Atrial Fibrillation in Heart Failure With Preserved Ejection Fraction: Pathophysiology and the Role of Catheter Ablation: AF in HFpEF

Atrial fibrillation (AF) and heart failure (HF) often coexist, and the prognosis of patients who have both these conditions is worse than those with either condition alone. Heart failure with preserved ejection fraction (HFpEF) is a clinical condition that was initially characterized as diastolic dysfunction HF, then as HF with normal ejection fraction, and more recently as HFpEF. About one-third of patients with HFpEF suffer from AF. Although, both clinical entities share common pathophysiologic mechanisms, current knowledge of the relationship between AF and HFpEF is limited. Catheter ablation, although data from randomized trials in this category of patients are limited, seems to have beneficial effects regarding maintenance of sinus rhythm and re-hospitalization rates. Rhythmos 2020;15(2):29-32

Recent Data on Epicardial Ablation of Ventricular Tachycardia in Nonischemic Heart Disease

Epicardial ablation has been adopted during the last years, mainly as a supplementary technique after a failed endocardial ablation procedure, both in patients with ischemic and nonischemic ventricular tachycardias (VTs). Sosa and colleagues were the first who described the percutaneous subxiphoidal puncture to approach the epicardial space in 1996. Using the 3D electroanatomic mapping systems, the endocardial and epicardial substrate mapping have become feasible during the same procedure. Because of its complexity and its potential risks this process is performed only in high experienced centers by skilled operators with a large number of VT ablation procedures.Endocardial ablation in patients with left ventricular nonischemic cardiomyopathy (NICM) has shown worst outcome compared with ablation in ischemic cardiomyopathy. The main reason seems to be the progressive nature of the disease and the presence of epicardial and intramural slow conduction areas forming reentry circuits. The pattern of fibrosis and scar in NICM is not predictable as in ischemic cardiomyopathy where it follows the distribution of the coronary artery disease. Data from the study of Hsia et al in patients with NICM and VT episodes supported that the critical endocardial low voltage substrate was located mainly in the basal and perivalvular area. In this study, epicardial mapping was performed only in few patients revealing abnormal fragmented potentials but data from later studies highlighted the important of epicardial substrate in NICM. Cano et al3 performed both endocardial and epicardial mapping in 22 patients either because of failed endocardial ablation or because of electrocardiographic signs suggesting epicardial localization of the exit point. Electroanatomic mapping revealed extended epicardial low voltage areas in the majority of the patients (about 82%) which were located mostly in basal left ventricular lateral wall. However, Haqqani et al described 31 of 266 patients with NICM (11.6%) who had septal involvement, mainly in the basal region, without lateral low voltage areas... (excerpt

Idiopathic Premature Ventricular Contraction (PVC)-Induced Cardiomyopathy: The Role of Catheter Ablation

Premature ventricular contractions (PVCs) are common and are considered benign in the absence of structural heart disease. However, high burden of PVCs potentially on 24-hour Holter monitoring, can potentially cause left ventricular dysfunction. In this case, catheter ablation has been demonstrated to be effective at PVC suppression and is associated with improvement or normalization of ventricular function. This form of reversible ventricular dysfunction termed as PVC cardiomyopathy and its pathogenesis is poorly understood at the current time. Rhythmos 2019;14(3):51-54

Long-Term Results of Atrial Fibrillation Ablation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in the general population, affecting about 0.4% of the general population. Its prevalence increases with age reaching 15% in adults over 70 years of age. During the past decade, as techniques and technologies have improved, catheter ablation of AF has become a standard and effective therapy for patients with symptomatic and drug-refractory AF. The improved three-dimensional electroanatomic mapping systems and the induction in the clinical practice of other ablation techniques, such as cryoablation, have contributed to the worldwide increase of the number of ablation procedures. Catheter ablation seems to be superior to antiarrhythmic drug therapy (ADT) which is also associated with potential toxic or proarrhythmic effects after long term use. The recently presented data from RAAFT 2 study, showed that 55% of the patients who had randomized to AF ablation had had a recurrence compared to 72%, of those who had received ADT after 2 years follow up. For the first time, the 2012 updated guidelines from the European Society of Cardiology, recommend catheter ablation as the first line therapy in selected patients with paroxysmal AF alternative to ADT (class IIa, level B). The main target of the AF catheter ablation is the circumferential electrical isolation of the pulmonary veins (PVs) ostium or antrum. In some patients suffering from persistent AF, a more aggressive strategy is adopted, including left atrial substrate modification with linear ablation or rarely with lesions in other anatomical structures as right atrium, superior or inferior vena cava, fossa ovalis, left atrial appendage and coronary sinus or the ligament of Marshall... (excerpt

Spontaneous Documentation of Bidirectional Block During Pulmonary Vein Isolation - Keep an Eye on the Electrograms!

AbstractIn the present case, we describe the abrupt transformation of intra-pulmonary vein activity from rapid firing to dissociated ectopic activity during sinus rhythm, as an easily identifiable, though rare to encounter, sign which documents the achievement of bidirectional block

Current Data on the Role of Specific Antidotes for the Reversal of Non-Vitamin K Oral Anticoagulant Action

The increasing use of the non-vitamin K oral anticoagulants during the recent years was associated with the need of development of targeted agents that could reverse the anticoagulative activity in cases of severe bleeding episodes or urgent high risk operations. Thus, several reversal agents are currently in development and the early results seem promising. Idarucizumab is a monoclonal antibody that can immediately and specifically reverse dabigatran action. Andexanet alfa is a recombinant modified factor Xa that can bind and reverse factor Xa inhibitors, including rivaroxaban, apixaban and edoxaban, and low molecular weight heparin. Aripazine is a universal reversal agent small molecule that can reverse the action of factor Xa inhibitors, unfractionated and low molecular weight heparin and possibly dabigatran. Currently, only idarucizumab has received approval from the United States Food and drug Administration for the reversal of the dabigatran. Rhythmos 2016;11(3):70-72.

Insights into Catheter Ablation of Ventricular Tachycardias in Arrhythmogenic Right Ventricular Cardiomyopathy / Dysplasia

Arrhythmogenic right ventricular cardiomyopathy/ dysplasia (ARVC/D), mostly affecting young/middle-aged individuals, poses a significant risk of malignant ventricular arrhythmias (VAs) and subsequent sudden cardiac death (SCD). Antiarrhythmic agents (AAA) provide insufficient arrhythmia suppression and prevention and can be proarrhythmic. Thus, the implantable cardioverters-defibrillator (ICD) is considered the first-line treatment, especially in patients with secondary prevention indication. Nevertheless, catheter ablation is an additional therapy to the ICD which has proved its efficacy in primary and secondary prevention of fatal arrhythmias and sudden cardiac death. The superiority of the combined endo- and epicardial VT ablation in this population is clear since the ARVC/D substrate has been shown to be mostly epicardial. Due to progressive nature of ARVC/D, ablation seems to be a useful tool for the patients who experience recurrent VT episodes or electrical storms

Diabetes Mellitus: Dipeptidyl Peptidase 4 Inhibitors and Cardiovascular Outcomes

Dipeptidyl peptidase 4 (DPP‑4) inhibitors represent a new pharmacological class of glucose – lowering agents, mainly used as add-on therapy, after metformin or combination of metformin with sulfonylurea or metformin with a thiazolidinedione. Over the last few years, several DPP‑4 inhibitors, also called gliptins, have been approved and introduced into clinical practice such as sitagliptin, linagliptin, saxagliptin, vildagliptin and alogliptin. Their mechanism of action relates to the inhibition of the DPP-4 enzyme which degrades the incretin hormones, e.g. glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), released from the small intestine into the circulation during a meal, potentially capable to stimulate the release of insulin from pancreatic beta cells, thus affording a glucose-lowering action. However, these incretins are swiftly degraded by the DPP-4 enzyme. Gliptins, therefore, inhibit this enzyme, enhancing the bioavailability of GLP-1 and GIP. They have been approved for better glycemic control in type 2 diabetic patients. Although, these new agents have been heralded as safe agents conferring pleiotropic or cardioprotective effects, recent studies showed that the new DPP-4 inhibitors may not have serious adverse cardiovascular effects, but have failed to show any pleiotropic actions or favorable cardiovascular effects. Additional data from ongoing studies may shed further light on this issue

Left Idiopathic Ventricular Tachycardia Amenable to Radiofrequency Ablation

An 18-year-old gentleman with a 5-year-long history of palpitations was referred for radiofrequency ablation of a wide-QRS complex tachycardia. He admitted having 2-3 tachycardia episodes per year, which had recently increased in frequency despite therapy with a beta blocker, recently combined with the antiarrhythmic medication flecainide (100 mg bid). The morphology of the tachycardia on the 12-lead electrocardiogram indicated a right bundle branch block with a left axis deviation at a cycle length of 290 ms (207 bpm) (Fig. 1A). Cardiac work-up revealed a normal heart anatomy by echocardiography, while a treadmill test was normal with no provokable arrhythmia... (excerpt

Insights into the Clinical Spectrum of Catecholaminergic Polymorphic Ventricular Tachycardia

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is induced by stress or exertion especially in young individuals with normal baseline ECG and without any structural heart disease. The most common type of ventricular tachycardia (VT) in these patients is bidirectional VT but could also be polymorphic VT or ventricular fibrillation. These two main types of CPVT are caused by mutations on the ryanodine (RyR2) or calsequestrin (CASQ2) receptor, with an autosomal dominant and recessive inheritance pattern respectively. The prognosis is dismal without treatment and the main therapeutic approach consists of administration of beta blocker, flecainide, calcium channel blockers or ICD implantation. Genetic testing is important for all family members of CPVT probands in order to identify asymptomatic carriers. Rhythmos 2018;13(1):6-8.