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Plasma norepinephrine in exercise-induced ventricular tachycardia.
Journal of the American College of Cardiology
|July 1, 1986
Summary
Plasma norepinephrine levels do not predict exercise-induced ventricular tachycardia. However, beta-adrenergic blockade with propranolol effectively prevents this arrhythmia, correlating with reduced norepinephrine levels.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Exercise testing can provoke ventricular tachycardia (VT).
- The role of plasma norepinephrine in exercise-induced VT is not fully understood.
Purpose of the Study:
- To investigate the relationship between plasma norepinephrine levels and exercise-induced VT.
- To assess the efficacy of beta-adrenergic blockade in preventing exercise-induced VT.
Main Methods:
- Prospective evaluation of 17 patients undergoing exercise testing.
- Measurement of plasma norepinephrine levels at rest, peak exercise, and recovery.
- Repeat exercise testing after beta-adrenergic blockade with propranolol in patients with VT.
Main Results:
- No significant difference in plasma norepinephrine levels between patients with and without exercise-induced VT.
- Exercise-induced VT did not occur in 90% of patients after propranolol administration.
- Propranolol significantly decreased plasma norepinephrine levels.
Conclusions:
- Plasma norepinephrine levels do not reliably identify patients at risk for exercise-induced VT.
- Beta-adrenergic blockade with propranolol is effective in suppressing exercise-induced VT.
- The antiarrhythmic effect of propranolol is associated with reduced norepinephrine levels.