bluuebunny/crossref_metadata_2025 huggingface dataset:
Association of risk factor variables and coronary artery disease documented with angiography.
Authors: Holmes D R , Elveback L R , Frye R L , Kottke B A , Ellefson R D
Published: June 2011

Stepwise linear discrimination was used to analyze risk factors in 431 consecutive patients who underwent coronary angiography to determine which variables were most closely associated with coronary artery disease. Twenty-one risk factors were considered: total plasma cholesterol and triglycerides; the cholesterol and triglyceride content of high-density lipoproteins (HDL), low-density lipoproteins (LDL) and very low density lipoproteins (VLDL); and the percentage of total cholesterol and triglycerides in each fraction. Age, smoking history, family history, hypertension, diabetes mellitus and relative weight were also considered. Coronary artery disease was assessed using three standard grading scores. There were significant differences in risk factors between males and females. In males, LDL cholesterol and age were selected by multivariate analysis. In females, the ratio of HDL cholesterol to total cholesterol, as well as relative weight, family history, age and smoking were selected. The discriminating value of HDL cholesterol as the percentage of total cholesterol was significantly greater than that of HDL cholesterol itself. Despite highly significant associations between risk factors and the presence of coronary artery disease, the discrimination did not provide sufficient separation of the groups to give results that are useful diagnostically in individual patients.
An automated system for blood pressure determination during exercise.
Authors: Glasser S P , Ramsey M R
Published: June 2011

Automation of blood pressure (BP) measurements during exercise has proved difficult because motion artifact is a major limitation in ultrasound techniques and noise artifact limits the application of sound transduction via microphone pickups. We assessed the value of a new automated system of indirect BP determination by comparing it with manually determined BP in 50 consecutive patients referred for treadmill testing. Automated BP determinations were blinded to the physician or technician who was simultaneously manually auscultating BP. The automated system uses acoustic transduction, but with ECG assist and microprocessing of nonsynchronous noise to overcome the limitations of other systems. The data were statistically analyzed and the correlation coefficient, mean difference and standard deviation of the difference for systolic and diastolic BP for differing levels of heart rate and treadmill stage were determined. The correlation between automated and manually determined BP was 0.964 for systolic BP and 0.848 for diastolic BP. Despite some limitations, this automated system offers significant advantages for exercise BP determination.
Comparative evaluation of the IBM (12-lead) and Royal Infirmary (orthogonal three-lead) ECG computer programs.
Authors: Macfarlane P W , Melville D I , Horton M R , Bailey J J
Published: June 2011

A comparison of two computer programs for ECG interpretation was undertaken. Twelve-lead ECGs from 300 patients with various clinical abnormalities were interpreted at the National Institutes of Health using version 1 of the IBM program and corresponding orthogonal three-lead ECGs were analyzed by the Glasgow Royal Infirmary (GRI) program. Interpretations were compared with respect to the clinical documentation, wherever possible, and with each other directly in the case of diagnostic statements for which non-ECG documentation was not available. The two programs had a similar performance in determining abnormalities such as myocardial infarction and ventricular hypertrophy. However, with respect to conduction defects and ST-T-wave statements, certain discrepancies between the two program performances were revealed. There were 222 disagreements between various diagnostic statements. GRI was judged correct in 119 of these disagreements and IBM in 70. In these 189 cases the disagreement could most often be accounted for by different criteria and/or algorithms in the two programs or by the use of different ECG lead sets. The remaining 33 disagreements had to be classified as inconclusive.
Platelets, thromboembolism and mitral valve prolapse.
Authors: Walsh P N , Kansu T A , Corbett J J , Savion P J , Goldburgh W P , Schatz N J
Published: June 2011

Cerebral and retinal ischemic events have been described in mitral valve prolapse. To determine whether platelets play a part in the pathogenesis of thromboembolism we studied 29 patients with mitral valve prolapse, including nine (group I) with thromboembolism (cerebral, retinal and deep venous), eight (group II) with transient visual obscurations and 12 (group III) with neither thromboembolism nor visual complaints, compared with 18 control patients and 38 normal subjects. Patients in groups I and II had increased platelet coagulant activities concerned with the initiation and early stages of intrinsic coagulation, and group I patients had an increased proportion of circulating platelet aggregates and platelets relatively insensitive top epinephrine in aggregation and secretion. The incidence of platelet coagulation hyperactivity in patients with mitral valve prolapse was 76% (100% in group I, 75% in group II, 58% in group III), compared with 6% in control patients. These results suggest that platelets play a role in the purported association of thromboembolism and mitral valve prolapse.
Incomplete mitral leaflet closure in patients with papillary muscle dysfunction.
Authors: Godley R W , Wann L S , Rogers E W , Feigenbaum H , Weyman A E
Published: June 2011

Clinical acceptance of an association between papillary muscle dysfunction and mitral regurgitation is widespread, despite the lack of objective support. To evaluate a possible association, we performed echocardiographic examinations on 22 patients with prior myocardial infarction and clinical evidence of papillary muscle dysfunction, 40 patients with prior myocardial infarction and no clinical evidence of papillary muscle dysfunction, and 20 normal subjects. There was a unique pattern of incomplete mitral leaflet closure in a high percentage (91%) of infarct patients with mitral regurgitation. In these patients, one or both leaflets were effectively arrested within the cavity of the left ventricle during ventricular systole. Dyskinetic wall motion in the region immediately surrounding one of the papillary muscles was present in 23 of 24 patients (96%) with demonstrated incomplete closure. This study provides the first objective evidence that de novo mitral regurgitation in patients with prior myocardial infarction is due to dyskinesis involving the left ventricular myocardium beneath one of the papillary muscles, producing increased tension on the mitral leaflets and preventing normal closure.
Radionuclide imaging of experimental myocarditis.
Authors: Reeves W C , Jackson G L , Flickinger F W , Kwee H G , Schwiter E J , Werner J , Whitesell L , Biddle M A , Copenhaver G , Shaikh B S , Zelis R
Published: June 2011

The ability of 67Ga citrate and 99mTc pyrophosphate cardiac imaging to detect myocarditis was assessed in an experimental rabbit model. Twenty-three rabbits were imaged approximately 72 hours after infusion of i.v. norepinephrine. Diffuse cardiac uptake was found in 13 of 15 rabbits scanned with 67Ga. Tissue distribution studies documented significant myocardial uptake of 67Ga in those with positive scans. Precordial imaging and tissue distribution studies revealed no cardiac uptake in the eight rabbits scanned with 99mTc. Histologic examination of all 23 hearts revealed qualitatively similar, typical lesions of myocarditis. This study suggests that cardiac imaging with 67Ga may be useful in the detection of myocarditis.
The effectiveness of antiarrhythmic agents on early-cycle premature ventricular complexes.
Authors: Krone R J , Miller J P , Kleiger R E , Clark K W , Oliver G C
Published: June 2011

Twelve patients completed a double-blind, crossover antiarrhythmic drug trial in which 300 mg of quinidine, 500 mg of procainamide, 100 mg of phenytoin, or placebo was given four times daily on subsequent weeks. Analysis of 24-hour Holter tapes with a computerized analysis system (Argus/H) permitted accurate counting of premature ventricular complexes (PVCs) subclassified according to coupling interval. No antiarrhythmic agent demonstrated a significant overall reduction in the number of PVCs, but both quinidine and procainamide showed a statistically significant (p less than 0.05) reduction of PVCs with coupling intervals less than 400 msec. This effect was noted both in isolated PVCs (quinidine only) and in PVCs that were part of a couplet or run (both drugs). These findings demonstrate that clinically important effects of procainamide and quinidine can occur in the absence of an overall reduction in the number of PVCs.
Drainage of right superior vena cava into both atria. Review of the literature and description of a case presenting with polycythemia and paradoxical embolization.
Authors: Shapiro E P , Al-Sadir J , Campbell N P , Thilenius O G , Anagnostopoulos C E , Hays P
Published: June 2011

An unusual cause of polycythemia, cyanosis and paradoxical embolus is described in a 37-year-old man, consisting of a rare congenital anomaly of the superior vena cava (SVC). The right-sided SVC received pulmonary venous drainage from the right lung and drained, through two channels, into both atria with the left atrium receiving the larger of the two channels. The atrial septum was intact. Corrective surgery and postoperative cardiac catheterization are described and the literature concerning anomalies of the right superior vena cava is reviewed.
Imaging the inflammatory response to acute myocardial infarction in man using indium-111-labeled autologous platelets.
Authors: Davies R A , Thakur M L , Berger H J , Wackers F J , Gottschalk A , Zaret B L
Published: June 2011

The feasibility of imaging the inflammatory response to acute transmural myocardial infarction in man using biologically active indium-111 (111In)-labeled autologous leukocytes was assessed in 36 patients. Indium-111 leukocytes (approximately 500 microCi) were injected i.v. 18-112 hours after the onset of chest pain. Cardiac imaging was performed 24 hours later with a mobile gamma camera. Twenty-one patients had positive images and 15 had negative images. The percent of positive images increased as the interval between infarction and 111In-leukocyte injection shortened; all patients injected within 24 hours of infarction had positive images. Patients with positive images were injected with 111In leukocytes earlier after infarction (mean +/- SEM, 43 +/- 4 vs 63 +/- 7 hours; p less than 0.05) and were younger (53 +/- 2 vs 65 +/- 3 years; p less than 0.05) than those with negative images. Several other parameters that could possibly have affected the imaging results were examined and were not significantly different in patients with positive and negative images. These included peak serum creatine kinase, location of infarction, incidence of pericarditis, use of antiinflammatory drugs (aspirin and indomethacin) or membrane-active antiarrhythmic drugs (lidocaine and procainamide), peripheral leukocyte count and cell labeling efficiency. The function of the labeled cell was similar in patients with positive and negative images. Six patients with acute infarction serving as controls and given free 111In oxine and six patients with stable coronary artery disease given 111In leukocytes all had negative cardiac images.
Anatomic correction of transposition of the great arteries: pre- and postoperative cardiac catheterization, with angiocardiography in five patients.
Authors: Freedom R M , Culham J A , Olley P M , Rowe R D , Williams W G , Trusler G A
Published: June 2011

Six of eight patients survived anatomic correction of transposition of the great arteries and repair of associated cardiovascular anomalies at the Hospital for Sick Children, Toronto, Canada. Two of the six survivors also had tricuspid atresia, and continuity between the right atrium and the subaortic outlet chamber in these patients was provided by a valved external conduit, in addition to the arterial switch and coronary artery reimplantation. Five of the six patients have undergone complete postoperative clinical, hemodynamic and angiocardiographic investigation and form the basis of this communication. Our present indications for anatomic repair are discussed.
Electrophysiologic effects on combined autonomic blockade in patients with sinus node disease.
Authors: Desai J M , Scheinman M M , Strauss H C , Massie B , O'Young J
Published: June 2011

Thirty-two patients were studied before and after i.v. administration of 0.15-0.20 mg/kg of propranolol. Twenty-one of the 32 underwent combined autonomic blockade with the additional infusion of 0.04 mg of atropine. Twenty other patients with sinus node disease underwent electrophysiologic studies both before and after i.v. administration of 0.04 mg of atropine alone. Spontaneous cycle length, maximal corrected sinus node recovery time, sinoatrial conduction time, secondary pauses and intrinsic heart rate were measured. Secondary pauses were more common in those with abnormal intrinsic heart rates, and they did not correlate with changes in maximal corrected sinus node recovery time or sinoatrial conduction time. In patients with normal intrinsic heart rate, abnormal test measurements usually returned to normal after combined blockade (hypervagotonia); however, some patients showed a new abnormality after propranolol that was not reversible with atropine (catecholamine-dependent). Abnormal test responses in patients with abnormal intrinsic heart rate persisted or increased after combined blockade. We conclude that patients with sinus node disease may be categorized as (1) those with intrinsic sinus node disease; (2) those with normal intrinsic sinus node function but either relative hypervagotonia or catecholamine dependency; and (3) those with abnormal intrinsic sinus node function affected by vagal or catecholamine factors.
Esophageal echocardiographic left ventricular anterolateral wall motion in normal subjects and patients with coronary artery disease.
Authors: Matsuzaki M , Matsuda Y , Ikee Y , Takahashi Y , Sasaki T , Toma Y , Ishida K , Yorozu T , Kumada T , Kusukawa R
Published: June 2011

Esophageal echocardiography was developed for recording left ventricular anterolateral wall (LVAW) echocardiograms and was applied clinically to 14 normal subjects and 21 patients with coronary artery disease. LVAW echocardiograms were obtained satisfactorily in 11 of 14 normal subjects (75%) and 20 of 21 patients (95%) with coronary artery disease. LVAW echocardiograms were obtained by conventional anterior echocardiography in eight of 21 patients (38%) with coronary artery disease. In 11 normal subjects, mm/sec (mean 34.3 +/- 5.2 mm/sec); and diastolic wall thickness ranged from 9-12.5 mm (mean 11.2 +/- 0.7 mm). In 20 patients with coronary artery disease, LVAW motion obtained by esophageal echocardiography was classified into five groups according to the excursion, and the findings were in good agreement (80%) with those obtained by left ventriculography. Classification of LVAW motion by conventional echocardiography agreed with that of left ventriculography in only three of eight patients, although all eight patients had abnormal LVAW motion by the conventional method. In all patients except one, whose LVAW echocardiograms were obtained by conventional echocardiography, excursion was much less than that obtained by esophageal echocardiography. We conclude that the projection of an ultrasonic beam from the intraesophageal transducer is a better approach for accurate measurement of LVAW motion.
His-Purkinje responses and refractory periods during atrial extrastimulation in children with heart defects.
Authors: Wolff G S , Mehta A , Tamer D , Garcia O L , Pickoff A S , Casta A , Ferrer P L , Sung R J , Gelband H
Published: June 2011

During atrial extrastimulation, split His potentials, prolonged His-to-ventricular (H2V2) intervals and block distal to the His bundle deflection were observed in both preoperative and postoperative children with heart defects. His-Purkinje responses and refractoriness were identified in 31 of 78 (40%) pediatric patients (20 of 51 preoperative and 11 of 27 postoperative) during atrial extrastimulation coupled to sinus and/or paced cycle lengths. Split His potentials were found in 14 patients (eight preoperative and six postoperative) and His bundle relative refractory periods ranged from 250--490 msec. Prolonged H2V2 intervals were found in these and in an additional 16 patients (11 preoperative and five postoperative) and the relative refractory period of the His-Purkinje system ranged from 230--500 msec. Block distal to the His deflection occurred in seven patients (five preoperative and two postoperative) and the effective refractory period ranged from 230--510 msec. Split His potentials, long H2V2 intervals and block distal to the His bundle deflection produced by atrial extrastimulation were found in peroperative as well as postoperative children. These responses probably represent functional electrophysiologic characteristics of the pediatric cardiac conduction system.
Intravenous infusion of prostacyclin sodium in man: clinical effects and influence on platelet adenosine diphosphate sensitivity and adenosine 3':5'-cyclic monophosphate levels.
Authors: Data J L , Molony B A , Meinzinger M M , Gorman R R
Published: June 2011

Clinical tolerance, inhibition of platelet aggregation and intracellular platelet adenosine 3':5'-cyclic monophosphate (cyclic AMP) levels were evaluated in normal volunteers given i.v. infusions of prostacyclin sodium at rates up to 15 ng/kg/min. Short-term infusions (30 and 60 minutes) were tolerated at rates up to 10.0 ng/kg/min; higher rates produced headaches, anxiety, nausea and vomiting. Six-hour and 24-hour infusions were tolerated at rates up to only 4.0 ng/kg/min. Twenty-four hour infusions at 4 ng/kg/min produced a consistent 4-7 microM shift to the right in the platelet ADP dose-response curve; this platelet inhibitory activity did not diminish during the infusion. Prostacyclin sodium infusion elevated intracellular cyclic AMP levels, the increases corresponding to the onset of measurable inhibition of ADP-induced aggregation, although the magnitude of the increase did not necessarily reflect the degree of inhibition. Increased template bleeding times were seen with a greater than 10-microM shift in the ADP dose-response curve. We conclude that although prostacyclin sodium has a narrow safety margin, the drug does produce platelet inhibition at infusion rates generally tolerated by healthy volunteers.
Angiographic anatomy of the normal heart through axial angiography.
Authors: Ceballos R , Soto B , Bargeron L M
Published: June 2011

We sectioned a series of hearts in a manner similar to that seen on angiographic axial views. A correlation with normal angiograms to identify the anatomic components of the four cardiac chambers showed that the components of the normal cardiac anatomy can be identified accurately through axial angiography in a manner not show previously.
Clinical evaluation of atenolol in hypertensive patients.
Authors: Ibrahim M M , Mossallam R
Published: June 2011

Atenolol, a cardioselective beta-adrenergic blocking agent, was given as the sole hypotensive drug for 8-12 weeks to 20 patients with hypertension of varying degrees of severity. Initial systolic blood pressure ranged from 162-238 mm Hg (mean +/- SEM 196 +/- 5.5 mm Hg) and diastolic blood pressure ranged from 105-143 mm Hg (118 +/- 2.5 mm Hg). Three patients had accelerated hypertension, six had cardiomegaly with recent exertional dyspnea and three were diabetics. Atenolol, 100-300 mg once daily, controlled both the supine and standing blood pressure and markedly attenuated the initial hypertensive response to severe exercise. In 17 patients (85%), atenolol therapy reduced blood pressure more than 20/10 mm Hg; however, adequate blood pressure control was not achieved in severe hypertension. A significant hypotensive action developed within 2 weeks of treatment, and control of hypertension was maintained for 2 weeks after sudden interruption of therapy. No patient had postural or postexercise hypotension. The drug appeared to exert its maximum hypotensive effect at the 100-mg dosage. The magnitude of the hypotensive response was related to the initial systolic blood pressure (r = 0.77, p less than 0.01) and the degree of inhibition of exercise tachycardia (r = 0.66, p less than 0.01). The atenolol plasma level and its hypotensive action were not related. Except for impairment of glucose tolerance in diabetic patients, atenolol had minimal side effects.
Long-term hemodynamic assessment of the porcine heterograft in the mitral position. Late development of valvular stenosis.
Authors: Lipson L C , Kent K M , Rosing D R , Bonow R O , McIntosh C L , Condit J , Epstein S E , Morrow A G
Published: June 2011

We undertook a study of patients who had porcine mitral valves in place for more than 5 years and who had no clinical signs or symptoms suggestive of valve dysfunction. Of the first 54 patients who had porcine valves implanted in the mitral position, 18 were available for catheterization; all had a routine hemodynamic study postoperatively (mean 7 months) for comparison. Mean follow-up was 85 months (range 61-111 months). Compared with the early postoperative data, there was a significant increase in mean mitral valve gradient, from 5.9 +/- 0.7 to 8.6 +/- 0.7 mm Hg (p less than 0.01), and a significant decrease in calculated mitral valve area, from 2.2 +/- 0.2 to 1.7 +/- 0.2 cm2 (p less than 0.01). Moreover, seven patients showed a decrease in valve area greater than 1.0 cm2, five with valves in place for more than 80 months and only two of 11 patients with valves in place for 80 months or less (p less than 0.05). We conclude that there is a significant incidence of hemodynamic deterioration of porcine heterografts in the mitral position for greater than 5 years, even in patients who are clinically stable.
Hemodynamic and angiographic evaluation of aortic regurgitation 8 and 27 months after aortic valve replacement.
Authors: Toussaint C , Cribier A , Cazor J L , Soyer R , Letac B
Published: June 2011

Eighteen patients with chronic aortic insufficiency were evaluated hemodynamically and angiographically 8 months after aortic valve replacement. Both the pulmonary artery diastolic pressure and the left ventricular end-diastolic volume decreased significantly (p less than 0.001), but the mean ejection fraction and the cardiac output remained identically lowered, though some individual cases showed improvement. The relative reduction in end-diastolic volume correlated only with the preoperative ejection (p less than 0.05) and regurgitation fractions (p less than 0.02). In the 10 patients whose left ventricular volume remained high or ejection fraction low, a second evaluation was performed 27 months after surgery. The left ventricular end-diastolic volume was significantly lowered (from 151 to 120 ml/m2, p less than 0.05) back to normal in five cases. The systolic and diastolic ventricular shape returned to normal. Cardiac index and ejection fraction were unchanged. These results show a marked improvement a few months after aortic valve replacement, with a further improvement several months later, as shown mainly by the decrease of left ventricular end-diastolic volume and the return to normal of left ventricular cavity shape. However, in most cases, the ejection fraction remained at its preoperative valve, suggesting that surgery should be performed early, before myocardial deterioration appears.
Clinical significance and hemodynamic correlates of the third heart sound gallop in aortic regurgitation. A guide to optimal timing of cardiac catheterization.
Authors: Abdulla A M , Frank M J , Erdin R A , Canedo M I
Published: June 2011

The hemodynamic and clinical data of 42 patients with chronic significant aortic regurgitation and 31 normal subjects were examined. Of the patients with aortic regurgitation, 28 had a third heart sound (S3) gallop and 14 did not. There was no significant difference in the severity of regurgitation between the patients with or without an S3 gallop. However, all patients with an S3 gallop had an abnormality increased left ventricular residual volume and depressed contractile state. These findings were supported by the hemodynamic data of two patients who underwent cardiac catheterization before and after the development of an S3 gallop. We conclude that the S3 gallop in patients with chronic AR reflects left ventricular dysfunction, rather than more severe degrees of regurgitation per se, and may therefore be useful for selecting patients for cardiac catheterization and consideration for prosthetic aortic valve replacement.
Acute regional circulatory and renal hemodynamic effects of converting-enzyme inhibition in patients with congestive heart failure.
Authors: Creager M A , Halperin J L , Bernard D B , Faxon D P , Melidossian C D , Gavras H , Ryan T J
Published: June 2011

The acute effects of the angiotensin converting-enzyme inhibitor captopril on regional blood flow, renal hemodynamics and sodium excretion were studied in 12 patients with severe congestive heart failure. Converting-enzyme inhibition decreased systemic vascular resistance by 27% and increased cardiac index by 16%. Estimated hepatic blood flow decreased 17%, but renal blood flow increased 60%. The ratio of renal-systemic blood flow increased from 0.10 +/- 0.01 to 0.14 +/- 0.02 (p = 0.031). Although renal plasma flow increased from 202.8 +/- 28.8 to 323.7 +/- 42.7 ml/min (p less than 0.008), the glomerular filtration rate did not change significantly from the mean pretreatment value of 82.1 +/- 12.3 ml/min. The filtration fraction decreased from 41.3 +/- 3.8% to 33.4 +/- 4.5% (p = 0.050), while urinary sodium excretion doubled, from 34.5 +/- 9.6 to 68.2 +/- 19.6 muEq/min. The plasma renin activity increased from 12.6 +/- 5.0 to 29.9 +/- 8.4 ng/ml/hr (p = 0.030) as plasma aldosterone concentration decreased from 30.5 +/- 6.5 to 11.3 4/- 1.2 ng/dl (p = 0.010) and norepinephrine concentrations decreased from 774 +/- 105 to 618 +/- 85 pg/ml (p = 0.020). We conclude that converting-enzyme inhibition reverses renal vasoconstriction in congestive heart failure and redistributes regional blood flow. The natriuresis may be mediated by one or more of the following: improved renal plasma flow, reduction in filtration fraction, suppression of hyperaldosteronism, and lowering of circulatory catecholamine concentrations.
Myocardial infarct size and location in relation to the coronary vascular bed at risk in man.
Authors: Lee J T , Ideker R E , Reimer K A
Published: June 2011

Recent infarcts were compared with the anatomic boundaries of the involved vascular bed in human hearts to determine the amount and location of necrosis in relation to the myocardium at risk. The coronary arteries were injected with BaSO4 in 18 human hearts with 3-16-day-old infarcts. Thin (3-4 mm) slices were cut at 10-15 mm intervals, photographed, x-rayed and used for histologic analysis. Infarct outlines were traced from gross photographs using histologic confirmation of infarct boundaries, and the vascular bed was independently traced from the x-rays. Ischemic bed size and infarct size were then calculated by computerized planimetry. Infarct size ranged from 13-72% of the left ventricle (mean 30 +/- 3.6%) and was linearly related to the size of the occluded vascular bed (r = 0.93). However, the infarcts were always smaller than the occluded beds. They involved 50-88% of the ischemic bed (mean 69 +/- 3.0%) due to variation in the transmural extent of necrosis. A lateral zone of viable muscle within the ischemic bed was present but was consistently narrow (mean 1.7 +/- 0.3 mm) so that the infarcts involved 93 +/- 2.3% of the width of the bed at risk. Thus, ischemic bed size is a major determinant of infarct size in fatal human infarcts. When natural limitation of infarct size occurs, it is due primarily to limitation of the transmural extent of necrosis.
Hemodynamic effects of nitroprusside in infants with a large ventricular septal defect.
Authors: Beekman R H , Rocchini A P , Rosenthal A
Published: June 2011

To evaluate the effect of acute vasodilator therapy, nitroprusside was administered at cardiac catheterization to five infants (ages 10 days to 6 months) with isolated ventricular septal defect and congestive heart failure. Intravenous nitroprusside was begun at a dose of 0.5 micrograms/kg/min and was increased by increments of 0.5 micrograms/kg. Hemodynamic measurements were made before nitroprusside, after 5 minutes at each dose, and 10 minutes after nitroprusside was discontinued. Baseline data were obtained before nitroprusside administration and compared with data obtained at maximal nitroprusside dose. The pulmonary-to-systemic flow ratio increased from 2.2 +/- 0.2 to 3.4 +/- 0.2 (mean +/- SEM, p less than 0.05) as a consequence of a marked decrease in systemic blood flow (5.3 +/- 0.7 to 3.6 +/- 0.51/min/m(2), p less than 0.05). Pulmonary flow did not change significantly. Mean pulmonary capillary wedge and right atrial pressures decreased by 53% (10.2 +/- 1.4 to 4.8 +/- 1.4 mm Hg [p less than 0.01] and 6.0 +/- 1.4 to 2.8 +/- 1.1 mm Hg [p less than 0.05], respectively). Decreases in mean aortic (63.6 +/- 3.0 to 54.6 +/- 2.1 mm Hg, p less than 0.05) and mean pulmonary artery pressure (41.4 +/- 6.2 to 32.0 +/- 6.7 mm Hg, p less than 0.05) were also observed. An apparently paradoxical increase in systemic resistance occurred (11.7 +/- 1.6 to 15.4 +/- 2.4 U, p less than 0.05. Our data show that nitroprusside causes a marked decrease in systemic blood flow and an increase in the pulmonary-to-systemic flow ratio in infants with a large ventricular septal defect. These findings may be related to the hemodynamic profile of these infants, in whom ventricular function, cardiac output and systemic resistance are normal.
Use of equilibrium (gated) radionuclide ventriculography to quantitate left ventricular output in patients with and without left-sided valvular regurgitation.
Authors: Konstam M A , Wynne J , Holman B L , Brown E J , Neill J M , Kozlowski J
Published: June 2011

We examined the accuracy with which left ventricular output can be estimated by equilibrium radionuclide ventriculography. After red blood cells were labeled in vivo, we measured left ventricular end-diastolic and end-systolic count rates and the count rate in 5 ml of the patient's blood. After estimating the average ratio of counting efficiency for the left ventricle to counting efficiency for the blood sample (Elv/Es) in six patients, we calculated left ventricular output in 26 other patients as (left ventricular activity ejected per minute divided by activity per liter of blood) divided by the previously estimated Elv/Es. Radionuclide left ventricular output closely approximated Fick cardiac output (r = 0.94) in patients without mitral or aortic regurgitation and exceeded Fick cardiac output in all patients with valvular regurgitation. Regurgitant fraction, calculated as the difference between the radionuclide and Fick outputs divided by the radionuclide output, correlated with the severity of of regurgitation as assessed angiographically. The equilibrium radionuclide ventriculogram is an excellent means for noninvasive estimation of left ventricular output.
Myocardial thallium-201 kinetics in normal and ischemic myocardium.
Authors: Grunwald A M , Watson D D , Holzgrefe H H , Irving J F , Beller G A
Published: June 2011

The initial myocardial uptake of thallium-201 depends on myocardial blood flow distribution. The phenomenon of delayed thallium redistribution after transiently or chronically altered myocardial perfusion has been described. The net myocardial accumulation of thallium-201 after injection depends upon the net balance between continuing myocardial extraction from low levels of recirculating thallium in the blood compartment and the net rate of efflux of thallium from the myocardium into the extracardiac blood pool. These experiments were designed to measure separately the myocardial extraction and intrinsic myocardial efflux of thallium-201 at normal and at reduced rates of myocardial blood flow. The average myocardial extraction fraction at normal blood flow in 10 anesthetized dogs was 82 +/- 6% (+/- SD) at normal coronary arterial perfusion pressures and increased insignificantly, to 85 +/- 7%, at coronary perfusion pressures of 10--35 mm Hg. At normal coronary arterial perfusion pressures in 12 additional dogs, the intrinsic thallium washout in the absence of systemic recirculation had a half-time (T 1/2) of 54 +/- 7 minutes. The intrinsic cellular washout rate began to increase as distal perfusion pressures fell below 60 mm Hg and increased markedly to a T 1/2 of 300 minutes at perfusion pressures of 25--30 mm Hg. A second, more rapid component of intrinsic thallium washout (T 1/2 2.5 minutes) representing approximately 7% of the total initially extracted myocardial thallium was observed. The faster washout component is presumed to be due to washout of interstitial thallium unextracted by myocardial cells, whereas the slower component is presumed due to intracellular washout. The net clearance time of thallium measured after i.v. injection is much longer than the intrinsic myocardial cellular washout rate because of continuous replacement of myocardial thallium from systemic recirculation. Myocardial redistribution of thallium-201 in states of chronically reduced perfusion cannot be the result of increased myocardial extraction efficiency, but rather, is the result of the slower intrinsic cellular washout rate at reduced perfusion levels.
George E. Brown memorial lecture. Local modulation of adrenergic neurotransmission.
Authors: Shepherd J T , Vanhoutte P M
Published: June 2011

The cardiovascular reflexes, by regulating the traffic in the sympathetic nerves, govern the amount of norepinephrine released from the nerve endings. However, the final adjustments in the amount of neurotransmitter available to activate the beta 1 receptors in the heart and the alpha receptors in the blood vessels take place at the sympathetic neuroeffector junction. Thus, a decrease in pH, hyperosmolarity, moderate increases in the concentration of K+ ion, adenosine and adenine nucleotides depress the release of norepinephrine at any given level of sympathetic nerve activity. These metabolic changes, which occur in active tissues, and in particular in adenosine, have been proposed as mediators of the accompanying local hyperemia. In addition, they apparently facilitate this local dilatation by disconnecting the blood vessels in the active tissues from sympathetic control. Acetylcholine, histamine and 5-hydroxytryptamine are present in and around certain blood vessels and can activate specific receptors on the prejunctional fibers and cause vasodilatation by reducing the output of neutrotransmitter. Some of the norepinephrine released into the synaptic cleft may depress its continued release by activating prejunctional alpha receptors. In contrast, angiotensin II, by a local action on the nerve endings, can augment the release of transmitter. Decreases in local temperature reduce transmitter release but augment the affinity of the postjunctional alpha receptors for norepinephrine. The role of these local events at the neuroeffector junction, their physiologic significance and potential clinical importance are discussed in this review.
The high-risk angina patient. Identification by clinical features, hospital course, electrocardiography and technetium-99m stannous pyrophosphate scintigraphy.
Authors: Olson H G , Lyons K P , Aronow W S , Stinson P J , Kuperus J , Waters H J
Published: June 2011

We evaluated 193 consecutive unstable angina patients by clinical features, hospital course and electrocardiography. All patients were managed medically. Of the 193 patients, 150 (78%) had a technetium-99m pyrophosphate (Tc-PYP) myocardial scintigram after hospitalization. Of these, 49 (33%) had positive scintigrams. At a follow-up of 24.9 +/- 10.8 months after hospitalization, 16 of 49 patients (33%) with positive scintigrams died from cardiac causes, compared with six of 101 patients (6%) with negative scintigrams (p less than 0.001). Of 49 patients with positive scintigrams, 11 (22%) had had nonfatal myocardial infarction at follow-up, compared with seven of 101 patients (7%) with negative scintigrams (p less than 0.01). Age, duration of clinical coronary artery disease, continuing angina during hospitalization, ischemic ECG, cardiomegaly and a history of heart failure also correlated with cardiac death at follow-up. Ischemic ECG and a history of angina with a crescendo pattern also correlated with nonfatal infarction at follow-up. Patients with continuing angina, an ischemic ECG and a positive scintigram constituted a high-risk unstable angina subgroup with a survival rate of 58% at 6 months, 47% at 12 months and 42% at 24 and 36 months. We conclude that the assessment of clinical features, hospital course, ECG and Tc-PYP scintigraphy may be useful in identifying high-risk unstable angina patients.
Trends in cardiovascular mortality in Spanish-surnamed, other white, and black persons in Texas, 1970--1975.
Authors: Kautz J A , Bradshaw B S , Fonner E
Published: June 2011

Certain categories of cardiovascular disease have significantly declined recently as causes of death. In the present investigation we describe the variation in cardiovascular mortality in Texas by ethnicity, age and sex during 1970--1975 using age-standardized proportional mortality ratios. Specifically, the question of whether the three major ethnic groups in Texas have shared equally in any changes in cardiovascular mortality is examined. Several subcategories of cardiovascular mortality are considered. Among the sex-ethnic groups both ischemic heart disease and acute myocardial infarction mortality declined less among Spanish-surnamed males and females than in their other white and black counterparts. Chronic ischemic heart disease increased in relative importance for all groups except Spanish-surnamed females, in whom it decreased. There was no significant decrease in cerebrovascular disease mortality among Spanish-surnamed males or females as there was in the other groups. These results suggest that important differences in cause-structure of mortality are occurring in the ethnic subpopulations of Texas.
Immunosuppressive therapy in patients with congestive cardiomyopathy and myocardial uptake of gallium-67.
Authors: O'Connell J B , Robinson J A , Henkin R E , Gunnar R M
Published: June 2011

Thirty-nine patients with idiopathic congestive cardiomyopathy underwent gallium-67 scintigraphy. Twenty had no evidence of myocardial uptake (group I) and 19 had demonstrable myocardial gallium-67 activity (group II). There was no significant difference in age, sex, duration of symptoms, antecedent viral illness, left ventricular end-diastolic pressure, pulmonary artery systolic pressure, or ejection fraction between the two groups. Fifteen patients in group II were treated with prednisone and azathioprine for a minimum of 8 months. Nine of 15 patients were clinically unchanged and gallium-67 scans remained positive (group IIa). Six patients had significant improvement and resolution of myocardial gallium-67 uptake (group IIb). The mean change in ejection fraction was +0.2% in group I, -4.8% in Group IIa, and +13.8% in group IIb. There were five deaths in group I (25% mortality), three in group IIa (33% mortality), and no deaths in group IIb. The only significant difference between patients in group IIa and those in group IIb was a greater left ventricular posterior wall thickness in group IIa patients. Twenty control patients without cardiac disease had negative gallium-67 scans. We conclude that gallium-67 myocardial scintigraphy may be a useful test for predicting the response to prednisone and azathioprine therapy.
Echocardiographic visualization of ventricular septal defect in infants and assessment of hemodynamic status using a contrast technique. Comparison of M-mode and two-dimensional imaging.
Authors: Funabashi T , Yoshida H , Nakaya S , Maeda T , Taniguchi N
Published: June 2011

Twenty-seven patients with ventricular septal defect (VSD), ages 2 months to 2 years, were evaluated by both M-mode and two-dimensional echocardiography (2-D echo) with the aid of a peripheral venous contrast technique. M-mode echocardiography was unreliable for imaging VSD. Using 2-D echo, defects in the interventricular septum were visualized in all patients examined; defects in the membranous portion (24 patients) were visualized by the subcostal frontal approach and defects in the supracristal portion (three patients) by the subcostal sagittal approach. The 2-D echo contrast study revealed negative contrast jets appearing through the defect in the right ventricle in 22 patients with a pulmonary-to-systemic blood flow ratio greater than 2.0, and positive contrast jets appearing through the defect in the left ventricle in 13 patients with a right-to-left ventricular peak pressure ratio greater than 0.71. We conclude that 2-D echo with peripheral contrast technique confirmed the anatomic location of VSD and indicated the approximate right-to-left ventricular peak pressure ratio, showing the contrast material shunting through the defect itself.
Side effects of therapy with prostaglandin E1 in infants with critical congenital heart disease.
Authors: Lewis A B , Freed M D , Heymann M A , Roehl S L , Kensey R C
Published: June 2011

The case reports of 492 infants with critical congenital cardiac disease treated with prostaglandin E1 (PGE1) were reviewed to determine the nature and incidence of intercurrent medical events. Forty-three percent of the infants had at least one such event, but only half of these were related to PGE1 and the majority required only minor changes in management. Cardiovascular events were the most common (18% incidence), with cutaneous vasodilation and edema occurring more frequently during intraaortic infusion than during i.v. infusion. Central nervous system events were reported in 16% of the patients. Respiratory depression was reported in 12%, and was particularly common in infants weighing less than 2.0 kg at birth (42%). Hematologic, infectious and renal events appeared for the most part to be unrelated to PGE1. The overall mortality (excluding 19 patients with hypoplastic left-heart syndrome) was 31%; the mortality for the patients with critical coarctation or interruption of the aortic arch was nearly twice that for the cyanotic infants (50% vs 27%). No death was attributed to PGE1 administration. During infusion of PGE1, arterial blood pressure and respiratory activity should be monitored carefully and appropriate supportive steps taken if hypotension or respiratory depression occurs. The development of fever or jitteriness may require reduction of the infusion rate and, in view of the possible increased incidence of infections, the prophylactic use of antibiotics is recommended.
Use of thallium-201 redistribution scintigraphy in the preoperative differentiation of reversible and nonreversible myocardial asynergy.
Authors: Rozanski A , Berman D S , Gray R , Levy R , Raymond M , Maddahi J , Pantaleo N , Waxman A D , Swan H J , Matloff J
Published: June 2011

Thallium-201 (201Tl) redistribution scintigraphy might differentiate reversibly from nonreversibly asynergic myocardial segments and thus predict the response of these segments to coronary artery bypass grafting (CABG). To test this hypothesis, 25 consecutive patients undergoing CABG, preoperative stress-redistribution 201Tl scintigraphy, and both pre- and postoperative resting equilibrium radionuclide ventriculography were evaluated. For both types of scintigraphic study, each patient was imaged in the same three views. Because of the effects of CABG on septal motion, this region was considered separately. Postoperative improvement was noted in 54% of 72 preoperative asynergic segments. Improvement was common not only in hypokinetic but also in akinetic and dyskinetic segments, and occurred in a similar proportion of studies performed early (less than 2 weeks) or late (3-6 months) after CABG. Thallium-201 redistribution scintigraphy was highly predictive of the pattern of postoperative asynergy: The redistribution pattern was normal in 90% of segments with reversible asynergy and abnormal in 76% of segments with nonreversible asynergy. The presence or absence of pathologic Q waves was less sensitive in this differentiation. Septal segments, however, frequently demonstrated abnormal wall motion postoperatively, despite normal 201Tl redistribution scintigraphy. Resting left ventricular ejection fraction (LVEF) was generally unchanged postoperatively, but in some patients with multiple areas of reversible asynergy it did improve. Thus, 201Tl redistribution scintigraphy appears to reliably distinguish viable from nonviable asynergic myocardial zones, and predicts the response of these segments to CABG.
Ejection fraction response to exercise in patients with chest pain and normal coronary arteriograms.
Authors: Gibbons R J , Lee K L , Cobb F , Jones R H
Published: June 2011

In this study we describe the ejection fraction response to upright exercise using first-pass radionuclide angiocardiography in a group of 60 patients with chest pain, normal coronary arteriograms and normal resting ventricular function. A wide range of resting function (heart rate and ejection fraction) and exercise function (heart rate, ejection fraction, peak work load and estimated peak oxygen uptake) were measured. The ejection fraction response to exercise demonstrated wide variation, ranging from a decrease of 23% to an increase of 24%. Six of 22 clinical and radionuclide angiocardiographic variables (resting ejection fraction, peak work load, age, sex, body surface area and the change in end-diastolic volume index with exercise) were significant univariate predictors of the ejection fraction response to exercise. Multivariable analysis identified resting ejection fraction, the change in end-diastolic volume index with exercise and either sex or peak work load as variables that provided significant independent predictive information. These observations indicate that the ejection fraction response to exercise is a complex response that is influenced by multiple physiologic variables. The wide variation in this population suggests that the ejection fraction response to exercise is not a reliable test for the diagnosis of coronary artery disease because of its low specificity.
Hemodynamic effects of n-acetylprocainamide compared with procainamide in conscious dogs.
Authors: Badke F R , Walsh R A , Crawford M H , Ludden T , O'Rourke R A
Published: June 2011

We examined the hemodynamic actions of clinically relevant i.v. doses (20 mg/kg and 10 mg/kg) of n-acetyl procainamide (NAPA) in conscious dogs preinstrumented with a left ventricular (LV) micromanometer, LV and aortic catheters, and ultrasonic crystals for measurement of LV internal diameter shortening (% delta D). Within 30 seconds after the 20-mg/kg dose, there were significant increases in heart rate (27 +/- 7 beats/min, mean +/- SEM; n = 6), maximum dP/dt (655 +/- 206 mm Hg/sec), and % delta D (2.2 +/- 0.9%; all p less than or equal to 0.05). However, by 6 hours after the dose there were reductions compared with control in peak LV pressure (19 +/- 9 mm Hg), dP/dt (610 +/- 210 mm Hg/sec), and % delta D (2.3 +/- 0.6%; all p less than or equal to 0.05). In contrast, equimolar doses of procainamide or drug vehicle alone evoked no response, as did NAPA after pretreatment with reserpine (0.25 mg/kg/day for 2 days) or hexamethonium (10-15 mg/kg). These data suggest NAPA produces a biphasic hemodynamic response with enhancement of LV performance early and a decrease later; this response is different from that of the parent compound, procainamide. These effects are likely mediated by the adrenergic nervous system at either a ganglionic or a central level.