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Biomedical subjects

S Kleinert

Publications and source records attributed to S Kleinert.

22 records · Page 2Linked to original sources
PubMed1994

Quantitated left ventricular systolic mechanics in children with septic shock utilizing noninvasive wall-stress analysis.

OBJECTIVE: To quantitate ventricular systolic mechanics in septic children. DESIGN: Prospective wall-stress analysis was compared to standard ejection phase indices. SETTING: University-based pediatric intensive care unit. PATIENTS: Fifteen children with sepsis (hemodynamically stable, n = 5; in shock, n = 10). MEASUREMENTS AND MAIN RESULTS: Left ventricular ejection phase indices: shortening fraction (shortening) and corrected mean velocity of circumferential shortening (velocity) were adjusted for end-systolic wall stress (stress). Ejection phase, performance (stress-shortening relation), contractility (stress-velocity relation), and afterload (stress) were indexed to age-corrected normal means, with variance of > or = 2 SD regarded as significant. Preload index represented variance between performance and contractility indices. All hemodynamically stable septic patients had normal performance, contractility, and preload. Afterload was increased in three of five patients. Of the patients with septic shock, six of ten had decreased performance (decreased contractility and increased afterload, n = 4; decreased afterload, n = 1; and severe preload deficit, n = 1). Despite aggressive volume resuscitation, six of ten children in septic shock had evidence of diminished preload. Follow-up studies in the septic shock patients demonstrated reversal of depressed ventricular contractility within 3 to 6 days in all four patients initially affected (p < .05). One patient developed late decreased performance and contractility in association with multiple organ failure. Ventricular loading abnormalities persisted in a follow-up study of these patients including a preload deficit in five of ten patients in shock. CONCLUSIONS: The frequency rate (40%) of reversible impaired ventricular contractility in children with septic shock is significant. Afterload is normal or increased in the majority of septic subjects, possibly due to acute ventricular dilation. Decreased preload contributes to altered ventricular performance in the majority of children with septic shock, persisting days after the initiation of therapy. Wall-stress analysis provided detailed information regarding ventricular mechanics that was not otherwise obtainable by standard ejection phase indices.

Adolescent↗
PubMed1993

Echocardiographic morphometry and geometry of the left ventricular outflow tract in fixed subaortic stenosis.

OBJECTIVES: This study was designed to identify, by echocardiography, morphometric abnormalities of the left ventricular outflow tract in children with fixed subaortic stenosis and to determine whether these abnormalities precede the development of subaortic obstruction. BACKGROUND: Fixed subaortic stenosis typically develops and progresses after the 1st year of life and is therefore often regarded as an acquired lesion. Although it has been speculated that there may be an underlying anatomic substrate, there are no data to support this hypothesis. METHODS: The size of the aortic annulus, mitral-aortic valve separation, aorto-left ventricular septal angle and degree of aortic override were determined in two groups of children. Group 1 comprised 35 patients with isolated subaortic stenosis noted on initial echocardiogram who were compared with an age- and weight-matched normal control group (Group 1A). Group 2 comprised 23 patients with ventricular septal defect or coarctation of the aorta, or both, who had no subaortic stenosis on initial echocardiogram but who developed it subsequently. This group was compared with an age-, weight- and lesion-matched control group (Group 2A). RESULTS: Compared with control subjects, patients with isolated subaortic stenosis had a significantly wider mitral-aortic separation ([mean +/- SD] 5.1 +/- 1.3 vs. 3.4 +/- 0.9 mm, p < 0.001), a steeper aortoseptal angle (131 +/- 6 degrees vs. 144 +/- 5 degrees, p < 0.001) and an exaggerated aortic override (p < 0.05). Similar differences were found on initial echocardiogram in Group 2 patients before development of subaortic stenosis: wider mitral-aortic separation (4.2 +/- 1.2 vs. 2.5 +/- 0.7 mm, p < 0.001), a steeper aortoseptal angle (132 +/- 7 degrees vs. 145 +/- 7 degrees, p < 0.001) and an exaggerated aortic override (p < 0.05). CONCLUSIONS: A left ventricular outflow tract malformation characterized by a wider mitral-aortic separation, an exaggerated aortic override and a steeper aortoseptal angle are present in children with ventricular septal defect or coarctation of the aorta, or both, who subsequently develop subaortic stenosis. These morphometric features can be used to identify by echocardiography patients who are at risk for developing fixed subaortic stenosis.

Age Factors↗