Background. Limited data exist regarding left atrial appendage (LAA) thrombi and spontaneous echocardiographic contrast (SEC) in patients with atrial flutter (AFL). Objectives. We sought to evaluate the LAA thrombi prevalzence in AFL ablation patients compared to atrial fibrillation (AFib) ablation patients. Methods and Results. 321 consecutive patients referred for either AFib (n = 229) or AFL ablation (n = 92) were included with a thrombus detected by transesophageal echocardiography (TEE) in 3.22% (12/321). The percentage of thrombi was similar between AFL and AFib ablation patients (5.4% [n = 5/92] vs. 3.1% [n = 7/229]; p = 0.3). In the overall population, LAA thrombi patients had a higher CHA²DS²-VASc score (3 ± 2 vs. 2 ± 1.5; p = 0.048) and a higher presence of valvular prothesis (25% vs. 4.9%; p=0.003), with relevant left atrial remodeling such as demonstrated by a higher left atrium (LA) volume (57 ± 19 vs. 46 ± 17 ml/m²; p = 0.04) and a lower LAA velocity (0.41 ± 0.3 vs. 0.55 ± 0.2; p=0.04). In patients with right AFL, patients with LAA thrombi had a higher CHA²DS²-VASc score (4.4 ± 1 vs. 2.5 ± 1.5; p = 0.008), had more hypertension (100% vs. 53%; p = 0.04) and more diabetes mellitus (60% vs. 18.4%; p = 0.03), and a more severe LAA echo contrast (80% vs. 5.7%; p <0.0001). Conclusions. The risk of LAA thrombi is better related to the presence of valvular prosthesis, CHA²DS²-VASc score and LA remodelling than the atrial arrhythmia itself.

Background. Scar-related atrial tachycardias (ATs) are very challenging and no comparative studies have been conducted between the up-to-date systems, namely the new Confidense HD coloring mapping module (HD) and the new Rhythmia (RM) mapping system. Objectives. Our study sought to compare both strategies in terms of: (1) diagnosis and immediate treatment success: (2) procedure parameters in AT presenting patients. Methods and Results. Overall, 38 patients (68±9 years old) were randomized (HD=20, RM=18). The AT mechanisms did not differ between the groups: macro/small loop reentrant mechanisms were more common in both groups (12/20 [60%] versus 10/18 [56%], P=0.9), with the remaining diagnosed as multiloop (5/20 [25%] versus 4/18 [22%]; p=0.9); focal (1/20 [5%] versus 2/18 [11%], P=0.9), and localized reentrant (2/20 [10%] versus 2/18 [11%]). The procedure parameters were as follows: tachycardia cycle length (275±30 vs. 280±50; p=0.7); number of activation maps per patient (2±1 vs 2±1; p=0.9); procedure time (138±90 vs. 139±90 min; p=0.98); X-ray time exposure (20±11 vs. 24±18 min; p=0.42); RF application time (39±36 vs. 25±28 min; p=0.21); and mean number of circuits per patient (1.8±1 vs. 1.6±0.9; 0.6). Acute success was obtained in 15/20 pts (75%) of the HD group and 14/18 (78%) of the RM group (p=0.9). The procedure failed in 2 patients with the HD coloring and they were converted to the RM group without success. No crossover was carried out in the RM group. Conclusions. This randomized study demonstrates that HD coloring and Rhythmia systems exhibit a similar efficacy in achieving acute AT termination.