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Conductance Catheter (conductance + catheter)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Cardiac function during mild hypothermia in pigs: increased inotropy at the expense of diastolic dysfunction

ACTA PHYSIOLOGICA, Issue 1 2010
H. Post
Abstract Aim:, The induction of mild hypothermia (MH; 33 °C) has become the guideline therapy to attenuate hypoxic brain injury after out-of-hospital cardiopulmonary resuscitation. While MH exerts a positive inotropic effect in vitro, MH reduces cardiac output in vivo and is thus discussed critically when severe cardiac dysfunction is present in patients. We thus assessed the effect of MH on the function of the normal heart in an in vivo model closely mimicking the clinical setting. Methods:, Ten anaesthetized, female human-sized pigs were acutely catheterized for measurement of pressure,volume loops (conductance catheter), cardiac output (Swan-Ganz catheter) and for vena cava inferior occlusion. Controlled MH (from 37 to 33 °C) was induced by a vena cava inferior cooling catheter. Results:, With MH, heart rate (HR) and whole body oxygen consumption decreased, while lactate levels remained normal. Cardiac output, left ventricular (LV) volumes, peak systolic and end-diastolic pressure and dP/dtmax did not change significantly. Changes in dP/dtmin and the time constant of isovolumetric relaxation demonstrated impaired active relaxation. In addition, MH prolonged the systolic and shortened the diastolic time interval. Pressure,volume analysis revealed increased end-systolic and end-diastolic stiffness, indicating positive inotropy and reduced end-diastolic distensibility. Positive inotropy was preserved during pacing, while LV end-diastolic pressure increased and diastolic filling was substantially impaired due to delayed LV relaxation. Conclusion:, MH negatively affects diastolic function, which, however, is compensated for by decreased spontaneous HR. Positive inotropy and a decrease in whole body oxygen consumption warrant further studies addressing the potential benefit of MH on the acutely failing heart. [source]

Left ventricular mechanical dyssynchrony is load independent at rest and during endotoxaemia in a porcine model

ACTA PHYSIOLOGICA, Issue 4 2009
R. A'roch
Abstract Aim:, In diseased or injured states, the left ventricle displays higher degrees of mechanical dyssynchrony. We aimed at assessing mechanical dyssynchrony ranges in health related to variation in load as well as during acute endotoxin-induced ventricular injury. Methods:, In 16 juvenile anaesthetized pigs, a five-segment conductance catheter was placed in the left ventricle as well as a balloon-tipped catheter in the inferior vena cava. Mechanical dyssynchrony during systole, including dyssynchrony time in per cent during systole and internal flow fraction during systole, were measured at rest and during controlled pre-load reduction sequences, as well as during 3 h of endotoxin infusion (0.25 ,g kg,1 h,1). Results:, Systolic dyssynchrony and internal flow fraction did not change during the course of acute beat-to-beat pre-load alteration. Endotoxin-produced acute pulmonary hypertension by left ventricular dyssynchrony measures was not changed during the early peak of pulmonary hypertension. Endotoxin ventricular injury led to progressive increases in systolic mechanical segmental dyssynchrony (7.9 ± 1.2,13.0 ± 1.3%) and ventricular systolic internal flow fraction (7.1 ± 2.4,16.6 ± 2.8%), respectively for baseline and then at hour 3. There was no localization of dyssynchrony changes to segment or region in the ventricular long axis during endotoxin infusion. Conclusion:, These results suggest that systolic mechanical dyssynchrony measures may be load independent in health and during acute global ventricular injury by endotoxin. More study is needed to validate ranges in health and disease for parameters of mechanical dyssynchrony. [source]

Effects of combined inhibition of the Na+,H+ exchanger and angiotensin-converting enzyme in rats with congestive heart failure after myocardial infarction

BRITISH JOURNAL OF PHARMACOLOGY, Issue 5 2005
Hartmut Ruetten
We investigated the single vs the combined long-term inhibition of Na+,H+ exchanger-1 (NHE-1) and ACE in rats with congestive heart failure induced by myocardial infarction (MI). Rats with MI were randomized to receive either placebo, cariporide (3000 p.p.m. via chow), ramipril (1 mg kg,1 day,1via drinking water) or their combination for 18 weeks starting on day 3 after surgery. Cardiac morphology and function was assessed by echocardiography and by means of a 2.0 F conductance catheter to determine left ventricular (LV) pressure volume relationships. MI for 18 weeks resulted in an increase in LV end-diastolic diameter (LVDed) in the placebo-treated group when compared to sham (placebo: 1.1±0.04 cm; sham: 0.86±0.01; P<0.05). Combined inhibition of NHE-1 and ACE, but not the monotherapies, significantly reduced LVDed (1.02±0.02 cm). Preload recruitable stroke work (PRSW), dp/dtmax (parameter of systolic function) and end-diastolic pressure volume relationship (EDPVR, diastolic function) were significantly impaired in placebo-treated MI group (PRSW: 39±7 mmHg; dp/dtmax: 5185±363 mmHg s,1; EDPVR: 0.042±0.001 mmHg ,l,1; all P<0.05). Cariporide treatment significantly improved PRSW (64±7 mmHg), dp/dtmax (8077±525 mmHg s,1) and EDPVR (0.026±0.014 mmHg ,l,1), and reduced cardiac hypertrophy in rats with MI. Combined inhibition of NHE-1 and ACE had even a more pronounced effect on PRSW (72±5 mmHg) and EDPVR (0.026±0.014 mmHg ,l,1), as well as cardiac hypertrophy that, however, did not reach statistical significance compared to cariporide treatment alone. The NHE-1 inhibitor cariporide significantly improved LV remodeling and function in rats with congestive heart failure induced by MI. The effect of cariporide was comparable or tended to be stronger (e.g. systolic function) compared to ramipril. Combined treatment with cariporide and ramipril tended to be more effective on LV remodeling in rats with heart failure than the single treatments. Thus, inhibition of the NHE-1 may be a promising novel therapeutic approach for the treatment of congestive heart failure. British Journal of Pharmacology (2005) 146, 723,731. doi:10.1038/sj.bjp.0706381 [source]

Left ventricular unloading and concomitant total cardiac output increase by the use of percutaneous impella recover LP 2.5 assist device during high-risk coronary intervention

CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 2 2005
Marco Valgimigli
Abstract A number of techniques have been proposed for circulatory support during high-risk percutaneous coronary interventions (PCI), but no single approach has achieved wide acceptance so far. We report on a patient with severe left ventricular (LV) impairment who underwent a PCI with the use of a new left ventricular assist device, the Impella Recover LP 2.5 system. The effects on global cardiac output were determined by thermodilution (TD) and LV pressure-volume loops obtained by conductance catheter. The activation of the pump resulted in a rapid and sustained unloading effect of the LV. At the same time, the continuous expulsion of blood into ascending aorta throughout the cardiac cycle produced by the pump resulted in an increase of systemic overall CO, measured by the TD technique, of 1.43 L/min. The procedure was uncomplicated and the patient remained uneventful at follow-up. Our single experience gives new input for future trials to assess the effect of the Impella Recover LP 2.5 assist device on outcome in this subset of patients. © 2005 Wiley-Liss, Inc. [source]