The Canadian journal of cardiology
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An association between rapid reversion of supraventricular tachycardia by carotid sinus stimulation and carotid sinus reflex hypersensitivity during sinus rhythm is described in a 55-year-old patient. The findings indicate that a high level of vagal tone facilitates vagal maneuvers in terminating some supraventricular tachyarrhythmias. The briskness of the response during tachycardia may also be a marker for underlying carotid sinus hypersensitivity.
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Electrophysiologic studies were performed in nine survivors of out-of-hospital cardiac arrest who had no overt heart disease on clinical, hemodynamic and angiographic evaluation. Cardiac arrest occurred during sedentary activity in seven patients and during exercise in two; no patient was on antiarrhythmic drugs at the time of cardiac arrest. Twenty-four hour ambulatory electrocardiographic monitoring demonstrated premature ventricular beats in four patients (44%). ⋯ Of the four patients with noninducible sustained VT or VF, three received no antiarrhythmic therapy and one was given a beta-blocker. None had recurrent cardiac arrest or symptomatic VT after an average follow-up of 17 months (range 13 to 20 months). Thus, inducibility of sustained VT or VF provided a reliable end point for long term antiarrhythmic therapy and noninducibility identified a subset of patients that had an excellent prognosis without specific antiarrhythmic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)