SIGNAL-AVERAGED ELECTROCARDIOGRAPHY (SAECG) IN PATIENTS ON HEMODIALYSIS

Cardiovascular diseases are the major cause of mortality in patients o n hemodialysis (HD). Recently, signal averaged electrocardiography (SA ECG) has been developed to detect venticular late potentials (LP) noni nvasively from the body surface for identifying patients at sudden dea th or venticular tachycardia. We performed SAECG in 42 patients before and after HD. As a result, postdialysis total filtered QRS duration ( FQRS) was significantly increased compared with predialysis FQRS. Post dialysis duration of low amplitude signal under 40 mu V in the latter part of QRS (LAS40) tended to increase compared with predialysis LAS40 . Before HD, there were no patients with LP and only one patient (2.4% ) with abnormal SAECGs. In contrast, after HD, there were three patien ts (7.1%) with LP and three more patients (7.1%) with abnormal SAECGs. Furthermore, there was a significant correlation between the changes in LAS40 (Delta LAS40) and those in potassium (K) (Delta K) during HD. We further examined the relation between LAS40 and the concentration of K, by comparing the correlation coefficient between patients in the high-K group (predialysis K greater than or equal to 5.0 mEq/L; 20 pa tients) and those in the low-K group (predialysis K < 5.0 mEq/L; 22 pa tients). In the low-K group, there was no significant correlation betw een Delta LAS40 and Delta K. However, in the high-K group, there was a significant correlation between Delta LAS40 and Delta K. In conclusio n, SAECG indices worsened during HD, and an insufficient decrement of serum potassium by HD is suggested to have been an arrhythmogenic fact or in the high-K group.