Persistent left superior vena cava: unusual wave contour of left jugular vein as the presenting feature.
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Cardiac Catheterization↗
Biomedical subjects
C V Leier
Publications and source records attributed to C V Leier.
Influence of positive inotropic therapy on pulsatile hydraulic load and ventricular-vascular coupling in congestive heart failure.
The aortic input impedance spectrum provides a description of the total hydraulic load imposed on the left ventricle and may be used to assess the coupling of the ventricle to the vasculature. The adaptation of the vasculature to positive inotropic intervention was examined in 10 patients with idiopathic dilated cardiomyopathy to test the hypothesis that increased myocardial contractility is matched by complementary changes in aortic impedance that optimize ventricular-vascular coupling and maximize power transfer to the circulation. High fidelity intravascular recordings of aortic pressure and flow were obtained at baseline study and during infusion of dobutamine to derive the aortic input impedance spectrum. In eight patients in whom increased staged infusion of dobutamine resulted in a significant increase in stroke volume (22.3 +/- 14.5 ml/beat increase over baseline), the significant (p less than 0.05) increase in the maximum of the first derivative left ventricular pressure pulse (dP/dt) was accompanied by significant decreases in characteristic impedance of the aorta (138 +/- 88 to 92 +/- 44 dyne.s.cm-5) wave reflection index (238 +/- 144 to 109 +/- 59 dyne.s.cm-5), and low frequency moduli of impedance. Effective positive inotropic therapy with dobutamine in the setting of congestive heart failure is accompanied by complementary changes in the aortic impedance spectrum, which represent a matching of impedance to the increased contractile state of the ventricle and facilitation of ventricular-vascular coupling.
Adult↗
The pharmacokinetics of midazolam in patients with congestive heart failure.
The disposition of midazolam was investigated in six patients with congestive heart failure (CHF) and six age- and weight-matched healthy subjects by administering two single doses of the drug (3.75 mg i.v. and 7.5 mg p.o.) separated by 1 week. Serial blood samples were collected for 24 h after each dose and plasma was assayed for midazolam by GC-MS. In the CHF patients, the elimination half-life was prolonged (4 to 4.5 vs less than 3 h), the systemic clearance was lowered (376 vs 551 ml min-1) and the peak plasma drug concentration after the p.o. dose was higher (76 vs 42 ng ml-1). The systemic availability (45 vs 41%), the steady state volume of distribution (111 vs 108 l) and the time of peak plasma drug concentration after the p.o. dose (0.9 vs 0.9 h) were unchanged. The predominant effect of CHF was on the clearance of midazolam which was decreased by 30%. The drug was well tolerated and did not cause any adverse effects.
Adult↗
Multicenter trial of oral enoximone in patients with moderate to moderately severe congestive heart failure. Lack of benefit compared with placebo. Enoximone Multicenter Trial Group.
A multicenter double-blind, randomized, placebo-controlled trial of oral enoximone, a phosphodiesterase inhibitor, was conducted in 102 outpatients (50 receiving enoximone and 52 receiving placebo) with moderate to moderately severe congestive heart failure. All were on a long-term regimen of digoxin and diuretics without vasodilators and converting enzyme inhibitors. Symptom score was obtained, and exercise testing was performed monthly for 4 months. There were no differences between groups in symptoms or exercise duration at the end of 4 months. A subgroup undergoing analysis of oxygen consumption with measurement of anaerobic threshold during exercise showed an increase (p less than 0.05) in anaerobic threshold at 1 month with enoximone. (2.7 +/- 0.8 ml O2/kg/min) compared with placebo (-0.8 +/- 1.2 ml O2/kg/min). This improvement was not sustained at 4 months (0.5 +/- 1.7 ml O2/kg/min with enoximone and 0.2 +/- 1.5 ml O2/kg/min with placebo). The dropout rate was significantly higher (p less than 0.02) with enoximone (46%) than with placebo (25%). Adverse effects other than death were slightly, but not significantly, higher with enoximone (32%) than with placebo (22%). During therapy, five deaths occurred in the enoximone group, and none occurred in the placebo group (p less than 0.05). Two deaths were sudden, two were from progressive congestive heart failure, and one was from acute myocardial infarction. With intention-to-treat analysis and inclusion of patients who were removed from therapy because of lack of study drug effect, 10 deaths occurred in the enoximone group, and three occurred in the placebo group (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Administration, Oral↗
Alpha-adrenergic component of the sympathetic nervous system in congestive heart failure.
The alpha-adrenergic component of the sympathetic nervous system plays a major role in the pathophysiology, clinical manifestations, and natural history of human congestive heart failure. While the augmentation of alpha-adrenergic tone (through the neuronal release of norepinephrine) is a valuable mechanism to maintain adequate systemic blood pressure and perfusion of vital organs in states of circulatory collapse, stimulation of alpha-adrenergic receptors produces detrimental hemodynamic effects in congestive heart failure. These undesirable effects result from alpha-mediated vasoconstriction and consist of excessive elevation of right and left ventricular filling pressures and pulmonary and systemic vascular resistances. The enhancement of alpha-adrenergic tone preferentially reduces blood flow to the hepatosplanchnic circulation. Many of the hemodynamic responses that are seen after activation of the renin-angiotensin system are related to the ability of angiotensin II to amplify the actions of the alpha-adrenergic system. Stimulation of myocardial alpha-adrenergic receptors in most species elicits a modest positive inotropic effect, but the presence and importance of this property in the human heart remains controversial. Chronic stimulation of myocardial alpha-adrenergic receptors may result in the hypertrophy of cardiomyocytes and may also contribute to the development of catecholamine-induced cardiomyopathy. Acute blockade of the heightened alpha-adrenergic tone in congestive heart failure (e.g., with first doses of prazosin) results in favorable hemodynamic effects, but repeated dosing leads to pharmacological tolerance. Consequently, the long-term administration of alpha-adrenergic blocking agents in human heart failure has not been accompanied by an improvement in clinical status, exercise capacity, or survival.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Invasive cardiovascular testing in chronic congestive heart failure.
The complexity of the congestive heart failure syndrome often calls for a complete evaluation of the patient's cardiovascular status. Determination of the cause, detection, and grading of surgically treatable lesions, assessment of diastolic dysfunction, and development of a therapeutic plan generally require diagnostic cardiac catheterization and/or placement of a flow-directed pulmonary artery catheter. Each procedure has its value and its limitations.
Cardiac Catheterization↗
Central and regional hemodynamic effects of flosequinan for congestive heart failure.
The central and regional hemodynamic effects of flosequinan, a new orally administered vasodilator, were examined in 10 patients with moderate to severe congestive heart failure. A single-blind design was used to compare a standard dose of flosequinan (100 mg) with placebo. Flosequinan produced a statistically significant increase in cardiac output, primarily through its augmentation of stroke volume. This response was accompanied by significant reductions in systemic vascular resistances and right and left ventricular filling pressures. A reduction in pulmonary artery pressure and total pulmonary vascular resistance also was observed. The vasodilatory actions of flosequinan improved overall left ventricular performance; the inotropic indexes measured were not altered. There were no significant changes in upper limb, renal or hepatic-splanchnic blood flow or in the vascular resistances of these regions after flosequinan administration. The upper limb venous capacitance increased significantly. First-dose flosequinan evokes favorable central hemodynamic changes and improves overall left ventricular performance in patients with congestive heart failure. The acute augmentation in cardiac output, however, is not accompanied by a preferential alteration of flow to any of the major vascular regions studied.
Adult↗
Disparity between improvement in left ventricular function and changes in clinical status and exercise capacity during chronic enoximone therapy.
Twenty patients with moderately severe congestive heart failure were randomized to chronic enoximone (n = 10) or placebo (n = 10) therapy in a double-blind manner and serially evaluated over a 16-week-period. The purpose of the study was to determine if the addition of standard doses (1 and 2 mg/kg) of this new phosphodiesterase inhibitor to conventional therapy (digitalis and diuretics) would alter the clinical and laboratory course of this patient population. Except for a transient improvement in the quality of life score, none of the symptomatology indicators were significantly affected by enoximone. Similarly, maximal exercise capacity was not altered. Enoximone did elicit a statistically significant augmentation of echocardiographic, radionuclide angiographic, and systolic time interval parameters of left ventricular function. These enoximone-induced effects were accompanied by a significant increase (7% to 11%) in resting heart rate. Enoximone is capable of improving ventricular function when added to digitalis-diuretic therapy in moderately severe congestive heart failure. While individual patients may benefit from enoximone, the ability of standard doses of this agent to improve symptoms and exercise capacity over a 16-week period appears somewhat limited in a moderately severe heart failure population as a whole. Furthermore, a disparity between improvement in ventricular function parameters and changes in clinical status and exercise performance is apparent in this heart failure population.
Adult↗
Left ventricular performance during the course of a day and meals in dilated cardiomyopathy and heart failure.
This study was performed to examine the influence of time during the day and of meals on left ventricular performance in patients with dilated cardiomyopathy and chronic congestive heart failure. Systolic time intervals and echocardiography were performed at set intervals with concomitant hemodynamic measurements in nine patients with chronic congestive heart failure over a 15 hour daytime period and during the three meals. Pulmonary capillary wedge pressure decreased (p less than 0.05) from a non-meal resting peak of 18 +/- 8 mm Hg at 1500 hours to 16 +/- 7 mm Hg at 2200 hours. The other non-meal cardiovascular variables, invasive and noninvasive, did not change significantly during the course of the day. Cardiac output and stroke volume rose and pulmonary and systemic vascular resistances, systemic blood pressure, pulmonary artery pressure, and pulmonary capillary wedge pressure generally fell significantly after meals. Although mean PEP/LVET tended to decrease and delta p/delta t increase after meals, these numerical changes were not statistically significant and none of the other noninvasive variables were affected by meals. Patients with dilated cardiomyopathy and chronic congestive heart failure have modest changes in central hemodynamics over the course of a day with rather striking changes with food ingestion. These alterations are generally not reflected in noninvasive cardiovascular parameters.
Adult↗
Magnesium content of serum, circulating mononuclear cells, skeletal muscle, and myocardium in congestive heart failure.
Deranged magnesium concentrations in serum and cardiovascular structures have been implicated in the pathophysiology of hypertension, ischemic heart disease, arrhythmias, and sudden death. This study was conducted to determine the status and interrelation of serum and tissue concentrations of magnesium in patients with congestive heart failure, a clinical setting purportedly predisposed to the development of depleted levels of this cation. Magnesium concentrations of serum, circulating mononuclear cells, skeletal muscle, and myocardium were measured in 23 patients with heart failure on standard therapy. Two patients were hypomagnesemic (less than 1.6 meq/l). Poor or no correlations were found between serum and tissue magnesium concentrations and among the magnesium concentrations of the three tissues studied. Strong direct correlations were, however, noted between magnesium and potassium concentrations of the tissues examined. The prevalence of hypomagnesemia in this typical ambulatory heart failure population is relatively low (9%) and serum, circulating mononuclear cell, skeletal muscle, and myocardial magnesium concentrations correlate poorly with each other. Serum, circulating mononuclear cell, and skeletal muscle magnesium concentrations are thus of little predictive value in assessing the status of myocardial magnesium in humans with heart failure.
Adult↗
Dopexamine in cardiorespiratory failure. Commentary on drug research in the critically ill.
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Adrenergic Agonists↗
Reproducibility of systolic and diastolic time intervals in normal humans: an important issue in clinical cardiovascular pharmacology.
The purpose of this study was to evaluate the long-term variability and reproducibility of systolic and diastolic time intervals in human subjects. Ten healthy volunteers underwent serial determinations of systolic and diastolic time intervals and, as internal physiologic standards, heart rate (HR), systemic blood pressures, and resting oxygen consumption (VO2). The protocol lasted 1 month and measurements were made on days 1, 2, and 30. No statistically significant differences were found in the various systolic time interval parameters, percentage of diastolic time, heart rate, systolic blood pressure (SBP) and resting oxygen consumption for the 3 study days. Diastolic blood pressure tended to rise slightly (p = 0.07) from day 1 to day 30. The average coefficients of variation for systolic and diastolic time interval parameters in individual study subjects ranged from 1.2 to 7.0%, whereas those for resting physiologic data ranged from 5.3 to 8.5%. In normal human subjects, systolic and diastolic time intervals are highly reproducible, with acceptable variation over time; these measurements should be thought of as possessing reproducibility equal to or greater than the resting physiologic parameters of HR, systemic blood pressure and oxygen consumption.
Adult↗
Augmentation of diastolic function with phosphodiesterase inhibition in congestive heart failure.
Phosphodiesterase inhibition promotes both cellular uptake and release of calcium, which should thus facilitate both myocardial relaxation and myocardial contraction. To test the hypothesis that phosphodiesterase inhibition augments both diastolic and systolic ventricular function, parameters of left ventricular ejection and filling were measured in patients with dilated cardiomyopathy before and after therapy with the phosphodiesterase inhibitor enoximone. Baseline radionuclide ventriculography was performed in all subjects with derivation of left ventricular ejection fraction and peak diastolic filling rate. These parameters were again assessed after 3 months of therapy with either placebo (six patients) or enoximone (seven patients). Ejection fraction increased significantly (p less than 0.05) in the enoximone group (change from baseline = 11 +/- 14 ejection fraction units) but did not change in the placebo group (0.2 +/- 5 ejection fraction units). Enoximone administration was associated with a significant (p less than 0.05) increase in peak filling rate, from 0.9 +/- 0.5 to 1.4 +/- 0.5 end-diastolic volumes per second, which was noted in the placebo group (1.2 +/- 0.6 to 1.4 +/- 0.9 end-diastolic volumes per second; p = not significant). Thus, in comparison with placebo, exoximone augmented both diastolic and systolic function in dilated cardiomyopathy. This identifies an additional influence of this class of inotropic agent on the function of the intact ventricle that is consistent with previously described cellular mechanisms and that may significantly contribute to a restoration of normal hemodynamic status in dilated cardiomyopathy.
Blood Pressure↗
Syncope in dental practice.
This article will provide an overview of the pathophysiologic mechanism and management of syncope. It will discuss the classifications and varieties of syncope, as well as syncope caused by dental practices. Finally, the authors will suggest management options for syncope.
Dental Care↗
The TPA controversy and the drug approval process. The view of the Cardiovascular and Renal Drugs Advisory Committee.
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Cerebral Hemorrhage↗
Regional blood flow responses to vasodilators and inotropes in congestive heart failure.
Regional blood flow and the distribution of cardiac output is an important aspect of the pathophysiology and pharmacology of human congestive heart failure. This study presents the cumulative experience and data from our laboratories with specific reference to (1) the regional blood flow responses, some rather unique, to various vasodilators and inotropes in patients with congestive heart failure (CHF), and (2) the pharmacophysiologic conclusions and concepts that have evolved from these data. Certain drugs and drug groups evoke rather consistent changes in the blood flow of certain organ systems in CHF. Renal blood flow is augmented by hydralazine, an effect that persists with chronic administration. The converting enzyme inhibitors, captopril and enalapril, increase renal blood flow; this implies that the renin-angiotensin II-aldosterone axis plays a major role in modifying renal blood flow and regional blood flow distribution in human CHF. Nitrates either reduce or do not change renal blood flow. Augmentation of hepatic-splanchnic blood flow occurs after first-dose alpha 1-adrenoceptor blockade suggesting that alpha-adrenergic agonism plays an important role in modifying hepatic-splanchnic flow and the regional distribution of cardiac output in CHF. A number of drugs and drug groups increase limb blood flow (e.g., dobutamine, dopexamine, intravenous nitrates, nitroprusside, hydralazine and nifedipine). With respect to regional blood flow and the distribution of cardiac output in CHF, major differences have been shown to exist between drug groups, between drugs within a group and between different doses of a drug. Certain agents can cause a redistribution of systemic flow without changing cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)
Adrenergic alpha-Antagonists↗
Cardiovascular pharmacology of dopexamine in low output congestive heart failure.
Dose-response infusions (0.25 to 4.0 micrograms/kg/min) and extended infusions of dopexamine, a new synthetic catechol with beta 2 adrenergic and dopaminergic agonist effects, were performed in 12 patients with low output congestive heart failure (CHF). The central and regional hemodynamic effects and responses in renal function were determined and compared with those of saline-placebo control patients in a randomized, double-blind, crossover design. Dopexamine significantly increased cardiac output at a dose greater than or equal to 0.25 micrograms/kg/min secondary to an increase in stroke volume at greater than or equal to 0.25 micrograms/kg/min and heart rate at greater than or equal to 0.50 micrograms/kg/min. Dopexamine evoked a significant decrease in systemic and pulmonary vascular resistances, with mild reductions noted for systemic and pulmonary diastolic pressures. Right and left ventricular filling pressures decreased over the entire dose range of dopexamine concomitant with a demonstrable improvement in the indexes of ventricular performance. Dopexamine preferentially increased visceral (renal, hepatic-splanchnic) blood flow over that of limb. Urine volume and sodium excretion increased slightly with dopexamine. Dopexamine elicits rather prominent vasodilating effects (particularly of visceral vascular beds), some positive inotropy and chronotropy and favorable responses in renal function.
Adrenergic Agonists↗
"A-wave" liver.
The finding and timing of hepatic pulsations can provide important information regarding the status of right heart structures and function. We report a 54-year-old woman with idiopathic dilated cardiomyopathy, who had prominent hepatic presystolic pulsations ("A-wave" liver). The clinical findings and the venous and hepatic pulse recordings are presented and discussed in terms of clinical pathophysiology and significance.
Cardiomyopathy, Dilated↗