Ventricular repolarization markers for predicting malignant arrhythmias in clinical practice

Abstract

Malignant cardiac arrhythmias which result in sudden cardiac death may be present in individuals apparently healthy or be associated with other medical conditions. The way to predict their appearance represents a challenge for the medical community due to the tragic outcomes in most cases. In the last two decades some ventricular repolarization (VR) markers have been found to be useful to predict malignant cardiac arrhythmias in several clinical conditions. The corrected QT, QT dispersion, Tpeak-Tend, Tpeak-Tend dispersion and Tp-e/QT have been studied and implemented in clinical practice for this purpose. These markers are obtained from 12 lead surface electrocardiogram. In this review we discuss how these markers have demonstrated to be effective to predict malignant arrhythmias in medical conditions such as long and short QT syndromes, Brugada syndrome, early repolarization syndrome, acute myocardial ischemia, heart failure, hypertension, diabetes mellitus, obesity and highly trained athletes. Also the main pathophysiological mechanisms that explain the arrhythmogenic predisposition in these diseases and the basis for the VR markers are discussed. However, the same results have not been found in all conditions. Further studies are needed to reach a global consensus in order to incorporate these VR parameters in risk stratification of these patients.

Effect of sodium‐glucose co‐transporter‐2 inhibitors on impaired ventricular repolarization in people with Type 2 diabetes

“…As shown in Table 1, QTc interval was not prolonged, but QTc dispersion (median 48.8 ms) was slightly longer than values in healthy participants in most studies (i.e. 30-40 ms), although the definition of 'normal' QTc dispersion varies among studies [5][6][7][8][9]. Treatment with an SGLT2 inhibitor did not change heart rate, QTc interval or T peak -T end but significantly reduced QTc dispersion (Table 1).…”

“…Although the 'normal' range of QTc dispersion has not been established, one analysis showed that QT dispersion in a total of 8455 healthy people was 33.4AE20.3 ms, with a median of 37 ms [5]. A varied relationship between QT dispersion/QTc dispersion and cardiovascular mortality has been reported in the literature [5][6][7][8], but an association of longer QT dispersion with higher mortality has been shown by the finding that relative risks of mortality in people with QT dispersion ≥80 ms and in those with QT dispersion of 30-80 ms were 1.80-fold and 1.65-fold higher than the relative risk in people with QT dispersion of ≤ 30 ms [12]. The present findings, therefore, although preliminary, suggest that SGLT2 inhibitor treatment improves ventricular repolarization heterogeneity in people with Type 2 diabetes and that this beneficial effect of SGLT2 inhibitors is involved in the reported reduction in mortality caused by empagliflozin treatment [4].…”

“…Increased ventricular repolarization heterogeneity is associated with the risk of fatal arrhythmias and sudden cardiac death, not only in groups with pathological conditions, such as heart failure and Type 2 diabetes, but also in the general population [5][6][7][8]. We and others have shown that QTc dispersion and interval from the peak to the end of the T-wave (T peak -T end ), markers of ventricular repolarization heterogeneity, are greater in people with Type 2 diabetes [6,8,9]. Furthermore, the increased heterogeneity in ventricular repolarization could not be normalized by glycaemic control with conventional antidiabetes agents [9].…”

Differential Diagnostic Models Between Vasovagal Syncope and Psychogenic Pseudosyncope in Children

“…QTd is an index measured in a 12-lead ECG, which was first proposed by Day et al (18). It represents the myocardial inconsistency of ventricular repolarization caused by inhomogeneous distribution of autonomic nerves in the ventricle and the duration of heterogeneity of myocardial cell action potentials (19,20). It has been suggested that patients with augmented ventricular repolarization heterogeneity, measured by elevated QTd, are predisposed to VVS (21).…”

Evaluation of arrhythmic effects of clarithromycin usage in patients with acute coronary syndrome via new parameters of 12 lead electrocardiography

“…One of the mostimportant of these parameters is Tp-e/ QTc which is a measure of spatial dispersion of ventricular repolarization [20,21].…”