This issue of Cardiac Electrophysiology Clinics examines Frontiers in Non-invasive Cardiac Mapping. Topics include imaging of heart rhythm disorders, experimental validation and modeling of validation, challenges and future directions of inverse problems, phase mapping of cardiac fibrillation, frequency domain analysis, analysis of diagnostic 12-lead electrocardiography and 3D non-invasive mapping, and many more.

This issue of Cardiac Electrophysiology Clinics examines Arrhythmias in Cardiomyopathies. Articles include Atrial and Ventricular Arrhythmias in Hypertrophic Cardiomyopathy and Its Variants; Role of Cardiac MRI in Risk Stratification of Hypertrophic Cardiomyopathy; Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy; Exercise-Induced Right Ventricular Cardiomyopathy; Dilated Cardiomyopathy; Sarcoidosis; Amyloidosis; Chagas Disease; Fabry Disease; Left Ventricular Hypertrophy: Ventricular Arrhythmias and SCD; Left Ventricular Non-compaction; Mitochondrial Cardiomyopathy and Related Arrhythmias; Arrhythmias in Viral Myocarditis and Pericarditis Cardiomyopathy; Takotsubo Cardiomyopathy; Post-partum Cardiomyopathy; Arrhythmias in Alcohol- and Drug-Associated Cardiomyopathies; Arrhythmias in Neuromuscular Dystrophies; Cardiomyopathies Related to Anti-cancer Therapy– and Radiation- Induced Heart Disease; Arrhythmias After Myocardial Stem Cell Therapy; and more.

The sodium channel, a ubiquitous member of the cardiac, neural, and muscular conduction systems, has been implicated in the pathogenesis of an array of human diseases. Mutations associated with the cardiac sodium channel are responsible for a wide spectrum of disorders. The cardiac sodium channel and associated disorders are comprehensively examined in this issues of the Cardiac Electrophysiology Clinics.

Controversies in Cardiac Electrophysiology are examined in this issue of Cardiac Electrophysiology Clinics. Difficult cases are presented and esteemed leaders in the field debate the pros and cons of various forms of management and treatment.

This book constitutes the refereed proceedings of the 9th International Conference on Functional Imaging and Modeling of the Heart, held in Toronto, ON, Canada, in June 2017. The 48 revised full papers were carefully reviewed and selected from 63 submissions. The focus of the papers is on following topics: novel imaging and analysis methods for myocardial tissue characterization and remodeling; advanced cardiac image analysis tools for diagnostic and interventions; electrophysiology: mapping and biophysical modeling; biomechanics and flow: modeling and tissue property measurements.

The latest developments in the field of Cardiac Resynchronization Therapy are featured in this issue of Cardiac Electrophysiology Clinics. The issue includes more than 20 articles in the following areas: heart failure; cost of heart failure; ventricular dissynchrony and resynchronization; assessment of dissynchrony; indication for CRT implantation; implantation technique; measures to improve CRT benefit on AF patients; and many more.

This issue of Cardiac Electrophysiology Clinics, guest edited by Mohammad Shenasa and Amin Al-Ahmad, will focus on Advances in Cardiac Mapping and Catheter Ablation. This is part one of a two-part issue and will include articles centered around Basic Concepts in Cardiac Mapping, Novel Mapping & Imaging Systems & Technologies, and Catheter and Energy Sources. Topics include, but are not limited to, Embryology of the Cardiac Conduction System Relevant to Cardiac Arrhythmias; Anatomical Consideration Relevant to Atrial and Ventricular Arrhythmias; Fundamentals of Cardiac Mapping; Novel Cardiac Mapping Systems; Non-invasive Mapping & ECGI in Atrial and Ventricular Arrhythmias; Optical Mapping; Omnipolar Mapping; Cardiac CT, MRI, and Fibrosis Quantification; High resolution mapping in patients with atrial and ventricular arrhythmias; Contact Force and Ablation Index; and New Catheter Balloons Including Radiofrequency.

Electrical activity in the myocardium coordinates the contraction of the heart, and its knowledge could lead to a better understanding, diagnosis, and treatment of cardiac diseases. This electrical activity generates an electromagnetic field that propagates outside the heart and reaches the human torso surface, where it can be easily measured. Classical electrocardiography aims to interpret the 12-lead electrocardiogram (ECG) to determine cardiac activity and support the diagnosis of cardiac pathologies such as arrhythmias, altered activations, and ischemia. More recently, a higher number of leads is used to reconstruct a more detailed quantitative description of the electrical activity in the heart by solving the so-called inverse problem of electrocardiography. This technique is known as ECG imaging. Today, clinical applications of ECG imaging are showing promising results in guiding a variety of electrophysiological interventions such as catheter ablation of atrial fibrillation and ventricular tachycardia. However, in order to promote the adoption of ECG imaging in the routine clinical practice, further research is required regarding more accurate mathematical methods, further scientific validation under different preclinical scenarios and a more extensive clinical validation

This issue of Cardiac Electrophysiology Clinics, Guest Edited by Giuseppe Bagliani, Roberto De Ponti, and Fabio Leonelli, will focus on Interpreting Complex Arrhythmias. Topics include, but are not limited to: Simple and complex Arrhythmias; Standard ECG recording; Advanced cardiac signal recording; P and QRS in arrhythmias: identification, analysis and relationship; The comparative value of basic and arrhythmia ECG in the interpretation of arrhythmic mechanism; Challenges in Bradycardias interpretation; Challenges in Narrow QRS tachycardia interpretation; Challenging cases of Wide complex tachycardias; QRS variations during arrhythmia: mechanisms and substrates; Polymorphic ventricular tachycardia: differential diagnosis; Arrhythmias due to acquired or inherited abnormalities of Ventricular repolarization; Arrhythmias in patients with implantable devices; Complex arrhythmias due to reversible causes; and Hidden complexities in routine adult and paediatric arrhythmias interpretation.

Effective identification of patients at increased risk of malignant cardiac arrhythmia presently represents a clinically important unmet need. Existing guidelines for the selection of candidates for the prophylactic implantation of cardioverters-defibrillators (ICD) are based solely on the reduction of ventricular haemodynamic performance. Although this guidance is based on statistical results of previously conducted randomized clinical trials, available experience shows that it does not serve clinical needs efficiently. The majority of patients who are implanted with ICDs for prophylactic reasons never utilize the device during its technical longevity whilst, at the same time, many patients who succumb to sudden cardiac death do not have ventricular haemodynamic performance particularly compromised. Recent results also showed that the previous statistical findings of ICD efficacy are not fully reproducible in patients with non-ischemic heart disease and that the reduction of sudden cardiac death after myocardial infarction by external automatic defibrillation vests is lower than expected. Advances in cardiac electrophysiology are needed for better understanding of the mechanisms that are the basis of different arrhythmic abnormalities. Increased understanding of these mechanisms will allow them to be more effectively classified so that optimum therapeutic options can be offered. Likewise, better understanding of the underlying electrophysiology processes is needed so that novel and more focused randomized clinical trials can be designed. Compared to invasive electrophysiological studies, noninvasive cardiac electrophysiology offers the possibility of screening larger number of patients as well as healthy subjects investigated under different provocations and conditions. To advance the field, broad spectrum of studies is needed together with meta-analyses and reviews facilitating research interactions.