Cardiac repolarization instability during psychological stress in patients with ventricular arrhythmias

Abstract

Introduction Changes in the autonomic nervous system activity (ANS) are a major trigger of life-threatening ventricular tachyarrhythmias (VTA). Mental arithmetic, a condition administered in a laboratory setting, can provide insight into the ANS effects on cardiac physiology. We examined the responses of cardiac repolarization to laboratory-induced psychological stressors in patients with implantable cardioverter defibrillators (ICDs) with the objective of identifying the indices that differentiate patients with and without subsequent VTA in follow-up. Methods Continuous ECG signals were recorded using 3 standard bipolar (Holter) leads in 56 patients (age: 63.6±11.9, female: 12%, LVEF: 32.3±11) with ICDs during mental arithmetic. The patients were separated into those with subsequent VTA during 3–4 years of follow-up (Group 1: N=9 pts) and those without VTA (Group 2: N=47 pts). Changes in repolarization (QT-interval, mean T-wave amplitude (Tamp), and T-wave area (Tarea) were analyzed during 5min of baseline, stress and recovery. The temporal instability of Tamp and Tarea was examined using the range (Δ) and variance (σ2) of beat-to-beat variations of the corresponding parameters. Results There were no significant differences in HR between the two groups at baseline (61 vs. 63 bpm, p=0.97), during stress (64 vs. 65 bpm, p=0.40), and recovery (62 vs. 61 bpm, p= 0.88). However, during mental stress and post-stress recovery ΔTamp was almost 2-fold greater in Group 1 compared with Group 2 (111 (57–203)) vs. 68 (44–94) μV p=0.04, respectively). Changes in QT-intervals were also greater in Group 1 compared with Group 2 (p=0.02). Conclusion Among patients with ICDs, changes of T-wave amplitude after psychological stress were greater in those with subsequent arrhythmic events. This might signal proarrhythmic repolarization response and help identify patients who would benefit the most from ICD implantation and proactive management.

ECG signatures of psychological stress

“…[12] (See Figure 2) Broad-range repolarization instability, which includes non-alternans frequencies, also increased during stress. [13] In a similar study by Kop et al, mental stress was also seen to increase TWA. [14]…”

Effect of mental stress on dynamic electrophysiological properties of the endocardium and epicardium in humans

“…Controlled data have showed implantable cardioverter-defibrillator shocks to be temporally associated with periods of mental stress. 1 , 2 In a series of elegant studies, mental stress increased T-wave alternans and decreased arrhythmia threshold in a series of ischemic heart disease patients with implantable cardioverter-defibrillators. 1 , 3 Furthermore, previous investigators have documented increased arrhythmogenicity in animal models during mental stress.…”

The Year of 2011 in Electrocardiology

“…Abisse et al 39 using three standard bipolar Holter leads, studied patients with subsequent lifethreatening ventricular tachyarrhythmias during 3-4 years of follow-up and patients without. During mental stress and poststress recovery, T-wave amplitude was almost 2-fold greater in the former than in the latter group, which may signal proarrhythmic repolarization response.…”