Modulation of the QT interval: Effects of graded exercise and reflex cardiovascular stimulation

J. A. Arrowood, Jeffrey Kline, P. M. Simpson, R. J. Quigg, J. J. Pippin, J. V. Nixon, P. K. Mohanty

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

During exercise, as heart rate (HR) increases, the QT interval of the electrocardiogram shortens. The mechanism(s) involved in this QT shortening has not been clearly defined. To distinguish the influence of increased circulating catecholamines from myocardial efferent stimulation, the relationship between HR and QT interval was investigated during exercise and cardiovascular reflex stimulation in cardiac transplant patients and normal control subjects. Because of cardiac denervation, increases in HR in these patients are solely due to circulating catecholamines and thus allow isolation of their effect on the QT interval. Twenty-one cardiac transplant patients were studied and compared with 16 normal control subjects. The QT- HR relationship was determined according to an exponential model during treadmill exercise in both groups [QT = 0.12 + 0.492e((-0.008 · HR)) and QT = 0.12 + 0.459e((-0.007 · HR)) in normal subjects and transplant patients, respectively] and was statistically similar between groups, suggesting similar QT interval shortening in both groups. During cold pressor and Valsalva maneuvers, HR increased significantly in normal subjects only, whereas QT interval changed minimally in both groups. These results suggest that during exercise the QT interval is influenced predominantly by increases in circulating catecholamines rather than by neurally mediated reflex autonomic changes.

Original languageEnglish (US)
Pages (from-to)2217-2223
Number of pages7
JournalJournal of Applied Physiology
Volume75
Issue number5
StatePublished - 1993
Externally publishedYes

Fingerprint

Reflex
Heart Rate
Exercise
Catecholamines
Transplants
Valsalva Maneuver
Denervation
Electrocardiography

Keywords

  • cardiac denervation
  • repolarization
  • sympathoexcitation

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Arrowood, J. A., Kline, J., Simpson, P. M., Quigg, R. J., Pippin, J. J., Nixon, J. V., & Mohanty, P. K. (1993). Modulation of the QT interval: Effects of graded exercise and reflex cardiovascular stimulation. Journal of Applied Physiology, 75(5), 2217-2223.

Modulation of the QT interval : Effects of graded exercise and reflex cardiovascular stimulation. / Arrowood, J. A.; Kline, Jeffrey; Simpson, P. M.; Quigg, R. J.; Pippin, J. J.; Nixon, J. V.; Mohanty, P. K.

In: Journal of Applied Physiology, Vol. 75, No. 5, 1993, p. 2217-2223.

Research output: Contribution to journalArticle

Arrowood, JA, Kline, J, Simpson, PM, Quigg, RJ, Pippin, JJ, Nixon, JV & Mohanty, PK 1993, 'Modulation of the QT interval: Effects of graded exercise and reflex cardiovascular stimulation', Journal of Applied Physiology, vol. 75, no. 5, pp. 2217-2223.
Arrowood, J. A. ; Kline, Jeffrey ; Simpson, P. M. ; Quigg, R. J. ; Pippin, J. J. ; Nixon, J. V. ; Mohanty, P. K. / Modulation of the QT interval : Effects of graded exercise and reflex cardiovascular stimulation. In: Journal of Applied Physiology. 1993 ; Vol. 75, No. 5. pp. 2217-2223.
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