Dalzell G W, Anderson J, Adgey A A
Regional Medical Cardiology Centre, Royal Victoria Hospital, Belfast, N. Ireland.
Q J Med. 1991 Jan;78(285):85-95.
Factors thought to affect the success of and energy requirements for cardioversion of atrial fibrillation were studied in 80 (49 male, 31 female) patients aged 21-88 (mean 61.5 years). Transthoracic impedance was measured in advance of the countershock using a 30 kHz low amplitude AC current passed through self-adhesive ECG/defibrillator pads (diameters 8 and 12 cm) applied to the chest in the antero-posterior (AP) position in 57 patients and the anteroapical (AA) position in 23 patients. Mean transthoracic impedance for all patients was 69.3 +/- 16 (SD) ohms (range 39-131 ohms), but transthoracic impedance was significantly greater in the AA than the AP position (75.4 +/- 13 vs. 66.7 +/- 16 ohms, p = 0.02). Initial energy was 50 J (delivered) and was gradually increased to a maximum of 360 J if required. Cardioversion was successful in 73 of 80 (91.2 per cent), and low energy shocks (< or = 200 J) were successful in 45 of 80 (56.2 per cent) patients. Using single factor analysis, sex, left atrial enlargement, electrode pad positions, aetiology of atrial fibrillation, presence of left ventricular failure, and prior treatment with verapamil or beta-adrenergic blockers were not significant determinants of cardioversion success or success of low energy shocks but prior treatment with digoxin was, both for cardioversion success and success at low energies. In patients with transthoracic impedance < or = 70 ohms, low energy shocks were more often successful (33 of 50, 66 per cent) than in patients with transthoracic impedance > 70 ohms (12 of 30, 40 per cent), p = 0.04. Using univariate analysis, cardioversion success with low energy shocks was not only significantly associated with prior treatment with digoxin but also with the duration of atrial fibrillation (24 hours to less than one month and one month to three years) and for shocks of < or = 100 J, with prior treatment with amiodarone. Multifactorial linear regression analysis selected, in rank order, only duration of atrial fibrillation of 24 hours to less than one month and one month to three years as significant predictors of both cardioversion success irrespective of shock strength, and success of low energy shocks.
在80例年龄为21至88岁（平均61.5岁）的患者（49例男性，31例女性）中，对可能影响心房颤动复律成功率及能量需求的因素进行了研究。在电击复律前，使用30kHz低振幅交流电通过自粘性心电图/除颤器电极片（直径8和12cm）测量经胸阻抗，57例患者电极片置于胸部前后位（AP），23例患者置于心尖前位（AA）。所有患者的平均经胸阻抗为69.3±16（标准差）欧姆（范围39 - 131欧姆），但AA位的经胸阻抗显著高于AP位（75.4±13对66.7±16欧姆，p = 0.02）。初始能量为50J（释放），必要时逐渐增加至最大360J。80例患者中有73例（91.2%）复律成功，80例患者中有45例（56.2%）低能量电击（≤200J）成功。单因素分析显示，性别、左心房扩大、电极片位置、心房颤动病因、左心室衰竭的存在以及维拉帕米或β - 肾上腺素能阻滞剂的既往治疗并非复律成功或低能量电击成功的显著决定因素，但地高辛的既往治疗对复律成功及低能量复律均有影响。经胸阻抗≤70欧姆的患者中，低能量电击成功的比例（50例中的33例，66%）高于经胸阻抗＞70欧姆的患者（30例中的12例，40%），p = 0.04。单变量分析显示，低能量电击复律成功不仅与地高辛的既往治疗显著相关，还与心房颤动持续时间（24小时至不足1个月以及1个月至3年）相关，对于≤100J的电击，还与胺碘酮的既往治疗相关。多因素线性回归分析按重要性排序，仅心房颤动持续时间24小时至不足1个月以及1个月至3年是复律成功（无论电击强度如何）及低能量电击成功的显著预测因素。
