Corlan A D, De Ambroggi L
Cardiology Research Unit, University Hospital, Bucharest, Romania.
Ital Heart J. 2000 Aug;1(8):542-8.
Left ventricular hypertrophy (LVH) is accompanied by specific changes in ventricular electrophysiology, which are potentially arrhythmogenic. Nevertheless, the electrocardiographic diagnostic signs for LVH have a relatively low predictive power for arrhythmic events and sudden death. We thought that other parameters derived from the surface ECG, not apparent at visual inspection, might be detected by specific analysis of electrocardiographic digital recordings. The purpose of our work was to analyze the surface distribution of repolarization potentials and search for subtle alterations not revealed by the usual electrocardiographic processing, which are likely to reflect ventricular repolarization heterogeneity.
Body surface potential maps were recorded from 62 chest leads in 16 patients with LVH due to aortic stenosis and in 35 normal subjects. By applying a principal component analysis of the ST-T waves, we computed the similarity index. The value of the similarity index is inversely proportional to the variability of T wave morphology and a low value is considered a marker of repolarization heterogeneity.
The similarity index was significantly lower in LVH patients than in normals both in 62 leads (0.73 +/- 0.067 vs 0.77 +/- 0.044, p = 0.03) and in 12 unipolar leads (V1- V8, V3R, VR, VL, VF) extracted from the map (0.77 +/- 0.075 vs 0.81 +/- 0.045, p = 0.03). Moreover, we computed the "late repolarization deviation index", which quantifies the instantaneous variations of surface potential distribution from peak to end of the T wave. This index was significantly higher in LVH patients than in controls (in 62 leads 0.07 +/- 0.05 vs 0.028 +/- 0.016, p = 0.005; in 12 leads 0.064 +/- 0.052 vs 0.024 +/- 0.020, p = 0.008).
The values of similarity index and of late repolarization deviation index found in LVH patients suggest a higher than normal degree of repolarization heterogeneity, not detected by the usual electrocardiographic analysis. Since both indices maintained statistical significance when calculated on the 12 leads derived from our map lead system, they could be reliably computed from digital recordings of the 12 conventional leads.
左心室肥厚（LVH）伴有心室电生理的特定变化，这些变化具有潜在的致心律失常性。然而，LVH的心电图诊断体征对心律失常事件和猝死的预测能力相对较低。我们认为，从体表心电图得出的其他参数，在肉眼检查时并不明显，可能通过心电图数字记录的特定分析来检测。我们研究的目的是分析复极电位的体表分布，并寻找常规心电图处理未揭示的细微改变，这些改变可能反映心室复极的异质性。
记录了16例因主动脉瓣狭窄导致LVH的患者和35例正常受试者62个胸导联的体表电位图。通过对ST-T波进行主成分分析，我们计算了相似性指数。相似性指数的值与T波形态的变异性成反比，低值被认为是复极异质性的标志。
LVH患者的相似性指数在62个导联中（0.73±0.067对0.77±0.044，p = 0.03）以及从图中提取的12个单极导联（V1-V8、V3R、VR、VL、VF）中（0.77±0.075对0.81±0.045，p = 0.03）均显著低于正常受试者。此外，我们计算了“晚期复极偏差指数”，该指数量化了从T波峰值到结束时体表电位分布的瞬时变化。该指数在LVH患者中显著高于对照组（在62个导联中为0.07±0.05对0.028±0.016，p = 0.005；在12个导联中为0.064±0.052对0.024±0.020，p = 0.008）。
LVH患者中发现的相似性指数和晚期复极偏差指数的值表明复极异质性程度高于正常，这是常规心电图分析未检测到的。由于在从我们的导联系统图得出的12个导联上计算时，这两个指数均保持统计学显著性，因此可以从12个常规导联的数字记录中可靠地计算出它们。
