Ablation of Persistent Atrial Fibrillation Targeting Low-Voltage Areas With Selective Activation Characteristics.

BACKGROUND: Complex-fractionated atrial electrograms and atrial fibrosis are associated with maintenance of persistent atrial fibrillation (AF). We hypothesized that pulmonary vein isolation (PVI) plus ablation of selective atrial low-voltage sites may be more successful than PVI only. METHODS AND RESULTS: A total of 85 consecutive patients with persistent AF underwent high-density atrial voltage mapping, PVI, and ablation at low-voltage areas (LVA < 0.5 mV in AF) associated with electric activity lasting > 70% of AF cycle length on a single electrode (fractionated activity) or multiple electrodes around the circumferential mapping catheter (rotational activity) or discrete rapid local activity (group I). The procedural end point was AF termination. Arrhythmia freedom was compared with a control group (66 patients) undergoing PVI only (group II). PVI alone was performed in 23 of 85 (27%) patients of group I with low amount (< 10% of left atrial surface area) of atrial low voltage. Selective atrial ablation in addition to PVI was performed in 62 patients with termination of AF in 45 (73%) after 11 ± 9 minutes radiofrequency delivery. AF-termination sites colocalized within LVA in 80% and at border zones in 20%. Single-procedural arrhythmia freedom at 13 months median follow-up was achieved in 59 of 85 (69%) patients in group I, which was significantly higher than the matched control group (31/66 [47%], P < 0.001). There was no significant difference in the success rate of patients in group I with a low amount of low voltage undergoing PVI only and patients requiring PVI+selective low-voltage ablation (P = 0.42). CONCLUSIONS: Ablation of sites with distinct activation characteristics within/at borderzones of LVA in addition to PVI is more effective than conventional PVI-only strategy for persistent AF. PVI only seems to be sufficient to treat patients with left atrial low voltage < 10%.

Randomized Comparison of Different Thienopyridine Loading Strategies in Patients Undergoing Elective Coronary Intervention: The ExcelsiorLOAD Trial.

OBJECTIVES: This randomized trial investigated to what extent loading with prasugrel can provide a more rapid peri-interventional antiplatelet effect than clopidogrel 600 mg. BACKGROUND: Effective platelet inhibition at the start of a percutaneous coronary intervention (PCI) reduces the risk of ischemic complications. With clopidogrel administered immediately before a PCI, effective platelet inhibition is delayed by 2 h. Prasugrel has the potential of shortening this period. METHODS: We randomly assigned 300 P2Y12 receptor blocker-naive patients undergoing an elective PCI to loading with clopidogrel 600 mg, prasugrel 30 mg, or prasugrel 60 mg immediately before the PCI. Platelet function was assessed serially by impedance aggregometry. The primary endpoint was the proportion of patients with high on-treatment platelet reactivity at 60 min after loading defined as ≥468 aggregation units × minute (Multiplate Analyzer, Roche Diagnostics, Mannheim, Germany). RESULTS: The 3 groups were well balanced with respect to clinical and angiographic characteristics. At 60 min, 33% of the patients assigned to prasugrel 60 mg, 37% of patients assigned to prasugrel 30 mg, but 55% of those assigned to clopidogrel had high on-treatment platelet reactivity (p < 0.001). At any time point starting from 30 min, prasugrel 60 mg achieved significantly lower platelet reactivity than clopidogrel. Platelet reactivity at 60 min after prasugrel was not significantly different from that at 120 min after clopidogrel (p = 0.18). Prasugrel 30 mg had an intermediate effect. The 30-day incidence of bleeding events was not different among the 3 groups. CONCLUSIONS: From 30 min onward, prasugrel 60 mg achieved a stronger platelet inhibition than clopidogrel loading in stable patients undergoing a PCI. Compared with clopidogrel, prasugrel 60 mg was associated with a twice as fast onset of platelet inhibition. (Impact of Extent of Clopidogrel-Induced Platelet Inhibition during Elective Stent Implantation on Clinical Event Rate-Advanced Loading Strategies [ExcelsiorLOAD]; DRKS00006102).