Peter Munk Cardiac Center, Division of Cardiology, Toronto General Hospital, University Health Network, Toronto, Canada.
Sunnybrook Health Sciences Center, Division of Cardiology, University Health Network, Toronto, Canada.
J Cardiovasc Electrophysiol. 2021 Jun;32(6):1572-1583. doi: 10.1111/jce.14999. Epub 2021 Mar 19.
An important substrate for atrial fibrillation (AF) is fibrotic atrial myopathy. Identifying low voltage, myopathic regions during AF using traditional bipolar voltage mapping is limited by the directional dependency of wave propagation. Our objective was to evaluate directionally independent unipolar voltage mapping, but with far-field cancellation, to identify low-voltage regions during AF.
In 12 patients undergoing pulmonary vein isolation for AF, high-resolution voltage mapping was performed in the left atrium during sinus rhythm and AF using a roving 20-pole circular catheter. Bipolar electrograms (EGMs) (Bi) < 0.5 mV in sinus rhythm identified low-voltage regions. During AF, bipolar voltage and unipolar voltage maps were created, the latter with (uni-res) and without (uni-orig) far-field cancellation using a novel, validated least-squares algorithm.
Uni-res voltage was ~25% lower than uni-orig for both low voltage and normal atrial regions. Far-field EGM had a dominant frequency (DF) of 4.5-6.0 Hz, and its removal resulted in a lower DF for uni-orig compared with uni-res (5.1 ± 1.5 vs. 4.8 ± 1.5 Hz; p < .001). Compared with Bi, uni-res had a significantly greater area under the receiver operator curve (0.80 vs. 0.77; p < .05), specificity (86% vs. 76%; p < .001), and positive predictive value (43% vs. 30%; p < .001) for detecting low-voltage during AF. Similar improvements in specificity and positive predictive value were evident for uni-res versus uni-orig.
Far-field EGM can be reliably removed from uni-orig using our novel, least-squares algorithm. Compared with Bi and uni-orig, uni-res is more accurate in detecting low-voltage regions during AF. This approach may improve substrate mapping and ablation during AF, and merits further study.
心房颤动（AF）的一个重要基质是纤维性心房肌病。在 AF 期间使用传统的双极电压图来识别低电压、肌病区域受到波传播方向依赖性的限制。我们的目的是评估具有远场消除功能的独立单极电压图，以在 AF 期间识别低电压区域。
在 12 例行 AF 肺静脉隔离的患者中，在窦性心律和 AF 期间使用游动 20 极圆形导管在左心房进行高分辨率电压图描记。窦性心律时双极电图（EGM）（Bi）<0.5 mV 识别出低电压区域。在 AF 期间，创建双极电压和单极电压图，后者使用一种新颖的、经过验证的最小二乘法算法具有（uni-res）和没有（uni-orig）远场消除功能。
低电压和正常心房区域的 uni-res 电压比 uni-orig 低约 25%。远场 EGM 的主导频率（DF）为 4.5-6.0 Hz，去除后 uni-orig 的 DF 低于 uni-res（5.1±1.5 与 4.8±1.5 Hz；p<0.001）。与 Bi 相比，uni-res 的接收者操作特征曲线下面积显著增大（0.80 与 0.77；p<0.05）、特异性（86%与 76%；p<0.001）和阳性预测值（43%与 30%；p<0.001），用于在 AF 期间检测低电压。uni-res 与 uni-orig 相比，特异性和阳性预测值的改善也很明显。
可以使用我们的新型最小二乘法算法从 uni-orig 中可靠地去除远场 EGM。与 Bi 和 uni-orig 相比，uni-res 在 AF 期间检测低电压区域更准确。这种方法可能会改善 AF 期间的基质标测和消融，并值得进一步研究。
