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Seitz BM, Orer HS, Krieger-Burke T, Darios ES, Thompson JM, Fink GD, Watts SW. 5-HT causes splanchnic venodilation. Am J Physiol Heart Circ Physiol 2017. [PMID: 28626072 DOI: 10.1152/ajpheart.00165.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by the 5-HT7 receptor antagonist SB-269970. Western blot analyses showed that the abdominal inferior vena cava and portal vein express 5-HT7 receptor protein. In contrast, the thoracic vena cava, outside the splanchnic circulation, did not relax to serotonergic agonists and exhibited minimal expression of the 5-HT7 receptor. Male Sprague-Dawley rats with chronically implanted radiotelemetry transmitters underwent repeated ultrasound imaging of abdominal vessels. After baseline imaging, minipumps containing vehicle (saline) or 5-HT (25 μg·kg-1·min-1) were implanted. Twenty-four hours later, venous diameters were increased in rats with 5-HT-infusion (percent increase from baseline: superior mesenteric vein, 17.5 ± 1.9; portal vein, 17.7 ± 1.8; and abdominal inferior vena cava, 46.9 ± 8.0) while arterial pressure was decreased (~13 mmHg). Measures returned to baseline after infusion termination. In a separate group of animals, treatment with SB-269970 (3 mg/kg iv) prevented the splanchnic venodilation and fall in blood pressure during 24 h of 5-HT infusion. Thus, 5-HT causes 5-HT7 receptor-dependent splanchnic venous dilation associated with a fall in blood pressure.NEW & NOTEWORTHY This research is noteworthy because it combines and links, through the 5-HT7 receptor, an in vitro observation (venorelaxation) with in vivo events (venodilation and fall in blood pressure). This supports the idea that splanchnic venodilation plays a role in blood pressure regulation.
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Affiliation(s)
- Bridget M Seitz
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Hakan S Orer
- Department of Pharmacology, School of Medicine, Koc University, Istanbul, Turkey
| | - Teresa Krieger-Burke
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Emma S Darios
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Janice M Thompson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Gregory D Fink
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
| | - Stephanie W Watts
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan; and
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Chantler PD, Nussbacher A, Gerstenblith G, Schulman SP, Becker LC, Ferrucci L, Fleg JL, Lakatta EG, Najjar SS. Abnormalities in arterial-ventricular coupling in older healthy persons are attenuated by sodium nitroprusside. Am J Physiol Heart Circ Physiol 2011; 300:H1914-22. [PMID: 21378146 DOI: 10.1152/ajpheart.01048.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The coupling between arterial elastance (E(A); net afterload) and left ventricular elastance (E(LV); pump performance), known as E(A)/E(LV), is a key determinant of cardiovascular performance and shifts during exercise due to a greater increase in E(LV) versus E(A). This normal exercise-induced reduction in E(A)/E(LV) decreases with advancing age. We hypothesized that sodium nitroprusside (SNP) can acutely ameliorate the age-associated deficits in E(A)/E(LV). At rest and during graded exercise to exhaustion, E(A) was characterized as end-systolic pressure/stroke volume and E(LV) as end-systolic pressure/end-systolic volume. Resting E(A)/E(LV) did not differ between old (70 ± 8 yr, n = 15) and young (30 ± 5 yr, n = 17) subjects because of a tandem increase in E(A) and E(LV) in older subjects. During peak exercise, a blunted increase in E(LV) in old (7.8 ± 3.1 mmHg/ml) versus young (11.4 ± 6.5 mmHg/ml) subjects blunted the normal exercise-induced decline in E(A)/E(LV) in old (0.25 ± 0.11) versus young (0.16 ± 0.05) subjects. SNP administration to older subjects lowered resting E(A)/E(LV) by 31% via a reduction in E(A) (10%) and an increase in E(LV) (47%) and lowered peak exercise E(A)/E(LV) (36%) via an increase in E(LV) (68%) without a change in E(A). Importantly, SNP attenuated the age-associated deficits in E(A)/E(LV) and E(LV) during exercise, and at peak exercise E(A)/E(LV) in older subjects on drug administration did not differ from young subjects without drug administration. In conclusion, some age-associated deficiencies in E(A)/E(LV), E(A), and E(LV), in older subjects can be acutely abolished by SNP infusion. This is relevant to common conditions in older subjects associated with a significant impairment of exercise performance such as frailty or heart failure with preserved ejection fraction.
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Affiliation(s)
- Paul D Chantler
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
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Sjögren A. Treatment of congestive heart failure. ACTA PHARMACOLOGICA ET TOXICOLOGICA 2009; 54 Suppl 1:93-101. [PMID: 6369885 DOI: 10.1111/j.1600-0773.1984.tb03640.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The past decade has improved our understanding of the pathophysiological mechanisms underlying the congestive heart failure syndrome. The same decade has seen a considerable expansion in modes of therapy for this syndrome. A review of the present forms of treatment is given.
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Cockrill BA, Kacmarek RM, Fifer MA, Bigatello LM, Ginns LC, Zapol WM, Semigran MJ. Comparison of the effects of nitric oxide, nitroprusside, and nifedipine on hemodynamics and right ventricular contractility in patients with chronic pulmonary hypertension. Chest 2001; 119:128-36. [PMID: 11157594 DOI: 10.1378/chest.119.1.128] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
STUDY OBJECTIVES The effects of inhaled nitric oxide (NO) on hemodynamics and right ventricular (RV) contractility were compared with those of nitroprusside and nifedipine in 14 patients with severe chronic pulmonary hypertension. STUDY DESIGN Micromanometer and balloon-tipped right heart catheterization were performed. Inhaled NO, IV nitroprusside, and sublingual nifedipine were administered sequentially while patients breathed > 90% oxygen. SETTING Cardiac catheterization laboratory in a tertiary care teaching hospital. PATIENTS Fourteen patients with severe pulmonary hypertension unrelated to left ventricular dysfunction. MEASUREMENTS AND RESULTS During NO inhalation, mean systemic arterial pressure (MAP) was unchanged, but pulmonary artery (PA) pressure ([mean +/- SEM] 49 +/- 2 mm Hg vs 44 +/- 2 mm Hg; p < 0.01), pulmonary vascular resistance (PVR; 829 +/- 68 vs 669 +/- 64 dyne x s x cm(-5); p < 0.01) and RV end-diastolic pressure (RVEDP; 12 +/- 1 vs 10 +/- 1 mm Hg; p < 0.01) decreased. Stroke volume index (SVI; 31 +/- 2 vs 35 +/- 3 mL/m(2); p < 0.05) increased, and the first derivative of RV pressure at 15 mm Hg developed pressure (RV +dP/dt at DP15) was unchanged. During nitroprusside administration, MAP decreased (105 +/- 5 vs 76 +/- 5 mm Hg; p < 0.01), PA was unchanged (48 +/- 2 vs 45 +/- 3 mm Hg; p = not significant), and PVR decreased (791 +/- 53 vs 665 +/- 53 dyne x s x cm(-5); p < 0.01). RV +dP/dt at DP15 increased (425 +/- 22 vs 465 +/- 29 mm Hg/s; p < 0.05), but SVI was unchanged. Nifedipine decreased MAP (103 +/- 5 vs 94 +/- 5 mm Hg; p < 0.01), PA and PVR were unchanged, RVEDP increased (12 +/- 1 vs 14 +/- 2 mm Hg; p < 0.01), and RV +dP/dt at DP15 decreased (432 +/- 90 vs 389 +/- 21 mm Hg/s; p < 0.05). CONCLUSIONS Inhaled NO is a selective pulmonary vasodilator in patients with chronic pulmonary hypertension that improves cardiac performance without altering RV contractility. Nitroprusside caused a similar degree of pulmonary vasodilation. In contrast to inhaled NO, nitroprusside caused systemic hypotension associated with an increase in RV contractility. Acute administration of nifedipine did not cause pulmonary vasodilation, but RVEDP increased and RV contractility decreased.
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Affiliation(s)
- B A Cockrill
- Pulmonary and Critical Care Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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6
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Nussbacher A, Gerstenblith G, O'Connor FC, Becker LC, Kass DA, Schulman SP, Fleg JL, Lakatta EG. Hemodynamic effects of unloading the old heart. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H1863-71. [PMID: 10564141 DOI: 10.1152/ajpheart.1999.277.5.h1863] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A reduction in upright exercise capacity with aging in healthy individuals is accompanied by acute left ventricular (LV) dilatation and impaired LV ejection. To determine whether acute vasodilator administration would improve LV ejection during exercise, sodium nitroprusside (NP) was administered to 16 healthy subjects, ages 64-84 yr, who had been screened for the absence of coronary heart disease by prior exercise thallium scintigraphy. Infusion of NP (0. 3-1.0 microgram. kg(-1). min(-1)), titrated to reduce the resting mean arterial pressure 10% (and eliminate the late augmentation of carotid arterial pressure), increased LV ejection fraction (EF) compared with placebo during upright, maximal graded cycle exercise at all work rates and permitted an equivalent stroke volume and stroke work from a smaller end-diastolic volume. The maximum increase in exercise EF in older subjects during NP infusion was equal to that in healthy, younger (22-39 yr) control subjects. The maximum cycle work rate and cardiac index were unchanged compared with placebo. Thus combined preload and afterload reduction with NP in older individuals improves overall LV ejection phase function: exercise LV stroke work is reduced, EF is increased, and stroke volume is maintained in the setting of a reduced ventricular size. These findings suggest that at least some of the age-associated decline in cardiac function during maximal aerobic exercise may be secondary to adverse loading conditions.
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Affiliation(s)
- A Nussbacher
- Gerontology Research Center, National Institute on Aging, Baltimore, Maryland 21224, USA
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7
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Davis RE, Wachholz JH, Jassir D, Perlyn CA, Agrama MH. Comparison of topical anti-ischemic agents in the salvage of failing random-pattern skin flaps in rats. ARCHIVES OF FACIAL PLASTIC SURGERY 1999; 1:27-32. [PMID: 10937072 DOI: 10.1001/archfaci.1.1.27] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To determine the efficacy of topical anti-ischemic drug therapy in the salvage of failing, random-pattern skin flaps. DESIGN Prospective, randomized, placebo-controlled, therapeutic trial. SETTING Academic medical center. SUBJECTS Sixty-one adult male Sprague-Dawley rats. INTERVENTION Each experimental rat underwent a caudally based random-pattern skin flap using the modified McFarlane technique. Rats were randomized to 1 of 6 treatment groups: topical nifedipine, topical trolamine salicylate, topical nitroglycerin, topical trolamine salicylate-nitroglycerin combination, topical nifedipine-trolamine salicylate-nitroglycerin combination, or inert carrier ointment (control). Treatment was initiated immediately following flap closure and continued every 6 hours for 7 days. At the end of the treatment period, animals were euthanized and flap survival was determined for each one. RESULTS Topical anti-ischemic drug therapy resulted in a statistically significant reduction in ischemic flap necrosis for each drug (or combination) tested relative to the 44.2% mean necrosis observed in control animals. Treatment with the combination of topical nitroglycerin and topical trolamine salicylate resulted in the best salvage response (25.2% mean necrosis) with a statistically significant improvement in flap survival relative to both controls and nitroglycerin alone. CONCLUSIONS Topical anti-ischemic agents are effective in reducing ischemic necrosis of failing, random-pattern skin flaps in the rat model. Although nitroglycerin, trolamine salicylate, and nifedipine possess unique pharmacologic mechanisms of action, each drug produced a statistically significant improvement in flap survival. The results of this study suggest that topical drug therapy may play an important role in clinical salvage of the failing skin flap. Further studies are needed to explore the potential of combination drug therapy.
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Affiliation(s)
- R E Davis
- Department of Otolaryngology, University of Miami School of Medicine, Fla., USA
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8
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Cotter G, Faibel H, Barash P, Shemesh E, Moshkovitz Y, Metzkor E, Simovitz A, Miller R, Schlezinger Z, Golik A. High-dose nitrates in the immediate management of unstable angina: optimal dosage, route of administration, and therapeutic goals. Am J Emerg Med 1998; 16:219-24. [PMID: 9596418 DOI: 10.1016/s0735-6757(98)90087-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nitrates are commonly used for rapid relief of ischemia in the initial management of unstable angina. However, their optimal dosage, route of administration, and therapeutic goals have not been fully established. This study was conducted to determine the optimal dosage and mode of administration (intravenous bolus versus sublingual spray) of nitrates and the therapeutic goals of their use in the immediate management of unstable angina. In a single-center prospective trial, 72 consecutive patients with unstable angina accompanied by typical ST-segment depression on electrocardiogram were randomly assigned to receive isosorbide dinitrate either as repeated intravenous boluses or as sublingual sprays while being delivered to the hospital by a mobile intensive care unit. Optimal nitrate dosage was tailored to pain relief while monitoring mean blood pressure reduction to an optimal range (5% to 20%) without dosage restriction. The mean nitrate dosage needed for ischemia control during the first hour of treatment was 7.8 +/- 3.8 mg. Optimal blood pressure reduction was achieved by significantly more intravenously treated patients than sublingually treated patients (68% v 41%, P = .037). Intravenously treated patients also experienced a more pronounced therapeutic effect, as assessed by reduction in chest pain score (67% v 39%, P = .0004) and decrease in ST-segment depressions (57% v 27%, P = .004). These results show that higher doses of nitrates than previously recommended are required for ischemia control during the initial management of unstable angina. The use of repeated intravenous boluses is safe and more easily controlled and, therefore, more efficacious than sublingual sprays in inducing the maximal anti-ischemic effect while avoiding significant hypotension.
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Affiliation(s)
- G Cotter
- Assaf Harofeh Medical Center, Zerifin, Israel
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Rogerson ME, Kong CH, Leaker B, Thompson FD, Oviasu E, Neild GH. The effect of recombinant human erythropoietin on cardiovascular responses to postural stress in dialysis patients. Clin Auton Res 1993; 3:271-4. [PMID: 8292883 DOI: 10.1007/bf01829017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The normal response to 45 degrees head-up tilt (decreased stroke volume and cardiac output and increased heart rate and peripheral resistance) is not seen in the majority of haemodialysis patients. This is due to both an abnormal baroreceptor reflex and increased venous tone which may be explained by a number of factors including hypoxia, acidosis and sodium retention. We have studied this response by impedance cardiography in eight chronic haemodialysis patients, both before and after 3 months of treatment with human recombinant erythropoietin. Before treatment the cardiovascular parameters were abnormal both at rest and on tilting in each patient. The change in each measurement following tilting was: stroke volume, 0.5 +/- 6%; cardiac output, 6 +/- 5%; peripheral resistance, -8 +/- 4%; and heart rate, 10 +/- 4%. After 3 months of erythropoietin (150 U/kg/week intravenously) the mean haematocrit had risen from 19.5 +/- 3% to 32.9 +/- 4% and all patients felt physically fitter. Impedance showed no change in the supine-indices but after tilting there was a dramatic fall in stroke volume (-26 +/- 7%) and cardiac output (-17 +/- 7%) and an increase in heart rate (15 +/- 4%) and peripheral resistance (28 +/- 10%) each moving towards the normal response. These results indicate that human recombinant erythropoietin normalizes the response to postural stress in these patients and suggest that anaemia is the principal cause of the abnormal venoconstriction seen in haemodialysis patients. The mechanisms involved warrant further investigation.
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Affiliation(s)
- M E Rogerson
- Department of Nephrology, UCMSM, St Peter's Hospital, London, UK
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10
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Nolan J, Sanderson A, Taddei F, Smith S, Muir AL. Acute effects of intravenous phosphodiesterase inhibition in chronic heart failure: simultaneous pre- and afterload reduction with a single agent. Int J Cardiol 1992; 35:343-9. [PMID: 1612797 DOI: 10.1016/0167-5273(92)90232-r] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Intravenous phosphodiesterase inhibition with milrinone is known to have a beneficial effect on haemodynamics in chronic heart failure. Its effect on lower limb capacitance vessels has not been previously investigated. We have studied the effect of intravenous milrinone in 10 patients with severe chronic heart failure. Thirty minutes after commencement of treatment mean cardiac index had risen by 26% and pulmonary artery wedge pressure, systemic vascular resistance and right atrial pressure had fallen by 51, 24 and 89%, respectively (p less than 0.05 for all changes). These changes were maintained for the 2 h observation period with no evidence of tolerance and were accompanied by a 17% increase in venous volume (p less than 0.01) and a 42% increase in ejection fraction (p less than 0.001) at 30 min; at 120 min the improvement in ejection fraction had been maintained and a further increase in venous volume to 38% above baseline was evident. The increase in venous volume was strongly correlated with the decrease in mean pulmonary artery wedge pressure and mean right atrial pressure at 30 min and 2 h (r = -0.80 and -0.69 for mean pulmonary artery wedge pressure, r = -0.88 and -0.56 for mean right atrial pressure). Milrinone therefore has clinically important venodilating properties, in addition to its known effects as an arterial vasodilator and a positive inotrope.
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Affiliation(s)
- J Nolan
- University Department of Medicine, Royal infirmary, Edinburgh, UK
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Capewell S, Wathen CG, Muir AL. Central and peripheral haemodynamic responses to felodipine in congestive heart failure. Eur J Clin Pharmacol 1991; 41:95-8. [PMID: 1743253 DOI: 10.1007/bf00265898] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Using non-invasive radionuclide techniques, we studied the arterial and venous effects of 0.1 mg/kg oral felodipine in 12 men with heart failure due to ischaemic heart disease aged 37-72 y. All were in New York Heart Association Class II or III, required frusemide 40-120 mg daily and were clinically stable. Felodipine produced significant falls in blood pressure (-19%) and systemic vascular resistance (-39%) with increases in cardiac index (+34%), heart rate (+12%) and left ventricular ejection fraction (from 0.25 to 0.32). Peripheral venous volume fell by 10.6% after felodipine indicating venoconstriction rather than venodilatation and may be caused by an acute sympathetic reflex associated with the increase in heart rate. Our results confirm that felodipine is an arterial vasodilator. The previously observed changes in cardiac filling pressures may simply represent improved ventricular function as a consequence of reduced afterload, not venodilatation.
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Affiliation(s)
- S Capewell
- Department of Medicine, Royal Infirmary, Edinburgh, UK
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12
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Ogawa S, Narita G, Nomura H, Yasuma F, Miyaguchi K, Hayashi H, Sotobata I. Effects of vasodilators on venous tone in vivo in dogs. Angiology 1991; 42:202-9. [PMID: 2018241 DOI: 10.1177/000331979104200304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The authors investigated, in vivo, the effects of four vasodilators on venous tone in dogs. Baseline venous tone was determined from the pressure: diameter relationships in the inferior vena cava (VSIVC) and femoral vein (VSFV) as measured during several seconds of occlusion of the proximal inferior vena cava. All of the slopes were nearly linear. All vasodilators were administered in dosages sufficient to lower blood pressure by approximately 20%; these dosages also decreased systemic vascular resistance by 15% to 30%. Isosorbide dinitrate reduced VSIVC from 7.17 +/- 0.81 to 5.81 +/- 0.73 mmHg/mm and VSIVC from 59.4 +/- 13.5 to 37.2 +/- 6.6 mmHg/mm. Neither nifedipine nor nisoldipine altered VSIVC or VSFV. However, prazosin decreased VSIVC from 13.2 +/- 3.3 to 10.7 +/- 2.7 mmHg/mm and VSFV from 43.5 +/- 11.3 to 29.9 +/- 8.8 mmHg/mm. These results suggest that isosorbide dinitrate and prazosin decrease venous tone in vivo, whereas nifedipine and nisoldipine do not.
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Affiliation(s)
- S Ogawa
- First Department of Internal Medicine, Nagoya University School of Medicine, Japan
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Masuyama T, Uematsu M, Nakatani S, Sato H, Kodama K. Doppler echocardiographic assessment of changes in pulmonary artery pressure associated with vasodilating therapy in patients with congestive heart failure. J Am Soc Echocardiogr 1991; 4:35-42. [PMID: 2003935 DOI: 10.1016/s0894-7317(14)80158-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Transpulmonic pressure gradient and pulmonary artery pressures can be estimated from the Doppler pulmonary regurgitant flow velocities by applying the simplified Bernoulli equation. In this study, continuous-wave Doppler echocardiography was used to assess changes in pulmonary regurgitant flow velocities associated with administration of vasodilators in 10 patients with congestive heart failure. M-Mode echocardiographic parameters such as left ventricular end-systolic and end-diastolic dimension and fractional shortening did not change with administration of vasodilators. Pulmonary regurgitant flow velocity at end diastole decreased from 1.9 +/- 0.6 to 1.3 +/- 0.3 m/sec (p less than 0.01), and Doppler-estimated transpulmonic pressure gradient at end diastole decreased from 16 +/- 11 to 8 +/- 4 mm Hg (p less than 0.01). Doppler-estimated transpulmonic pressure gradient at end diastole was compared with catheterization-determined pulmonary arterial end-diastolic pressure before and after administration of vasodilators in three patients, and there was a good agreement between these measurements. Thus noninvasive and sensitive assessment of the effect of vasodilators on pulmonary arterial end-diastolic pressure in patients with congestive heart failure is possible with continuous-wave Doppler echocardiographic measurement of pulmonary regurgitant flow velocities.
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Affiliation(s)
- T Masuyama
- Cardiovascular Division, Osaka Police Hospital, Japan
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Abstract
There are five variables affecting cardiac output: heart rate and rhythm; contractility; ventricular preload; and ventricular afterload. The choice of specific drugs to augment myocardial performance is based on the spectra of their effects on these variables. In order to use inotropes and vasodilators efficiently in clinical situations, it is important to recognize the dose-response relationship, to consider route and rate of administration, and to take into account the presence of other drugs as well as the abnormal pathophysiology of the patient. The safe and effective use of inotropes and vasodilators in critically ill patients is most readily achieved when there is a systematic plan for introducing the drug, evaluating its effects, and adjusting those hemodynamic variables that can be controlled.
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Affiliation(s)
- C C Hug
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia
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Palevsky HI, Schloo BL, Pietra GG, Weber KT, Janicki JS, Rubin E, Fishman AP. Primary pulmonary hypertension. Vascular structure, morphometry, and responsiveness to vasodilator agents. Circulation 1989; 80:1207-21. [PMID: 2805259 DOI: 10.1161/01.cir.80.5.1207] [Citation(s) in RCA: 159] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The use of pharmacologic agents in the treatment of pulmonary hypertension has not proved to be uniformly successful or predictable. One possible reason for the vagaries in response is that the pulmonary vascular lesions are not consistent. We examined the relation between the structure of the pulmonary resistance vessels in unexplained (primary) pulmonary hypertension and the response to pulmonary vasodilators. Our study involved 19 patients with clinically unexplained pulmonary hypertension (mean pressure, 59 +/- 14 mm Hg). After characterizing them clinically and performing control hemodynamic measurements, we determined the acute effects of a series of vasodilator agents that have different mechanisms of action. In 16 patients, lung biopsy material was related to the hemodynamic studies; in nine patients, including six who had undergone open lung biopsy, the hemodynamic studies were related to the pathologic changes found at autopsy. Histologic specimens from all 19 patients were evaluated qualitatively and sorted into three subsets of hypertensive pulmonary arteriopathy: medial hypertrophy (with minimal intimal proliferation), arteriopathy with plexiform lesions (associated predominantly with concentric laminar intimal proliferation and fibrosis), and arteriopathy with microthrombotic lesions (associated predominantly with eccentric intimal proliferation and fibrosis). The 16 lung biopsies were also quantitated by morphometric techniques. Using a decrease in calculated pulmonary vascular resistance of more than 30% accompanied by a decrease in mean pulmonary arterial pressure of at least 10% to define vasodilation, only four patients were responders. The patients varied considerably in their responses to different vasodilator agents. Patients with similar clinical and hemodynamic profiles differed considerably with respect to the nature of their pulmonary vascular obstructive lesions and their responses to vasodilator agents. Qualitative histologic examination of lung tissue did not provide a basis for predicting how individual patients would respond to vasodilator agents. However, quantitative morphologic analysis of the initial open lung biopsy specimens did prove helpful in predicting acute responsiveness to vasodilator agents and the subsequent clinical course of these patients with unexplained (primary) pulmonary hypertension. An intimal area of more than 18% of the vascular cross-sectional area had an 85% predictive value for identifying the patients who did poorly during the first 36 months of follow-up.
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Affiliation(s)
- H I Palevsky
- Department of Medicine, University of Pennsylvania, Philadelphia 19104-4283
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Capewell S, Taverner D, Hannan WJ, Muir AL. Acute and chronic arterial and venous effects of captopril in congestive cardiac failure. BMJ (CLINICAL RESEARCH ED.) 1989; 299:942-5. [PMID: 2508945 PMCID: PMC1837786 DOI: 10.1136/bmj.299.6705.942] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE To determine whether captopril alters peripheral venous tone in patients with congestive cardiac failure. DESIGN Open study of patients at start of captopril treatment and three months later. SETTING A hospital gamma camera laboratory. PATIENTS 16 Men with congestive cardiac failure in New York Heart Association class II or III, aged 57-73. INTERVENTIONS Patients were initially given 500 micrograms sublingual glyceryl trinitrate followed by 25 mg oral captopril. The study was then repeated after three months' captopril treatment. MAIN OUTCOME MEASURES Previously validated non-invasive radionuclide techniques were used to measure changes in central haemodynamic variables and peripheral venous volumes in the calf. RESULTS After 25 mg captopril there were falls in blood pressure and relative systemic vascular resistance and increases in cardiac index and left ventricular ejection fraction. This was accompanied by a 16% increase in peripheral venous volume (95% confidence interval 13.4% to 18.4%, p less than 0.01), which compared with an 11% increase after 500 micrograms glyceryl trinitrate (10% to 12%, p less than 0.01). Eleven patients were restudied after three months' continuous treatment with captopril. The resting venous volume was higher than it had been initially, by about 10%, and increased by a further 8.4% after 25 mg captopril (5.4% to 11.4%, p less than 0.05). CONCLUSIONS Captopril is an important venodilator. Venous and arterial dilatation are produced short term and during long term treatment.
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Affiliation(s)
- S Capewell
- University Department of Medicine, Royal Infirmary, Edinburgh
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18
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Tsai SC, Adamik R, Manganiello VC, Moss J. Effects of nitroprusside and nitroglycerin on cGMP content and PGI2 formation in aorta and vena cava. Biochem Pharmacol 1989; 38:61-5. [PMID: 2535935 DOI: 10.1016/0006-2952(89)90149-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Nitroprusside (NP) and nitroglycerin (NG) are potent vasodilators that are used clinically on the basis of their abilities to cause relaxation of smooth muscle. In vitro, both agents cause activation of guanylate cyclase, resulting in increased intracellular cGMP. They also have effects on arachidonate metabolism. Despite apparent similarities in their mechanisms of action, the two drugs have different therapeutic applications based in part on differences in their effectiveness on the arterial and venous systems in vivo. To understand better their target tissue preference, slices of aorta and vena cava were incubated with the agents; cGMP and the vasodilatory prostanoid, prostacyclin, were quantified. NP was more effective in increasing the cGMP content of aorta than of vena cava; it was more active than NG in both tissues. Prostaglandin formation by vascular tissue was influenced by the preliminary equilibration period. Under optimal conditions, it appeared that NG enhanced prostacyclin formation in aorta more than did NP. This in vitro model for NP and NG action may be useful in studying the mechanisms of action of these and other vasoactive agents.
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Affiliation(s)
- S C Tsai
- Laboratory of Cellular Metabolism, National Heart, Lung, and Blood Institute, Bethesda, MD 20892
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19
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Young JB, Leon CA, Pratt CM, Kingry C, Taylor AA, Roberts R. Intravenous fenoldopam in heart failure: comparing the hemodynamic effects of dopamine1 receptor agonism with nitroprusside. Am Heart J 1988; 115:378-84. [PMID: 2893527 DOI: 10.1016/0002-8703(88)90485-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Dopamine1 receptors mediate hemodynamic effects that may be beneficial in patients with congestive heart failure. We infused the selective dopamine1 receptor agonist, fenoldopam mesylate (SKF 82526 J), to evaluate hemodynamic and neurohumoral changes during continuous intravenous infusion in patients with congestive heart failure and compared them with the effects of nitroprusside, a traditional vasodilator that works by a distinctly different mechanism. In 15 patients with a mean radionuclide ejection fraction of 17%, the agents were infused in a random-ordered, double-blinded, crossover, active drug-controlled protocol after optimal dosing was determined during a titration period. Hemodynamic changes were induced in minutes with both drugs during a mean (+/- standard deviation) infusion dose of 1.45 +/- 1.66 micrograms/kg/min for fenoldopam and 2.99 +/- 1.59 micrograms/kg/min for nitroprusside. At 1 hour, mean blood pressure decreased and cardiac index rose with both drugs, and the effect lasted throughout the 6-hour infusion period. Nitroprusside, but not fenoldopam, reduced right heart filling pressures (including mean pulmonary capillary wedge, mean right atrial, and mean pulmonary artery pressures) during the infusion period. Both drugs caused significant reduction in systemic vascular and pulmonary arteriolar resistances. No significant change occurred in plasma norepinephrine levels. Fenoldopam ameliorates some of the adverse hemodynamic changes that occur during heart failure but does not reduce right heart filling pressures as does nitroprusside. Because of fenoldopam's unique characteristics, it may benefit certain patients with heart failure.
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Affiliation(s)
- J B Young
- Section of Cardiology, Methodist Hospital, Houston, TX
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20
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Watkins RW, Sybertz EJ, Tedesco RP. Nitroprusside, but not ANF inhibits venoconstriction in an in situ rat model. Eur J Pharmacol 1987; 143:299-304. [PMID: 2961584 DOI: 10.1016/0014-2999(87)90453-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Potential venodilator actions of nitroprusside (10 and 50 micrograms/min) and ANF (23 amino acid rat sequence, 10 and 30 micrograms/min) were assessed in rats subjected to cardiopulmonary bypass. Norepinephrine (NE, 10 micrograms) caused arterial pressor, i.e. increased perfusion pressure and venoconstrictor, i.e. increased venous flow, effects. ANF infusion failed to alter NE-induced pressor and venoconstrictor effects while nitroprusside significantly inhibited NE responses. Thus nitroprusside but not ANF, shows venodilator properties in this in situ rat model.
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Affiliation(s)
- R W Watkins
- Department of Pharmacology, Schering Research, Bloomfield, NJ 07003
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21
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Goldsmith SR. Treatment of congestive heart failure. Pathophysiologic and pharmacologic concepts. Postgrad Med 1987; 81:257-66, 268. [PMID: 3035525 DOI: 10.1080/00325481.1987.11699878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Congestive heart failure is a serious health problem in Western society. Understanding of both the basic pathophysiology and the design of rational and effective treatment of this syndrome has increased dramatically in the last ten years. However, congestive heart failure remains a highly lethal disease, which kills at a rate exceeding that of most cancers. Prevention is therefore of the utmost importance and has to come primarily from a reduction in the incidence and damage done from myocardial infarction. Improved understanding of the pathophysiology of idiopathic dilated cardiomyopathy is also needed. Through understanding of pathophysiologic principles, effective therapy based on interference with known mechanisms that are operative in the disease is now available but can be refined in the future.
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22
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Young JB, Leon CA, Pratt CM. Potentially deleterious effects of long-term vasodilator therapy in patients with heart failure. Chest 1987; 91:737-44. [PMID: 3032523 DOI: 10.1378/chest.91.5.737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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23
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Griffin RM, Kaplan JA. Myocardial ischaemia during non-cardiac surgery. A comparison of different lead systems using computerised ST segment analysis. Anaesthesia 1987; 42:155-9. [PMID: 3548475 DOI: 10.1111/j.1365-2044.1987.tb02989.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Computerised ST segment analysis was used to compare the frequency of ischaemia occurring in electrocardiographic leads II, V5, CS5 and CB5. Three out of 15 patients with ischaemic heart disease developed ischaemic changes, which were evident in all four leads in each patient. A single bipolar lead may be substituted for a true V5 lead when monitoring patients at increased risk of developing myocardial ischaemia. ST segment analysis facilitates the early diagnosis of peri-operative myocardial ischaemia, which may otherwise be missed on the standard electrocardiogram.
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Young JB, Leon CA, Pratt CM, Suarez JM, Aronoff RD, Roberts R. Hemodynamic effects of an oral dopamine receptor agonist (fenoldopam) in patients with congestive heart failure. J Am Coll Cardiol 1985; 6:792-6. [PMID: 2863295 DOI: 10.1016/s0735-1097(85)80484-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Dopamine receptor stimulation causes vascular and neurohumoral responses that may be beneficial in patients with heart failure. Oral inactivity, emesis and adrenergic-induced arrhythmias have limited the use of currently available compounds. Fenoldopam (SKF-82526-J) is a new, orally available, selective, dopamine-receptor agonist with potent renal vasodilating properties (six times that of dopamine) without positive inotropic or adrenergic activity. Drug efficacy was clinically evaluated in 10 patients with heart failure after single oral doses of placebo and 50, 100 and 200 mg of medication. Placebo produced no changes. Peak efficacy was noted 30 minutes to 1 hour after the 200 mg dose with mean blood pressure decreasing from 96 +/- 15 (mean +/- SD) to 83 +/- 8 mm Hg (p less than 0.05), pulmonary capillary wedge pressure decreasing from 23 +/- 6 to 20 +/- 8 mm Hg (p less than 0.05) and mean pulmonary artery pressure decreasing from 32 +/- 9 to 29 +/- 8 mm Hg (p less than 0.05). Systemic vascular resistance decreased from 1,987 +/- 887 to 1,191 +/- 559 dynes.s.cm-5 (p less than 0.05) with a subsequent 55% increase in cardiac index from 2.2 +/- 1.1 to 3.1 +/- 1.3 liters/min per m2 (p less than 0.05). Heart rate and right atrial pressure did not change (p greater than 0.05). No emesis or new tachycardia was noted at any dose. Baseline hemodynamics generally returned within 3 to 4 hours. Fenoldopam, therefore, is a short-acting, orally effective drug that decreases systemic vascular resistance and increases cardiac index in patients with heart failure and represents a new class of oral compounds that may be useful in treating such patients.
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25
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Faison EP, Siegl PK, Morgan G, Winquist RJ. Regional vasorelaxant selectivity of atrial natriuretic factor in isolated rabbit vessels. Life Sci 1985; 37:1073-9. [PMID: 3162073 DOI: 10.1016/0024-3205(85)90599-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Synthetic atrial natriuretic factor (ANF) exhibited a marked selectivity in its ability to relax isolated rabbit arteries and veins. The aorta, renal and mesenteric arteries and the facial vein were the most sensitive vessels with the more distal arteries and most veins being relatively unresponsive to ANF. All preparations were effectively relaxed by sodium nitroprusside. ANF (up to 10(-7) M) failed to elicit any effect on isolated rabbit right atria or papillary muscles. The profound regional vasorelaxant selectivity of ANF may help to explain the hemodynamic effects of this substance in vivo.
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26
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Marzilli M, Simonetti I, Levantesi D, Trivella MG, De Nes M, Perissinotto A, Puntoni R, Buzzigoli G, Boni C, Michelassi C. Effects of dilazep on coronary and systemic hemodynamics in humans. Am Heart J 1984; 108:276-85. [PMID: 6431792 DOI: 10.1016/0002-8703(84)90612-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The cardiovascular effects of dilazep, a new antianginal drug, were investigated in 18 patients, who underwent cardiac catheterization and coronary angiography for the evaluation of chest pain. Dilazep, 0.2 mg/kg, was injected intravenously over 1 to 2 minutes. The changes induced by dilazep in coronary tone were assessed by quantitative angiography in four patients, changes in systemic and coronary hemodynamics and blood gases in eight patients, and changes in systemic and pulmonary hemodynamics and blood gases in six. In 6 of the 18 patients the effects on hemoglobin-O2 oxygen binding were also investigated. Following dilazep administration, we observed a marked reduction of coronary resistance (six patients) (0.5 vs 1.0 mm Hg X min X ml-1, p less than 0.01) and of aortic-coronary sinus oxygen difference (seven patients) (4.6 vs 12.3 vol%, p less than 0.01), and a 23% increase in coronary diameter (four patients) (p less than 0.001). Total systemic resistance was also reduced by dilazep (six patients). Conversely, only minimal or insignificant changes were observed in heart rate (14 patients), aortic pressure (14 patients), total pulmonary resistance (six patients), myocardial oxygen consumption (six patients), double product (14 patients), blood gases (seven patients), and hemoglobin-oxygen affinity (six patients). We conclude that dilazep exerts a powerful dilating action on coronary vasculature without appreciable increase of myocardial oxygen consumption and cardiac work simultaneously with a reduction of peripheral resistance.
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27
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Benfey BG, Elfellah MS, Ogilvie RI, Varma DR. Anti-arrhythmic effects of prazosin and propranolol during coronary artery occlusion and re-perfusion in dogs and pigs. Br J Pharmacol 1984; 82:717-25. [PMID: 6743921 PMCID: PMC1987014 DOI: 10.1111/j.1476-5381.1984.tb10811.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Open-chest dogs and pigs anaesthetized with pentobarbitone were used to evaluate the anti-arrhythmic effect of prazosin and propranolol during a 30 min period of occlusion of the left anterior descending coronary artery followed by 15 min of re-perfusion. In dogs, both prazosin and propranolol reduced the incidence of ventricular premature depolarizations and ventricular tachycardia during the occlusion period. During the 45 min period of occlusion and re-perfusion, the incidence of ventricular fibrillation was significantly reduced in the prazosin-treated and propranolol-treated dogs. In pigs prazosin reduced the incidence of ventricular premature depolarizations during occlusion and propranolol reduced the incidence of both ventricular premature depolarizations and ventricular tachycardia during occlusion, but the incidence of ventricular fibrillation was not significantly reduced in the prazosin- and propranolol-treated pigs. Prazosin reduced arterial pressure and propranolol lowered heart rate in both dogs and pigs, but a comparison of mean arterial pressure and heart rate in animals surviving and those not surviving the 30 min of coronary artery occlusion and 15 min of re-perfusion showed no significant difference.
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Young JB, Pratt CM, Farmer JA, Luck JC, Fennell WH, Roberts R. Specialized delivery systems for intravenous nitroglycerin. Are they necessary? Am J Med 1984; 76:27-37. [PMID: 6430075 DOI: 10.1016/0002-9343(84)91040-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nitroglycerin is absorbed in vitro into polyvinyl chloride tubing, and it has been recommended that nitroglycerin be administered intravenously through specialized polyethylene infusion sets. To determine if tubing type is essential to achieve physiologic effectiveness, we studied dose responses to intravenous nitroglycerin in 15 patients with heart failure using standard polyvinyl chloride tubing in seven (group 2) and special polyethylene infusion sets in seven (group 1) (one patient was excluded from analysis because of technical difficulties). We monitored heart rate, blood pressure, right atrial pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, and cardiac output. Cardiac index, systemic and pulmonary vascular resistance, triple index, rate pressure product, stroke volume, stroke volume index, and stroke work index were calculated. Baseline and treatment measurements were obtained from five to 15 minutes after the infusion of 10, 20, 40, and 80 micrograms of nitroglycerin per minute. Over-all, systolic blood pressure decreased (p less than 0.05) about 8 percent and mean blood pressure approximately 12 percent, mean pulmonary artery pressure and mean pulmonary capillary wedge pressure decreased 30 to 40 percent, and the decline in mean right atrial pressure was 35 percent of baseline (all p less than 0.05). Heart rate and cardiac index did not change (p greater than 0.05). Pulmonary vascular resistance decreased slightly (p = 0.07) and systemic vascular resistance significantly (p less than 0.05). When the two groups were compared physiologic changes were virtually identical (p less than 0.05). Two-way analysis of variance for baseline corrected data proved no differences between tubing sets (p less than 0.05), but the infusion concentration rate was highly related to response (p = 0.0001). A significant (p less than 0.05) decrease in mean blood pressure and mean right atrial pressure was noted at lower dose rates (20 micrograms per minute and 40 micrograms per minute, respectively) in group 1. Beneficial hemodynamic effects in heart failure patients can, then, be predicted to occur at 80 micrograms per minute infusion rates; these responses seem independent of the type of infusion tubing system employed. Additionally, when patients given intravenous nitroglycerin for various reasons were followed for 48 hours, the majority receiving infusions via polyvinyl chloride tubing (group 2) did not require dosage adjustments. Also, at lower flow rates, more solution than calculated may be delivered when polyethylene tubing infusion sets are employed with volumetric infusion pumps.
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29
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Kurnik PB, Tiefenbrunn AJ, Ludbrook PA. The dependence of the cardiac effects of nifedipine on the responses of the peripheral vascular system. Circulation 1984; 69:963-72. [PMID: 6705172 DOI: 10.1161/01.cir.69.5.963] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
To elucidate the mechanisms of reduction of left ventricular end-diastolic pressure by nifedipine in certain individuals, we evaluated cardiac and peripheral hemodynamic responses in 32 patients after they were randomly assigned to nifedipine (20 mg sublingually) or to placebo treatment. Forearm plethysmography was performed during cardiac catheterization with micromanometers. No hemodynamic parameters were changed after placebo. Left ventricular end-diastolic pressure declined by 14% (p less than .02) after nifedipine in patients with impaired left ventricular function, but was unchanged in those with normal function; indexes of peripheral venous hemodynamics (forearm venous tone, forearm volume change) were not affected. In those patients with abnormal left ventricular function, forearm vascular resistance decreased 36% and forearm blood flow increased 31% (p less than .0005 for both), while neither changed in those with normal function. Cardiac output increased by 10% in patients with impaired left ventricular function but was unchanged in the remainder, while calculated total systemic resistance fell by 24% in those with abnormal left ventricular function (p less than .002 for both). Thus, reduction of left ventricular preload by nifedipine is not attributable to venous pooling, but rather this beneficial effect appears to be attributable to improved left ventricular systolic function in response to afterload reduction, particularly in patients with impaired left ventricular function.
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Manno BV, Iskandrian AS, Hakki AH. Right ventricular function: methodologic and clinical considerations in noninvasive scintigraphic assessment. J Am Coll Cardiol 1984; 3:1072-81. [PMID: 6423715 DOI: 10.1016/s0735-1097(84)80368-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Right ventricular function plays an important role in many cardiac disorders. Changes in left ventricular function, right ventricular afterload and preload, cardiac medications and ischemia may affect right ventricular function. Radionuclide ventriculography permits quantitative assessment of regional and global function of the right ventricle. This assessment can be made at rest, during exercise or after pharmacologic interventions. The overlap between right ventricle and right atrium is a major limitation for gated scintigraphic techniques. The use of imaging with newer short-lived radionuclides may permit more accurate and reproducible assessment of right ventricular function by means of the first pass method. Further work in areas related to improvement of techniques and the impact of right ventricular function on prognosis is needed.
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Bush EN, Vollmer RR. Contribution of beta-adrenergic receptor mediated renin release to the maintenance of blood pressure during nitroprusside infusion in conscious rats. CLINICAL AND EXPERIMENTAL HYPERTENSION. PART A, THEORY AND PRACTICE 1984; 6:2161-72. [PMID: 6099784 DOI: 10.3109/10641968409052201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The extent to which beta-adrenergic receptor mediated renin release contributes to the maintenance of blood pressure during hypotension induced by sodium nitroprusside (SNP, 40 micrograms/kg/min for 30 min) was assessed in conscious Wistar rats fitted with chronic aortic and vena caval catheters. Propranolol, (1.5 mg/kg, i.v.), reduced the basal level of plasma renin activity (PRA) in control rats from 4.4 +/- 0.4 to 2.4 +/- 0.4 ng angiotensin I/ml/min (p less than .05) and decreased PRA obtained during SNP infusion from 35.3 +/- 6.6 to 16.7 +/- 2.2 ng angiotensin I/ml/min (p less than .01). Despite the reduced PRA, the hypotensive response to SNP was not enhanced after propranolol. Treatment of these animals with captopril in order to block the actions of the remaining non-beta-receptor released renin, resulted in augmentation of the SNP hypotension. Captopril also potentiated SNP hypotension in rats that had not received propranolol. The addition of propranolol to the captopril treated rats produced no further change in SNP hypotension. The results of this study indicate that beta-receptor-mediated and beta-receptor-independent mechanisms contribute to the renin released during SNP hypotension. However, if the beta-receptor-mediated component alone is blocked, the remaining renin secretion is adequate to maintain blood pressure during SNP infusion.
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Wathen CG, Hannan WJ, Adie CJ, Muir AL. A radionuclide method for the simultaneous study of the effects of drugs on central and peripheral haemodynamics. Br J Clin Pharmacol 1983; 16:45-50. [PMID: 6224502 PMCID: PMC1427954 DOI: 10.1111/j.1365-2125.1983.tb02142.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
1 The central and peripheral cardiovascular effects of hydralazine and glyceryl trinitrate (GTN) have been contrasted using radionuclide techniques. 2 Following intravenous injection of technetium-99m labelled human serum albumin, radionuclide ventriculography was performed by the equilibrium blood pool method using a mobile gamma camera. Simultaneous measurements of `peripheral venous volume' were made using a collimated scintillation probe positioned above the patient's calf. 3 Ten patients with angina pectoris were studied at rest, after sublingual administration of 0.5 mg GTN and after intravenous administration of 10 mg hydralazine. 4 GTN caused a mean reduction in the end diastolic volume of the left ventricle of 14.6% ± 4.5% (P < 0.005) but ejection fraction increased by 0.034 ± 0.007 (P < 0.005) so that stroke volume was only reduced by 4.9% ± 5.0% (NS). There was a mean increase in heart rate of 10.8 ± 2.3 beats/min (P < 0.001) but no significant change in cardiac output. The calculated systemic vascular resistance fell by 10.0% ± 5.4% (P < 0.05). Associated with these changes there was a mean increase of 9.6% ± 1.5% (P < 0.05) in the counts from the calf. 5 Hydralazine caused a significant reduction in blood pressure and increase in heart rate. End-diastolic volume was reduced by 6.0% ± 2.7% but there was a mean increase in ejection fraction of 0.058 ± 0.010 (P < 0.001) so that in this instance stroke volume increased by 9.0% ± 3.7% (P < 0.05) and cardiac output increased by 16.4% ± 4.4% (P < 0.005). The calculated systemic vascular resistance fell by 18.9% ± 3.8% (P < 0.001). Despite these haemodynamic changes there was no significant change in counts from the calf. 6 The results confirm that GTN has a predominant venodilator effect while hydralazine acts largely on the arterial bed. These relatively simple radionuclide methods will allow a more detailed assessment of the cardiovascular effects of drugs.
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