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Author
Block:
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Rachel
Lampert, Vladimir
Shusterman, Matthew M. Burg, Forrester A. Lee, Christine Earley, Anna
Goldberg, Craig A. McPherson, William P. Batsford, Robert Soufer, Yale
University School of Medicine, New Haven, CT, University of Pittsburgh,
Cardiovascular Institute, Pittsburgh, PA
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Background: Psychological stress can
precipitate ventricular arrhythmias in patients with ICDs, as well as sudden
death. However, the physiologic pathways remain unknown. We hypothesized that
stress would increase heterogeneity of repolarization, known to be
arrhythmogenic.
Methods: 32 pts with ICDs and a history of ventricular arrhythmia
underwent ambulatory ECG monitoring during a laboratory mental stress
protocol (anger recall and mental arithmetic.) Continuous changes in
repolarization indices known to be correlated with myocardial dispersion of
refractoriness, including T-wave alternans (TWA), T-wave amplitude (Tamp),
and T-wave area (Tarea), were analyzed in the time-domain. QT and mean
activation-recovery interval (MARI), a correlate of mean epicardial
activation-recovery time, were also measured.
Results: 27 pts had adequate holter recordings, 23 male, mean age 62
+/- 12 years, 23 with CAD, mean EF 32 +/- 10%, 24 on beta-blockers.
Norepinephrine, BP, and HR increased during mental stress. TWA increased, as
did Tamp and Tarea. QT interval and MARI decreased. TWA changes were greater
during late repolarization (peak to end of T.) (See table). Changes in TWA
were associated with changes in HR, systolic BP, and catecholamines. Conclusion:
Psychological stress increased heterogeneity of repolarization as measured by
TWA, Tamp, Tarea, although total QT duration shortened.
Autonomically-mediated repolarization changes may be a pathophysiologic link
between emotion and arrhythmia.
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Baseline
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Mental
Stress
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p
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TWA, mV-msec
†
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2.12
(1.40-2.99)
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2.48
(1.48-3.88)
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<0.001
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TWA-early,
mV-msec †
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1.55
(0.092-2.29)
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1.81
(0.96-2.80)
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<0.01
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TWA-late,
mV-msec †
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1.03 (0.56-1.58)
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1.33 (0.69-1.97)
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<0.001
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Tamp, mV†
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-0.04 (-0.11-0.09)
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-0.02 (-0.08-0.13)
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<0.001
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Tarea, mV-msec†
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-3.73 (-9.32-10.37)
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-1.67 (-6.22-13.11)
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<0.01
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ARI, msec
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271 (±8)
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267 (±7)
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<0.01
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QT, msec
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442
(±9)
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427
(±8)
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<0.001
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†Data
expressed as median (interquartile range) because distribution highly
skewed
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