Background: The index of myocardial performance has prognostic power in patients with cardiomyopathy and following myocardial infarction. As the index of myocardial performance has been shown to be preload and afterload dependent, the effect of altering contractility on IMP and its components with left ventricular dysfunction has been incompletely delineated.
Methods: Chronic left ventricular dysfunction was induced in 10 canines using coronary microsphere embolization. Each dog was instrumented and imaged with 2D echo and Doppler. At the same atrially paced rate, contractility was increased with a dobutamine infusion and then following 4 weeks of oral digoxin.
Results: With chronic left ventricular dysfunction, a reduced left ventricular ejection fraction (42 +/- 3%, p < 0.001) and increased index of myocardial performance (0.58 +/- 0.17, p < 0.01) due to isovolumic contraction time lengthening and shortened left ventricular ejection time were noted. Dobutamine increased ejection fraction (p < 0.001), reduced left ventricular end diastolic pressure (p < 0.01), and reduced the index of myocardial performance (0.33 +/- 0.17, p < 0.001) due to isovolumic contraction time, isovolumic relaxation time, and left ventricular ejection time shortening. Digoxin increased ejection fraction (p < 0.05), reduced left ventricular end diastolic pressure (p < 0.05), and reduced the index of myocardial performance (0.42 +/- 0.13, p < 0.01) due to isovolumic contraction time shortening (p < 0.001). Both dobutamine and digoxin lengthened the diastolic filling period (p < 0.01).
Conclusion: Increased inotropy with digoxin and dobutamine reduced the index of myocardial performance in dogs with left ventricular dysfunction. Shortened isovolumic contraction time, increased diastolic filling period, and reduced left ventricular end diastolic pressure with digoxin may provide insight into its efficacy in heart failure.
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http://dx.doi.org/10.1186/1476-7120-4-45 | DOI Listing |
Curr Cardiol Rep
January 2025
Pediatric Advanced Heart Failure and Heart Transplant Program, University of Mississippi Medical Center, 2500 N State Street, Jackson, MS, USA.
Purpose Of Review: Traditionally viewed as a passive player in circulation, the right ventricle (RV) has become a pivotal force in hemodynamics. RV failure (RVF) is a recognized complication of primary cardiac and pulmonary vascular disorders and is associated with a poor prognosis. Unlike treatments for left ventricular failure (LVF), strategies such as adrenoceptor signaling inhibition and renin-angiotensin system modulation have shown limited success in RVF.
View Article and Find Full Text PDFPediatr Cardiol
January 2025
Department of Cardiac Surgery, University Hospital of Gent, Corneel Heymanslaan 10, 9000, Ghent, Belgium.
Restenosis occurs commonly after aortic coarctation (CoA) repair, usually requiring treatment by balloon dilation. Its effect on physical exercise performance is not documented. A retrospective analysis of exercise testing and echocardiographic assessment was performed in children after CoA repair.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
January 2025
Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Department of Cardiology, Amsterdam, The Netherlands.
The acute response to therapeutic afterload reduction differs between heart failure with preserved (HFpEF) versus reduced ejection fraction (HFrEF), with larger left ventricular (LV) stroke work augmentation in HFrEF compared to HFpEF. This may (partially) explain the neutral effect of HFrEF-medication in HFpEF. It is unclear whether such differences in hemodynamic response persist and/or differentially trigger reverse remodeling in case of long-term afterload reduction.
View Article and Find Full Text PDFScand J Med Sci Sports
January 2025
Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway.
The maximal oxygen uptake (V̇O) is typically higher in endurance-trained adolescents than in non-endurance-trained peers. However, the specific mechanisms contributing to this remain unclear, as well as the impact of training during this developmental stage. This study aims to compare V̇O and cardiovascular functions between 12-year-old endurance athletes and non-endurance-trained over a 14-month period.
View Article and Find Full Text PDFCrit Care
January 2025
Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark.
Background: Low-volume hypertonic solutions, such as half-molar lactate (LAC), may be a potential treatment used for fluid resuscitation. This study aimed to evaluate the underlying cardiovascular effects and mechanisms of LAC infusion compared to sodium-matched hypertonic sodium chloride (SAL).
Methods: Eight healthy male participants were randomized in a controlled, single-blinded, crossover study.
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