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Biomedical subjects

G M Weisfogel

Publications and source records attributed to G M Weisfogel.

6 recordsLinked to original sources
PubMed1979

Increasing pre-excitation during exercise and isoproterenol infusion. Evidence for a catecholamine sensitive bypass tract.

A patient with atypical chest pain developed pre-excitation during exercise and isoproterenol infusion, with "ischemic" ST depression only during the pre-excited beats. Coronary angiography and myocardial lactate extraction showed no evidence of abnormal coronary vessels. Electrophysiologic study and pacing-induced tachycardia did not induce pre-excitation, whereas exercise induced progressive increase in pre-excitation. The data are consistent with an unusual form of pre-excitation, perhaps related to responsiveness of an accessory bypass tract to catecholamine stimulation. The data also show that the false positive exercise test in this syndrome is due to progressively increasing pre-excitation and therefore more abnormal repolarization.

Adult↗
PubMed1975

Sinus node re-entrant tachycardia in man.

Sinus node re-entry (SNR) usually appears as a single beat. Tachycardias (SNRT) consistent with sustained SNR were seen in six patients and were initiated by premature stimulation of the high right atrium (six patients) and coronary sinus (four patients), and after continuous pacing from the high right atrium (four patients) or right ventricle (one patient) at rates of 130 to 200 per minute. During SNRT: (1) atrial beats exhibited a high-to-low atrial activation sequence, (2) the P-waves were similar in morphology to P-waves during sinus rhythm, and (3) re-entry in the A-V node or at the site of stimulation could be excluded. The cycle length of SNRT ranged from 625 to 320 msec. and SNRT either terminated spontaneously (six patients) or after premature atrial capture and/or vagal maneuvers (two patients). The electrophysiologic characteristics of SNRT and differentiation of SNRT from A-V nodal re-entry are discussed.

Aged↗
PubMed1975

Induction of atrioventricular nodal reentrant tachycardia after atropine. Report of five cases.

After intravenous administration of 0.5 mg of atropine sustained atrioventricular (A-V) nodal reentrant tachycardia could be produced in five patients who had no prior historical or electrocardiographic evidence of supraventricular tachycardia. During the control period single atrial echo beats could be demonstrated in four of the five patients, but no instance of sustained tachycardia occurred. Atropine, known to enhance A-V nodal conduction, allowed achievement of longer A-H intervals (Case 1) and provided the necessary balance of conduction and refractoriness within the A-V nodal reentrant pathways (Cases 1 to 5) to sustain A-V nodal reentry in these patients.

Adolescent↗