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Biomedical subjects

J I Gliklich

Publications and source records attributed to J I Gliklich.

5 recordsLinked to original sources
PubMed1982

Response to programmed ventricular stimulation: sensitivity, specificity and relation to heart disease.

This prospective study of 100 patients evaluated the sensitivity and specificity of the repetitive ventricular response and ventricular tachycardia induced by programmed electrical stimulation for identifying patients with spontaneous ventricular tachyarrhythmias. The influence of underlying heart disease on such sensitivity and specificity was also evaluated. The repetitive ventricular response was sensitive (92 percent) for detecting patients with prior spontaneous ventricular tachyarrhythmias, but lacked specificity (57 percent); the rate of false positive responses was 43 percent. Inducible ventricular tachycardia was less sensitive (65 percent) but more specific (98 percent); the rate of false positive responses was only 3 percent. Among the 100 patients, 71 had heart disease, 29 did not. The presence of underlying heart disease had no significant effect on the sensitivity and specificity of repetitive ventricular responses or ventricular tachycardia induced by programmed stimulation; it did not increase the rate of false positive responses. It is concluded that (1) ventricular tachycardia induced with programmed ventricular stimulation is an excellent basis for guiding the management of clinically significant ventricular tachyarrhythmias, regardless of underlying heart disease; and (2) the repetitive ventricular response is not useful for this purpose because of its high rate of false positive responses among patients with or without significant heart disease.

Adolescent↗
PubMed1982

Four-contact glove probe method for rapid recording of cardiac electrograms during surgery.

A technique is presented for recording four simultaneous electrograms from the heart during operation for cardiac arrhythmias. this technique permits intraoperative maps of cardiac electrical activity to be constructed more rapidly than is possible with single-point mapping, thereby decreasing the risks to the patient and yielding more information about cardiac events.

Arrhythmias, Cardiac↗
PubMed1978

Sites of action and active forms of lidocaine and some derivatives on cardiac Purkinje fibers.

We have compared the effects of lidocaine (L) to those of several derivatives in an attempt to determine the sites of action and active forms of the molecules. We studied cardiac Purkinje fibers with intracellular microelectrodes, and drugs were administered by superfusion or by iontophoretic intracellular injection. We compared to L the effects of QX-314 and QX-572, two quaternary derivatives, and also compound 6603, a tertiary analogue with a pKa of 9.81. When administered by superfusion in concentrations of 10(-5) and 10(-4) M, all four agents exerted qualitatively similar effects on the transmembrane action potential. The rate of onset of action of the quaternary derivatives was considerably slower than that of L and their actions were not reversed by superfusion for 1 hour with drug-free solution. Comparison of effects of L and QX-314 after intracellular injection showed that attenuation of Vmax, and thus of the fast inward current, results from interaction of the charged form acting form acting from the inner surface of the sarcolemma. After intracellular injection, QX-314 diffused readily along the long axis of fiber bundles, and it was thus possible to expose the inner surface of a large number of contiguous cells to drug. Comparison of results of extracellular and intracellular application suggests that effects on the voltate during phase 2 result from the charged form acting from the inner surface, but effects on total action potential duration result only from drug acting from the outer surface of the sarcolemma. Unlike L, the three derivatives did not decrease the slope of normal phase 4 depolarization. The results may help relate antiarrhythmic action to specific effects on transmembrane potentials.

Action Potentials↗
PubMed1975

Effects of AY-22,241 (Actodigin) on electrical and mechanical activity of cardiac tissues.

AY-22,241 (Actodigin) is a new rapid-acting semisynthetic cardiotonic steroid. In experiments on contractility of cat papillary muscle, Actodigin (2 times 10(-7) to 4 times 10(-6) M) produced a dose-dependent positive inotropic effect, a marked increase in the maximum rate of force development, and no change in resting tension. Electrophysiologic studies performed with microelectrode techniques on isolated Purkinje fibers superfused with Tyrode solution, revealed dose-dependent decreases in resting membrane potential, action potential amplitude and duration, and the maximum rate of rise of phase 0 (Vmax). Purkinje fibers superfused with extracorporeally circulated blood from a donor dog receiving 0.075 mg/kg/min Actodigin showed small decreases in resting membrane potential preceding the onset of donor premature ventricular contractions. Progressive decreases in resting membrane potential, action potential amplitude and duration, and Vmax accompanied donor ventricular tachycardia. All effects were rapidly reversible, and compared to ouabain, equi-inotropic concentrations of Actodigin caused significantly less electrophysiologic toxicity.

Animals↗