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Biomedical subjects

T Fenyvesi

Publications and source records attributed to T Fenyvesi.

At least 37 records · Page 2Linked to original sources

The effects of overdrive pacing and lidocaine on atrioventricular junctional rhythm in man: the role of abnormal automaticity.

The effects of overdrive pacing and lidocaine were studied in 22 patients with atrioventricular (AV) junctional rhythms. Based on the responses to cardiac pacing and lidocaine, patients were divided into two groups. AV junctional rhythms in group I (17 patients) were suppressed by overdrive pacing, and their rates were decreased by lidocaine. Lidocaine also prolonged the junctional recovery time in these patients. AV junctional rhythms in group II (five patients) were not suppressed by overdrive pacing. In contrast, the rate increased after overdrive pacing. Lidocaine did not alter the basic cycle lengths or the recovery times of the AV junctional rhythms in this group of patients. The data suggest that AV junctional rhythms in group I were caused by normal automaticity, while those in group II were probably due to abnormal automaticity.

Adult↗

Concealed re-entry in the human heart.

The mechanism and electrophysiologic manifestations of concealed re-entry were studied in human electrocardiograms and intracardiac recordings. Previously described patterns of concealed re-entry were documented in 49 patients. In seven cases concealed re-entry was involved in the genesis of Wenckebach periodicity and alternating Wenckebach periodicity in the AV node, and "reversed" Wenckebach periods in the His-Purkinje system. These manifestations of concealed re-entry were not described so far. In five cases re-entry was apparently concealed. Complete (but hidden) circus movement of the supraventricular impulses in these patients were detected by intracardiac recordings and by analysing the effects of echo beats on timing of the subsequent sinus beats. Concealed re-entry of the cardiac impulse is a well-documented electrophysiologic event which explains many common and peculiar manifestations of impulse formation and impulse conduction in the human heart.

Arrhythmias, Cardiac↗

Assessment of selective beta-adrenoceptor blockade in man.

1. Selective antagonism of the cardiac beta(1)-adrenoceptors has been studied in normal human volunteers.2. Practolol and UK 6558 produced greater antagonism of the chronotropic and inotropic responses to i.v. isoprenaline than of the vasodilator response to either i.v. or intra-arterial isoprenaline. A third drug, M&B 17,803A, produced non-selective beta-adrenoceptor blockade in 2 of 3 subjects studied.3. Practolol, UK 6558 and M&B 17,803A, produced an attenuation of the responses to Valsalva's manoeuvre.4. A substantial reduction in blood pressure was seen in 3 of 4 normotensive subjects given UK 6558.

Adrenergic beta-Antagonists↗