 have differing and distinct spatial resolutions in their relationship with AF organisational indices. In conclusion a new model of AF has been found, and structure function correlations shown on an unprecedented scale, but with caveats of electrode size and direction dependence. These findings impact structure function methods and prove the effect of substrate on AF organisation.Open Acces

Arrhythmogenic Right Ventricular Cardiomyopathy: Prognostic Value of Electroanatomic Voltage Mapping

Background: Endocardial voltage mapping (EVM) identifies low-voltage right ventricular (RV) areas, which may represent the electroanatomic scar substrate of life-threatening tachyarrhythmias. We prospectively assessed the prognostic value of EVM in a consecutive series of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Methods: We studied 69 consecutive ARVC patients [47 males; median age 35 years(28-45)] who underwent electrophysiological study and both bipolar and unipolar EVM. The extent of confluent bipolar (<1.5mV) and unipolar (<6.0mV) low-voltage electrograms was estimated using the CARTO-incorporated area calculation software. Results: Fifty-three patients (77%) showed ≥1 RV electroanatomic scars with an estimated burden of bipolar vs unipolar low-voltage areas of 24.8% (7.2-31.5) and 64.8% (39.8-95.3), respectively (P=0.009). In the remaining patients with normal bipolar-EVM (n=16;23%), the use of unipolar EVM unmasked ≥1 region of low-voltage electrogram affecting 26.2% (11.6-38.2) of RV wall. During a median follow-up of 41 (28-56) months, 19(27.5%) patients experienced arrhythmic events, such as sudden death (n=1), appropriate ICD interventions (n=7), or sustained ventricular tachycardia (n=11). Univariate predictors of arrhythmic outcome included previous cardiac arrest or syncope (HR=3.4; 95%CI:1.4-8.8; P=0.03) and extent of bipolar low-voltage areas (HR=1.7 per 5%; 95%CI=1.5-2; P<0.001), while the only independent predictor was the bipolar low-voltage electrogram burden (HR=1.6 per 5%; 95% CI:1.2-1.9; P<0.001). Patients with normal bipolar-EVM had an uneventful clinical course. Conclusions: The extent of bipolar RV endocardial low-voltage area was a powerful predictor of arrhythmic outcome in ARVC, independently of history and RV dilatation/dysfunction. A normal bipolar-EVM characterized a low-risk subgroup of ARVC patients