University of Kentucky, Lexington, Kentucky; Lexington VA Medical Center, Lexington, Kentucky.
J Cardiovasc Electrophysiol. 2013 Sep;24(9):995-1001. doi: 10.1111/jce.12174. Epub 2013 May 23.
Adenosine-induced hyperpolarization may identify pulmonary veins at risk of reconnection following electrical isolation for atrial fibrillation. The potential role of adenosine testing in other arrhythmic substrates, such as cavotricuspid isthmus (CTI)-dependent atrial flutter, remains unclear. We assessed whether dormant conduction across the CTI may be revealed by adenosine after ablation-induced bidirectional block, and its association with recurrent flutter.
Patients undergoing catheter ablation for CTI-dependent flutter were prospectively studied. After confirming bidirectional block across the CTI by standard pacing maneuvers, adenosine (≥ 12 mg IV) was administered to assess resumption of conduction, followed by isoproterenol (ISP) bolus. Further CTI ablation was performed for persistent (but not transient) resumption of conduction. Bidirectional block across the CTI was achieved in all 81 patients (63 males), age 61.2 ± 11.0 years. The trans-CTI time increased from 71.9 ± 18.1 milliseconds preablation to 166.2 ± 26.4 milliseconds postablation. Adenosine elicited resumption of conduction across the CTI in 7 patients (8.6%), 2 of whom had transient recovery. No additional patient with dormant conduction was identified by ISP. Over a follow-up of 11.8 ± 8.0 months, atrial flutter recurred in 4 (4.9%) patients, 3/7(42.9%) with a positive adenosine challenge versus 1/74 (1.3%) with a negative response, P = 0.0016 (relative risk 31.7).
Adenosine challenge following atrial flutter ablation provoked transient or persistent resumption of conduction across the CTI in almost 9% of patients and identified a subgroup at higher risk of flutter recurrence. It remains to be determined whether additional ablation guided by adenosine testing during the index procedure may further improve procedural outcomes.
腺苷诱导的超极化作用可能有助于识别在心房颤动进行电隔离后有重新连接风险的肺静脉。腺苷检测在其他心律失常基质（如三尖瓣峡部依赖性心房扑动）中的潜在作用尚不清楚。我们评估了在消融诱导的双向阻滞后，腺苷是否可以揭示三尖瓣峡部（CTI）内的休眠传导，以及其与复发性扑动的关系。
前瞻性研究了接受 CTI 依赖性扑动导管消融的患者。在通过标准起搏操作确认 CTI 内双向阻滞后，给予腺苷（≥12mgIV）以评估传导的恢复情况，然后给予异丙肾上腺素（ISP）推注。对于持续（而非短暂）传导恢复的患者进行进一步的 CTI 消融。所有 81 例（63 例男性）患者的 CTI 均实现了双向阻滞，年龄为 61.2±11.0 岁。消融前 CTI 时间为 71.9±18.1ms，消融后增加至 166.2±26.4ms。腺苷在 7 例（8.6%）患者中引起 CTI 内传导恢复，其中 2 例为短暂恢复。ISP 未发现其他具有休眠传导的患者。在 11.8±8.0 个月的随访中，4 例（4.9%）患者出现心房扑动复发，7 例中有腺苷阳性反应的患者中有 3 例（42.9%）复发，74 例中有腺苷阴性反应的患者中有 1 例（1.3%）复发，P=0.0016（相对风险 31.7）。
心房扑动消融后，腺苷激发试验几乎可使近 9%的患者 CTI 内传导短暂或持续恢复，并确定了一组复发扑动风险较高的患者。尚不确定在指数手术期间，是否可以通过腺苷检测指导进一步消融来进一步改善手术结果。
