Archive for the ‘Heart’ Category - Part 2

Left Ventricular Mechanics and Myocardial Blood Flow: LV contractile dysfunction

This means that long-term asynchronous ventricular activation leads to LV contractile dysfunction that is, at least in part, reversible immediately after the restoration of a normal ventricular activation sequence. In a study by Nielsen et al, it was found that a change in pacing mode from DDD to AAI in patients receiving long-term pacing (ie, […]

Left Ventricular Mechanics and Myocardial Blood Flow: Discussion

The new findings of this study are as follows: (1) the restoration of a normal ventricular activation sequence after long-term right apical stimulation improves LV contractility and ventriculoarterial coupling in the short term but has no significant effect on diastolic function and MV02; and (2) the change from long-term asynchronous ventricular activation to synchronous ventricular […]

Left Ventricular Mechanics and Myocardial Blood Flow: LV Diastolic Performance

Although dP/ dtmax did not change, its correlation to end diastolic volume (dP/dtmax-Ved), which is a preload-insensitive and afterload-insensitive contractile index, improved during AAI pacing (73.48 ± 3.2 mm Hg/s/mL vs 77.48 ± 4.7 mm Hg/s/mL, respectively; p = 0.002). There were no statistically significant differences in cardiac and stroke index, SW, LV Pes or […]

Left Ventricular Mechanics and Myocardial Blood Flow: Statistical Analysis

All measurements in these arteries were recorded during DDD and AAI pacing modes. Continuous variables are summarized as the mean ± SD. Changes in the various parameters between DDD and AAI pacing modes were assessed with the t test for dependent samples and the Wilcoxon signed rank test. Both parametric and nonparametric tests gave significant […]

Left Ventricular Mechanics and Myocardial Blood Flow: Coronary Blood Flow Measurements

We determined the LVEF, the LV end-systolic pressure (Pes)-end-systolic volume (Ves) relationship slope (ie, end-systolic elastance [Ees]), the LV stroke work (SW)-end-diastolic volume (Ved) relationship slope (ie, the preload recruitable SW [PRSW]), the ratio of Pes to stroke volume (SV) [ie, effective arterial elastance [Ea]), ventriculaorterial coupling (as the Ees/Ea ratio), and the maximal rate […]

Left Ventricular Mechanics and Myocardial Blood Flow: Pressure-Volume Loops

Measurements were made during DDD pacing (ie, the mode that was programmed for the long term) and 5 min after a change of pacing mode to AAI, preserving the same pacing frequency. All drugs with a possible negative inotropic and/or chronotropic effect were stopped five half-lives before the study. All patients provided written, informed consent, […]

Left Ventricular Mechanics and Myocardial Blood Flow: Materials and Methods

This study included patients who were being observed in the pacing clinic and had been referred for coronary angiography because of chest pain. The inclusion criteria were as follows: (1) dual-chamber pacing with optimal AV delay for at least 1 year for sick sinus syndrome; (2) normal intraventricular conduction before pacemaker implantation and throughout the […]

Left Ventricular Mechanics and Myocardial Blood Flow

The right ventricular apex is still the most usual site for the ventricular electrode in patients who have a permanent pacemaker. The asynchronous ventricular activation and contraction that can result from this kind of pacing have a negative effect on left ventricular (LV) systolic and diastolic function, while also causing regional changes in myocardial perfusion […]

Hyperosmolar Solutions Stimulate Mucus Secretion in the Ferret Trachea: Conclusion

This suggests that the increase in mucus transport after saline solution inhalation is probably due to other factors such as changes in mucus properties or acute secretion of preformed mucus in response to the hyperosmolarity. We chose concentrations of hyperosmolar solutions based on concentrations used in clinical stud-ies.” We recognize that immersion of a tracheal […]

Hyperosmolar Solutions Stimulate Mucus Secretion in the Ferret Trachea: CBF

Hyperosmolar solutions probably induce secretion through a direct action on secretory cells or by release of mediators that secondarily trigger receptor-mediated secretion. Because all central neural connections are severed in the excised ferret trachea, this secretagogue effect could not be due to central reflexes.

Pages: Prev 1 2 3 4 Next
anosiahuman.com