The epicardial outflow tract can be a site of origin of idiopathic ventricular arrhythmias. These arrhythmias are most commonly perivalvular and can be targeted from within the coronary venous system or from other adjacent structures, such as the right ventricular and left ventricular outflow tracts or the coronary cusp region. The authors report a case of an epicardial idiopathic outflow tract premature ventricular contraction originating from the midseptal epicardial left ventricle. In this case, direct epicardial access was crucial to identify early local activation and achieve successful catheter ablation.

Catheter ablation of ventricular tachycardia (VTs) has emerged as an effective treatment modality. Ablation procedures for idiopathic VTs depends on the anatomical origin of the arrhythmias, is highly effective in certain cases, and has been implemented as a first-line therapy in recent European guidelines. In contrast, catheter ablation of VTs in patients with structural heart disease has a significant risk of arrhythmia recurrence. Interventional treatment for patients with ischemic cardiomyopathy was studied in multiple randomized multicenter trials and it was shown that catheter ablation was more effective in arrhythmia suppression compared to conservative treatment modalities. Catheter ablation of nonischemic cardiomyopathy suffers from far higher rates of arrhythmia recurrences as documented in several long-term studies and often needs complex procedures with or without epicardial mapping and ablation. There is still no clear proof of a mortality benefit from catheter ablation of VTs in patients with or without structural heart disease. Nevertheless, recent guidelines recommend catheter ablation as an alternative to implantation of cardioverter-defibrillators (ICD) in selected cases.
UNASSIGNED: Die Katheterablation von Kammertachykardien hat sich in den letzten Jahren durch zunehmende Erfahrung und technologische Fortschritte zu einer effektiven Behandlungsmodalität entwickelt. Die Katheterablation idiopathischer Kammertachykardien ist auch im Langzeitverlauf in Abhängigkeit der anatomischen Zielregion teils hocheffektiv und daher in bestimmten Fällen als Erstlinientherapie in den aktuellen Leitlinien der Fachgesellschaften verankert. Die Katheterablation bei Patienten mit Kammertachykardien und struktureller Herzerkrankung hat deutlich eingeschränkte Erfolgsaussichten. Die Katheterablation bei Patienten mit ischämischer Kardiomyopathie ist in mehreren randomisierten multizentrischen Studien evaluiert. Bei diesen Patienten konnte eine signifikant höhere Effektivität zur Reduktion von Arrhythmierezidiven durch die Ablation im Vergleich zu konservativen Behandlungen nachgewiesen werden. Die Katheterablation bei Patienten mit nichtischämischer Kardiomyopathie ist insbesondere im Langzeitverlauf mit hohen Rezidivraten vergesellschaftet. Der sichere Nachweis eines Mortalitätsbenefits durch die Katheterablation konnte bislang nicht erbracht werden. Die Ablation kann somit auch nur in Ausnahmefällen als Alternative zur Implantation eines Kardioverter-Defibrillators (ICD) gesehen werden.

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.

Ventricular arrhythmias present with a wide spectrum of clinical manifestations, from mildly symptomatic frequent premature ventricular contractions to life-threatening events. Pathophysiologically, idiopathic ventricular arrhythmias occur in the absence of structural heart disease or ion channelopathies. Ventricular arrhythmias in the context of structural heart disease are usually determined by scar-related reentry and are associated with increased mortality. Catheter ablation is safe and highly effective in treating ventricular arrhythmias. The proper characterization of the arrhythmogenic substrate is essential for accurate procedural planning. We provide an overview on the main mechanisms of ventricular arrhythmias and their implications for catheter ablation.

Previous studies have reported the presence of subtle abnormalities in the right ventricular outflow tract (RVOT) in patients with apparently normal hearts and ventricular arrhythmias (VAs) from the RVOT, including the presence of low voltage areas (LVAs). This LVAs seem to be associated with the presence of ST-segment elevation in V1 or V2 leads at the level of the 2nd intercostal space (ICS).
Our aim was to validate an electrocardiographic marker of LVAs in the RVOT in patients with idiopathic outflow tract VAs.
A total of 120 patients were studied, 84 patients referred for ablation of idiopathic VAs with an inferior axis by the same operator, and a control group of 36 patients without VAs. Structural heart disease including arrhythmogenic right ventricular cardiomyopathy was ruled out in all patients. An electrocardiogram was performed with V1-V2 at the 2nd ICS, and ST-segment elevation ≥1 mm and T-wave inversion beyond V1 were assessed. Bipolar voltage map of the RVOT was performed in sinus rhythm (0.5-1.5 mV color display). Areas with electrograms <1.5 mV were considered LVAs, and their presence was assessed. We compared three groups, VAs from the RVOT (n = 66), VAs from the LVOT (n = 18) and Control group (n = 36). ST-elevation, T-wave inversion and left versus right side of the VAs were tested as predictors of LVAs, respective odds ratio (ORs) (95% confidence interval [CI]) and p values, were calculated with univariate logist regression. Variables with a p < .005 were included in the multivariate analysis.
ST-segment elevation, T-wave inversion and LVAs were present in the RVOT group, LVOT group and Control group as follows: (62%, 17%, and 6%, p < .0001), (33%, 29%, and 0%, p = .001) and (62%, 25%, and 14%, p < .0001). The ST-segment elevation, T-wave inversion and right-sided VAs were all predictors of LVAs, respective unadjusted ORs (95% CI), p values were, 32.31 (11.33-92.13), p < .0001, 4.137 (1.615-10.60), p = .003 and 8.200 (3.309-20.32), p < .0001. After adjustment, the only independent predictor of LVAs was the ST-segment elevation, with an adjusted OR (95% CI) of 20.94 (6.787-64.61), p < .0001.
LVAs were frequently present in patients with idiopathic VAs. ST-segment elevation was the only independent predictor of their presence.

Idiopathic ventricular arrhythmias (VA) are common and treatment options include anti-arrhythmic drugs (AAD) or catheter ablation. Patients presenting with idiopathic VA which is originating from the left ventricular summit (LVS) poses a particular challenge as the success for catheter ablation is low and AAD\'s may not be used long-term due to side effects. Ivabradine is an inhibitor of funny current (If) in cardiac pacemaker cells by blocking hyperpolarization-activated cyclic nucleotide-gated (HCN). In the present case, we reported the use of ivabradine in treatment of idiopathic VA which was originated from LVS and was resistant to multiple AAD\'s and catheter ablation.

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.