Cardioplegia and ventricular late potentials in cardiac surgical patients

Abstract

ABSTRACT. Background and objective. Ventricular late potentials (LP) recording with signal-averaged electrocardiogram allow identifying patients at risk of sudden death and ventricular tachycardia. Cardiac surgery with cardiopulmonary bypass (CPB) could predispose to the development of myocardial ischemia related to imperfect cardioplegia. To the best of our knowledge, no study investigated the protection of cardioplegia and CPB regarding the occurrence of LP in patients without previous myocardial infarction and undergoing cardiac surgery. Methods. In 61 elective patients scheduled for cardiac surgery involving CPB, signal-averaged electrocardiogram was performed the day before and 24-48 h after the surgery. The electrodes were positioned according to Frank's orthogonal derivations. Twenty five patients were excluded because of poor quality signals, leaving 36 patients (age, 64 ± 14) available for the analyses. An abnormal signal-averaged electrocardiogram was considered when ‡2 of the recorded indexes were present. McNemar's tests were performed on the dichotomized values to investigate differences in pre-post scores. Results. The mean CPB duration was of 110 ± 57 min. Patients scheduled for cardiac surgery do not exhibited LP after CPB (no significant difference in pre-post CPB scores, P = NS). The probability of a patient with a negative score transitioning to a positive score was 0.23 (P = NS).Conclusions. The present study in cardiac surgical patients suggests that cardioplegia associated to CPB has no significant impact on the occurrence of LP, irrespective of surgery performed.

Single Guide League Ventricular Late Potentials Extraction Based on Signal Correlation

“…Because VLP compared with normal ECG signal waveform has a relative independence, at the same time ICA algorithm can accurately distinguish relatively independent component from the ECG, so it can be used to identify VLP. Svensson's [6] research showed that the analysis of VLP based on single guide league was superior to analysis of vector amplitude based on orthogonal XYZ three guide leagues. The processing method of traditional single guide league is template matching [7], although this method is simple, it is influenced seriously by the form of ECG waveform and high frequency noise, therefore it is not suitable for extracting VLP due that VLP signal has a property of high frequency.…”