Idiopathic ventricular outflow tract arrhythmias from the great cardiac vein: challenges and risks of catheter ablation.

INTRODUCTION: Catheter ablation for idiopathic ventricular arrhythmia is well established but epicardial origin, proximity to coronary arteries, and limited accessibility may complicate ablation from the venous system in particular from the great cardiac vein (GCV). METHODS: Between April 2009 and October 2010 14 patients (56 ± 15 years; 9 male) out of a total group of 117 patients with idiopathic outflow tract tachycardias were included undergoing ablation for idiopathic VT or premature ventricular contractions (PVC) originating from GCV. All patients in whom the PVC arose from the GCV were subject to the study. In these patients angiography of the left coronary system was performed with the ablation catheter at the site of earliest activation. RESULTS: Successful ablation was performed in 6/14 (43%) and long-term success was achieved in 5/14 (36%) patients. In 4/14 patients (28.6%) ablation was not performed. In another 4 patients (26.7%), ablation did not abolish the PVC/VT. In the majority, the anatomical proximity to the left coronary system prohibited effective RF application. In 3 patients RF application resulted in a coronary spasm with complete regression as revealed in repeat coronary angiography. CONCLUSION: A relevant proportion idiopathic VT/PVC can safely be ablated from the GCV without significant permanent coronary artery stenosis after RF application. Our data furthermore demonstrate that damage to the coronary artery system is likely to be transient.

[Catheter ablation for atrial fibrillation: clinically established or still an experimental method].

Interventional treatment for atrial fibrillation has been introduced as a therapeutic option since the pulmonary veins (PV) have been discovered as the dominant sources of paroxysmal atrial fibrillation (PAF). Elimination of PV conduction is the initial goal during catheter ablation in this setting. The success rate after the initial procedure varies between 60 and 85 %, with more than 80 % after subsequent interventions. Supported by the current guidelines, interventional treatment of AF is indicated in case of symptomatic arrhythmias refractory to antiarrhythmic treatment. The introduction of the combined, stepwise approach has been another important breakthrough with regard to the treatment of chronic persistent atrial fibrillation (CAF). This strategy includes the combination of all conventional ablation strategies (PV isolation, ablation of complex fractionated atrial electrograms, linear ablation) with the goal of AF termination. The first procedure for CAF treatment is quite frequently also only the first step towards stable sinus rhythm with a favourable outcome after AF termination (> 80 % sinus rhythm). In more than half of the patients predominantly other atrial arrhythmias than AF have to be targeted in a second procedure. This approach is currently under clinical investigation and so far not "clinically established" due to the fact that it is a quite time consuming and challenging procedure even in experienced centres. Future studies may help to identify predictors for procedure failure (e.g. LA size, AF duration, atrial cycle length, spectral analysis) in order to improve patient selection. Additionally, it has to be underscored, that in paroxysmal atrial fibrillation the relatively high recurrence rate after the first procedure still is the subject of further investigations. This aspect might be improved by the introduction of novel strategies (i.e. testing of concealed PV conduction after ablation with adenosine) or new technologies (i.e. robotic navigation) for PAF ablation.

[Interventional therapy of atrial fibrillation: possibilities and limitations]. / Möglichkeiten und Grenzen der interventionellen Therapie von Vorhofflimmern.

Recently, significant progress has been made treating atrial fibrillation (AF) with catheter ablation emerging as an increasingly important technique. Electrical disconnection of the pulmonary veins (PV) is a widely accepted endpoint for interventional treatment of paroxysmal AF (PAF). According to the current guidelines, catheter ablation can be considered as a therapeutic option in patients who failed antiarrhythmic drug treatment for PAF. The procedural endpoint for PVI is achievement of permanent electrical isolation of the PVs, which in the vast majority of patients harbor triggered electrical activity inducing and maintaining PAF. The success rate of this approach in patients with PAF ranges between 60 and 80% after a single procedure and augments to > 80 % in patients undergoing a repeat procedure to abolish recovered PV connection. However, it is now evident that persistent or long-standing persistent AF may not be successfully treated by PVI alone since the majority of patients have AF maintaining substrate beyond the PV. From a pathophysiological perspective this is explained by structural and electrical remodeling of the atrial myocardium in patients with persistent AF. Therefore, it is today widely accepted that additional substrate modification is required to effectively address persistent AF using catheter ablation. It has been shown that a combined approach of PV isolation, ablation of fractionated atrial electrograms and application of lines to treat atrial macro-reentrant tachycardias ("stepwise approach") aiming for restoration of sinus rhythm is a favorable strategy to treat persistent AF. However, significant expertise is needed to accomplish all steps within these complex procedures. Therefore, catheter ablation for persistent AF cannot yet be considered "clinically established" and should only be performed in high volume centers. Additional data is needed to verify the beneficial effect of this strategy and determine "predictors" identifying patients profiting most from these ablation strategies. In patients with PAF, catheter ablation has emerged as an established therapy also in comparison to antiarrythmic drug treatment. Recent studies have shown that catheter ablation for PAF is superior to antiarrhythmic drug treatment with regard to mid-term suppression of any atrial arrhythmia. Overall, catheter ablation for AF has still to be considered as a symptomatic treatment since evidence for beneficial effects with regard to more robust clinical endpoints such as death, rehospitalization and ischemic cerebral events are not yet available.

[Surface ECG presentation and intracardiac electrogram characteristics of uncommon supraventricular tachycardia entities]. / Differenzialdiagnose ungewöhnlicher Elektrogramme - vom Oberflächen-EKG zur elektrophysiologischen Diagnose.

The vast majority of patients with supraventricular tachycardias present with specific 12-lead surface ECG characteristics allowing the diagnosis of the underlying mechanisms prior to the invasive electrophysiological study. However, an accurate diagnosis remains challenging in a subset of patients, even when using well-established stimulation maneuvers and sophisticated conventional mapping methods. Thus, the aim of the present manuscript is to describe some cases with uncommon entities of supraventricular tachycardias where the combined interpretation of 12-lead ECG presentation and invasive electrophysiological characteristics revealed the correct diagnoses.