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  • Warren, S E  (4)
  • 1985-1989  (4)
  • 1
    Online Resource
    Online Resource
    Assessment of left ventricular and aortic valve function after aortic balloon valvuloplasty in adult patients with critical aortic stenosis.
    Ovid Technologies (Wolters Kluwer Health) ; 1987
    In:  Circulation Vol. 75, No. 1 ( 1987-01), p. 192-203
    Details
    In: Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 75, No. 1 ( 1987-01), p. 192-203
    Abstract: Preliminary reports have documented the utility of balloon aortic valvuloplasty as a palliative treatment for high-risk patients with critical aortic stenosis, but the effect of this procedure on cardiac performance has not been studied in detail. Accordingly, 32 patients (mean age 79 years) with long-standing, calcific aortic stenosis were treated at the time of cardiac catheterization with balloon dilatation of the aortic valve, and serial changes in left ventricular and valvular function were followed before and after valvuloplasty by radionuclide ventriculography, determination of systolic time intervals, and Doppler echocardiography. Prevalvuloplasty examination revealed heavily calcified aortic valves in all patients, a mean peak-to-peak aortic valve gradient of 77 +/- 27 mm Hg, a mean Fick cardiac output of 4.6 +/- 1.4 liters/min, and a mean calculated aortic valve area of 0.6 +/- 0.2 cm2. Subsequent balloon dilatation with 12 to 23 mm valvuloplasty balloons resulted in a fall in aortic valve gradient to 39 +/- 15 mm Hg, an increase in cardiac output to 5.2 +/- 1.8 liters/min, and an increase in calculated aortic valve area to 0.9 +/- 0.3 cm2. Individual hemodynamic responses varied considerably, with some patients showing major increases in valve area, while others demonstrated only small increases. In no case was balloon dilatation accompanied by evidence of embolic phenomena. Supravalvular aortography obtained in 13 patients demonstrated no or a mild (less than or equal to 1+) increase in aortic insufficiency. Serial radionuclide ventriculography in patients with a depressed left ventricular ejection fraction (i.e., that less than or equal to 55%) revealed a small increase in ejection fraction from 40 +/- 13% to 46 +/- 12% (p less than .03). In addition, for the study group as a whole there was a decrease in left ventricular end-diastolic volume index (113 +/- 38 to 101 +/- 37 ml/m2, p less than .003), a fall in stroke-volume ratio (1.49 +/- 0.44 to 1.35 +/- 0.33, p less than .04), and no immediate change in left ventricular peak filling rate (2.05 +/- 0.77 to 2.21 +/- 0.65 end-diastolic counts/sec, p = NS). Serial M mode echocardiography and phonocardiography showed an increase in aortic valve excursion (0.5 +/- 0.2 to 0.8 +/- 0.2 cm, p less than .001), a decrease in time to one-half carotid upstroke (80 +/- 30 to 60 +/- 10 msec, p less than .001), and a small decrease in left ventricular ejection time (0.44 +/- 0.03 to 0.42 +/- 0.02 sec, p less than .001).(ABSTRACT TRUNCATED AT 400 WORDS)
    Type of Medium: Online Resource
    ISSN: 0009-7322 , 1524-4539
    URL: Article
    DOI: 10.1161/01.CIR.75.1.192
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 1987
    detail.hit.zdb_id: 1466401-X
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  • 2
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    Improvement in symptoms and left ventricular performance after balloon aortic valvuloplasty in patients with aortic stenosis and depressed left ventricular ejection fraction.
    Ovid Technologies (Wolters Kluwer Health) ; 1988
    In:  Circulation Vol. 78, No. 5 ( 1988-11), p. 1181-1191
    Details
    In: Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 78, No. 5 ( 1988-11), p. 1181-1191
    Abstract: The application of balloon aortic valvuloplasty to elderly patients with severe aortic stenosis and a low ventricular ejection fraction is undefined. Balloon aortic valvuloplasty was performed in a subset of 28 patients with low left ventricular ejection fraction (37 +/- 11%), severe aortic stenosis, and a mean age of 79 +/- 5 years. After valvuloplasty, significant increases were seen in aortic valve area (from 0.5 +/- 0.1 to 0.9 +/- 0.2 cm2), aortic systolic pressure (from 120 +/- 12 to 135 +/- 22 mm Hg), and cardiac output (from 4.2 +/- 1.1 to 4.8 +/- 1.6 l/min) (p less than 0.01), and significant decreases were seen in transaortic pressure gradient (from 69 +/- 25 to 35 +/- 15 mm Hg) and pulmonary capillary wedge pressure (from 24 +/- 9 to 20 +/- 7 mm Hg) (p less than 0.01). All patients had symptomatically improved at the time of discharge. Serial radionuclide ventriculography showed an increase in left ventricular ejection fraction from 37 +/- 11% before valvuloplasty to 44 +/- 14% within 48 hours after dilatation and to 49 +/- 13% at 3 months after dilatation. However, there was substantial heterogeneity of response. Thirteen patients (group A) showed progressive increases in left ventricular ejection fraction (from 34 +/- 11% to 49 +/- 15% to 58 +/- 11%, p less than 0.0001), whereas 15 patients (group B) showed no significant change in ejection fraction (from 41 +/- 10% to 40 +/- 13% to 41 +/- 10%, p = NS) over 3 months. There was no difference between these groups with respect to age, extent of coronary artery disease, history of myocardial infarction, and aortic valve area before and after valvuloplasty. However, peak systolic wall stress and left ventricular dimensions were higher in group B compared with group A. In conclusion, balloon aortic valvuloplasty may result in symptomatic improvement in patients with aortic stenosis and depressed left ventricular ejection fraction; some patients develop progressive increases in ejection fraction, whereas others fail to show improvement.
    Type of Medium: Online Resource
    ISSN: 0009-7322 , 1524-4539
    URL: Article
    DOI: 10.1161/01.CIR.78.5.1181
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 1988
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  • 3
    Online Resource
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    Deficient production of cyclic AMP: pharmacologic evidence of an important cause of contractile dysfunction in patients with end-stage heart failure.
    Ovid Technologies (Wolters Kluwer Health) ; 1987
    In:  Circulation Vol. 75, No. 2 ( 1987-02), p. 331-339
    Details
    In: Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 75, No. 2 ( 1987-02), p. 331-339
    Abstract: We studied the effects of different classes of inotropic drugs on human working myocardium in vitro that was isolated from the hearts of patients with end-stage heart failure, and compared the responses to these drugs with those noted in muscles from nonfailing control hearts. Although peak isometric force generated in response to increased extracellular calcium reached control levels in the muscles from patients with heart failure, the time course of contraction and rate of relaxation were greatly prolonged. The inotropic effectiveness of the beta-adrenergic agonist isoproterenol and the phosphodiesterase inhibitors milrinone, caffeine, and isobutylmethylxanthine was markedly reduced in muscles from the patients with heart failure. In contrast, the effectiveness of inotropic stimulation with acetylstrophanthidin and the adenylate cyclase activator forskolin was preserved. After a minimally effective dose of forskolin was given to elevate intracellular cyclic AMP levels, the inotropic responses of muscles from the failing hearts to phosphodiesterase inhibitors were markedly potentiated. These data indicate that an abnormality in cyclic AMP production may be a fundamental defect present in patients with end-stage heart failure that can markedly diminish the effectiveness of agents that depend on generation of this nucleotide for production of a positive inotropic effect.
    Type of Medium: Online Resource
    ISSN: 0009-7322 , 1524-4539
    URL: Article
    DOI: 10.1161/01.CIR.75.2.331
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 1987
    detail.hit.zdb_id: 1466401-X
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  • 4
    Online Resource
    Online Resource
    Assessment of the end-systolic pressure-volume relationship in human beings with the use of a time-varying elastance model.
    Ovid Technologies (Wolters Kluwer Health) ; 1986
    In:  Circulation Vol. 74, No. 1 ( 1986-07), p. 97-104
    Details
    In: Circulation, Ovid Technologies (Wolters Kluwer Health), Vol. 74, No. 1 ( 1986-07), p. 97-104
    Abstract: The analysis of left ventricular end-systolic pressure-volume relationships in human beings has been hindered by the lack of a practical method of serial volume assessment and by an imprecise definition of end-systole. Modifications of the end-systolic relationship that have been used to circumvent these problems have included the use of single-point end-systolic pressure-volume ratios, the use of peak systolic pressure/minimum ventricular volume points for end-systolic points, and the use of end-ejection as a marker for end-systole. To assess the correlation between the parameters generated by these modifications with the slope (Emax) and volume intercept (VO) of the end-systolic line as defined by Sagawa's model of time-varying elastance, simultaneous measurement of left ventricular pressure and gated radionuclide volume was made in 26 patients under various loading conditions and pressure-volume diagrams were constructed for each loading condition from 32 simultaneous pressure-volume coordinates. Two pressure-volume diagrams were recorded in 14 patients and three pressure-volume diagrams were recorded in 12 patients. Emax and VO were determined in all patients from the slope and volume intercept of the isochronic pressure-volume line with the maximum time-varying elastance as described by Sagawa's model and were designated true Emax and true VO, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
    Type of Medium: Online Resource
    ISSN: 0009-7322 , 1524-4539
    URL: Article
    DOI: 10.1161/01.CIR.74.1.97
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 1986
    detail.hit.zdb_id: 1466401-X
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