Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China.
Heart Rhythm. 2013 Mar;10(3):428-35. doi: 10.1016/j.hrthm.2012.11.019. Epub 2012 Nov 24.
We studied the effects of transcutaneous electrical stimulation at the tragus, the anterior protuberance of the outer ear, for inhibiting atrial fibrillation (AF).
To develop a noninvasive transcutaneous approach to deliver low-level vagal nerve stimulation to the tragus in order to treat cardiac arrhythmias such as AF.
In 16 pentobarbital anesthetized dogs, multielectrode catheters were attached to pulmonary veins and atria. Three tungsten-coated microelectrodes were inserted into the anterior right ganglionated plexi to record neural activity. Tragus stimulation (20 Hz) in the right ear was accomplished by attaching 2 alligator clips onto the tragus. The voltage slowing the sinus rate or atrioventricular conduction was used as the threshold for setting the low-level tragus stimulation (LL-TS) at 80% below the threshold. At baseline, programmed stimulation determined the effective refractory period (ERP) and the window of vulnerability (WOV), a measure of AF inducibility. For hours 1-3, rapid atrial pacing (RAP) was applied alone, followed by concomitant RAP+LL-TS for hours 4-6 (N = 6). The same parameters were measured during sinus rhythm when RAP stopped after each hour. In 4 other animals, bivagal transection was performed before LL-TS.
During hours 1-3 of RAP, there was a progressive and significant decrease in ERP, increase in WOV, and increase in neural activity vs baseline (all P < .05). With RAP+LL-TS during hours 4-6, there was a linear return of ERP, WOV, and neural activity toward baseline levels (all P < .05, compared to the third-hour values). In 4 dogs, bivagal transection prevented the reversal of ERP and WOV despite 3 hours of RAP+LL-TS.
LL-TS can reverse RAP-induced atrial remodeling and inhibit AF inducibility, suggesting a potential noninvasive treatment of AF.
我们研究了经耳甲(transcutaneous electrical stimulation at the tragus)刺激外侧耳前突对抑制心房颤动(atrial fibrillation, AF)的作用。
开发一种非侵入性的经皮方法，将低水平迷走神经刺激传递到耳甲(tragus)，以治疗 AF 等心律失常。
在 16 只戊巴比妥钠麻醉的狗中，将多电极导管附着在肺静脉和心房上。将三根涂有钨的微电极插入前右神经节丛以记录神经活动。通过将两个鳄鱼夹夹在耳甲上来实现右耳的耳甲刺激(tragus stimulation, TS)。将减慢窦性心率或房室传导的电压用作设置低水平耳甲刺激(low-level tragus stimulation, LL-TS)的阈值，设定为阈值的 80%以下。在基线时，程控刺激确定有效不应期(effective refractory period, ERP)和易损窗口(window of vulnerability, WOV)，这是 AF 可诱导性的一个指标。在第 1-3 小时，仅应用快速心房起搏(rapid atrial pacing, RAP)，然后在第 4-6 小时同时应用 RAP+LL-TS (n = 6)。在每个小时结束时 RAP 停止后，在窦性节律下测量相同的参数。在另外 4 只动物中，在进行 LL-TS 之前进行双迷走神经切断术。
在 RAP 的第 1-3 小时期间，与基线相比，ERP 逐渐显著降低，WOV 增加，神经活动增加(P <.05)。在第 4-6 小时应用 RAP+LL-TS 时，ERP、WOV 和神经活动线性回归至接近基线水平(P <.05，与第 3 小时值相比)。在 4 只狗中，尽管进行了 3 小时的 RAP+LL-TS，但双迷走神经切断术阻止了 ERP 和 WOV 的逆转。
LL-TS 可以逆转 RAP 诱导的心房重构并抑制 AF 的可诱导性，提示 AF 的一种潜在非侵入性治疗方法。
