Background: High power ultra-short duration (HPUSD) ablation has been advocated to prevent esophageal injuries during atrial fibrillation (AF) ablation procedures. Prior research using the standard circular mapping catheter (CMC) has shown that ultra-short ablations may compromise lesion durability resulting in an increased need for redo procedures. The purpose of this study was to determine if HD mapping of concealed pulmonary vein (PV) connections could improve freedom from atrial fibrillation and redo procedures compared to CMC guided AF ablation. Methods: A total of 472 consecutive first time AF ablation procedure patients with at least one year of follow up were includedwith an average follow-up of 18 months. HPUSD AF ablation consisted of 50 W for 2-3 seconds on the posterior wall and 5-15 seconds on the anterior wall of the left atrium. Acute pulmonary vein isolation (PVI) was defined as no concealed 1) PV signals, 2) activation into PVs, or 3) voltage into PVs with no intra-procedural waiting period utilizing the HD Grid catheter versus entrance/exit block with a 30-minute wait with the circular mapping catheter. Freedom from atrial fibrillation and all atrial arrhythmias following a 90-day blanking period were assessed. Results: Acute pulmonary vein isolation was achieved in all 472 patients. HPUSD ablation using the HD Grid was associated with shorter procedure (70.2 vs 104.3 minutes, p<0.001) and fluoroscopy times (4.2 vs 15.0 minutes, p<0.001) when compared to CMC. The recurrence of any atrial arrhythmias at 1 year was 13% with HD Grid and 25% with CMC (p<0.001) with the need for redo procedures of 6% for HD Grid and 20% for CMC (p<0.001). No esophageal ulcerations/perforations were seen. No deaths, strokes, or TIAs were observed in either group. Conclusion: HPUSD AF Ablation, as guided by HD Grid mapping, may prevent esophageal injuries while at the same time improve freedom from any atrial arrhythmias and the need for redo procedures. Procedure and fluoroscopy times were also significantly decreased when compared to traditional CMC mapping.