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Biomedical subjects

P J Kuijer

Publications and source records attributed to P J Kuijer.

5 recordsLinked to original sources
PubMed1990

Post-extrasystolic potentiation without a compensatory pause in normal and diseased hearts.

Variables derived from left ventricular volume were used to study post-extrasystolic potentiation. Left ventriculograms were obtained from 11 healthy individuals and 49 patients with coronary heart disease (30 with a previous myocardial infarction and 19 without any signs of myocardial damage). Post-extrasystolic potentiation was induced by a regularly driven right atrial rhythm that was interrupted by one atrial extrasystole in such a way that the post-extrasystolic RR interval was kept equal to the basic RR interval. The left ventricular end diastolic volumes of the pre-extrasystolic and post-extrasystolic beats were equal. In all groups there was evidence of post-extrasystolic potentiation in one or more of the indices of left ventricular function (ejection fraction, mean normalised systolic ejection rate, and systolic volume, and stroke volume). Potentiation was especially evident in patients with left ventricular damage; this suggests that a compensating mechanism is an intrinsic property of the myocardium. The Frank-Starling mechanism does not contribute to the increased performance of the post-extrasystolic beat in normal individuals or in patients with coronary artery disease.

Action Potentials↗
PubMed1989

Electrode catheter ablation for ventricular tachycardia: efficacy of a single cathodal shock.

Electrode catheter ablation was used to treat 11 distinct types of sustained ventricular tachycardias in eight patients. Rigid electrophysiological criteria were used to identify five left and five right ventricular arrhythmogenic sites; one of them gave rise to tachycardia with two distinct configurations. A single R-wave-synchronised 250 or 150 J cathodal shock was delivered at each site. One patient had mildly symptomatic episodes of sustained ventricular tachycardia during the first four days after the shock--there were no other complications. At discharge none of the patients was taking antiarrhythmic drugs. They were followed for 8-20 months (mean 14). Ablation abolished five of the 11 ventricular tachycardias. There was no recurrence in three of the eight patients. In two patients identical ventricular tachycardias recurred because the identification of the arrhythmogenic site was incorrect.

Adult↗
PubMed1982

Clinical relevance of postextrasystolic potentiation.

The significance and clinical relevance of postextrasystolic potentiation resides in the fact that any change in duration of the cardiac cycle results in a change in the contractile behavior of the heart. Since neither a normal nor a diseased heart ever beats strictly regularly, postextrasystolic potentiation is continuously operative, and all hemodynamic or circulatory data obtained in the intact organism are affected by it. This means that postextrasystolic potentiation should be taken into account when cardiovascular clinical data are analyzed and subsequently used for diagnosis or treatment. Postextrasystolic potentiation used as an intervention for the evaluation of residual viable myocardium in scar tissue areas in patients with coronary heart disease may contribute to out insights in the prognosis of and therapeutic judgments in those patients. Postextrasystolic potentiation is a fundamental physiologic property of all myocardium under all circumstances and as such does not allow for integrating or averaging data obtained during more than one cardiac cycle, if cardiac rhythm has not been strictly regular. This fact is insufficiently appreciated in nuclear cardiology and two-dimensional echocardiography.

Animals↗
PubMed1978

Postextrasystolic relaxation in the dog heart.

Left ventricular relaxation was studied in 8 dogs using parameters derived from the left ventricular pressure: the fastest pressure fall and the time constant of pressure decline. Effects of extrasystolic rhythm interventions were examined on the relaxation parameters of the post-relative to the preextrasystolic beat. Postextrasystolic potentiation of these parameters could not be demonstrated. Possible influences of physiologic variables as peak left ventricular pressure, endiastolic aortic and enddiastolic left ventricular pressure on relaxation mechanism were evaluated. The nonselective description of myocardial relaxation by pressure derived parameters is discussed.

Animals↗