Department of Cardiology, Sint-Jan Hospital, Ruddershove 10, 8000 Bruges, Belgium.
Department of Advanced Biomedical Sciences, University of Naples Federico II, Italy.
Europace. 2020 Aug 1;22(8):1189-1196. doi: 10.1093/europace/euaa071.
The relation between atrial tachyarrhythmia (ATA) burden in paroxysmal atrial fibrillation (AF), atrial remodelling, and efficacy of catheter ablation (CA) is unknown. We investigated whether high vs. low-burden paroxysmal AF patients have distinct clinical characteristics or electro-mechanical properties of the left atrium (LA) and whether burden impacts outcome of CA.
Atrial tachyarrhythmia burden, defined as the percentage of time spent in ATA, was assessed by insertable cardiac monitors in 105 patients before and after CA. Clinical characteristics and electro-mechanical properties of LA were compared between patients with high vs. low ATA burden. Catheter ablation efficacy was assessed by reduction in ATA burden and 1-year freedom from any ATA. Median ATA burden was 2.7% (highest tertile 9.3%). Clinical characteristics and electrical properties of LA (refractoriness, conduction velocity, low voltage) did not differ between high (≥9.3%) vs. low ATA burden (<9.3%) patients. High ATA burden patients had larger LA diameter (46.5 ± 6 vs. 42.5 ± 6mm, P < 0.01), volume (93.8 ± 22 vs. 80.4 ± 21mL, P = 0.01), and lower LA reservoir and contractile strain (19.7 ± 6 vs. 24.7 ± 6%, P < 0.01; 10.3 ± 3 vs. 12.8 ± 4%, P = 0.01). Catheter ablation reduced ATA burden by 100% (100-100) in both groups (P = 1.0). Freedom from ATA after CA was equally high (83% vs. 89%, P = 0.38).
Paroxysmal AF patients with high ATA burden have altered LA mechanical properties, reflected by larger size and impaired function. Despite mechanical remodelling of the atria, they are excellent responders to CA. Most likely the lack of fibrosis and/or advanced electrical remodelling explain why pulmonary veins remain the dominant trigger for AF in this patient cohort.
阵发性心房颤动（AF）中房性心动过速（ATA）负荷与心房重构以及导管消融（CA）疗效之间的关系尚不清楚。我们研究了高与低阵发性 AF 患者是否具有不同的临床特征或左心房（LA）的电机械特性，以及负荷是否会影响 CA 的结果。
通过可植入心脏监测器在 105 例 CA 前后评估房性心动过速负荷，定义为 ATA 时间百分比。比较高与低 ATA 负荷患者之间的 LA 临床特征和电机械特性。通过 ATA 负荷降低和 1 年无任何 ATA 自由来评估 CA 的疗效。ATA 负荷中位数为 2.7%（最高三分位数为 9.3%）。高（≥9.3%）与低（<9.3%）ATA 负荷患者之间的临床特征和 LA 电特性（不应期、传导速度、低电压）无差异。高 ATA 负荷患者的 LA 直径更大（46.5±6 与 42.5±6mm，P<0.01）、容积更大（93.8±22 与 80.4±21mL，P=0.01）、LA 储备和收缩应变更低（19.7±6 与 24.7±6%，P<0.01；10.3±3 与 12.8±4%，P=0.01）。两组均通过 CA 降低 ATA 负荷 100%（100-100）（P=1.0）。CA 后 ATA 无复发率也一样高（83%与 89%，P=0.38）。
高 ATA 负荷的阵发性 AF 患者具有改变的 LA 机械特性，表现为更大的大小和受损的功能。尽管心房发生了重塑，但它们对 CA 的反应良好。很可能缺乏纤维化和/或晚期电重塑解释了为什么在这一患者群体中肺静脉仍然是 AF 的主要触发因素。
