Relation of ventricular late potentials and intradialytic changes in serum electrolytes, ultrafiltration, left ventricular ejection fraction and left ventricular mass index in haemodialysis patients

Abstract

Background: End-stage renal failure patients on haemodialysis (HD) suffer from increased risk of sudden cardiac death. Abnormal late potentials (LP) on signal-averaged electrocardiogram (SAAECG) has proved valuable for identification of increased risk of malignant ventricular tachyarryhythmias in various settings of patients. Abnormalities in LP were reported in HD patients, but their role is still not clear. The aim of the study was to evaluate: 1. the influence of HD on SAECG, 2. the correlation of intradialytic changes of serum electrolytes, weight change and ultrafiltration with intradialytic changes of LP, 3. the correlation of left ventricular ejection fraction (LVEF) and left ventricular mass index (LVMI) with LP before and after HD.

Methods: LP (parameters fQRSd, RMS40, LAS40) were obtained in 39 patients in sinus rhythm within one hour before and after chronic maintenance HD. Patients with permanent atrial fibrillation or on antiarrhythmic therapy (other than betablockers) were excluded. Echocardiography was performed within three days before HD.

Results: No difference in fQRSd before and after HD was found. Postdialytic RMS40 (47.0 +/- 30.1 microV vs 37.1 +/- 22.6 microV, p < 0.05) and LAS40 (25.9 +/- 9.7 ms vs 30.8 +/- 12.5 ms, p < 0.05) significantly improved. Weak significant negative correlation between intradialytic Na change and fQRSd change was found (R = -0.33, p < 0.05). Correlations between intradialytic changes of other electrolytes (K, Ca, P. Mg) and individual LP parameters were nonsignificant. There was no correlation found between intradialytic weight change/ultrafiltration and intradialytic differencies of SAECG. LVEF was weakly inversely correlated with predialytic fQRSd (R = -0.37, p < 0.05) and postdialytic fQRSd (R = -0.35, p < 0.05). LVMI was weakly positively correlated with predialytic fQRSd (R=0.39, p < 0.05) and postdialytic fQRSd (R = 0.40, p < 0.05). LVEF respectively LVMI did not correlate neither with RMS40 nor with LAS40 before or after HD.

Conclusions: SAECG partially improved in end-stage renal failure patients after HD (RMS40 and LAS40 but not fQRSd). Intradialytic differencies of SAECG were not correlated neither with ultrafiltration nor with weight change. Pre-/postdialytic fQRSd inversely correlated with LVEF and positively correlated with LVMI. Further controlled, prospective studies investigating the impact of LP on HD patient care are needed. (Tab. 6, Ref. 19.).