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Signal averaged electrocardiography (SAECG) in patients on hemodialysis
H Ichikawa1, Y Nagake, H Makino
1Department of Medicine III, Okayama University Medical School, Japan.
Insights
Signal-averaged electrocardiography (SAECG) revealed worsening cardiac electrical activity after hemodialysis (HD). Insufficient potassium reduction during HD may increase arrhythmia risk in high-potassium patients.
Area of Science:
- Cardiology
- Nephrology
- Medical Technology
Background:
- Cardiovascular diseases are a leading cause of mortality in hemodialysis patients.
- Signal-averaged electrocardiography (SAECG) noninvasively detects ventricular late potentials (LP) for risk stratification of sudden cardiac death and ventricular tachycardia.
Observation:
- SAECG was performed on 42 patients before and after hemodialysis (HD).
- Post-HD measurements showed increased filtered QRS duration (FQRS) and a trend towards increased low amplitude signal duration (LAS40).
- The prevalence of LPs and abnormal SAECGs increased after HD.
Findings:
- A significant correlation was observed between changes in LAS40 and potassium levels (delta K) during HD.
- This correlation was significant in the high-potassium group (predialysis K ≥ 5.0 mEq/L) but not in the low-potassium group.
- Worsening SAECG indices during HD suggest an arrhythmogenic role for insufficient potassium reduction.
Implications:
- SAECG can identify electrophysiological changes associated with HD.
- Inadequate serum potassium reduction during HD may contribute to cardiac arrhythmias.
- Further research is needed to optimize HD protocols for cardiovascular safety.
Abstract:
Cardiovascular diseases are the major cause of mortality in patients on hemodialysis (HD). Recently, signal averaged electrocardiography (SAECG) has been developed to detect ventricular late potentials (LP) noninvasively from the body surface for identifying patients at sudden death or ventricular 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. Postdialysis duration of low amplitude signal under 40 microV 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 patients (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 > or = 5.0 mEq/L; 20 patients) and those in the low-K group (predialysis K < 5.0 mEq/L; 22 patients). In the low-K group, there was no significant correlation between delta LAS40 and delta K. However, in the high-K group, there was a significant correlation between delta LAS40 and delta K. In conclusion, SAECG indices worsened during HD, and an insufficient decrement of serum potassium by HD is suggested to have been an arrhythmogenic factor in the high-K group.