Mitchell L B, Hubley-Kozey C L, Smith E R, Wyse D G, Duff H J, Gillis A M, Horacek B M
Department of Medicine, University of Calgary, Alberta, Canada.
Circulation. 1992 Aug;86(2):383-93. doi: 10.1161/01.cir.86.2.383.
Body surface maps of net QRST deflection areas (isointegrals) reflect regional ventricular repolarization properties. Vulnerability to ventricular tachyarrhythmias is associated with maps that feature multiple islands (extrema) of positive and negative values; such maps reflect regional disparity of ventricular recovery properties. The value of body surface mapping in prediction of the efficacy of antiarrhythmic therapy for ventricular tachyarrhythmias has not been determined.
Isointegral ECG body surface mapping was performed in 51 patients with inducible ventricular tachycardia having programmed stimulation studies at baseline and after oral quinidine therapy. The degree of nondipolarity of QRST isointegral distribution was expressed by the number of extrema and by the percentage contribution of nondipolar eigenvectors after Karhunen-Loeve transformation. QRST isointegral nondipolarity was greater in ventricular tachycardia patients than in 51 age- and sex-matched normal subjects expressed as mean number of extrema (4.1 +/- 2.8 versus 2.0 +/- 0.2, respectively), mean eigenvector-determined nondipolar content percentages (12.4 +/- 10.1% versus 4.5 +/- 4.9%), prevalence of abnormal numbers of extrema (63% versus 4%), or prevalence of abnormal nondipolar content percentages (33% versus 4%) (each p less than 0.01). Quinidine prevented ventricular tachycardia induction in 14 patients. Patients for whom quinidine was or was not effective had similar nondipolarity indexes at baseline. However, maps on quinidine differed as a function of antiarrhythmic efficacy. Although effective therapy produced no significant mean changes in nondipolarity, ineffective therapy increased the number of extrema compared with baseline (5.4 +/- 3.4 versus 3.8 +/- 2.5, respectively) (p = 0.002). Individually, 43% of patients on effective therapy had drug-induced decreases in numbers of extrema compared with 14% of those on ineffective therapy (p = 0.02). Furthermore, 29% of patients on effective therapy showed drug-induced increases in numbers of extrema compared with 62% of those on ineffective therapy (p = 0.03).
QRST isointegral body surface mapping shows promise as a noninvasive measure of drug efficacy in patients with ventricular tachycardia.
净QRST偏移区域（等积分）的体表图反映了局部心室复极特性。室性快速心律失常的易感性与具有多个正负值岛（极值）的图相关；此类图反映了心室恢复特性的局部差异。体表标测在预测抗心律失常治疗对室性快速心律失常疗效方面的价值尚未确定。
对51例可诱发室性心动过速的患者进行了等积分心电图体表标测，这些患者在基线时以及口服奎尼丁治疗后进行了程控刺激研究。QRST等积分分布的非偶极程度通过极值数量以及卡尔胡宁 - 勒夫变换后非偶极特征向量的贡献百分比来表示。室性心动过速患者的QRST等积分非偶极性高于51名年龄和性别匹配的正常受试者，表现为平均极值数量（分别为4.1±2.8与2.0±0.2）、平均特征向量确定的非偶极含量百分比（12.4±10.1%与4.5±4.9%）、极值数量异常的患病率（63%与4%）或非偶极含量百分比异常的患病率（33%与4%）（各p均小于0.01）。奎尼丁预防了14例患者的室性心动过速诱发。奎尼丁有效或无效的患者在基线时具有相似的非偶极性指标。然而，服用奎尼丁后的图因抗心律失常疗效而异。虽然有效治疗未使非偶极性产生显著的平均变化，但无效治疗与基线相比增加了极值数量（分别为5.4±3.4与3.8±2.5）（p = 0.002）。单独来看，有效治疗的患者中有43%出现药物诱导的极值数量减少，而无效治疗的患者中这一比例为14%（p = 0.02）。此外，有效治疗的患者中有29%出现药物诱导的极值数量增加，而无效治疗的患者中这一比例为62%（p = 0.03）。
QRST等积分体表标测有望成为室性心动过速患者药物疗效的一种非侵入性测量方法。
