BACKGROUND: Beta-blockers (BB) or dihydropyridine calcium channel blockers (CCBs) are still the first choices in the treatment of idiopathic premature ventricular complexes (PVCs), with low-modest efficacy. Antiarrhythmic drugs (AADs) of Ic class are moderate to highly efficient but the evidence on their benefits is still limited.
OBJECTIVE: To compare effectiveness and safety of flecainide, propafenone, and sotalol in the treatment of symptomatic idiopathic PVCs.
METHODS: Our single-center retrospective study analyzed 104 consecutive patients with 130 medication episodes of frequent idiopathic PVCs treated with AADs flecainide, propafenone (Ic class) or sotalol (III class). The primary outcome was complete/near complete reduction of PVCs after medication episode (PVCs burden reduction >99%), and the secondary outcome was significant PVC burden reduction (≥80%).
RESULTS: The complete/near complete PVCs burden reduction occurred in 31% and was significant in 43% of treated patients. A reduction of PVC burden for >99% was achieved in 56% of patients on flecainide, in 11% of patients on propafenone (p = .002), and in 21% of patients receiving sotalol (p = .031). There was no difference between propafenone and sotalol (p = .174). A reduction of PVC burden for ≥80% was achieved in 64% of patients on flecainide, in 30% of patients on propafenone (p = .009), and 33% of patients on sotalol (p = .020). There was no difference between propafenone and sotalol (p = .661).
CONCLUSIONS: The efficacy of AADs class Ic and III in the treatment of idiopathic PVCs was modest. Flecainide was the most effective AAD in the achievement of complete/near complete or significant PVC burden reduction, compared to propafenone and sotalol.

The objective of this study was to present a new system, the Automatic Arrhythmia Origin Localization (AAOL) system, which used incomplete electroanatomic mapping (EAM) for localization of idiopathic ventricular arrhythmia (IVA) origin on the patient-specific geometry of left ventricular, right ventricular, and neighboring vessels. The study assessed the accuracy of the system in localizing IVA source sites on cardiac structures where pace mapping is challenging.
An intraprocedural automated site of origin localization system was previously developed to identify the origin of early left ventricular activation by using 12-lead electrocardiograms (ECGs). However, it has limitations, as it could not identify the site of origin in the right ventricle and relied on acquiring a complete EAM.
Twenty patients undergoing IVA catheter ablation had a 12-lead ECG recorded during clinical arrhythmia and during pacing at various locations identified on EAM geometries. The new system combined 3-lead (III, V2, and V6) 120-ms QRS integrals and patient-specific EAM geometry with pace mapping to predict the site of earliest ventricular activation. The predicted site was projected onto EAM geometry.
Twenty-three IVA origin sites were clinically identified by activation mapping and/or pace mapping (8, right ventricle; 15, left ventricle, including 8 from the posteromedial papillary muscle, 2 from the aortic root, and 1 from the distal coronary sinus). The new system achieved a mean localization accuracy of 3.6 mm for the 23 mapped IVAs.
The new intraprocedural AAOL system achieved accurate localization of IVA origin in ventricles and neighboring vessels, which could facilitate ablation procedures for patients with IVAs.

Ventricular arrhythmias (VAs) occurring in the absence of structural heart disease or ion channelopathies are referred to as idiopathic. They can clinically present with frequent monomorphic premature ventricular contractions, nonsustained ventricular tachycardia (VT), or sustained VT, and generally share a benign prognosis. Approximately 4% to 10% of idiopathic VAs have an epicardial site of origin, represented in most cases by the left ventricular summit and, less frequently, by the cardiac crux. Epicardial foci can be addressed by catheter ablation via the coronary venous system tributaries. In rarer instances, a direct epicardial access from a subxiphoid approach is needed.

The management of ventricular arrhythmias (VA) in the presence of an apparently normal heart represents a major clinical challenge and a main field of clinical research. In the past years, new imaging techniques and the spreading of new generation genetic testing have improved our knowledge of the pathogenesis of apparently idiopathic VA. However, in the absence of specific recommendations, the type and the number of noninvasive and invasive studies necessary to rule out a possible underlying cause of VA or sudden cardiac death remain extremely variable. Therefore, in many patients the underlying cardiac disease is not recognized, and a possible specific therapeutic approach cannot be initiated. Endomyocardial biopsy (EMB) can provide a significant contribution to the identification of myocardial disorders causing VA but has never been definitively included in the routine diagnostic work-up of these patients due to the possible sampling error particularly in disorders with a focal or patchy distribution. Three-dimensional electroanatomic mapping (EAM) may guide EMB allowing to draw myocardial samples from abnormal voltage, areas of the ventricular wall, thus reducing sampling error and increasing the sensitivity of EMB. The systematic association of EAM with EMB represents a crucial approach to characterize the pathological substrate of electroanatomic abnormalities and VA and to further clarify the arrhythmogenic mechanisms of acquired and also inherited arrhythmic disorders.

Idiopathic ventricular arrhythmia (IVA) is a term used to describe a spectrum of ventricular arrhythmia without structural heart disease (SHD). IVAs contain premature ventricular contractions (PVCs), nonsustained monomorphic ventricular tachycardia (VT), and sustained VT. Electrocardiography is a fundamental and important tool to diagnose and localize IVAs. More detailed, IVAs originating from different origins exhibit characterized ECGs due to their specific anatomic backgrounds. As catheter ablation becomes widely used to eliminate these arrhythmias, its high success rate is based on accurate localization of their origins. Therefore, these ECG characteristics show great importance for precise localization of their origins and subsequently successful ablation. This review aims to sum up ECG characteristics of IVAs based on anatomy and give brief introduction of mechanisms and treatment of IVAs.

OBJECTIVE: Idiopathic outflow tract ventricular arrhythmias are ventricular tachycardias or premature ventricular contractions presumably not related to myocardial scar or disorders of ion channels. These arrhythmias have focal origin and display characteristic electrocardiographic features. The purpose of this article is to review the state of the art of diagnosis and treatment of idiopathic outflow tract ventricular arrhythmias.
METHODS: We systematically reviewed scientific literature about idiopathic outflow tract ventricular arrhythmias selecting the most relevant papers on this topic.
RESULTS: The right ventricle outflow tract is the most common site of origin for outflow tract ventricular arrhythmias, but also left ventricle outflow tract can harbour these arrhythmias. Outflow tract ventricular arrhythmias are generally benign and may require treatment if they are symptomatic, incessant or give rise to cardiomyopathy. Radiofrequency catheter ablation is an effective and safe therapeutic strategy. A successful procedure requires a thorough preoperative analysis of the 12-lead electrocardiogram of the spontaneous arrhythmia combined with a detailed electroanatomical mapping and intracardiac echocardiography.
CONCLUSIONS: Idiopathic outflow tract arrhythmias are frequent in daily clinical practice and can be successfully eliminated through discrete radiofrequency catheter ablation with low rates of complications.

The slow pathway region (SPR) is commonly targeted during ablation of atrioventricular nodal reentrant tachycardia. However, its role in idiopathic ventricular arrhythmias (IVAs) remains unknown.
The purpose of this study was to describe the electrocardiographic and electrophysiological characteristics of IVAs that were successfully ablated from the SPR.
Medical records of consecutive patients undergoing ablation of IVAs in the para-Hisian region between 2010 and 2018 were reviewed to identify subjects whose ventricular arrhythmias were targeted from the SPR.
Among 63 patients with para-Hisian IVAs undergoing ablation, the SPR was targeted in 12 (20%; mean age 64 ± 7 years; 9 men). All patients presented with ventricular premature depolarizations manifesting left bundle branch block morphology with variable precordial transition (leads V2-V5) and a mean QRS duration of 131 ± 11 ms. In all cases, leads I and aVL had positive forces (R or Rs) and lead aVR had negative forces (QS or Qr). In the majority of cases, lead II had positive forces (R or Rs; n = 9 [75%]) and lead III had negative forces (rS or QS; n = 9 [75%]). Mean activation at the SPR was 31 ± 5 ms pre-QRS. All patients had initial ablation with radiofrequency, resulting in junctional rhythm in 9 (75%); 3 (25%) patients required additional cryoablation. Ablation was successful in 11 patients (92%). One patient required a permanent pacemaker for heart block but subsequently recovered intrinsic conduction.
The SPR can be a source of IVAs, which can be safely and successfully ablated in most cases using radiofrequency energy. IVAs arising from this location manifest unique electrocardiographic features.

Delayed efficacy of radiofrequency energy can suppress ventricular arrhythmias after a failed ablation procedure. The implant of cardiac defibrillator for arrhythmia-induced cardiomyopathy should be procrastinated after a period of follow-up. Waiting for delayed efficacy is a reasonable choice to reduce the risk of complications associated with aggressive ablative approaches.

Ablation of premature ventricular complexes (PVCs) originating from left ventricular outflow tract (LVOT)/left ventricular summit (LVS) is challenging with considerable rate of failure. Recently, in a novel approach to ablation of these arrythmias, application of radiofrequency energy to anatomically opposite sites of presumed origin of arrythmia, has been associated with moderate procedure success. Although late elimination of PVCs that are persistent following an ablation procedure has been previously reported, this observation has not been studied sufficiently. In this report, firstly, we present three cases of lately eliminated LVS PVCs, then, we discuss possible mechanism of this observation and conclude that after an initial failed attempt of anatomic ablation, operators may choose a period of watchful waiting before attempting a redo procedure.

Frequent premature ventricular contractions (PVCs) originating from the right ventricular outflow tract (RVOT) are usually considered a benign entity and the ECG is typically normal. The aim of this study was to assess whether upward displacement of the ECG to the second intercostal space (ICS) would reveal any abnormal pattern.
A total of 18 consecutive patients with apparently normal hearts were studied, mean age 44±16 years, 12 women, who underwent catheter ablation of the RVOT due to frequent PVCs. A 12-lead ECG was performed in the standard position and repeated in a higher position, at the level of the second ICS. Three-dimensional bipolar electroanatomical voltage mapping (EVM) was performed in all patients and low voltage areas (LVAs) were defined as areas with amplitude <1.5 mV.
The ECG in the second ICS was normal in eleven patients but in seven (39%) it revealed a pattern of ST-segment elevation in V1. EVM revealed the presence of LVAs in six patients (33%) which included the earliest activation site (EAS) in five. The ST elevation was associated with the presence of LVAs (p<0.0001) and with the LVAs at the EAS (p=0.002).
In this group of patients with apparently normal hearts and with frequent PVCs of the RVOT, upward displacement of the ECG revealed the presence of ST elevation in more than one third of patients, and the ST elevation was associated with the presence of LVAs in the RVOT.