[Supraventricular tachycardia induced by effort and by catecholamines].

The role played by catecholamines in the initiation of certain forms of ventricular tachycardia is now recognised. On the other hand, a similar predominant or exclusive mechanism has not been demonstrated in supraventricular tachycardia. We observed a rate case of reproducible attacks of junctional tachycardia on effort in a 45 year old man. This patient had experienced attacks of tachycardia on effort for a number of years, stopping about 10 minutes after the end of effort. An exercise stress test performed for an anginal attack, induced a narrow complex tachycardia at 270/min at the first minute of the recovery period which terminated spontaneously 18 minutes later after a brief episode of atrial fibrillation. During a second exercise stress test, an episode of tachycardia at 250/min was recorded at the second minute of recovery, lasting 11 minutes. Investigations showed a retrograde concealed septal bundle of Kent activated retrogradely during reciprocating tachycardia. A similar form of tachycardia was induced by an injection of isoproterenol. The adrenergic mechanism of the arrhythmia led to the prescription of a beta-blocker (propranolol 120 mg/day), which effectively prevented clinical tachycardia and the forms of tachycardia induced by ergometric tests 15 days and 3 months after the initiation of treatment.