tbuckley/cabot-search huggingface dataset:
Lewis A. Conner Memorial Lecture. Mechanisms leading to myocardial infarction: insights from studies of vascular biology.
Authors: VFuster
Journal: Circulation (1994)

Myocardial infarction is the most frequent cause of mortality in the United States as well as in most western countries. In this review, the processes leading to myocardial infarction are described based on the most recent studies of vascular biology; in addition, evolving strategies for prevention are outlined. The following was specifically discussed. (1) Five phases of the progression of coronary atherosclerosis (phases 1 to 5) and eight morphologically different lesions (types I, II, III, IV, Va, Vb, Vc, and VI) in the various phases are defined. (2) The present understanding of the pathogenesis of each of the phases of progression and of the various lesion types preceding myocardial infarction is described; particular emphasis is placed on the physical, structural, cellular, and chemical characteristics of the vulnerable or unstable plaques prone to disruption (types IV and Va lesions). (3) The fate of plaque disruption (type VI lesion) in the genesis of the various coronary syndromes and especiall...
Dissociation constant of the norepinephrine-receptor complex in normotensive and hypertensive rats.
Authors: R BStrecker, W CHubbard, A MMichelakis
Journal: Circulation Research (1975)

Previous reports have suggested that smooth muscle obtained from the thoracic aorta of spontaneously hypertensive rats is less responsive to vasoconstrictive agents than that obtained from normotensive rats. The present study was undertaken to determine whether the responsiveness of aortic muscles from normotensive and spontaneously hypertensive rats correlates with a difference in the affinity of the adrenergic receptors for norepinephrine and whether antihypertensive therapy alters the affinity of the adrenergic receptors for norepinephrine. The affinity of the adrenergic receptors for norepinephrine was determined by computing the dissociation constant of the norepinephrine-receptor complex (KDR). The values computed for KDR in aortic muscles from normotensive and spontaneously hypertensive rats that had received no antihypertensive therapy were 1.07 X 10(-7)M and 1.17 X 10(-7)M, respectively. The values computed for KDR in aortic muscles from normotensive and spontaneously hypertensive rats that had r...
Standards for analysis of ventricular late potentials using high-resolution or signal-averaged electrocardiography. A statement by a Task Force Committee of the European Society of Cardiology, the American Heart Association, and the American College of Cardiology.
Authors: G Breithardt, M E Cain, N el-Sherif, N C Flowers, V Hombach, M Janse, M B Simson, G Steinbeck
Journal: Circulation (1991)

Sufficient data are available to recommend the use of the high-resolution or signal-averaged electrocardiogram in patients recovering from myocardial infarction without bundle branch block to help determine their risk for developing sustained ventricular tachyarrhythmias. However, no data are available about the extent to which pharmacological or nonpharmacological interventions in patients with late potentials have an impact on the incidence of sudden cardiac death. Therefore, controlled, prospective studies are required before this issue can be resolved. As refinements in techniques evolve, it is anticipated that the clinical value of high-resolution or signal-averaged electrocardiography will continue to increase.
Heterosexual Transmission of HIV
Authors: Isabelle De Vincenzi
Journal: JAMA (1992)

To the Editor.  —In a partner study on HIV transmission among heterosexual couples, Padian et al 1 observed only one case (1.4%) of male-to-female transmission of HIV in their study of 72 male partners of HIV-infected women. The observed case was in a couple described as unique in that vaginal and penile bleeding during intercourse was noted. However, since nearly half (32/72) of the couples studied used condoms, the risk of transmission may have been underestimated.  On the other hand, male-to-female transmission was estimated to be 17.5 times more effective than female-to-male transmission (crude OR). Apart from the fact that the 90% CI for the OR given in the article is large (3.5 to 353), and the usual 95% CI would be still larger, the crude measurement of the relative efficiency of HIV transmission in both directions may be invalid for at least one reason: the authors did not take
Failure of an implantable cardioverter-defibrillator to redetect ventricular fibrillation in patients with a nonthoracotomy lead system.
Authors: WJung, MManz, RMoosdorf, BLüderitz
Journal: Circulation (1992)

BACKGROUNDShock delivery of an implantable defibrillator may cause a change in the amplitude of endocardial electrograms and impair the detection of ventricular fibrillation. Thus, the effects of shock discharges on the amplitude of endocardial electrograms were evaluated in five patients undergoing implantation of a cardioverter-defibrillator in combination with a new nonthoracotomy lead system.METHODS AND RESULTSAt implant, bipolar endocardial electrograms were recorded before each shock application, during ventricular fibrillation, during redetection of ventricular fibrillation in case the applied shock was ineffective, and at intervals of 5, 10, 20, 30, 60, and 120 seconds after each shock delivery. The amplitude of the endocardial electrograms decreased from 10.5 +/- 3.8 mV during sinus rhythm to 6.3 +/- 1.9 mV during initial ventricular fibrillation and declined to 2.2 +/- 1.3 mV during redetection of ventricular fibrillation. After successful termination, the following bipolar electrograms could be...
Expression and pharmacological characterization of a stimulatory subtype of adenosine receptor in fetal chick ventricular myocytes.
Authors: DXu, H YKong, B TLiang
Journal: Circulation Research (1992)

Ventricular and atrial myocytes cultured from chick embryos 14 days in ovo were used as model systems to study cardiac adenosine receptors. In membranes of ventricular cultures, blocking of the A1-adenosine receptor pathway by the A1-selective antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) or by pertussis toxin treatment of the myocyte resulted in a significant adenosine agonist-mediated stimulation of the adenylate cyclase activity. The maximal increases in adenylate cyclase activity caused by the equipotent or the A2-adenosine receptor-selective agonists (from 52.1 +/- 3% to 63 +/- 10% [mean +/- SEM]) were significantly greater than those caused by the A1-selective agonists (from 11 +/- 5% to 34.6 +/- 7%) (p less than 0.01, by t test, n = 4-8). However, in membranes of atrial myocytes, when A1-subtype had been blocked, the various adenosine agonists had no effect on the adenylate cyclase activity. Whether the stimulatory adenylate cyclase-coupled adenosine receptor is also capable of stimulating ...
Echocardiographic assessment of right bundle branch injury after repair of tetralogy of Fallot.
Authors: A SPickoff, A VMehta, ACasta, P LFerrer, G SWolff, D FTamer, O LGarcia, HGelband
Journal: Circulation (1981)

Nineteen patients, ages 3 1/2-18 years, with electrocardiographic evidence of right bundle branch injury after intracardiac repair of tetralogy of Fallot, underwent invasive intracardiac electrophysiologic evaluation 1-13 years (mean 4.4 years) postoperatively. Categorization of the site of right bundle branch injury as proximal or distal was made by determining the V-RVA interval. In 11 of the patients, the V RVA interval was prolonged (> 35 msec), indicating proximal right bundle branch injury and in the other eight it was normal (< 35 msec), indicating distal bundle branch injury. Within 24 hours of the study, all patients were studied by M-mode echocardiography. Measurements were made of the tricuspid valve closure, mitral valve closure and the difference between the two, or the delta value. All but one patient with distal bundle branch injury had delta values of less than 40 msec (range 8-38 msec), while 10 or 11 patients with proximal bundle branch injury had delta values greater than 40 msec (range...
Epicardial and endocardial activation during sustained ventricular tachycardia in man.
Authors: L NHorowitz, M EJosephson, A HHarken
Journal: Circulation (1980)

Ventricular activation during ventricular tachycardia was studied by intraoperative epicardial and endocardial mapping in 21 patients with coronary artery disease and previous myocardial infarction who underwent operation for recurrent ventricular tachycardia. Twenty-nine morphologically distinct tachycardias were mapped; 18 tachycardias had a right bundle branch block morphology and 11 had a left bundle branch block morphology. After cannulation for bypass, the tachycardias were induced and electrograms were recorded at 55-75 epicardial sites. After starting cardiopulmonary bypass, the infarction was incised and electrograms were recorded at 28-55 left ventricular endocardial sites during ventricular tachycardia. All mapping data were analyzed with three simultaneously recorded ECG lead and two reference electrograms. Earliest activation in all tachycardias occured on the endocardial surface of the infarction. In each tachycardia, endocardial electrical activity was recorded before the onset of the QRS c...
Comparison of single-dose and double-dose thallium-201 myocardial perfusion scintigraphy for the detection of coronary artery disease and prior myocardial infarction.
Authors: D KBlood, D MMcCarthy, R RSciacca, P JCannon
Journal: Circulation (1978)

Thallium-201 myocardial perfusion scintigraphy was performed after exercise, 4 hours after exercise (redistribution) and after a separate rest injection in 87 patients undergoing coronary arteriography. Significant coronary lesions were present in 62 of the patients. Interpretation of the rest and redistribution scintiscans was the same in 69 patients, 45 of whom had coronary artery disease (CAD). In 16 of the 17 patients with CAD and differing interpretations, defects were present on redistribution scintiscans but not on rest scintiscans; 11 of these patients had evidence of prior transmural myocardial infarction and the other five had an occluded coronary artery supplying the region of the defect. Redistribution scintiscans were more sensitive than rest scintiscans for the detection of prior myocardial infarction (93% vs 54%; P less than 0.01). The increased sensitivity was confined to the detection of prior inferior myocardial infarctions. In 36 of 38 patients with persistent perfusion defects on 4-hou...
Amiodarone versus amiodarone and a type IA agent for treatment of patients with rapid ventricular tachycardia.
Authors: F EMarchlinski, A EBuxton, J MMiller, J AVassallo, B TFlores, M EJosephson
Journal: Circulation (1986)

Induction of rapid ventricular tachycardia or fibrillation during therapy with amiodarone is associated with an increased risk of sudden death. To determine whether the addition of a type IA antiarrhythmic agent to therapy would improve outcome, 37 patients in whom ventricular tachyarrhythmia of a cycle length less than 350 msec was induced after 14 +/- 2 days of amiodarone were randomly assigned to therapy with amiodarone alone (group 1, 20 patients) or amiodarone plus type IA agent (group 2, 17 patients). Type IA therapy consisted of procainamide in 13 patients and quinidine in four procainamide-intolerant patients. To assess the short-term effects of a type IA agent on inducibility of ventricular tachyarrhythmia, cycle length, and hemodynamic tolerance, 16 of 20 patients in group 1 and all patients in group 2 underwent repeat programmed stimulation after the intravenous administration of procainamide during amiodarone therapy (mean procainamide serum concentration 7.2 +/- 2.0 micrograms/ml). Procainami...
Reflex changes in hindlimb and renal vascular resistance in response to distention of the isolated pulmonary arteries of the dog.
Authors: J RLedsome, W OKan
Journal: Circulation Research (1977)

We describe a preparation that uses a constant flow, right heart bypass for perfusion of an isolated pouch of the main pulmonary arteries at controlled pressures, and show that increments in pressure in the pulmonary arterial pouch are accompanied by increases in systemic vascular resistance and in hindlimb vascular resistance. These changes are demonstrated over the whole range of 5-120 cm H2O pressure in the pulmonary arterial pouch. In contrast there are no significant changes in renal vascular resistance or heart rate. We find that changing the temperature of the perfusate in the pulmonary arterial pouch from 37 degrees C to 30 degress C is associated with a decrease in systemic vascular resistance. Furthermore, the effects of raising the pulmonary arterial pouch pressure and of cooling are abolished by cervical vagotomy. These findings suggest that there is a tonic reflex vasoconstrictor tone generated by the activity of receptors lying in or close to the walls of the pulmonary artery. These findings...
Alteration of diastolic filling rate during exercise radionuclide angiography: a highly sensitive technique for detection of coronary artery disease.
Authors: L RPoliner, S HFarber, D HGlaeser, LNylaan, M SVerani, RRoberts
Journal: Circulation (1984)

Diastolic and systolic parameters of left ventricular performance were characterized from high-frequency time-activity curves obtained in 10 normal volunteers (mean age 29 +/- 4 yr), in 25 patients with normal coronary arteries, and in 50 patients with coronary artery disease (CAD) at rest and during three stages of exercise radionuclide angiography. In the normal volunteers ejection fraction was 65 +/- 5% (SD) at rest and 78 +/- 5% with exercise (p less than .001). In patients with normal coronary arteries ejection fraction was 64 +/- 5% at rest and 72 +/- 8% with exercise (p less than .0001). In patients with CAD resting ejection fraction was 60 +/- 10% and that during exercise was 61 +/- 13% (p = NS). Peak diastolic filling rate in the first half of diastole, peak systolic ejection rate, and times to peak rates and to end-systole were measured. In the normal subjects resting peak diastolic filling rate was 3.1 +/- 0.6 end-diastolic counts/sec and it increased in all subjects with exercise to 3.6 +/- 0....
Significance of block distal to the His bundle induced by atrial pacing in patients with chronic bifascicular block.
Authors: R CDhingra, CWyndham, RBauernfeind, SSwiryn, P CDeedwania, TSmith, PDenes, K MRosen
Journal: Circulation (1979)

Twenty-one of 496 (4%) patients with chronic bifascicular block, studied and followed prospectively, had block distal to the His bundle (BDH) induced by atrial pacing during initial electrophysiologic studies. In six, BDH was noted during pacing-induced atrioventricular (AV) nodal Wenckebach periods (at paced rates of 150--190 beats/min), with BDH in the short HH cycles after the AV nodal blocked P (lond cycle). The AH interval was normal in all six patients and HV was normal in four. None of the six patients has developed AV block during a mean follow-up of 5.33 +/- 0.48 years. In 15 patients, pacing-induced BDH was noted during intact AV nodal conduction (paced rate of 80--200 beats/min). The AH interval was prolonged in one, and HV was prolonged in 10 of the 15 patients. During a mean follow-up of 3.4 +/- 0.59 years, seven of these patients developed AV block, one had treadmill-provoked AV block, and two died suddenly (major morbid event in 10 of 15 patients). In conclusion, BDH induced by atrial pacin...
From the authors
Authors: I. Horvath
Journal: European Respiratory Journal (2006)

We appreciate the opportunity to reply to the letter by Z.L. Borrill and coworkers regarding the European Respiratory Society (ERS)/American Thoracic Society (ATS) exhaled breath condensate (EBC) Task Force report. EBC pH measurement is indeed a rapidly growing field of research with the promise of providing previously unknown information about the airways. The measurement is simple, can be performed sample by sample and there is no problem with the detection limit. EBC, however, is a diluted fluid with a low buffering capacity, which makes its pH value sensitive to changes in CO2 content. Although the CO2 concentration of fresh EBC samples is probably similar to that found in the airway lining fluid, this CO2 concentration will change spontaneously due to the rapid interaction with environmental air after sampling. That is the main …
Monoclonal antibody therapy for prevention of acute coxsackievirus B3 myocarditis in mice.
Authors: CKishimoto, W HAbelmann
Journal: Circulation (1989)

The efficacy of monoclonal antibodies against T cell subsets in the therapy of experimental myocarditis caused by coxsackievirus B3 (CB3) was investigated. Two-week-old male C3H/He mice were inoculated with CB3 virus. Treatment was begun in the viremic stage (starting on the day of inoculation) in experiment 1 and in the later aviremic stage (starting on day 10) in experiment 2. Rat anti-mouse monoclonal antibodies, Lyt 1 (helper/inducer T) at 1 microgram/mouse (group 2 in experiment 1; group 6 in experiment 2), Lyt 2 (suppressor/cytotoxic T) at 1 microgram/mouse (group 3 in experiment 1; group 7 in experiment 2), and Lyt 1 at 1 microgram plus Lyt 2 at 1 microgram/mouse (group 4 in experiment 1; group 8 in experiment 2), were administered subcutaneously daily for 2 weeks. The treatment groups were compared with infected controls (group 1 in experiment 1; group 5 in experiment 2). In experiment 1, the survival rate in group 4 was higher (p less than 0.01) than in group 1. In experiment 2, mice treated with...
Reperfusion after brief ischemia disrupts the microtubule network in canine hearts.
Authors: HSato, MHori, MKitakaze, KIwai, STakashima, HKurihara, MInoue, TKamada
Journal: Circulation Research (1993)

Histological changes in the stunned myocardium are believed to be minimal. This study examined whether cytoskeletal structures of microtubules are disrupted in the stunned myocardium. In 38 dogs, the left anterior descending coronary artery was occluded for 15 minutes and reperfused to produce the stunned myocardium. Microtubules were stained immunohistochemically. In intact myocardium, microtubules appeared as a filamentous network throughout the cytoplasm and encircled the nucleus. This pattern was not affected by 15 minutes of ischemia. One hour of reperfusion, however, disrupted microtubular structure substantially (disruption score in the endocardium, 53.4 +/- 6.0%) although actin filaments remained intact. Microtubular structures were reconstituted 1-3 days after reperfusion, showing supernormal immunoreactivity. Five days after reperfusion, the pattern of microtubular staining was normal. In another protocol, the role of Ca2+ during reperfusion in microtubular disruption was examined. When intracor...
Active downregulation of myocardial energy requirements during prolonged moderate ischemia in swine.
Authors: A EArai, G APantely, C GAnselone, JBristow, J DBristow
Journal: Circulation Research (1991)

We studied the effects of rapid atrial pacing during the final 10 minutes of a 70-minute, 31% reduction in coronary blood flow in anesthetized swine to understand the significance of apparent metabolic improvements during the initial 60 minutes of segmental ischemia. Within 5-10 minutes of ischemia, subendocardial phosphocreatine (PCr) and ATP were depleted to 47% and 63% of control, respectively; lactate accumulated within the subendocardium to 300% of control; and net arteriovenous lactate production occurred. Despite continued ischemia and no significant changes in the external determinants of myocardial oxygen consumption, by 60 minutes subendocardial PCr and lactate contents returned to near control levels and there was net arteriovenous lactate consumption. Ischemic left ventricular wall thickening and ATP levels remained depressed throughout the experiment. Atrial pacing during the final 10 minutes of ischemia again resulted in depletion of PCr and lactate production. Since the myocardium was capab...
Avoiding the Coming Tsunami of Common, Chronic Disease
Authors: Robert M. Califf
Journal: Circulation (2021)

During the past year, clinicians and the public have been focused on the coronavirus disease 2019 (COVID-19) pandemic and its associated societal and economic effects. However, once the acute phase of this crisis has passed, we will face an enormous wave of death and disability as a result of common chronic diseases (CCDs), with cardiometabolic diseases at the crest (Figure). A tsunami results when an earthquake on the ocean floor creates huge waves that can wreak devastation far distant from the original upheaval, especially when warnings are ignored. Similarly, underlying global and national demographic and risk factor profiles have for some time presaged an overwhelming burden of CCDs. However, although the pandemic has created additional impetus that unless heeded will amplify the consequences of this burden, the rapid adaptations and innovations in care and research prompted by the urgent response to it may also offer us the means to stem this flood.
Ultimate salvation: feasibility of NOTES for complications of ERCP and endoscopic ultrasound-guided procedures
Authors: Marina Kim, Romy Bareket, Mishal Reja, Avik Sarkar, Haroon Shahid, Amy Tyberg, Michel Kahaleh
Journal: Endoscopy (2021)

A 60-year-old woman with a history of morbid obesity status post sleeve gastrectomy 2 months prior to presentation arrived at the emergency department with painless jaundice. Computed tomography (CT) revealed a 3-cm pancreatic head mass. Endoscopic ultrasound (EUS) with a fine needle biopsy was performed. However, endoscopic retrograde cholangiopancreatography (ERCP) for biliary decompression was complicated by a duodenal perforation due to a pre-existing severe duodenal stricture, which was managed with Ovesco clip placement [1]. Because further endoscope passage was prohibited, EUS-guided hepaticogastrostomy was then performed [2].
Abstract 10693: Long-term Outcome in Patients With Electrical Isolation of the Left Atrial Appendage Performed at the 1st Procedure vs Redo in Patients With Long-standing Persistent Atrial Fibrillation
Authors: Sanghamitra Mohanty, Chintan G Trivedi, Domenico G Della Rocca, Carola Gianni, Bryan MacDonald, John Burkhardt, Javier Sanchez, Patrick M Hranitzky, Joe Gallinghouse, Ugur Canpolat, Amin Al-ahmad, Rodney P Horton, Mohammed Bassiouny, Luigi Di Biase, Andrea Natale
Journal: Circulation (2019)

Background: We evaluated the long-term outcome of electrical isolation of LAA (LAAEI) performed at the 1st procedure vs at the redo in a series of long-standing persistent (LSPAF) patients. Methods...
Energy, current, and success in defibrillation and cardioversion: clinical studies using an automated impedance-based method of energy adjustment.
Authors: R EKerber, J BMartins, M GKienzle, LConstantin, BOlshansky, RHopson, FCharbonnier
Journal: Circulation (1988)

The purposes of this study were two. First, we wanted to evaluate in patients a technique for automated adjustment of selected energy for defibrillation or cardioversion based on transthoracic impedance. Second, we wanted to define the relationship of peak current and shock success in various arrhythmias. Applying a previously validated method of predicting transthoracic impedance in advance of any shock, we modified defibrillators to automatically double the operator-selected energy if the predicted impedance exceeded 70 omega. Success rates of shocks given for ventricular and atrial arrhythmias from these modified energy-adjusting defibrillators were compared with success rates for shocks given from standard defibrillators. We prospectively collected data on 347 patients who received a total of 1009 shocks. Low-energy (100 J) shocks given to high-impedance (greater than or equal to 70 omega) patients had a poor success rate; in such high-impedance patients significant improvement in shock success rate w...