Improving Interpretation of Cardiac Phenotypes and Enhancing Discovery With Expanded Knowledge in the Gene Ontology.

Background: A systems biology approach to cardiac physiology requires a comprehensive representation of how coordinated processes operate in the heart, as well as the ability to interpret relevant transcriptomic and proteomic experiments. The Gene Ontology (GO) Consortium provides structured, controlled vocabularies of biological terms that can be used to summarize and analyze functional knowledge for gene products.

Methods And Results: In this study, we created a computational resource to facilitate genetic studies of cardiac physiology by integrating literature curation with attention to an improved and expanded ontological representation of heart processes in the Gene Ontology.

Correction: Long-term intra-individual reproducibility of heart rate dynamics during exercise and recovery in the UK Biobank cohort.

[This corrects the article DOI: 10.1371/journal.pone.

Systematic review and meta-analysis of left ventricular endocardial pacing in advanced heart failure: Clinically efficacious but at what cost?

Introduction: Cardiac resynchronization using a left ventricular (LV) epicardial lead placed in the coronary sinus is now routinely used in the management of heart failure patients. LV endocardial pacing is an alternative when this is not feasible, with outcomes data sparse.

Objective: To review the available evidence on the efficacy and safety of endocardial LV pacing via meta-analysis.

Does presence of left ventricular contractile reserve improve response to cardiac resynchronization therapy? An updated meta-analysis.

Background: Up to a third of patients undergoing cardiac resynchronization therapy (CRT) do not have a clinical or echocardiographic response. It is also unclear, whether contractile reserve (CR) could predict CRT response. This meta-analysis examines whether the presence of CR improves response to CRT and whether this is modulated by other clinical factors.

Ajmaline blocks I and I without eliciting differences between Brugada syndrome patient and control human pluripotent stem cell-derived cardiac clusters.

The class Ia anti-arrhythmic drug ajmaline is used clinically to unmask latent type I ECG in Brugada syndrome (BrS) patients, although its mode of action is poorly characterised. Our aims were to identify ajmaline's mode of action in human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs), and establish a simple BrS hiPSC platform to test whether differences in ajmaline response could be determined between BrS patients and controls. Control hiPSCs were differentiated into spontaneously contracting cardiac clusters.

Syncope in a young man: Role of Purkinje fibres in idiopathic ventricular fibrillation.

A young man suffered cardiac arrests with polymorphic ventricular tachycardia (PVT) and ventricular fibrillation (VF) triggered by ventricular premature contractions (PVCs). The arrhythmia was resistant to anti-arrhythmics, so after ICD implantation he underwent successful ablation of the triggering VE beat, which was pace-mapped to the left posterior hemi-fascicle. We review the evidence for the role of the Purkinje network in the initiation and maintenance of PVT and VF, postulating a channelopathy as a possible underlying cause, and provide recommendations for PVC ablation.

Limitations and Challenges in Mapping Ventricular Tachycardia: New Technologies and Future Directions.

Recurrent episodes of ventricular tachycardia in patients with structural heart disease are associated with increased mortality and morbidity, despite the life-saving benefits of implantable cardiac defibrillators. Reducing implantable cardiac defibrillator therapies is important, as recurrent shocks can cause increased myocardial damage and stunning, despite the conversion of ventricular tachycardia/ventricular fibrillation. Catheter ablation has emerged as a potential therapeutic option either for primary or secondary prevention of these arrhythmias, particularly in post-myocardial infarction cases where the substrate is well defined.

Empowerment of athletes with cardiac disorders: a new paradigm.

Athletes with cardiac disorders frequently pose an ethical and medical dilemma to physicians assessing their eligibility to participate in sport. In recent decades, patient empowerment has been gaining increasing recognition in clinical decision-making. Empowerment is a process through which people are involved over the decisions and actions that affect their own lives.

Temporal pattern/episode duration-based classification of atrial fibrillation as paroxysmal vs. persistent: is it time to develop a more integrated prognostic score to optimize management?

Atrial fibrillation (AF) is a clinically heterogeneous arrhythmia that is currently classified according to the variety of temporal rhythm based manifestations observed clinically, including 'first detected episode', 'paroxysmal', 'persistent', or 'permanent' AF. Despite being widely adopted by the most recent consensus guidelines, the utility of this classification system to stratify patients into distinct and clinically useful groups that have different outcomes including mortality, morbidity, specific cardiovascular outcomes, and quality of life (QoL), remains questionable. This is particularly true regarding the distinction between paroxysmal and persistent AF.

Impact of QTc formulae in the prevalence of short corrected QT interval and impact on probability and diagnosis of short QT syndrome.

Objective: To assess the prevalence of short corrected QT (QTc) intervals and its impact on short QT syndrome (SQTS) diagnosis using different QT correction formulae.

Methods: Observational study. The prevalence of short QTc intervals was estimated using four different QT correction formulae in 14 662 young adults from the 'Sudden Cardiac Death Screening of Risk FactOrS' (SCD-SOS) cohort.

Call for joint informed consent in athletes with inherited cardiac conditions.

Informed consent is of the utmost importance, especially in complex clinical situations where patients may be exposed to a life-threatening risk. A particularly complex example is the eligibility of competitive athletes with inherited cardiac conditions on medical grounds, especially when the risk is low or unquantifiable. The rationale and benefits of a joint informed consent for athletes to compete with potentially life-threatening cardiac conditions are discussed in this manuscript.

Long-term intra-individual reproducibility of heart rate dynamics during exercise and recovery in the UK Biobank cohort.

Background: The heart rate (HR) response to exercise provides useful information about the autonomic function and has prognostic value, but its reproducibility over a long period of time, a critical requirement for using it as a clinical biomarker, is undetermined.

Aim: To determine the intra-individual reproducibility of HR dynamics during sub-maximum exercise and one minute recovery.

Methods: 1187 individuals from the Cardio physical fitness assessment test of the UK Biobank repeated a standard exercise stress test twice (recall time 34.

Implant and Midterm Outcomes of the Subcutaneous Implantable Cardioverter-Defibrillator Registry: The EFFORTLESS Study.

Background: The subcutaneous implantable cardioverter-defibrillator (S-ICD) was developed to defibrillate ventricular arrhythmias, avoiding drawbacks of transvenous leads. The global EFFORTLESS S-ICD (Evaluation oF FactORs ImpacTing CLinical Outcome and Cost EffectiveneSS of the S-ICD) registry is collecting outcomes in 985 patients during a 5-year follow-up.

Objectives: The primary goal of the EFFORTLESS registry is to determine the safety of the S-ICD by evaluating complications and inappropriate shock rate.

Impact of an Age-Adjusted Co-morbidity Index on Survival of Patients With Heart Failure Implanted With Cardiac Resynchronization Therapy Devices.

Age is an adverse prognostic factor in patients with heart failure. We aimed to assess the impact of age and noncardiac co-morbidities in the outcome of patients undergoing cardiac resynchronization therapy (CRT), and determine which of these two factors is the most important predictor of survival. The study involved a single-center retrospective assessment of 697 consecutive CRT implants during a 12-year period.

D242N, a K7.1 LQTS mutation uncovers a key residue for I voltage dependence.

K7.1 and KCNE1 co-assemble to give rise to the I current, one of the most important repolarizing currents of the cardiac action potential. Its relevance is underscored by the identification of >500 mutations in K7.

Electrical and Structural Substrate of Arrhythmogenic Right Ventricular Cardiomyopathy Determined Using Noninvasive Electrocardiographic Imaging and Late Gadolinium Magnetic Resonance Imaging.

Background: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a significant cause of sudden cardiac death in the young. Improved noninvasive assessment of ARVC and better understanding of the disease substrate are important for improving patient outcomes.

Methods And Results: We studied 20 genotyped ARVC patients with a broad spectrum of disease using electrocardiographic imaging (a method for noninvasive cardiac electrophysiology mapping) and advanced late gadolinium enhancement cardiac magnetic resonance scar imaging.

Mechano-electrical feedback in the clinical setting: Current perspectives.

Mechano-electric feedback (MEF) is an established mechanism whereby myocardial deformation causes changes in cardiac electrophysiological parameters. Extensive animal, laboratory and theoretical investigation has demonstrated that abnormal patterns of cardiac strain can induce alteration of electrical excitation and recovery through MEF, which can potentially contribute to the establishment of dangerous arrhythmias. However, the clinical relevance of MEF in patients with heart disease remains to be established.

Catheter ablation for ventricular tachycardia in patients with cardiac sarcoidosis: a systematic review.

Aims: Cardiac sarcoidosis (CS) is associated with a poor prognosis. Important features of CS include heart failure, conduction abnormalities, and ventricular arrhythmias. Ventricular tachycardia (VT) is often refractory to antiarrhythmic drugs (AAD) and immunosuppression.