bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of spontaneous and streptokinase-induced recanalization on left ventricular function after myocardial infarction.
Authors: De Feyter P J , van Eenige M J , van der Wall E E , Bezemer P D , van Engelen C L , Funke-Kupper A J , Kerkkamp H J , Visser F C , Roos J P
Published: June 2011

The effect of recanalization of the "infarct vessel" on left ventricular (LV) function was assessed 6-8 weeks after acute myocardial infarction (MI) in two groups: patients who had streptokinase-induced recanalization during the acute phase and control patients who had spontaneous recanalization. The ejection fraction and severity of LV wall motion abnormalities in 100 patients with recanalization were compared with those in 78 patients with persistent occlusion of the infarct vessel. Among patients with inferior MI, LV function was significantly better in those with spontaneous (n = 41, p less than 0.05) and streptokinase-induced recanalization (n = 15, p less than 0.02) than in those with persistent occlusion of the infarct vessel (n = 40) in the control group. The LV function was equally good in patients with spontaneous and streptokinase-induced recanalization. Among anterior MI patients, LV function was significantly better in those with streptokinase-induced recanalization (n = 10) than in those with spontaneous recanalization (n = 34, p less than 0.01) or persistent occlusion in the control group (n = 28, p less than 0.001). We conclude that recanalization has a beneficial effect on LV function in patients with MI.
Balloon dilation angioplasty of hypoplastic and stenotic pulmonary arteries.
Authors: Lock J E , Castaneda-Zuniga W R , Fuhrman B P , Bass J L
Published: June 2011

Balloon dilation angioplasty (BDA) was attempted in seven children with either stenosis or hypoplasia (a narrowing greater than 1 cm long extending past the lung hilum) of both right and left pulmonary arteries (PAs). In two of these seven, the procedure could not be performed because of technical difficulties. In each of the remaining five children (1 1/2-16 years old), the right ventricular (RV) pressure was greater than 2/3 left ventricular pressure, main PA pressure was greater than 60 mm Hg, and previous operative attempts to relieve RV outflow obstruction, including the branch PA obstruction, were unsuccessful. BDA was performed in only one PA in each patient, and was considered successful if the pressure gradient decreased, angiographic diameter increased and the percentage of blood flow directed to the dilated lung increased. BDA was successful in all five children: RV pressure fell from 104 +/- 42 to 80 +/- 30 mm Hg (p less than 0.05), the gradient across the obstruction fell from 61 +/- 51 to 32 +/- 22 mm Hg (p less than 0.05), the diameter of the narrowed segment increased from 3.7 +/- 1.2 to 6.8 +/- 1.1 mm, p = 0.02), and the percentage of blood flow (as determined by quantitative lung scan) to the dilated lung increased from 41 +/- 16% to 52 +/- 22% (p less than 0.05). No morbidity was observed in any patient. Follow-up angiograms (2-12 months) in three of five patients indicate persistence of the anatomic improvement. While BDA did not restore right-heart pressures and anatomy to normal, it provided significant hemodynamic relief to a group of patients in whom traditional operative management has usually been unsuccessful. Final determination of the role of BDA in such patients must await the results of further studies.
Quantitation of regional cardiac function by two-dimensional echocardiography. I. Patterns of contraction in the normal left ventricle.
Authors: Haendchen R V , Wyatt H L , Maurer G , Zwehl W , Bear M , Meerbaum S , Corday E
Published: June 2011

Regional differences in wall motion and wall thickening were quantitated in the normal left ventricle using two-dimensional echocardiography (2-D echo). Using a computer-aided system, the left ventricle was subdivided in a standardized manner into 40 segments of five 2-D echo short-axis cross sections from the mitral valve level to the low left ventricle or apex. Measurements of sectional and segmental cavity areas, muscle areas and endocardial as well as epicardial perimeters, allowed assessment of contractile function using such indexes as endocardial systolic fractional area change (FAC), wall thickening (WTh), and circumferential fiber shortening (shortening). In 50 normal anesthetized, closed-chest dogs (including 10 studies in the conscious state) and in 32 normal humans, left ventricular contractile function increased significantly from base to apex. Thus, in anesthetized dogs, sectional FAC, WTh and shortening increased from left ventricular base to apex as follows: 39.4 +/- 5.1% to 61.6 +/- 7.2%, 20.5 +/- 6.6% to 46.7 +/- 11.5% and 22.7 +/- 3.4% to 35.4 +/- 5.9%, respectively. Similar trends were noted in conscious dogs. In man, sectional FAC, WTh and shortening also increased from the mitral valve to the low left ventricular level: 38.8 +/- 3.3% to 60.7 +/- 4.5%, 23.9 +/- 5.6% to 28.9 +/- 7.6% and 21.4 +/- 5.0% to 30.6 +/- 5.6%, respectively. Detailed segmental analysis in individual cross sections also revealed regional differences in contraction. Generally, contraction was most vigorous in posterior regions of the left ventricle. The septal regions exhibited lowest contraction at the base, but also the greatest increase from base to apex, both in the canine and human. Lateral regions did not show significant changes along the length of the left ventricle. Diastolic wall thickness also varied. We conclude that contraction in the normal left ventricle cannot be assumed to be uniform or symmetrical. These normal regional differences in function should be taken into account when evaluating altered physiologic states and in studying effects of therapeutic interventions.
Evaluation of high-energy phosphate metabolism during cardioplegic arrest and reperfusion: a phosphorus-31 nuclear magnetic resonance study.
Authors: Pernot A C , Ingwall J S , Menasche P , Grousset C , Bercot M , Piwnica A , Fossel E T
Published: June 2011

Hypothermic potassium cardioplegia is now commonly used to protect the myocardium during surgically induced ischemia. Because the potassium-related membrane depolarization has been shown to increase calcium influx, we undertook this study to define the effects of varying the calcium content in hyperkalemic perfusates and the effects of using magnesium instead of or in addition to potassium as the arresting agent on the ability of hearts to recover normal function after ischemic arrest. We subjected isolated perfused working rat hearts to 60 minutes of cardioplegic arrest followed by 30 minutes of reperfusion, and measured high-energy phosphate levels every 2 1/2 minutes by phosphorus-31 nuclear magnetic resonance spectroscopy. These data were correlated with postischemic recovery of function. Our results show that potassium cardioplegia may be harmful when the calcium concentration is greater than 1 mM. The kalemic injury is significantly reduced when the calcium content is lowered to 0.25 mM and the greatest extent of preservation is provided by a calcium-poor perfusate (0.25 mM) containing 13 mM magnesium. The beneficial effects of magnesium are not enhanced by subsequent addition of potassium. Close correlations were found between all observed metabolic changes during arrest and the degree of recovery of contractile performance after reperfusion. We conclude that the ability of the myocardium to maintain or resynthesize high-energy phosphate after cardioplegic arrest may be an important determinant of postischemic mechanical performance. These results show that phosphorus-31 nuclear magnetic resonance spectroscopy is a valuable method for evaluating interventions to reduce the severity of ischemic damage.
Effect of nitroprusside on hydraulic vascular loads on the right and left ventricle of patients with heart failure.
Authors: Yin F C , Guzman P A , Brin K P , Maughan W L , Brinker J A , Traill T A , Weiss J L , Weisfeldt M L
Published: June 2011

We studied the effect of nitroprusside on the hydraulic vascular load of the right and left ventricle in seven patients with severe left ventricular failure. At doses of 0.25-0.75 micrograms/kg/min, stroke volume increased progressively from 40.1 to 48.6 ml and left ventricular end-diastolic pressure decreased from 24.5 to 11.2 mm Hg. Accompanying this improvement in left ventricular performance were dose-related decreases in mean ventricular pressures, pulmonic and systemic resistances and the lower-frequency components of input impedance moduli. Characteristic impedance and both total and oscillatory external power were decreased in the pulmonic, but not the aortic, vasculature. In this class of patients, right ventricular unloading is a striking and direct effect of nitroprusside and may account, in part, for improved left ventricular performance through ventricular interdependence.
Hemodynamic assessment after palliative surgery for hypoplastic left heart syndrome.
Authors: Lang P , Norwood W I
Published: June 2011

Ten patients with hypoplastic left heart syndrome underwent cardiac catheterization to assess the effectiveness of palliative surgery designed to prepare them for a modified Fontan procedure. The objectives of palliation were to establish unobstructed systemic blood flow, normalize pulmonary blood flow and pressure, and relieve pulmonary venous obstruction. In the first four patients, systemic blood flow from the right ventricle was established by means of a conduit from either the right ventricular free wall or the proximal main pulmonary artery to the thoracic aorta. Pulmonary blood flow was limited by pulmonary artery banding and ligation of the ductus arteriosus in three patients and by a Blalock-Taussig shunt in one. Conduit obstruction of systemic blood flow developed in two of these infants, and pulmonary vascular abnormalities precluded reparative surgery in the other two. In the other six patients, systemic blood flow was established by direct anastomosis of the proximal main pulmonary artery to the ascending aorta and aortic arch. The pulmonary vasculature was protected by providing pulmonary flow through a central or Blalock-Taussig shunt. The interatrial communication was enlarged by atrial septectomy or balloon atrial septotomy. One infant had progressive tricuspid regurgitation necessitating valve replacement. One, in whom balloon atrial septotomy had been performed, developed an obstructive interatrial communication necessitating late atrial septectomy. These six patients were candidates for physiologic correction. To date, three patients have undergone a modified Fontan procedure; two are clinically well at 9 and 12 months after surgery. Three patients await this procedure.
Secular trends in ischemic heart disease mortality: regional variation.
Authors: Kimm S Y , Ornstein S M , DeLong E R , Grufferman S
Published: June 2011

We compared secular trends in ischemic heart disease (IHD) mortality in four southeastern states (North Carolina, Georgia, South Carolina, and Virginia) with those in three selected other states (California, New York, and Utah). Mortality data were obtained from U.S. vital statistics and population information from the U.S. Census Bureau. Age-adjusted IHD mortality increased until 1968 in the southeastern states and then declined and declines were greatest in the nonwhite female population. In contrast, IHD mortality in all groups in California and in the female population in New York and Utah began to decline in the early 1950s, with accelerated declines since 1968. In all states the decline in rates in nonwhite populations have been greatest in the younger age groups. This has not been true in the white populations. Declining IHD mortality correlated moderately well with the decline in death from all cardiovascular disease and from all causes, but not with the declining cerebrovascular disease mortality. Respiratory cancer mortality increased in similar proportions in California and South Carolina, two states with dissimilar IHD trends. These findings suggest that improved control of hypertension and changing patterns of cigarette smoking may not be responsible for the recent decline in IHD mortality.
Systolic anterior motion of the posterior mitral leaflet: a previously unrecognized cause of dynamic subaortic obstruction in patients with hypertrophic cardiomyopathy.
Authors: Maron B J , Harding A M , Spirito P , Roberts W C , Waller B F
Published: June 2011

Dynamic obstruction to left ventricular outflow in patients with hypertrophic cardiomyopathy usually occurs when the anterior mitral leaflet moves forward in systole and approaches or contacts the ventricular septum. However, we have recently identified, by M mode and two-dimensional echocardiography, 21 patients with hypertrophic cardiomyopathy who had a unique pattern of mitral valve motion characterized by abnormal mitral valve coaptation and systolic anterior motion of the posterior mitral leaflet. This abnormality of mitral valve motion was most reliably identified with two-dimensional echocardiography in views of the left ventricle obtained from the apex. At end-diastole the anterior and posterior mitral leaflets did not appear to coapt at their distal free margins. Rather, at mitral valve closure, the anterior mitral leaflet contacted the basal portion of posterior mitral leaflet. Subsequently, during systole the "residual" distal portion of posterior mitral leaflet approached or contacted the ventricular septum. Morphologic observations in nine other patients with hypertrophic cardiomyopathy suggested that systolic anterior motion of the posterior mitral leaflet is due to elongation of the middle scallop of the posterior leaflet, which probably comes into apposition with the ventricular septum during systole by passing through the space created by the normal pattern of chordal attachments onto the anterior mitral leaflet. Of the 16 patients who underwent cardiac catheterization, nine had basal subaortic gradients of 20 to 85 mm Hg, which were apparently due to moderate or marked systolic anterior motion of the posterior mitral leaflet. Ventricular septal myotomy-myectomies were performed in two patients and resulted in markedly diminished systolic anterior motion of the posterior mitral leaflet in each and abolition of subaortic gradient in the one patient who underwent postoperative cardiac catheterization. Hence, in patients with hypertrophic cardiomyopathy, systolic anterior motion of the posterior mitral leaflet (1) is not uncommon (identifiable in about 10% of a consecutively studied series of patients), (2) constitutes a previously undescribed mechanism for dynamic subaortic obstruction, and (3) is due to a malformation of the posterior mitral leaflet.
Hydrodynamic compression of the right atrium: a new echocardiographic sign of cardiac tamponade.
Authors: Gillam L D , Guyer D E , Gibson T C , King M E , Marshall J E , Weyman A E
Published: June 2011

The relationship of right atrial inversion, a previously undescribed cross-sectional echocardiographic sign, to the presence of cardiac tamponade was examined. We studied 127 patients with moderate or large pericardial effusions. Cardiac tamponade was present in 19 and absent in 104. Four patients with equivocal tamponade were excluded from analysis. Right atrial inversion was present in 19 of 19 patients with cardiac tamponade and 19 of 104 without cardiac tamponade (sensitivity, 100%; specificity, 82%; predictive value, 50%). The degree of inversion as quantitated by the area-corrected curvature did not improve the ability to discriminate between patients with and without cardiac tamponade. However, consideration of the duration of inversion by the right atrial inversion time index (duration of inversion/cardiac cycle length) and an empirically derived cut-off of 0.34 did improve the specificity and predictive value (100% and 100%, respectively) without a significant loss of sensitivity (94%). We conclude that right atrial inversion, particularly if prolonged, is a useful echocardiographic marker of cardiac tamponade that may be of particular diagnostic value when the clinical picture is unclear.
Value of QRS alteration in determining the site of origin of narrow QRS supraventricular tachycardia.
Authors: Green M , Heddle B , Dassen W , Wehr M , Abdollah H , Brugada P , Wellens H J
Published: June 2011

To determine the value of alternation of QRS morphology in determining the site of origin of sustained narrow QRS supraventricular tachycardia (SVT), we retrospectively studied 163 distinct tachycardias in 161 patients (ages 4 to 91 years) in whom the site of origin of SVT was proven by intracardiac electrophysiologic study. Sustained SVT was defined as lasting longer than 30 sec. Narrow QRS was defined as QRS width less than 0.12 sec. Atrial fibrillation and flutter were excluded. The presence or absence of QRS alternation was judged at least 10 sec after initiation of SVT. Circus movement tachycardia with anterograde AV node conduction and a retrograde accessory AV pathway was seen in 89 patients (58 with Wolff-Parkinson-White syndrome, 31 with concealed accessory pathway); intra-AV nodal reentrant tachycardia (AVNT) was present in 57 cases, and 17 tachycardias were atrial in origin. QRS alternation was present in 36 of 163 cases (22%). In only eight of these 36 did RR interval length alternation accompany alternation in QRS morphology. Thirty-three of 36 (92%) tachycardias with QRS alternation were circus movement tachycardias. Two were atrial in origin and one was AVNT. We conclude that the presence of QRS alternation during sustained narrow QRS SVT is highly indicative of a retrograde accessory AV pathway in the tachycardia circuit.
Induction and termination of triggered activity by pacing in isolated canine Purkinje fibers.
Authors: Moak J P , Rosen M R
Published: June 2011

The clinical importance of delayed afterdepolarizations and resultant triggered activity as a cause of cardiac arrhythmias is uncertain. We studied the response of ouabain-induced delayed afterdepolarizations and triggered activity to a pacing protocol similar to those used clinically in an effort to quantify the types of responses to pacing that occur as a result of this arrhythmogenic mechanism. Isolated canine Purkinje fibers were superfused with 2 X 10(7)M ouabain until delayed afterdepolarizations occurred and attained an amplitude of 5 mV at a paced cycle length of 500 msec. We then studied the induction of triggered activity in these fibers by pacing. We found that: (1) As the pacing cycle length decreased, the coupling interval from the last paced beat to the first triggered beat decreased and 83% of fibers developed triggered activity. (2) The coupling interval of the first triggered beat after single (S2) or double (S2S3) premature beats was in part dependent on preceding pacing cycle lengths. S2 pacing induced triggered activity in 39% of fibers, and S2S3 pacing induced triggered activity in 48% of fibers. We then studied the termination of ouabain-induced sustained rhythmic activity by pacing: 89% of sustained rhythmic activity could be terminated by overdrive pacing at a cycle length less than or equal to 300 msec. The coupling interval of the first beat or first delayed afterdepolarization after the termination of overdrive decreased as pacing cycle length decreased. S2 premature beats reset the sustained rhythmic activity and terminated 14% of sustained rhythmic activity. The coupling interval of the first escape beat or delayed afterdepolarization after S2S3 premature beats decreased as the S2S3 interval shortened, and S2S3 terminated 26% of sustained rhythmic activity. Pacing at an S1S1 cycle length of 400 msec followed by an S2 terminated 50% of sustained rhythmic activity; S1S1 at a cycle length of 400 msec followed by S2S3 terminated 85% of sustained rhythmic activity. This quantitative demonstration of the responses of delayed afterdepolarizations, triggered activity, and sustained rhythmic activity to pacing may be useful in differentiating these from other mechanisms for arrhythmias.
Potential adverse effects of volume loading on perfusion of vital organs during closed-chest resuscitation.
Authors: Ditchey R V , Lindenfeld J
Published: June 2011

To determine whether expansion of blood volume improves vital organ perfusion pressures and blood flow during closed-chest cardiopulmonary resuscitation in dogs, we recorded intracranial and high-fidelity ascending aortic and right atrial pressures and measured total and regional blood flow with radioactive microspheres during cardiopulmonary resuscitation before and after rapid infusion of 1 liter of saline or dextran in 12 animals. Volume loading increased total forward blood flow from 327.1 +/- 50.9 to 692.7 +/- 105.9 ml/min (p less than .01). However, blood flow to the cerebral hemispheres, cerebellum, brainstem, and ventricular myocardium all decreased significantly. For example, blood flow to the left cerebral hemisphere fell from 16.5 +/- 2.4 to 5.5 +/- 1.7 ml/min/100 g (p less than .001), while left ventricular myocardial blood flow fell from 12.0 +/- 3.1 to 4.1 +/- 0.8 ml/min/100 g (p less than .05). These changes in critical regional flow were accompanied by disproportionate increases in right atrial and intracranial pressures (relative to aortic pressure), which reduced the average pressure differences generated across the coronary and cerebral circulations from 11.0 +/- 2.5 to 3.7 +/- 1.3 mm Hg (p less than .01) and from 16.1 +/- 2.3 to 10.5 +/- 1.5 mm Hg (p less than .01), respectively. The overall rise in forward flow was associated with a marked increase in extracranial, brachiocephalic blood flow. These findings suggest that large increments in blood volume can reduce vital organ perfusion during cardiopulmonary resuscitation despite an increase in total forward blood flow.
The influence of changes in lipid values induced by cholestyramine and diet on progression of coronary artery disease: results of NHLBI Type II Coronary Intervention Study.
Authors: Levy R I , Brensike J F , Epstein S E , Kelsey S F , Passamani E R , Richardson J M , Loh I K , Stone N J , Aldrich R F , Battaglini J W
Published: June 2011

The National Heart, Lung and Blood Institute Type II Coronary Intervention Study, a double-blind, placebo-controlled trial, evaluated the efficacy of reduction in cholesterol levels induced by cholestyramine on progression of coronary artery disease (CAD). The rate of CAD progression in patients treated with cholestyramine plus diet was compared with that of patients treated with placebo plus diet. CAD progression was defined angiographically. Significant decrease in total cholesterol (TC) and low-density lipoprotein cholesterol (LDLc) and increases in high-density lipoprotein cholesterol (HDLc), as well as in HDLc/TC and HDLc/LDLc ratios, were observed with cholestyramine. HDLc change was due to increase in HDL2A and HDL2B. When the relationship between CAD progression and lipid changes was examined independent of specific treatment group, a significant inverse relationship was found between progression at 5 years and the combination of an increase in HDLc and a decrease in LDLc; changes in HDLc/TC and HDLc/LDLc were the best predictors of CAD change. While the testing of these relationships independent of treatment group was not part of the initial study design, the trends were observed in both the placebo-treated and cholestyramine-treated groups. Moreover, with multivariate analysis, the effect of cholestyramine treatment on CAD progression was eliminated by adding changes in HDLc/TC to the regression model. These findings support the hypothesis that increases in HDLc and decreases in TC (or LDLc) can prevent or delay CAD progression.
Quantitative pharmacologic responses of normal and atherosclerotic isolated human epicardial coronary arteries.
Authors: Ginsburg R , Bristow M R , Davis K , Dibiase A , Billingham M E
Published: June 2011

We studied quantitative aspects of coronary artery contraction in isolated epicardial coronary ring segments from 49 human hearts. The order of maximal tension developed by drugs in normal calcium (ionized calcium, 1.26 mM) solution was U-44069 (a prostaglandin endoperoxide analog) greater than histamine greater than carbachol greater than serotonin greater than phenylephrine greater than ergonovine. In Ca2+-free solution these same drugs mediated a lesser degree of contraction, which demonstrates that the human coronary artery uses both "intracellular" and "extracellular" calcium in hormone receptor-activated contraction. U-44069, histamine, carbachol, and phenylephrine produced calcium-free/normal calcium maximal responses of 62.9% 48.7%, 39.8%, and 37.2%, respectively. Morphologic characteristics of the atherosclerotic plaques within the vessel lumen and the degree of myocardial dysfunction did not qualitatively alter these contractile responses. However, severely atherosclerotic coronary segments were supersensitive to histamine, but not to carbachol or calcium. In conclusion, the human epicardial coronary artery is a highly reactive vessel that uses at least two calcium pools to couple contraction. Receptor-coupled agonists differ in their abilities to mediate contraction and in the degree to which each calcium pool is used, and the presence of atherosclerosis potentiates the contractile response to histamine.
Echocardiographic measurement of right ventricular volume.
Authors: Levine R A , Gibson T C , Aretz T , Gillam L D , Guyer D E , King M E , Weyman A E
Published: June 2011

The volume of the right ventricle can be determined angiographically from its projections in two mutually perpendicular planes. Echocardiographic techniques for measuring right ventricular volume, however, have been more difficult and less successful. In this study, a method was developed for calculating right ventricular volume from two intersecting cross-sectional echocardiographic views: the apical four-chamber and subcostal right ventricular outflow tract views. First, the areas and lengths of casts of 12 human right ventricles obtained at autopsy were directly measured in the chosen views. Actual cast volumes correlated best with a formula giving volume as 2/3 times the area in one view times the long axis in the other view. The degree of correlation was similarly high for calculations involving the area derived from either view and the length of the roughly orthogonal section. This relationship for right ventricular volume was then confirmed with two-dimensional echocardiographic images of hollow latex molds made from the casts (r = .95, p less than .0001). The significance of these findings is discussed in relation to angiographic results and models of the right ventricle.
A randomized comparison of crystalloid and blood-containing cardioplegic solutions in 60 patients.
Authors: Buttner E E , Karp R B , Reves J G , Oparil S , Brummett C , McDaniel H G , Smith L R , Kreusch G
Published: June 2011

To determine whether adding blood to a cardioplegic solution affects myocardial preservation, a randomized prospective study was carried out in 60 patients undergoing coronary revascularization to compare the effects of crystalloid potassium cardioplegics (group C) and potassium cardioplegic solutions to which blood has been added (group B) on markers of myocardial metabolism (lactate, inorganic phosphate, base deficit release, glucose and lactate uptake, oxygen extraction), myocardial damage (creatine kinase [CK]-MB levels), and cardiac performance (cardiac index and left atrial pressure). The solution with added blood had a significantly (p less than .05) greater oxygen content, a lower pH, and higher concentrations of potassium, calcium, sodium, and glucose. In group B patients there was a suggestion (p less than .06) of greater uptake of oxygen during the beginning of the initial cardioplegic infusion. During reperfusion there was no evidence of differential release of the metabolites of anaerobiosis and myocardial oxygen extraction and glucose and lactate uptake were similarly depressed in both groups. Likewise, CK-MB release after bypass was the same in both groups. Prompt, adequate functional recovery of cardiac index and left atrial pressure was observed in both groups. It was concluded that although there may be more oxygen available from the blood-containing solution during early infusion, there is no evidence that under the conditions of this investigation adding blood to cardioplegic solution improves myocardial preservation.
Family history of heart attack as an independent predictor of death due to cardiovascular disease.
Authors: Barrett-Connor E , Khaw K
Published: June 2011

Although a family history of ischemic heart disease is a well-accepted risk factor for cardiovascular disease, only three prospective studies--all in men--have examined the predictive strength of a positive family history after adjusting for other heart disease risk factors. The present analysis is based on a 9 year follow-up of 4014 men and women from 40 to 79 years old who resided in Rancho Bernardo, CA, and who reported no known cardiovascular disease in response to a standardized interview. At baseline 38% of this group reported a family history of a heart attack in a parent, sibling, or child; 15% of those with a positive family history in a first-degree relative indicated that the heart attack had occurred before the relative was 50 years old. Younger men (less than 60 years) with a positive family history at any age had significantly higher mean blood pressures and total plasma cholesterol levels; older men were more likely to have diabetes mellitus. Younger women with a positive family heart attack to subsequent cardiovascular death was determined by the Cox model after adjusting for age, systolic blood pressure, total plasma cholesterol level, obesity, cigarette smoking, personal history of diabetes, and estrogen use (in women). In men, but not in women, a positive family history of heart attack was independently predictive of death from all causes and from cardiovascular and ischemic heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)
The use of preintervention and postintervention thallium imaging for assessing the early and late effects of experimental coronary arterial reperfusion in dogs.
Authors: Okada R D , Pohost G M
Published: June 2011

To determine if thallium-201 imaging of myocardial perfusion can be used as an early predictor of myocardial salvage after reperfusion, 24 adult dogs were subjected to complete occlusion of the left anterior descending coronary artery with release of the snare 2 hr later. Separate doses of thallium (1 mCi) and microspheres were given 15 min before, 5 min after, and 1 hr after release of the snare. Gamma camera images of the heart were obtained after each injection of thallium. Preinjection images were also acquired before the second and third doses and were subtracted from the postinjection images to eliminate the counts due to residual activity from the prior injections. The chest was then closed and the dog allowed to recover. The chest was reopened 48 hr later, final doses of thallium and microspheres were administered, and the heart was imaged. After the dog was killed, the left ventricle was sliced from apex to base, and any infarct was outlined with triphenyltetrazolium (TTC) staining. The slices were then subdivided into pieces of approximately 1 g each and then well counted for microsphere determination of regional myocardial blood flows. Thallium images were interpreted qualitatively and quantitatively. Fifteen dogs with myocardial infarctions, as assessed by TTC staining, all had thallium image defects during coronary arterial occlusion. Thallium scans obtained immediately after reperfusion demonstrated increased anterior wall thallium activity in nine dogs, normal activity in four dogs, and decreased activity in two dogs. In 14 of the 15 dogs, relative thallium activity correlated with the occlusion/normal zone flow ratios.(ABSTRACT TRUNCATED AT 250 WORDS)
Gallium-67 imaging in patients with dilated cardiomyopathy and biopsy-proven myocarditis.
Authors: O'Connell J B , Henkin R E , Robinson J A , Subramanian R , Scanlon P J , Gunnar R M
Published: June 2011

Current standards for detection of myocarditis in a clinical setting rely on endomyocardial biopsy for accurate diagnosis. With this technique a subset of patients with dilated cardiomyopathy show unsuspected myocarditis histologically. Endomyocardial biopsy, despite its specificity, may lack sensitivity due to sampling error if the inflammation is patchy or focal. Therefore, inflammation-sensitive radioisotopic imaging may be a useful adjunct in the diagnosis of myocarditis. This study was designed to evaluate the applicability of gallium-67 (67Ga) myocardial imaging as an adjunct to endomyocardial biopsy in the diagnosis of myocarditis. Sixty-eight consecutive patients referred for evaluation of dilated cardiomyopathy underwent 71 parallel studies with 67Ga imaging and biopsies that served as the basis of comparison for this study. Histologic myocarditis was identified in 8% of biopsy specimens. Clinical and hemodynamic parameters could not be used to predict the presence of myocarditis. Five of six biopsy samples (87%) with myocarditis showed dense 67Ga uptake, whereas only nine of 65 negative biopsy samples (14%) were paired with equivocally positive 67Ga scans (p less than .001). The single patient with myocarditis and no myocardial 67Ga uptake had dense mediastinal lymph node uptake that may have obscured cardiac uptake. The incidence of myocarditis on biopsy with a positive 67Ga scan was 36% (5/14); however, the incidence of myocarditis with a negative 67Ga scan was only 1.8% (1/57). Follow-up scans for three patients showed close correlation of 67Ga uptake with myocarditis on biopsy. In conclusion 67Ga may be a useful screening test for identifying patients with a high yield of myocarditis on biopsy, and serial scans may eliminate the need for frequent biopsies in patients with proven myocarditis.
Idiopathic restrictive cardiomyopathy.
Authors: Siegel R J , Shah P K , Fishbein M C
Published: June 2011

This report details the clinical, hemodynamic, and morphologic data from four patients 59 to 77 years old (mean 66) with a primary restrictive cardiomyopathy. All patients had symptoms of congestive heart failure, jugular venous distention, and murmurs of mitral and tricuspid regurgitation. Four patients required pacemakers, three for the brady-tachy syndrome and one for complete heart block. Chest x-ray demonstrated cardiomegaly in all four patients and pulmonary congestion and/or pleural effusions in three. Echocardiographic examination documented left atrial enlargement in all patients, along with normal left ventricular internal dimensions. Global left ventricular systolic function was normal in all, and left and right ventricular filling pressures were elevated and similar in three. A dip and plateau pattern was present in the pressure tracings of two of three patients. Unlike previous reports of restrictive cardiomyopathy, in our four patients there was no specific morphologic cause noted at necropsy. Pathologic evaluation demonstrated biatrial dilatation in all patients, with thrombi present in the atrial appendages in three. Normal ventricular cavity size and mild right ventricular hypertrophy were present in all patients and mild-to-moderate left ventricular hypertrophy was present in two. There were no significant pericardial, endocardial, or valvular abnormalities and no infiltrative myocardial disorders were present. Light and electron microscopic studies demonstrated only interstitial fibrosis of the myocardium. A restrictive hemodynamic profile may be observed in the absence of specific infiltrative disorders and affected patients may exhibit a prolonged clinical course of 4 to 14 years (mean 9). However, in these patients congestive heart failure responded poorly to medical therapy or surgical correction of valvular regurgitation, which is common in this disorder.
Ergonovine-induced myocardial ischemia: no role for serotonergic receptors?
Authors: Freedman S B , Chierchia S , Rodriguez-Plaza L , Bugiardini R , Smith G , Maseri A
Published: June 2011

Because ergonovine appears to produce coronary contractions by a serotonergic (5-HT) mechanism, we attempted to prevent ergonovine-induced ischemia in patients with vasospastic angina by pretreatment with ketanserin, a new selective 5-HT blocker. We studied seven patients with consistently positive results of ergonovine testing (ST segment elevation in three and ST segment depression in four). Ergonovine testing was performed before and after a bolus of 10 mg of ketanserin (all patients) and infusion of 2 to 4 mg/hr for 8 hr (six patients). To assess 5-HT blockade during ketanserin infusion, the constrictor response of hand veins to 5-HT was tested before and after ketanserin. Despite evidence of 5-HT blockade in hand veins, ergonovine-induced ischemia was not prevented by ketanserin in any patient, and there was no significant change in the dose of ergonovine required to provoke ischemia. In one patient, four spontaneous episodes of ST segment elevation occurred during infusion of ketanserin. The plasma concentrations of ketanserin at the time of ergonovine testing ranged from 61 to 127 ng/ml (mean 102) and were well above those that completely inhibit canine coronary 5-HT contractions in vitro. Although human coronary arteries may differ in their responsiveness to 5-HT or ketanserin, these data suggest that ischemia from ergonovine-induced coronary vasospasm is not mediated by 5-HT receptors.
Long-term effects of ileal bypass on lipoproteins in patients with familial hypercholesterolemia.
Authors: Koivisto P , Miettinen T A
Published: June 2011

Partial ileal bypass is effective in reducing circulating cholesterol levels. In our study the 10 year effects of the procedure on serum lipids and lipoproteins were studied in 27 patients with heterozygous familial hypercholesterolemia. The ileal bypass patients were compared with conservatively treated case controls matched for age, sex, serum cholesterol level, relative body weight, blood pressure, and smoking habits and also for the existence of diabetes and coronary heart disease. Serum triglycerides were initially slightly higher in the patients undergoing ileal bypass. During the 10 year follow-up eight surgically treated and seven control patients suffered fatal or nonfatal myocardial infarctions. Of these all but one male subject who underwent surgery had had manifest coronary heart disease at entry. Male sex, smoking, triglyceride levels, and angina were significant predictors of new coronary events. The fall in serum cholesterol in patients who underwent ileal bypass and had fatal myocardial infarctions was smaller than in the corresponding subjects without events. The serum lipid levels of the survivors at the end of the 10 year follow-up showed that ileal bypass, as compared with the conservative treatment, had led to a larger decrease in total serum cholesterol (-33% vs -11% in the control patients; p less than .001); lower total serum cholesterol (360 vs 468 mg/dl; p less than .001), low-density lipoprotein (LDL) cholesterol (236 vs 324 mg/dl, p less than .001), and LDL apoprotein B levels (186 vs 231 mg/dl; p less than .001); and higher serum high-density lipoprotein (HDL) (46 vs 38 mg/dl; p less than .05) and HDL2 cholesterol levels (25 vs 16 mg/dl; p less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)
Evidence of impaired left ventricular performance after an uninterrupted competitive 24 hour run.
Authors: Niemelä K O , Palatsi I J , Ikäheimo M J , Takkunen J T , Vuori J J
Published: June 2011

The effect of extremely exhaustive exercise on left ventricular performance was studied echocardiographically in 13 experienced male ultramarathon runners who took part in a competitive 24 hr run, completing distances of 114 to 227 km. Although the left ventricular end-diastolic dimension (EDD) was reduced by 7% (54 +/- 5 to 50 +/- 7 mm; p less than .005), the end-systolic dimension (ESD) increased slightly (33 +/- 5 to 34 +/- 6 mm; NS). As a consequence, the stroke dimension (21 +/- 2 to 16 +/- 2 mm; p less than .005) and fractional shortening (38 +/- 5% to 32 +/- 5%; p less than .005) declined by 24% and 16%, respectively. The reduction in fractional shortening was related to delta ESD (r = -.66; p less than .05) but not to delta EDD (r = .22; NS). In spite of reduced afterload, the mean velocity of circumferential fiber shortening also decreased by an average of 9% (p less than .01) in proportion to the distance completed (r = -.69; p less than .01). The systolic blood pressure/ESD ratio was 21% lower after the race (4.2 +/- 0.9 to 3.3 +/- 0.6; p less than .005). Body weight loss was not related to any alterations in left ventricular dimensions or ejection phase indexes. The stroke dimension and ejection phase indexes continued to decline within the last 6 hr of the race but returned to the prerace level 2 to 3 days after the race. Total serum creatine kinase peaked at 3917 to 64740 U/liter (mean 27427) and its MB percentage peaked at 2% to 6%.(ABSTRACT TRUNCATED AT 250 WORDS)
Dynamic variability of binding of antiarrhythmic drugs during the evolution of acute myocardial infarction.
Authors: Kessler K M , Kissane B , Cassidy J , Pefkaros K C , Kozlovskis P , Hamburg C , Myerburg R J
Published: June 2011

We tested the hypothesis that the changes in free fatty acid and alpha 1-glycoprotein concentrations, which occur during acute myocardial infarction, exert asynchronous and opposing influences on the serum protein binding of selected drugs. Free drug fractions of two antiarrhythmic agents with contrasting binding characteristics, quinidine and procainamide, were related to free fatty acid and alpha 1-glycoprotein concentrations on days 1 through 5 and 10 in 20 patients with acute myocardial infarction. The mean free quinidine fraction was elevated on day 1 (9.0 +/- 4.4% vs 6.7 +/- 2.7% in patients with stable heart disease; p less than .05) and fell progressively to day 10 (4.0 +/- 2.8%; p less than .0002) as free fatty acid concentration decreased (day 1 = 464 +/- 272 meq/liter; day 10 = 264 +/- 155 meq/liter; p less than .01) and alpha 1-glycoprotein concentration increased (day 1 = 98 +/- 31 mg/dl; day 10 = 141 +/- 47 mg/dl; p less than .02). Multiple stepwise regression showed a major influence of changing alpha 1-glycoprotein concentration on the observed sequential changes in the free quinidine fraction (p less than .005). In contrast, no serial changes in procainamide binding were noted. In conclusion, metabolic changes during the course of acute myocardial infarction sequentially alter free quinidine fraction and, consequently, may influence pharmacodynamics.
Low zero-flow pressure and minimal capacitance effect on diastolic coronary arterial pressure-flow relationships during maximum vasodilation in swine.
Authors: Pantely G A , Ladley H D , Bristow J D
Published: June 2011

During maximum dilation with adenosine in dogs, the diastolic coronary pressure at which flow ceases (Pzf) has been observed to be up to 27 mm Hg above coronary sinus and right atrial pressures. We studied swine to measure the Pzf and to determine the effects of interventions that change collateral flow and coronary capacitance. In 44 swine, the left anterior descending coronary artery (LAD) was instrumented with two catheters, a hydraulic occluder, and a flowmeter. Late diastolic and mean pressure-flow relationships were constructed at a series of pressures produced by partial LAD occlusions during maximum vasodilation. The late diastolic Pzf was 7.0 +/- 2.2 mm Hg (mean +/- SD), less than 4 mm Hg above right atrial pressure; the mean Pzf was 12.1 +/- 3.1 mm Hg, less than 9 mm Hg above right atrial pressure. The Pzf in the LAD did not change significantly (1) during transient simultaneous occlusion of the right coronary artery (RCA) in seven swine (late diastolic Pzf with the RCA open was 6.6 +/- 1.5 mm Hg and with the RCA closed it was 6.0 +/- 1.5 mm Hg), (2) during increased left ventricular systolic pressure (LVSP) in seven swine (late diastolic Pzf with LVSP of 123 mm Hg was 5.5 +/- 2.2 mm Hg and with LVSP of 184 mm Hg it was 7.3 +/- 2.8 mm Hg), or (3) during increased heart rate in eight swine (late diastolic Pzf at heart rate of 107 per minute was 10.8 +/- 2.9 mm Hg and at 180 per minute it was 12.7 +/- 2.1 mm Hg). Similar results were obtained from analysis of the mean pressure and flow data. The Pzf in the LAD of swine is very close to right atrial pressure, and it did not change significantly during interventions that would modify collateral flow (reduced by RCA occlusion and enhanced by increased LVSP) and coronary capacitance (increased LVSP and increased heart rate). This low Pzf is beneficial in maintaining flow at lower coronary arterial perfusion pressures.
Postural changes in diastolic blood pressure and the risk of myocardial infarction: the Normative Aging Study.
Authors: Sparrow D , Tifft C P , Rosner B , Weiss S T
Published: June 2011

To assess the relationship of postural changes in blood pressure to risk of myocardial infarction, 1359 men were followed for an average of 8.7 years. The men were participants in the Normative Aging Study, a longitudinal study of aging initiated in 1963 at the Veterans Administration Outpatient Clinic in Boston. It was found that the relationship of sitting blood pressure to the subsequent incidence of myocardial infarction was modified by a variable formed by subtracting supine from standing diastolic blood pressure (delta DBP). The effect of sitting diastolic blood pressure on risk of myocardial infarction was confined primarily to men with a delta DBP of 10 mm Hg or more. The effect of sitting systolic blood pressure on risk of myocardial infarction was apparent in all categories of delta DBP (less than 1, 1 to 9, greater than or equal to 10 mm Hg), but the gradient of risk became stronger with increasing levels of delta DBP. The modifying influence of delta DBP remained even when standard coronary risk factors were included in multivariate analyses. These findings suggest a relationship of vascular responsiveness to risk of subsequent myocardial infarction and may have clinical utility.
Quantification of regional myocardial blood flow in vivo with H215O.
Authors: Bergmann S R , Fox K A , Rand A L , McElvany K D , Welch M J , Markham J , Sobel B E
Published: June 2011

Using H215O (half-life = 2.1 min) we demonstrated that a modification of the tissue autoradiographic approach permitted quantitation of myocardial blood flow in open-chest dogs by direct assay of myocardial tissue and that noninvasive estimation with positron-emission tomography (PET) delineated relative myocardial blood flow in intact dogs. In open-chest anesthetized dogs, the single-pass extraction fraction of H215O averaged 96 +/- 5% at flows of 80 to 100 ml/100 g/min. This high extraction fraction did not differ significantly over the range of 12 to 238 ml/100 g/min. Myocardial blood flow calculated after a 60 sec intravenous infusion of H215O and direct analysis of tissue correlated well with results obtained with microspheres (r = .94, n = 9 dogs). Subsequently the approach was adapted for preliminary use with PET. Estimation of myocardial content of radiolabeled H2O after intravenous infusion of 20 to 30 mCi of H215O was corrected for vascular pool radioactivity with the use of tomographic data obtained after administration of C15O by inhalation to label red blood cells. Tomograms obtained in vivo in six dogs with either normal or reduced regional blood flow correlated closely with the tomographically detectable distribution of 68Ga-labeled microspheres (r = .93) and with postmortem microsphere distribution (r = .95). The technique accurately reflects myocardial blood flow. With the use of PET, rapid sequential noninvasive estimation of relative regional myocardial blood flow has been demonstrated that should ultimately permit improved objective assessment of nutritional blood flow in patients in response to medical and surgical interventions designed to augment perfusion.