bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of oral hydralazine on rest and exercise hemodynamics in patients with aortic or mitral regurgitation and left ventricular dysfunction
Authors: Slosky D. A. , Hindman M. C. , Peter R. H. , Wallace A. G. 
Published: February 2009

AbstractThe hemodynamic effects of afterload reduction were studied at rest and during two levels of upright exercise in patients with aortic or mitral regurgitation and left ventricular dysfunction. Eleven patients underwent invasive hemodynamic monitoring before and after 50–70 mg of oral hydralazine was given every 6 h for 48 h. At rest, heart rate and mean arterial pressure after hydralazine were unchanged from control. During exercise, there was no significant change in heart rate, but mean arterial pressure fell significantly during the first level of exercise. Systemic vascular resistance was elevated before hydralazine and was significantly reduced after treatment at both exercise levels. After hydralazine, the resting oxygen consumption was significantly elevated at rest but was unchanged during exercise, the arteriovenous oxygen difference was significantly narrowed at both rest and exercise, and the pulmonary capillary wedge pressure was also significantly lower at both rest and exercise. In this select group of patients who are not candidates for surgical valve replacement, chronic afterload reduction with oral hydralazine may result in increased cardiac performance, decreased pulmonary congestion, reduced myocardial oxygen demands, and improvement in resting and/or exertional symptoms.
Effects of exercise on plasma viscosity in athletes and sedentary normal subjects
Authors: Letcher R. L. , Pickering T. G. , Chien S. , Laragh J. H. 
Published: February 2009

AbstractTo assess the immediate and long‐term effects of exercise on factors regulating blood flow, we measured plasma viscosity (ηp) and plasma renin activity (PRA) in 17 trained runners and 16 sedentary healthy subjects before and 10 min after graded treadmill exercise. Resting ηp was lower in runners primarily because of significantly lower fibrinogen concentration. Compared to nonrunners with similar 24‐h urine electrolyte excretion rates, runners were characterized by lower PRA at rest. In view of the overall correlation between heart rate and PRA before exercise, reduced adrenergic tone was probably a major factor contributing to the lower PRA in runners. After exercise, plasma viscosity and PRA exceeded control levels, and were similar in magnitude in runners and sedentary subjects. Changes in plasma viscosity were less than expected from the degree of hemoconcentration, primarily because enhanced fibrinolysis maintained fibrinogen level constant. To the extent that plasma viscosity affects viscous flow resistance, the results suggest that tissue perfusion and oxygen delivery rate at rest are greater in trained runners than in sedentary subjects, but these variables become similar after maximum exertion.
PISA: A noninvasive method in detection and quantification of acid‐induced myocardial infarction in dogs
Authors: Prasad K. , Gupta M. M. 
Published: February 2009

AbstractPhase invariant signature algorithm (PISA), a new noninvasive technique, was used in the detection and quantification of acid‐induced myocardial damage in anesthetized dogs. The diagnostic capabilities of this method were compared with those of conventional electrocardiogram and biochemical markers, MB‐creatine phosphokinase (MB‐CPK) and lactic dehydrogenase (LDH1). Myocardial damage of varying degree was induced by injecting diluted sulphuric acid (0.01 to 0.10 ml) into the free wall of the left ventricle. Conventional ECG, wideband ECG for PISA analysis, blood samples for LDHI, and MB‐CPK were taken before and after 15, 30, 60, and 90 min of acid injection. The heart was removed at the end of 90 min for estimation of myocardial damage. PISA Index increased within 10–15 min of acid injection and remained elevated for the duration of the experiment (90 min). The increase in the PISA index was directly related to the extent of myocardial damage and the amount of acid injected. Although the conventional electrocardiogram detected large myocardial damage, it was unable to detect small myocardial damage. Also, most of initial changes in conventional ECG with large myocardial damage disappeared within 90 min, while the PISA index was still elevated to the maximum level. The MB‐CPK was not detected before or after myocardial damage. There was no significant change in the LDH1 at any time after myocardial infarction. These results suggest that the PISA technique is superior to the conventional ECG and the biochemical markers and would be a valuable diagnostic tool in the detection and quantification of incipient as well as advanced myocardial infarction.
Large mobile pedunculated left ventricular thrombus: Identification by two‐dimensional echocardiography
Authors: Chen C. C. , Webster G. W. , Morganroth J. 
Published: February 2009

AbstractTwo‐dimensional echocardiography has permitted the noninvasive detection and determination of the course of the natural history of left ventricular thrombus. In this report we cite an illustrative case of the development of a large pedunculated mobile left ventricular thrombus in the setting of idiopathic congestive cardiomyopathy. A fatal cerebral embolization occurred despite full‐dose intravenous anticoagulation before left ventricular thrombectomy could be performed. The presence of a large mobile pedunculated left ventricular thrombus in the setting of embolization and adequate anticoagulation may require surgical intervention.
Initial experience with a fully implantable, programmable, scanning, extrastimulus pacemaker for tachycardia termination
Authors: Nathan A. W. , Camm A. J. , Bexton R. S. , Hellestrand K. J. , Spurrell R. A. J. 
Published: February 2009

AbstractSummary: A fully implantable automatic scanning pacemaker designed for tachycardia termination has been used in three patients with regular paroxysmal supraventricular tachycardia. The pacemaker recognizes tachycardia and delivers one or two extrastimuli which automatically scan inwards if tachycardia continues. A memory is incorporated to retain and immediately reuse a successful pacing sequence if tachycardia recurs. Ventricular pacing has been used in two patients and atrial stimulation in one. Although all had suffered frequent attacks of tachycardia after implantation no sustained episodes of tachycardia have been appreciated. No unwanted arrhythmias have been induced and drug treatment has been stopped in all three patients. Fully implantable scanning pacemakers which automatically recognize and revert tachycardia offer an effective and versatile form of treatment for recurrent paroxysmal tachycardias.
Wide vascular pedicle on thoracic roentgenogram in complete transposition of the great arteries
Authors: Schneeweiss A. , Blieden L. C. , Shem‐Tov A. , Fiegal A. , Neufeld H. N. 
Published: February 2009

AbstractSummary: A narrow vascular pedicle on the thoracic roentgenogram is an important sign in the clinical diagnosis of complete transposition of the great arteries (Shaher, 1973a). Rarely a wide vascular pedicle is present in this condition, mainly due to associated lesions. The differential diagnosis in these cases is discussed, based on our experience with 14 cases.
The applicability of the signal averaging technique in clinical cardiology
Authors: Hombach V. , Braun V. , Höpp H.‐W. , Gil‐Sanchez D. , Scholl H. , Behrenbeck D. W. , Tauchert M. , Hilger H. H. 
Published: February 2009

AbstractSummary: Since 1963 the signal averaging technique has been applied to improve the signal to noise ratio in highly amplified EKG registrations. Based on the experiences from the literature and the authors own laboratory, the applications of the signal averaging technique in clinical cardiology are reviewed: extraction and analysis of the fetal EKG and P‐wave variations, His bundle electro‐grams from the body surface (recovery rate 33–100% of cases), ventricular delayed depolarizations within the ST segment of the surface EKG (recovery rate, 40–90% of cases, depending on patient groups investigated), preatrial activity (sinus nodal potentials) from intra‐cardiac (recovery rate, 80–90% of individuals), or surface EKGs (recovery rate, 60% of patients), analysis of frequency components of surface EKG‐QRS complexes in patients with previous myocardial infarctions, and detection of low amplitude diastolic signals from surface phonocardiogram (recovery rate, 80% of cases). At present, advantages and limitations of the signal averaging technique may be appraised as follows: (1) sinus nodal potentials: S‐A conduction times may be more reliable than those obtained by the extra‐stimulus technique, since with averaging they are recorded during undisturbed sinus rhythm; direct recordings of changing S‐A blocks may be impossible due to the summation process; validation of sinus nodal potentials in man necessary, (2) A‐V nodal potentials: demonstration of true A‐V nodal rhythm rather than His bundle rhythm; possibly direct identification of abnormal pathways in A‐V nodal tachycardias; direct recordings of single A‐V nodal blocks impossible due to summation process; (3) surface His bundle potentials: follow‐up or screening of patients with A‐V nodal and particularly His‐Pur‐kinje‐system blocks; monitoring of antiarrhythmic drug therapy; atrial overlap in one‐third of cases; direct identification of higher degree A‐V nodal blocks impossible due to summation process (future developments may overcome this problem); (4) ventricular delayed depolarizations: possible identification of patients at high risk of sudden cardiac death; follow‐up of therapeutic measures like antiarrhythmic drug therapy or cardiac surgery (bypass grafting, aneurysmectomy); validation of delayed depolarizations from body surface by direct intracardiac and/or epicardial mapping necessary.
Mitral valve echocardiographic pattern within the left atrium
Authors: Motor M. , Schneeweiss A. , Neufeld H. N. , Grenadier E. 
Published: February 2009

AbstractSummary: In a patient with a left atrial myxoma, the tumor adhered to the anterior leaflet of the mitral valve. This caused movement of the tumor's stalk in the left atrium in a pattern similar to that of a mitral valve in M‐mode echocardiography. An accurate diagnosis was made by cross‐sectional echocardiography and confirmed at surgery.
The value of grip test as an index of autonomic function in hypertension
Authors: Chrysant S. G. 
Published: February 2009

AbstractSummary: The autonomic sympathetic adjustments to sustained handgrip, upright tilt, and the Valsalva maneuver, were tested in a total of 52 patients, 26 with labile and 26 with fixed essential hypertension. Sustained handgrip (SHG) increased arterial pressure, heart rate (HR), cardiac index (CI), and tension time index (TTI) (p<0.01), but had no effect on total peripheral resistance index (TPRI) and left ventricular ejection rate index (LVERI) in either group of patients. The response to upright tilt and the Valsalva maneuver was different in the two groups. Upright tilt in labile hypertensives increased diastolic arterial pressure (DAP), mean arterial pressure (MAP), HR, and TPRI (p<0.001), and decreased CI, stroke index (SI), and LVERI (p<0.01), and had no effect on systolic arterial pressure (SAP). In fixed hypertensives, it decreased SAP, MAP, CI, SI, and LVERI (p<0.001), increased HR (p<0.01), and had no effect on DAP and TPRI. The diastolic pressure overshoot of the Valsalva maneuver was attenuated in fixed hypertensives compared to labile hypertensives (p<0.001). Also, when the percent changes from control in diastolic and mean arterial pressure, heart rate, and total peripheral resistance index after sustained handgrip and upright tilt between the two groups of patients were compared, only upright tilt brought out the differences between the two groups. The results of this study indicate that upright tilt and the Valsalva maneuver are better predictors of autonomic function in hypertension than the grip test.
Tissue and coronary venous pH in ischemic canine myocardium
Authors: Cobbe S. M. , Parker D. J. , Poole‐Wilson P. A. 
Published: February 2009

AbstractSummary: The relationship between changes in myo‐cardial tissue pH and local coronary venous pH during and after transient occlusion of the left anterior descending artery was investigated in 6 open chested an‐esthesized dogs. Tissue pH was recorded with a needle pH electrode, and coronary venous pH with a specially designed catheter tip pH electrode. Myocardial tissue pH fell steadily after coronary occlusion, and had fallen by 0.107±0.043 pH units (mean±SD, n=12 occlusions) after 150 s. On reperfusion there was a further small fall in tissue pH to 0.138±0.035 units before tissue pH returned to control. In contrast, the fall of coronary venous pH during ischemia was small (0.15±0.027 after 150 s, n=12 occlusions). Within 5 s of reperfusion, a large fall in venous pH occurred, reaching a maximum of 0.150±0.072 at 20–30 s after reperfusion.During ischemia changes in tissue pH are poorly represented by changes in coronary venous pH. The size of the early change of venous pH during the reperfusion washout of retained metabolites is a better estimate of the fall of tissue pH. Measurement of metabolites in the coronary sinus of man during the washout after the end of an ischemic intervention such as atrial pacing is superior to measurements performed during pacing in providing biochemical evidence of myocardial ischemia.
Rheumatic Heart Disease and Pregnancy in Nigerian Women
Authors: Cole T. O. , Adeleye J. A. 
Published: February 2009

AbstractSummary: The early onset of rheumatic fever and rapid progression to severe and incapacitating chronic valve disease, as in other developing tropical countries, has been repeatedly highlighted in Nigeria. Of interest is the fact that the peak frequency of age distribution is in the early child‐bearing age. This study was undertaken to evaluate the clinical course of 44 pregnancies in 32 Nigerian women between 16 and 38 years of age (mean 27), with rheumatic heart disease. The patients received careful clinical assessment on follow‐up at 1 to 4 week intervals depending on grade of symptoms and stage of gestation. All deliveries were conducted in the hospital and patients were clinically reassessed 6 months after delivery. The key to grading of symptoms was the New York Heart Association functional classification, coordinated with findings on detailed clinical examination. The majority of the cases were gravida 3 but closely followed by primigravidae. Mitral valve disease with dominant incompetence was the commonest valve lesion. Nevertheless, acute pulmonary edema (11 cases), the cause in 2 of the 3 maternal deaths, was the most frequent complication. Congestive heart failure occurred in 7 cases, and infective endocarditis in 4 cases. The only patient with mitral valve prosthesis was on warfarin prophylaxis and had 2 of the 3 stillbirths in the series. On clinical reassessment 6 months later, there was evidence of progression of functional state in 8, and interestingly, more maternal deaths occurred in less than a year. These findings are no doubt related to the presently limited medical facilities, inadequate socioeconomic and public health standards, and the need for health education in the country, and not excluding the seemingly rapid progression of rheumatic heart disease itself. In light of such circumstances, the relevant aspects of the accepted program of management in the more developed temperate countries would need to be meaningfully adjusted and suggestions have been made to this effect.
Influence of Myocardial Substrate Utilization on the Oxygen Consumption of the Heart
Authors: Kahles H. , Hellige G. , Hunneman D. H. , Mezger V.‐A. , Bretschneider H. J. 
Published: February 2009

AbstractThe effect of changing myocardial metabolism from predominantly lipid to predominantly carbohydrate utilization on myocardial oxygen consumption (v̇O2) was studied in 10 closed‐chest dogs. Oxygen saving potency df different metabolic interventions was quantified over a wide hemodynamic range by comparing the directly determined v̇O2 with the hemodynamic parameter total left ventricular energy demand (Et), which correlates closely under control conditions with v̇O2 (r = 0.98). Stimulation of carbohydrate metabolism by addition of glucose and β‐pyridyl carbinol or by activation of pyruvate dehydrogcnase with di‐chloroacetate (DCA) shifted the cardiac respiratory quotient during β‐stimulation from 0.73 to 1.00 and 0.89, respectively, the nonesterified fatty acid/albumin ratio decreased from 4.0 to 0.5, or remained unchanged with DCA, and v̇O2 was reduced by 25 and 16%, respectively. Therapeutic approaches aimed at decreasing v̇O2 by changing substrate utilization are discussed.
Mid‐Diastolic Aortic Valve Opening in Bacterial Endocarditis of Aortic Valve
Authors: Ravindra Nathan M. P. , Arora R. , Rubenstein H. 
Published: February 2009

AbstractSummary: Echocardiographic features of acute aortic regurgitation resulting from bacterial endocarditis have been well documented (Nathan et al., 1980; Weaver et al., 1977; Wray, 1975a), and include thick shaggy echoes from aortic valve in diastole, fine diastolic flutter of aortic valves suggestive of rupture of cusps, and premature closure of mitral valves. Echocardiography being a sensitive noninvasive technique for detecting aortic valve vegetations is heavily relied on for earlier diagnosis and prompt therapy of these patients. Prognosis of echocardiographically positive endocarditis is known to be worse than for echo‐negative patients. The following case is being presented because of an unusual echocardiographic manifestation with mid‐diastolic aortic valve opening secondary to flail aortic valve from staphylo‐coccal endocarditis of the aortic valve.
Obstructive Cardiomyopathy in a Male Dwarf with Cryptorchidism
Authors: Fatourechi V. , Sheikhzadeh A. H. , Gavam M. 
Published: February 2009

AbstractSummary: Obstructive cardiomyopathy has been reported in cases of male and female Turner phenotype with normal chromosomes. We report here a case of a male dwarf with bilateral undescended testes and bi‐ventricular obstructive cardiomyopathy. Clinical features included choreoathetoid movements, chorioretin‐itis, bilateral nystagmus, and unusual red color of the hair, associated with some features of Turner phenotype. Endocrine studies were normal except for a lack of thy‐rotrophic stimulating hormone (TSH) response to thy‐rotrophic releasing hormone (TRH) stimulation. Pro‐pranolol removed the gradient during cardiac cathe‐terization and relieved the exertional chest pain clinically.
Computer enhanced digital angiography
Authors: Vas R. , Diamond G. A. , Levisman J. A. , Nakano F. H. , Neidorf B. S. , Rose R. M. , Whiting J. S. , Forrester J. S. 
Published: February 2009

AbstractSummary: A new computer image enhancement technique was employed on cardiac images of 10 dogs and 7 patients to demonstrate the feasibility of an on‐line automatic delineation of the left ventricular endocardial silhouette with a peripheral venous injection of contrast material while simultaneously reducing the x‐ray dosage. This technique employs a very fast analog‐to‐digital conversion system capable of digitizing on‐line video frames. By storing and continuously updating the first 30 video frames and then subtracting each incoming frame from this memory, most of the background is eliminated leaving only the contrast filled ventricle. Using calibrated densitometric measurements, we found that iodine concentrations in the human left ventricle following venous injection of 40 ml Renografin®‐76 (25 ml/s), peaked at 4.3±0.3 mg/ml (mean±SD) compared to 14.8±0.8 mg/ml following direct injection of 40 ml at 13 ml/s (p<0.001). The computer enhanced venous‐injected images had an optical contrast 14 times greater than that of the unenhanced direct left ventric‐ulogram. This increase in optical contrast provided unambiguous subjective definition of the endocardial borders. This technique is applicable to both central and peripheral contrst injection whereby high quality images can be obtained at approximately 98% reduction in radiation (5 mA, 65–85 kV), allowing performance of serial studies.
The acute electrophysiological effects of intravenous metoprolol
Authors: Camm A. J. , Whitmarsh V. B. , Ward D. E. 
Published: February 2009

AbstractSummary: The cardiac electrophysiological effects of metoprolol were studied in ten patients (pts) aged 22–51 years undergoing intracardiac stimulation studies for paroxysmal palpitations. The following measurements were made: (1) basic sinus cycle length (SCL); (2) sinus node recovery time (SRT) following overdrive pacing; (3) atrio‐His (A‐H) and His‐ventricular (H‐V) conduction intervals during regular atrial pacing; (4) effective refractory periods of the atria (AERP), A‐V node (AVERP) and ventricular myocardium (VERP); and (5) A‐V nodal functional refractory period (AVFRP). All measurements were repeated 10–20 min after a slow bolus intravenous injection of metoprolol (0.2 mg/kg body weight). Results were analyzed by the Wilcoxon Signed Rank test. Highly significant increases in: SRT (932±166 to 1107±225 ms, p<0.001) and A‐H (72±14 to 103± 14 ms, p<0.001) were observed. There were also small increases of lesser significance in SCL (794± 160 to 898±190 ms, p<0.01), AVERP (308±46 to 341±66 ms, p<0.02), and AVFRP (376±43 to 416±59 ms, p<0.01). Metoprolol did not affect the H‐V interval, the AERP, or the VERP. These results are similar to those of other beta blockers.
PR Interval in middle‐aged men with overt and latent coronary heart disease compared to PR in angionegative and normal men of similar age
Authors: Erikssen J. , Amlie J. P. , Thaulow E. , Kjekshus J. 
Published: February 2009

AbstractSummary: PR was measured prospectively in 2014 apparently healthy men ranging in age from 40 to 59 years (P subjects), and retrospectively in 652 hospitalized men with a diagnosis of coronary heart disease (CHD) (R subjects). A cardiovascular survey examination suggested CHD in 115 of the 2014 P subjects, coronary angiography of 105 of these confirmed this suspicion in 69. The following observations concerning PR were made: (1) the shortest PR was found in angiopositive P subjects, intermediate PR in 1832 normal P subjects, and PR was longest in 36 angionegative subjects. (2) PR was shortest in angiopositive P subjects with triple‐vessel disease, and longest in P subjects with single‐vessel disease. (3) PR increased with age, and an inverse association was found between PR and resting heart rate in P‐subjects. (4) In 98 of 1832 normal P subjects, all without signs or symptoms of heart disease, PR was ±0.22 s. (5) Prolonged PR was no more frequent among the 652 R subjects than among P subjects, despite significant CHD in 595, and a frequent use of drugs known to delay atrioventricular conduction. It is suggested that advanced stable clinical CHD only rarely gives rise to prolonged PR at rest, and that PR in subjects with latent CHD may have somewhat shorter PR than age counterparts without symptoms or signs of CHD. Conflicting data in the literature are probably related to differences in material and methods.