tbuckley/cabot-search huggingface dataset:
Mitral regurgitation: relationship of noninvasive descriptors of right and left ventricular performance to clinical and hemodynamic findings and to prognosis in medically and surgically treated patients.
Authors: CHochreiter, NNiles, R BDevereux, PKligfield, J SBorer
Journal: Circulation (1986)

To determine objective predictors of survival, 53 patients with chronic, hemodynamically severe mitral regurgitation underwent rest and exercise radionuclide cineangiography, echocardiography, treadmill exercise testing, and ambulatory electrocardiographic monitoring before prospective (average 30 month) follow-up. At entry, symptom status correlated best with radionuclide-based right ventricular ejection fraction (RVEF) and left atrial size, while treadmill exercise tolerance correlated best with RVEF during exercise (r = .48, p less than .005). Correspondingly, in 23 patients who underwent cardiac catheterization, pulmonary arterial systolic and wedge pressures were significantly inversely related to RVEF. On the 24 hr ambulatory electrocardiogram, nonsustained ventricular tachycardia was present in 29% of patients, most frequently when both RVEF and left ventricular ejection fraction (LVEF) were subnormal (p = .03 vs other patients). Since entry, 35 patients have been managed without surgery for 9 to 5...
Abstract 11777: Dysregulation of Glucose Transport in Left Ventricular Myocardium of Dogs With Chronic Heart Failure
Authors: Hani N Sabbah, Ramesh C Gupta, Vinita Singh-Gupta, David E Lanfear
Journal: Circulation (2019)

Introduction: Cardiomyocytes depend on a delicate balance of free fatty acids and glucose as energy sources, a balance that is disrupted in heart failure (HF). Insulin resistance, along with dysreg...
Uncertainty in Management of Carotid Stenosis in Women
Authors: Paola De Rango, Virginia J. Howard, Valeria Caso
Journal: JAMA Surgery (2014)

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA Surgery HomeNew OnlineCurrent IssueFor Authors Podcast Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA Surgery journal
Collagen phenotypes during development and regression of myocardial hypertrophy in spontaneously hypertensive rats.
Authors: DMukherjee, SSen
Journal: Circulation Research (1990)

The myocardium contains collagen matrix that is a major determinant of its architecture, structural integrity, and mechanical properties. This fibrillar matrix consists primarily of type I and type III collagens having epimysial, perimysial, and endomysial components. The present study shows the alteration of collagen phenotypes during the evolution of hypertensive hypertrophy. Therapy with captopril, an angiotensin-converting enzyme inhibitor that regresses cardiac hypertrophy, not only reduces the total amount of collagen but reverses the altered distribution of type I and type III collagen. In normotensive rats, captopril did not significantly reduce collagen content or alter the ratio of type I to type III collagen.
Lisinopril lowers cardiac adrenergic drive and increases beta-receptor density in the failing human heart.
Authors: E MGilbert, ASandoval, PLarrabee, D GRenlund, J BO'Connell, M RBristow
Journal: Circulation (1993)

BACKGROUNDIn subjects with heart failure, angiotensin converting enzyme inhibitors exhibit mild systemic antiadrenergic effects, as deduced from treatment-related lowering of systemic venous norepinephrine levels. The effects of angiotensin converting enzyme inhibitors on cardiac adrenergic drive in subjects with heart failure has not previously been investigated.METHODS AND RESULTSIn a placebo-controlled, double-blind crossover study of 14 patients, we measured cardiac and systemic adrenergic drive, myocardial and lymphocyte beta-adrenergic receptors, and hemodynamic changes at baseline and after 12 weeks of therapy. Relative to placebo, lisinopril therapy was associated with only minimal, statistically insignificant changes in hemodynamics, a significant increase in myocardial beta-receptor density, no significant (P < .05) changes in cardiac or systemic adrenergic drive, and no detectable change in lymphocyte beta-receptor density. When subjects were rank ordered into groups with the highest and lowest...
Improved efficiency of treadmill exercise testing using a multiple lead ECG system and basic hemodynamic exercise response.
Authors: B RChaitman, M GBourassa, PWagniart, FCorbara, R JFerguson
Journal: Circulation (1978)

One hundred consecutive men with a normal ECG at rest had a maximal treadmill test using 14 leads during and post-exercise. Coronary arteriography performed the following day revealed coronary stenoses greater than or equal to 70% in 66 patients. Test results obtained from a V5 lead were compared to different lead combinations and were correlated with arteriographic findings. A positive exercise test occurred in 37 men using an isolated V5 lead compared to 50 men (P less than 0.05) using 11 leads, 52 men (P less than 0.05) using a combined CM5, CC5, Cl (inferior) lead system and 58 (P less than 0.001) men using all 14 leads. The predictive value of a positive test varied between 89-95% and was not changed significantly by the addition of multiple leads. The 14 lead ECG was positive in 43/45 (96%) patients with multivessel disease. Parameters which helped to predict multivessel disease using 14 leads were 1) the time that ischemia first appeared 2) the pressure-rate product at the time ischemia first appea...
Peripheral chemoreceptor control of fetal renin responses to hypoxia and hypercapnia.
Authors: C EWood, CKane, HRaff
Journal: Circulation Research (1990)

The renin response to hypoxia in late gestation fetal sheep has been well characterized. However, the renin response to asphyxia--the combination of hypoxia and hypercapnia--has not been extensively studied. The purpose of this study was to determine 1) the interaction of hypoxia and hypercapnia in the control of renin secretion in late gestation fetal sheep and 2) the role of peripheral arterial chemoreceptors therein. Chronically catheterized fetal sheep (intact or sinoaortic denervated) were exposed to hypoxia and/or hypercapnia for 30 minutes. Hypercapnia alone had no effect on plasma renin activity or aldosterone but did result in a significant increase in angiotensin II. Hypercapnia combined with hypoxia resulted in a significant increase in renin activity, angiotensin II, and aldosterone. Sinoaortic denervation attenuated the renin and angiotensin II responses to hypercapnia plus hypoxia. The increase in renin and angiotensin II in response to hypercapnia with or without concomitant hypoxia strongl...
Changes in heart rate during obstructive sleep apnoea
Authors: S Andreas, G Hajak, B von Breska, E Ruther, H Kreuzer
Journal: European Respiratory Journal (1992)

The mechanisms behind the decrease in heart rate during apnoeas in patients with obstructive sleep apnoea (OSA) are little known. Recent findings in animal experiments indicate that stimulation of the upper airway activates postinspiratory and cardiac vagal neurones in the medullary respiratory centre, causing alterations in heart rate and respiratory rhythm. Since OSA leads to a collapse of the airway and consequent stimulation of upper airway receptors, we studied the interrelations between heart rate and respiratory rhythm during apnoea and during negative intrathoracic pressure generated by the Mueller manoeuvre (MM). Fifteen patients with OSA (apnoea hypopnoea index (AHI) 45 +/- 28.h-1) were studied by polysomnography, during a MM and a Valsalva manoeuvre, each of 15 s duration. The heart rate decrease (delta HRA) and the increase in total respiratory cycle duration (TOT) were evaluated during apnoea in non-rapid eye movement (REM) sleep. Patients with OSA demonstrated a decrease in heart rate during apnoea (-14.4 +/- 9.0 beats.min-1), and during MM (-11.5 +/- 13.5 in OSA vs 3.1 +/- 7.8 beats.min-1 in a control group). TOT increased during apnoea (4.6 +/- 3.1 s). There was a significant correlation between delta HRA and AHI (r = -0.64) as well as between delta HRA and increase in TOT (r = 0.62). These findings indicate that upper airway obstruction may cause an activation of receptors at the site of airway collapse or distortion leading to changes in heart rate and respiratory rhythm.
Cryoablation of drug-resistant ventricular tachycardia in a patient with a variant of scleroderma.
Authors: J JGallagher, R WAnderson, JKasell, J RRice, E LPritchett, H JGault, LHarrison, A GWallace
Journal: Circulation (1978)

A 37-year-old man with a benign variant of scleroderma (CRST syndrome: calcinosis circumscripta, Raynaud's phenomenon, sclerodactyly, and telangiectasia) presented with recurrent ventricular tachycardia. Preoperative electrophysiologic study suggested that the mechanism of tachycardia was an ectopic pacemaker focus in the right ventricle. Right ventricular dilatation, tricuspid insufficiency, normal pulmonary pressures, and normal coronary arteries were also demonstrated. At surgery, epicardial mapping localized the site of origin of ventricular tachycardia to the anterior right ventricle near the crista supraventricular. Intramural recordings of the site of tachycardia demonstrated autonomous activity unreflected on the peripheral ECG during brief periods of sinus rhythm. Local epicardial cooling of this area with a cryoprobe promptly terminated ventricular tachycardia with resumption of tachycardia on warming. The focus was ablated by freezing the area at -60 degrees C. The patient remained free of dysr...
Geometric determinants of electrocardiographic left ventricular hypertrophy.
Authors: R BDevereux, M CPhillips, P NCasale, R REisenberg, PKligfield
Journal: Circulation (1983)

Experimental studies have suggested that electrocardiographic recognition of left ventricular hypertrophy depends on geometric relationships involving wall thickness and chamber size. To determine the clinical significance of these observations, we studied the effects of echocardiographic LV mass (LVM), posterior wall thickness (PWT), interventricular septal thickness (IVST) and internal dimension (LVID) on ECG voltage in 360 patients. Standard voltage and nonvoltage manifestations of LVH correlated modestly with LVM (r = 0.33-0.44, p less than 0.001). Sokolow-Lyon precordial voltage (SLV) (SV1 + RV5 or V6) correlated moderately with LVM (r = 0.41, p less than 0.001), but correlated less well with IVST (r = 0.26), PWT (r = 0.24) or LVID (r = 0.22). Stepwise regression revealed that there was no relation, independent of LVM, between SLV and IVST (r = 0.03), PWT (r = 0.03) or LVID (r = 0.01). The 90 patients with increased LVM (greater than 215 g) but without LVH by SLV (false negatives) were compared with ...
Identification of concealed posteroseptal Kent pathways by comparison of ventriculoatrial intervals from apical and posterobasal right ventricular sites.
Authors: J DMartínez-Alday, JAlmendral, AArenal, J MOrmaetxe, APastor, J PVillacastín, OMedina, RPeinado, J LDelcán
Journal: Circulation (1994)

BACKGROUNDThe differential diagnosis of supraventricular tachycardia with concentric atrial activation usually requires the inducibility of sustained tachycardia and needs a complex and time-consuming electrophysiological evaluation. To develop a simple test to establish if ventriculoatrial conduction uses a posteroseptal accessory pathway or the normal conduction system, we compared the ventriculoatrial intervals during right ventricular pacing from apical and posterobasal sites.METHODS AND RESULTSContinuous pacing was performed from an apical and a posterobasal right ventricular site in 34 patients with retrograde conduction over the normal conduction system (group A) and in 22 patients with conduction over a posteroseptal accessory pathway (group B). During apical pacing, ventriculoatrial intervals in group A (176 +/- 40 milliseconds) were not significantly different than those in group B (197 +/- 47 milliseconds, P = NS). During posterobasal pacing, group B patients had significantly shorter ventricul...
Role of Histamine in Hypoxic Pulmonary Hypertension in the Rat
Authors: Antonhouge
Journal: Circulation Research (1968)

Pharmacological agents that block or potentiate the effects of naturally occurring vasoactive substances were used to try to determine which substance, if any, mediates the vasoconstrictor response to acute alveolar hypoxia in isolated rat lungs. Isolated and ventilated lungs of rats were perfused at 37°C with homologous blood at constant-volume, pulsatile inflow, and pressor responses to brief periods of ventilation hypoxia (2% O2) were recorded (control, 21% O2). Antihistamines of four different chemical classes in concentrations of 70 to 140 µg/ml abolished all pressor responses to alveolar hypoxia without interfering with the effects of injected bradykinin, ATP, or serotonin. A histaminase-inhibiting compound, semicarbazide, potentiated the hypoxic pressor response. The hypoxic pressor response could not be abolished by α-receptor-, serotonin-, or ATP-blocking agents. The results suggest that endogenous histamine in the lung is involved in the vasoconstrictor response to acute alveolar hypoxia.
Effect of protein kinase C activation on sarcoplasmic reticulum function and apparent myofibrillar Ca2+ sensitivity in intact and skinned muscles from normal and diseased human myocardium.
Authors: J KGwathmey, R JHajjar
Journal: Circulation Research (1990)

Protein kinase C regulates the activity of a diverse group of cellular proteins including membrane ion channel proteins. Although protein kinase C and its substrate protein have been identified in both membrane and cytosolic fractions in the heart, the physiological role of this kinase in the regulation of cardiac function remains unknown. We examined the physiological role of protein kinase C by stimulating its activity with 12-deoxyphorbol 13 isobutyrate 20 acetate (DPBA) in human trabeculae carneae. This resulted in decreased peak isometric twitch force and peak intracellular sarcoplasmic reticulum calcium release as detected with aequorin. Furthermore, in the presence of DPBA, steady-state force-[Ca2+] relations were shifted to higher intracellular calcium concentrations, and the Hill coefficient was reduced, indicating a decrease in responsiveness of the myofilaments to calcium and a change in cooperativity among thin filament proteins, respectively. Thus, DPBA affects not only intracellular calcium ...
Female sterilisation-no more tubal coagulation.
Authors: A Kenney
Journal: BMJ (1980)

poststerilisation syndrome,"9 which I believe does exist.A combined approach by gynaecologists and general practitioners is likely to be most fruitful.The analysis of consulting patterns and referrals for gynaecological complaints in sterilised women, both before and after operation, and in controls is currently being explored in this practice.
Primary Outcome Evaluation of a Next-Generation Left Atrial Appendage Closure Device
Authors: Saibal Kar, Shephal K. Doshi, Ashish Sadhu, Rodney Horton, Jose Osorio, Christopher Ellis, James Stone, Manish Shah, Srinivas R. Dukkipati, Stuart Adler, Devi G. Nair, Jamie Kim, Oussama Wazni, Mathew J. Price, Federico M. Asch, David R. Holmes, Robert D. Shipley, Nicole T. Gordon, Dominic J. Allocco, Vivek Y. Reddy
Journal: Circulation (2021)

Left atrial appendage (LAA) occlusion provides an alternative to oral anticoagulation for thromboembolic risk reduction in patients with nonvalvular atrial fibrillation. Since regulatory approval in 2015, the WATCHMAN device has been the only LAA closure device available for clinical use in the United States. The PINNACLE FLX study (Protection Against Embolism for Nonvalvular AF Patients: Investigational Device Evaluation of the Watchman FLX LAA Closure Technology) evaluated the safety and effectiveness of the next-generation WATCHMAN FLX LAA closure device in patients with nonvalvular atrial fibrillation in whom oral anticoagulation is indicated, but who have an appropriate rationale to seek a nonpharmaceutical alternative.This was a prospective, nonrandomized, multicenter US Food and Drug Administration study. The primary safety end point was the occurrence of one of the following events within 7 days after the procedure or by hospital discharge, whichever was later: death, ischemic stroke, systemic embolism, or device- or procedure-related events requiring cardiac surgery. The primary effectiveness end point was the incidence of effective LAA closure (peri-device flow ≤5 mm), as assessed by the echocardiography core laboratory at 12-month follow-up.A total of 400 patients were enrolled. The mean age was 73.8±8.6 years and the mean CHA2DS2-VASc score was 4.2±1.5. The incidence of the primary safety end point was 0.5% with a 1-sided 95% upper CI of 1.6%, meeting the performance goal of 4.2% (P<0.0001). The incidence of the primary effectiveness end point was 100%, with a 1-sided 95% lower CI of 99.1%, again meeting the performance goal of 97.0% (P<0.0001). Device-related thrombus was reported in 7 patients, no patients experienced pericardial effusion requiring open cardiac surgery, and there were no device embolizations.LAA closure with this next-generation LAA closure device was associated with a low incidence of adverse events and a high incidence of anatomic closure. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02702271.
Contrasting effects of nifedipine and adenosine on regional myocardial flow distribution and metabolism distal to a severe coronary arterial stenosis: observations in sedated, closed-chest, domestic swine.
Authors: HGewirtz, S LGross, D OWilliams, A SMost
Journal: Circulation (1984)

This study tested the hypothesis that intrinsic negative inotropic effects of a drug used to induce coronary vasodilation distal to a severe coronary arterial stenosis may influence the extent of redistribution of transmural flow and its metabolic consequences. To test this hypothesis, studies were conducted in eight closed-chest, sedated swine with severe (82% reduction in luminal diameter) coronary arterial stenoses. Measurement of hemodynamic parameters, regional myocardial blood flow (microsphere technique), lactate metabolism, and oxygen consumption were made (1) under control conditions, (2) after 10 min of intracoronary infusion of a vasodilator distal to the stenosis, and (3) under repeat control conditions. Each animal received both intracoronary adenosine (400 micrograms/min) and nifedipine (50 micrograms/min). The order of drug infusion was chosen at random and a control period separated administration of each. In response to nifedipine there was no significant change in the group mean (+/- SD)...
Renin expression by vascular endothelial cells in culture.
Authors: L SLilly, R EPratt, R WAlexander, D MLarson, K EEllison, M AGimbrone, V JDzau
Journal: Circulation Research (1985)

Cultured bovine aortic endothelial cells were examined for renin activity by biochemical, immunological, and immunohistochemical techniques. When cell sonicates were incubated with renin substrate, linear generation of angiotensin I was observed (1.12 +/- 0.2 ng angiotensin I/10(6) cells per hr). The effect of pH on this activity was similar to that of bovine renal renin, and renin antibodies inhibited a large portion of the enzymatic activity. Furthermore, immunofluorescence microscopy with antirenin antisera confirmed the presence of renin within these cells. Biosynthetic radiolabeling, followed by immunoprecipitation, demonstrated de novo synthesis of a renin precursor in the endothelial cells, which was processed to a more mature protein. Thus, bovine aortic endothelial cells in culture contain and biosynthesize renin, a key component of the renin-angiotensin system. The expression of renin activity by endothelium may contribute to the local regulation of vascular tone.
Pulmonary vasodilator responses to vagal stimulation and acetylcholine in the cat.
Authors: P ANandiwada, A LHyman, P JKadowitz
Journal: Circulation Research (1983)

Responses to vagal stimulation and acetylcholine were investigated in the feline pulmonary vascular bed under conditions of controlled pulmonary blood flow and constant left atrial pressure. Under baseline conditions, electrical stimulation of vagal efferent fibers increases lobar arterial pressure. However, when vasoconstrictor tone was increased, a depressor response was unmasked. The pressor response under baseline conditions and the depressor response under enhanced tone conditions were blocked by phenoxybenzamine and atropine. These data suggest that, in the cat, the vagus is composed of efferent fibers from both the sympathetic and parasympathetic systems. After treatment with 6-hydroxydopamine to destroy the integrity of the sympathetic system, vagal stimulation caused significant frequency-dependent decreases in lobar arterial pressure when lobar vascular tone was increased by infusion of a stable prostaglandin endoperoxide analog or ventilatory hypoxia. Injections of acetylcholine also caused sig...
Spontaneous variability of complex ventricular arrhythmias detected by long-term electrocardiographic recording.
Authors: E LMichelson, JMorganroth
Journal: Circulation (1980)

Variations in the frequency of complex ventricular arrhythmias were evaluated by consecutive 24-hour long-term electrocardiographic recordings over 4 days using a two-channel recorder and computer-assisted analysis system with a weighted relative mean error of 7.5 +/ 5% (SD). Twenty patients (mean age 58 +/- 9 years [SD] with various cardiac disorders were selected if they had a daily average of more than 30 ventricular ectopic complexes per hour. Twenty patients had ventricular couplets and 14 patients had ventricular tachycardia (at least triplets). The mean daily number of either couplets or ventricular tachycardia was subjected a four-factor nested analysis of variance to determine the sources of variation in ectopic frequency. Differences in hourly rates accounted for 30% of the variation in the frequency of ectopic complexes. Statistical methods were applied to determine the change in frequency of complex arrhythmias necessary to exceed that attributable to spontaneous variation alone at the p less ...