The contribution of intracardiac echocardiography in catheter ablation of ventricular arrhythmias.

Catheter ablation is a well-established treatment option for patients with ventricular arrhythmias. Recent advances in various imaging modalities, including three-dimensional electroanatomic mapping systems, magnetic resonance imaging, transesophageal and intracardiac echocardiography (ICE) have been adopted in catheter ablation of ventricular arrhythmias improving procedural outcome and safety. ICE is an imaging tool which provides real-time visualization of anatomical structures of the heart, facilitating catheter manipulation and navigation during ablation procedures. In this review we aim to highlight the benefits of ICE use in catheter ablation of ventricular arrhythmias and to describe practical techniques for visualization of cardiac structures with ICE during ventricular tachycardia ablations.

Ablation of residual potentials along the circumferential line reduces acute pulmonary vein reconnection.

INTRODUCTION: Acute pulmonary vein (PV) reconnection is frequently encountered in patients undergoing PV isolation (PVI) procedure for the treatment of atrial fibrillation. In this study, we investigated whether the identification and ablation of residual potentials (RPs), after the initial achievement of PVI, reduces acute PV reconnection rate. METHODS: Following PVI in 160 patients, mapping along the ablation line was performed to identify RPs, defined as bipolar amplitude ≥0.2 mV or 0.1-0.19 mV combined with a negative component of the unipolar electrogram. Ipsilateral PV sets with RPs were randomized to either no further ablation (Group B) or to additional ablation of the identified RPs (Group C). The primary study endpoint was spontaneous or adenosine-mediated acute PV reconnection after a 30-min waiting period and was also evaluated in ipsilateral PV sets without RPs (Group A). RESULTS: After isolation of 287 PV pairs, 135 had no RPs (Group A), whereas the remaining PV pairs were randomized to either Group B (n = 75) or Group C (n = 77). Ablation of RPs resulted in a reduction of spontaneous or adenosine-mediated PV reconnection rate (16.9% in Group C vs 48.0% in Group B; p < 0.001). Group A was associated with a significantly lower percentage of acute PV reconnection as compared to Group B (5.9% vs 48.0%; p < 0.001) and Group C (5.9% vs 16.9%; p = 0.016). CONCLUSION: After PVI achievement, the absence of RPs along the circumferential line is associated with a low likelihood of acute PV reconnection rate. Ablation of RPs significantly reduces spontaneous or adenosine-mediated acute PV reconnection rate.