Effect of mental stress on dynamic electrophysiological properties of the endocardium and epicardium in humans.
BACKGROUND
Striking temporal associations exist between ventricular arrhythmia and acute mental stress, for example, during natural disasters, or defibrillator shocks associated with stressful events. We hypothesized that electrophysiological changes in response to mental stress may be exaggerated at short coupling intervals and hence relevant to arrhythmia initiation.


OBJECTIVE
The aim of this study was to determine the dynamic response in human electrophysiology during mental stress.


METHODS
Patients with normal hearts and supraventricular tachycardia underwent electrophysiological studies avoiding sedation. Conditions of relaxation and stress were induced with standardized psychometric protocols (mental arithmetic and anger recall) during decremental S1S2 right ventricular (RV) pacing. Unipolar electrograms were acquired simultaneously from the RV endocardium, left ventricular (LV) endocardium (LV endo), and epicardium (LV epi), and activation-recovery intervals (ARIs) computed.


RESULTS
Twelve patients ( 9 women; median age 34 years) were studied. During stress, effective refractory period (ERP) reduced from 228 ± 23 to 221 ± 21 ms (P < .001). ARIs reduced during mental stress (P < .001), with greater reductions in LV endocardium than in the epicardium or RV endocardium (LV endo -8 ms; LV epi -5 ms; RV endo -4 ms; P < .001). Mental stress depressed the entire electrical restitution curve, with minimal effect on slope. A substantial reduction in minimal ARIs on the restitution curve in LV endo occurred, commensurate with the reduction in ERP (LV endo ARI 195 ± 31 ms at rest to 182 ± 32 ms during mental stress; P < .001). Dispersion of repolarization increased sharply at coupling intervals approaching ERP during stress but not at rest.


CONCLUSIONS
Mental stress induces significant electrophysiological changes. The increase in dispersion of repolarization at short coupling intervals may be relevant to observed phenomena of arousal-associated arrhythmia.
University College London, Queen Mary University of London & St Bartholomew's Hospital, London, United Kingdom.
Malcolm C
MC
Finlay
University College London, Queen Mary University of London & St Bartholomew's Hospital, London, United Kingdom.
Pier D
PD
Lambiase
Barts Heart Centre, St Bartholomew's Hospital, London, United Kingdom.
Ron
R
Ben-Simon
University College London, University College London Hospitals NHS Foundation Trust, London, United Kingdom. Electronic address: p.taggart@ucl.ac.uk.
Peter
P
Taggart
D000328:Adult; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D055724:Electrophysiological Phenomena; D004699:Endocardium / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D010496:Pericardium / Q000503:physiopathology; D013223:Statistics as Topic; D013315:Stress, Psychological / Q000503:physiopathology*; D013617:Tachycardia, Supraventricular / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology
Arrhythmia; Dispersion of repolarization; Human electrophysiology; Mental stress; Restitution