Safety of pulmonary vein isolation and left atrial complex fractionated atrial electrograms ablation for atrial fibrillation with phased radiofrequency energy and multi-electrode catheters.

AIMS: Recently, a multi-electrode catheter system using phased radiofrequency (RF) energy was developed specifically for atrial fibrillation (AF) ablation: the pulmonary vein ablation catheter (PVAC), the multi-array septal catheter (MASC), and the multi-array ablation catheter (MAAC). Initial results of small trials have been promising: shorter procedure times and low adverse event rates. In a large single-centre registry, we evaluated the adverse events associated with multi-electrode ablation catheter procedures with PVAC alone, or combined with MASC and MAAC. METHODS AND RESULTS: In all, 634 consecutive patients with AF had 663 procedures with multi-electrode ablation catheters, 502 patients with the PVAC alone, 128 patients with PVAC/MASC/MAAC, 29 redo procedures with the PVAC or PVAC/MASC/MAAC, and 4 patients had a complicated transseptal puncture. Major and minor adverse events during 6 month follow-up were registered. In 15 cases (2.3%), major adverse events were seen within the first month after the procedure. These included complicated transseptal puncture (4), stroke (2), transient ischaemic attack (5), acute coronary syndrome (2), femoral pseudoaneurysm (1), and arteriovenous fistulae (1). Minor adverse events were seen in 10.7% at 6 months, mostly due to femoral haematoma (3.9%), and non-significant PV stenosis (5.2%). There was no difference in the occurrence of major adverse events between PVAC alone, or PVAC/MASC/MAAC ablation. CONCLUSION: Ablation with phased RF and multi-electrode catheters is accompanied by a major adverse event rate of 2.3% within 1 month and a minor event rate of 10.7% at 6 months.

Pulmonary vein isolation and left atrial complex-fractionated atrial electrograms ablation for persistent atrial fibrillation with phased radio frequency energy and multi-electrode catheters: efficacy and safety during 12 months follow-up.

AIMS: Ablation for persistent atrial fibrillation (AF) remains a difficult and time-consuming procedure with varying degrees of success. We evaluated the long-term effects of a novel approach for ablation of persistent AF using multi-electrode catheters. METHODS AND RESULTS: In 89 patients with longstanding persistent AF (>1 year), multi-electrode ablation was performed with a pulmonary vein ablation catheter (PVAC), a multi-array septal catheter (MASC), and a multi-array ablation catheter (MAAC) for ablation of complex-fractionated atrial electrograms (CFAE) at the septum, left atrial (LA) roof, floor, posterior wall, and mitral isthmus. Follow-up was performed at 6 and 12 months with electrocardiogram, 7 days Holter, and occasionally ambulant event recordings. Average procedure and fluoroscopy times were 112 ± 32 and 21 ± 10 min. The pre-specified endpoint of pulmonary vein isolation and LA CFAE ablation was reached in all patients. No procedural complications were observed. At 12 months after a single treatment 44 of 89 (49%) remained in sinus rhythm, including direct current cardioversion in 12 patients. At 12 months, after a redo PVAC/MASC/MAAC, an additional 6 of 15 patients (40%) were free of AF. In 18 of 89 (20%) patients AF was changed to paroxysmal. CONCLUSIONS: In this single centre study, ablation for longstanding persistent AF with the PVAC/MASC/MAAC resulted in 56% freedom of AF at 1 year after 1.2 ± 0.4 procedures. This approach is time efficient and has a favourable safety profile.

Identification of successful catheter ablation sites in patients with ventricular tachycardia based on electrogram characteristics during sinus rhythm.

BACKGROUND: Zones of slow conduction facilitate reentry, the major mechanism of ventricular tachycardia (VT) after myocardial infarction (MI). Identification of these zones during sinus rhythm (SR) is desirable for radiofrequency (RF) catheter ablation of VT. Local conduction velocity may correlate with electrogram duration. OBJECTIVES: The purpose of this study was to revise the definition of normal electrogram characteristics and to reevaluate the significance of low-amplitude, long-duration electrograms recorded during SR to select RF catheter ablation sites in patients with VT. METHODS: Electroanatomic mapping was performed during SR in 10 control patients with normal left ventricles (LVs) and in 10 patients with stable VT after MI. From the controls, reference values for electrogram amplitude, duration (first peak to last peak distance), and fragmentation (positive deflection) were derived. In patients after MI, areas with signals exceeding these values were annotated and related to successful ablation sites. RESULTS: Ninety-five percent of normal LV electrograms were > or =1.0 mV and < or =28 ms (range 5-39 ms) and all had < or =4 deflections. Based on these results, cutoff values were set at 1 mV, four deflections, and 40 ms. In infarcted hearts, 653 electrograms (44%) were <1.0 mV and of these, 303 were > or =40 ms with >4 deflections and restricted to circumscribed areas. Twenty-seven of 28 targeted VTs remained noninducible after RF catheter ablation within these areas, resulting in 86% sensitivity and 94% specificity for low-amplitude, long-duration electrograms predicting successful ablation sites. CONCLUSION: Identification of successful RF target areas during SR in patients with VT is feasible with high sensitivity and specificity using a mapping strategy based on voltage and duration criteria.