bluuebunny/crossref_metadata_2025 huggingface dataset:
Follow-up technetium-99m stannous pyrophosphate myocardial scintigrams after acute myocardial infarction.
Authors: Olson H G , Lyons K P , Aronow W S , Brown W T , Greenfield R S
Published: June 2012

Technetium-99m stannous pyrophosphate (99mTc-PYP) myocardial scintigrams were obtained in 68 patients during acute myocardial infarction (AMI) and at follow-up 15.9 +/- 8.8 weeks later. All patients with AMI had a positive scintigram (2+ or greater); only one of 46 control patients (2%) had a positive (2+) scintigram. At follow-up scintigraphy 6 to 37 weeks following AMI, 57% of patients had a persistently positive scintigram even though recurrent AMI was suspected in only one of these patients. Patients with persistently positive scintigrams tended to have more severe disease as evidenced by compensated congested heart failure (41%) persistent angina (77%), and ECG evidence of ventricular dyssynergy (51%), We conclude that 1) in patients with prior AMI, a 2+ abnormality on 99mTc-PYP scintigram may not represent new AMI; 2) a persistently positive 99mTc- PYP scintigram may have prognostic implications since it occurs predominantly in patients with severe symptomatic coronary disease.
The effect of acute coronary artery occlusion on subepicardial transmembrane potentials in the intact porcine heart.
Authors: Downar E , Janse M J , Durrer D
Published: June 2012

Subepicardial transmembrane potentials were recorded from intact pig hearts to observe the changes induced by acute ischemia. Ischemia shortened action potential duration, and decreased its amplitude, upstroke velocity, and resting potential. The cells were unresponsive after 12 to 15 minutes of coronary artery occlusion, yet near normal action potentials could be restored by flushing the occluded artery with saline as late as 40 minutes after occlusion. The unipolar extracellular electrogram reflected unresponsiveness by a monophasic potential. Local refractory periods initially shortened by up to 100 msec. Later, postrepolarization refractoriness occurred and refractory periods lengthened often in excess of basic cycle length, thus resulting in 2:1 responses. The onset of early ventricular arrhythmias often coincided with a period of alternation and 2:1 responses, especially when these got out of phase in different regions. Reperfusion frequently led to ventricular fibrillation, and was associated with marked inhomogeneity in cellular responses. Re-entry within ischemic myocardium was the most likely mechanism for arrhythmias.
Re-entrant ventricular arrhythmias in the late myocardial infarction period. 3. Manifest and concealed extrasystolic grouping.
Authors: El-Sherif N , Lazzara R , Hope R R , Scherlag B J
Published: June 2012

Re-entrant beats with regular extrasystolic grouping were seen in 44- of dogs 3--7 days following ligation of the anterior descending coronary artery. Utilizing direct recording of the re-entrant pathway (RP) from the epicardial surface of the infarction zone, we found extrasystolic grouping to be based on the infarction tachycardia-dependent conduction disorders in a potentially RP. Trigeminy and quadrigeminy were related, respectively, to a 3:2 and 4:3 Wenckebach-like conduction cycle in a RP. However, quadrigeminy could also be due to an underlying bigeminal rhythm with concealment of alternate re-entrant beats, i.e., concealed bigeminy. A bigeminal rhythm was the result of a 2:1 conduction pattern in a re-entrant pathway with a sufficient degree of conduction delay during the conducted beat of the 2:1 cycle to result in re-entry. A trigeminal or quadrigeminal rhythm could change to a bigeminal rhythm on critical shortening of the cardiac cycle. Fixed and variable coupling were related, respectively, to stable and changing conduction pattern in a re-entrant pathway. On the other hand, extrasystolic grouping could be concealed due to either block in the re-entrant pathway or entrapment in a small area of the closely bordering normal zone.
Echocardiographic measurement of right ventricular wall thickness. A new application of subxiphoid echocardiography.
Authors: Matsukubo H , Matsuura T , Endo N , Asayama J , Watanabe T
Published: June 2012

The feasibility of subxiphoid echocardiography to measure the thickness of the right ventricular wall (RVWT) was investigated. In 87 (90.6%) of the 96 patients studied, adequate visualization of the echoes from the right ventricular wall was obtained using the subxiphoid technique. RVWT averaged 0.34 +/- 0.08 cm (mean +/- 1 SD), ranging from 0.2 to 0.5 cm in 25 normal individuals. This was not significantly different from the values in the left ventricular overload group (0.36 +/- 0.10 cm). However, the RVWT was increased significantly (P less than 0.001) in the combined group (0.62 0.18 cm), the right ventricular (RV) pressure overload group (0.60 +/- 0.13 cm) and the RV volume overload group (0.53 +/- 0.11 cm). Thirty-two patients underwent diagnosis right heart catheterization which revealed a good correlation between the RVWT measured echocardiographically and the right ventricular peak systolic pressure (r = 0.84). Subxiphoid echocardiography was considered to be useful in diagnosing right ventricular hypertrophy in adults.
Clinicopathologic correlations. De subitaneis mortibus. XXV. Sarcoid heart disease.
Authors: James T N
Published: June 2012

Postmortem findings within the cardiac conduction system are described from the case of a black woman with sarcoid heart disease who died suddenly. Her clinical course had been characterized by recurring ventricular arrhythmias and bouts of syncope. Both the sinus node artery and the atrioventricular (A-V) node artery were sites of focal fibromuscular dysplasia, which thickened slightly the wall of the former but markedly narrowed the lumen of the latter. Small foci of sarcoid infiltration were present in the sinus node and the A-V node. Fatty replacement within the His bundle was attributable to the probable ischemia caused by narrowing of the A-V node artery. Sarcoid granulomata and infiltration with epithelioid cells were present throughout the ventricular myocardium, but were conspicuously less prevalent in the atria. All the large coronary arteries were normal. Many small coronary arteries in the ventricular myocardium were involved by the sarcoidosis and their lumen were narrowed. These findings and analogous ones reported by others are discussed relative to the pathogenesis of syncopal attacks and sudden death which seem to peculiarly prevalent in sarcoid heart disease.
Immediate effect of contrast medium injection on left ventricular volumes and ejection fraction. A study using metallic epicardial markers.
Authors: Vine D L , Hegg T D , Dodge H T , Stewart D K , Frimer M
Published: June 2012

The immediate effect of contrast medium injection on left ventricular (LV) volume, stroke volume (SV) and ejection fraction (EF) was evaluated from postoperative LV biplane cineangiograms of 10 patients with 4-6 epicardial markers placed at the time of coronary artery surgery. After calibrating marker distances with respect to volume (r = 0.97-0.99) over one cardiac cycle for each patient, regression equations were used to compute LV volume from marker measurements for beats prior to, during and following injection. End-diastolic volumes (EDV) prior to injection ranged from 93-263 ml and did not change significantly with injection. End-systolic volumes (ESV) showed a mean decrease of 7.3 ml by beat 7 following injection; this was of borderline significance. Similarly, there was no significant change of SV or EF until beat 7 when there were small but significant increases of 6.4 ml and 0.04, respectively. The injection of moderate amounts of contrast in man does not cause significant changes in LV volume or EF through the sixth post-injection beat.
Limitations of the echocardiogram in diagnosing valvular vegetations in patients with mitral valve prolapse.
Authors: Chandraratna P A , Langevin E
Published: June 2012

In order to assess the reliability of the echocardiogram in detecting valvular vegetations in patients with mitral valve prolapse (MVP), echocardiograms from 85 consecutive patients with mitral valve prolapse were reviewed. Eleven patients had thick shaggy echoes confined to the anterior mitral leaflet; eighteen patients had shaggy echoes on the posterior leaflet; and five had abnormal echoes on both the anterior and posterior leaflets. Only one patient had clinical evidence of infective endocarditis. Redundant leaflets which present multiple surfaces for the production of echoes may explain the abnormal echoes that were observed. Patients with echographic features suggesting mild prolapse less commonly exhibited shaggy leaflet echoes than those with more severe prolapse. Because a significant proportion (40%) of patients with MVP had shaggy echoes which closely resembled those seen in valvular vegetations, we feel that the echocardiogram is of limited value in diagnosing infective endocarditis in patients with mitral valve prolapse.
Systemic collateral and pulmonary artery stenosis in patients with congenital pulmonary valve atresia and ventricular septal defect.
Authors: McGoon M D , Fulton R E , Davis G D , Ritter D G , Neill C A , White R I
Published: June 2012

Angiograms of 30 patients with congenital pulmonary valve atresia, ventricular septal defect, and large systemic-pulmonary collateral arteries (SPCAs) were evaluated. All had aortography, 28 had SPCA arteriography, and 26 had right ventriculography. Seventeen (65%) of 26 patients had a right ventricular infundibulum, 23 (77%) had a pulmonary artery confluence, and five of the nine patients without a right ventricular infundibulum had a confluence. Sixty-six SPCAs of aortic origin were seen; 28 (42%) had narrowing and 21 patients (70%) had one or more narrowed SPCAs. Five patients had collaterals from internal mammary, subclavian or innominate arteries. Fourteen (47%) had hilar pulmonary artery stenosis. Of these 14 patients mild peripheral stenosis was demonstrated in five. Right aortic arch was present in 15 patients (50%). Complete angiographic delineation of pulmonary vasculature is an essential procedure for preoperative detection of pulmonary and SPCA stenoses in these patients.
Angled views in cineangiocardiography of congenital heart disease.
Authors: Fellows K E , Keane J F , Freed M D
Published: June 2012

Simple and compound sagittally angled views of the heart obtained cineangiocardiographically with a parallelographic U-arm device were evaluated clinically in 132 patients with congenital heart disease. The principle advantage of the apparatus was the case with which axial and oblique projections were obtained without repositioning of the patient, although rotation and angulation of the image intensifier-X-ray tube unit resulted in some increase in scattered radiation. Certain angled views, particularly the 40 degree cranial and the compound 25 degrees cranial/70 degrees left oblique projections, were better than standard frontal and lateral views for visualization of pulmonary arteries in the mediastinum, in ventricular septal defects and anomalies of the left ventricular outflow tract.
Conjoined thoracopagus twins.
Authors: Edwards W D , Hagel D R , Thompson J , Whorton C M , Edwards J E
Published: June 2012

A case of vaginally delivered stillborn female thoracopagus conjoined twins is presented. Each twin had a cleft lip and cleft palate. They shared a common pericardial sac and a common abdominal cavity. The liver was conjoined, and the small bowel was common to both twins. One twin was asplenic. Although the twins were monozygotic, their viscera were neither identical nor mirror-image to each other, and the visceral anomalies were unique to each twin. The hearts were fused, and communications existed between the circulations at the atrial and ventricular levels. One twin had single atrium, solitary (right) ventricle, malposed great arteries, pulmonary valvular atresia and infundibular stenosis, right aortic arch with aberrant left subclavian artery and with left ductus arteriosus, and atresia of the common pulmonary vein. The other twin had two atrial septal defects of the fossa ovalis and sinus venosus types, partial anomalous pulmonary venous connection, persistent left superior vena cava to coronary sinus, solitary (left) ventricle, malposed great arteries, and left aortic arch with aberrant right subclavian artery and with left ductus arteriosus. There was atrial and ventricular fusion. On hypothetical grounds, and in a comparable anatomic situation, salvage of one twin might be possible by surgical means, while the other twin was sacrificed.
The influence of heart rate on pulmonary arterial-left ventricular pressure relationships at end-diastole.
Authors: Enson Y , Wood J A , Mantaras N B , Harvey R M
Published: June 2012

Increased resistance to blood flow stemming from structural and functional abnormalities of the lungs may cause pressure in the pulmonary artery to exceed that in the left ventricle at the end of ventricular diastole. This study explores the possible contribution of heart rate to the diastolic pressure gradient observed in the presence of acutely induced hypoxia. Pulmonary hemodynamics were examined in mongrel dogs with chronic atrioventricular dissociation with and without hypoxia at two different heart rates and during sequential increments in heart rate while the animals breathed room air. Studies during sequential pacing indicate that heart rate was of greater importance than blood flow in determining the magnitude of the gradient. Heart rate has to be considered when the causes of pulmonary hypertension and the effects of drugs or other agents on the pulmonary circulation are being investigated.
Accuracy of treadmill testing in assessment of direct myocardial revascularization.
Authors: McConahay D R , Valdes M , McCallister B D , Crockett J E , Conn R D , Reed W A , Killen D A
Published: June 2012

Near-maximal treadmill exercise tests (TET) performed at the time of coronary arteriography and bypass graft visualization an average of 13 months after direct myocardial revascularization were analyzed in 217 consecutive patients to assess the accuracy of the TET in predicting completeness of revascularization. TET results were correlated with bypass patency and extent of revascularization. Although conversion of a TET from an abnormal to a normal test or relief of TET-induced angina following surgery is closely correlated with bypass graft patency, the high incidence of normal exercise tests in the presence of residual coronary disease limits their usefulness in the individual postoperative patient in estimating the completeness of revascularization.
Inhalation imaging with oxygen-15 labeled carbon dioxide for detection and quantitation of left-to-right shunts.
Authors: Boucher C A , Ahluwalia B , Block P C , Brownell G L , Beller G A
Published: June 2012

Quantitation of left-to-right shunts was determined noninvasively from the pulmonary clearance pattern of inhaled 15oxygen-labeled carbon dioxide (C15O2). After a single breath inhalation of C15O2, counts over the lungs were obtained from sequential 0.5 sec positron camera images. In 21 patients without left-to-right shunts, counts declined exponentially due to the washout of C15O2 by the pulmonary blood flow. In 22 patients with left-to-right shunts, this monoexponential pulmonary clearance pattern was interrupted by an abnormal upward deviation, indicating tracer recirculation through the shunt to the lungs. Following surgical shung closure in 10 patients, pulmonary C15O2 clearance patterns became normal in nine and showed a small residual left-to-right shunt in one. Shunt size was derived from the ratio of the height of the recirculation curve to the height of the initial inhalation peak. These values significantly correlated with shunt size as determined by oximetry (r = 0.83).
Estrogens and experimental atherosclerosis in the baboon (Papio cynocephalus).
Authors: McGill H C , Axelrod L R , McMahan C A , Wigodsky H S , Mott G E
Published: June 2012

One hundred twenty-six adult female baboons (Papio cynocephalus) were hysterectomized and all except 18 were ovariectomized. The animals were fed a moderately atherogenic diet (40% calories form hydrogenated vegetable oil, 1.5 gm cholesterol/kcal) for two years. Ovariectomized-hysterectomized animals received estrone sulfate, ethynyl estradiol, or diethylstilbestrol orally in daily doses similar to those given humans. An ovariectomized-hysterectomized group and a hysterectomized group received no drug. The average total serum cholesterol concentration rose from 136 mg/dl to 223 mg/dl and declined to 186 mg/dl. Concentrations of cholesterol, triglyceride, and phospholipid in whole serum, low density lipoproteins and high density lipoproteins showed no consistent statistically significant differences among the groups. Triglyceride and phospholipid concentrations were higher in the estrogen-treated and intact-ovary groups than in the ovariectomized nonestrogen treated group, but not all pairwise comparisons were statistically significant. There were no consistent statistically significant differences in atherosclerotic lesions among the groups. Neither ovariectomy nor estrogen replacement influence diet-induced experimental atherosclerosis in the baboon within two years.
A comparison of unipolar and bipolar electrograms for cardiac pacemaker sensing.
Authors: DeCaprio V , Hurzeler P , Furman S
Published: June 2012

Simultaneous unipolar and bipolar electrograms were recorded and compared from 49 pacemaker patients with bipolar endocardial electrodes. Average bipolar depolarization signal voltage equalled that of unipolar but showed greater variation. Bipolar and unipolar slew rates were equal in both mean and variance. The proximal pole voltage had little effect on the bipolar result in 8% of the cases, tended to cancel the tip voltage in 49% of the cases and augmented the tip voltage in 43% of the electrograms. The average bipolar R wave duration was 28% less, the T wave amplitude 34% less, and the ST-segment elevation 37% less than the unipolar values. By consistently attenuating the undersirable T waves and ST elevations, while leaving the depolarization signal unaffected, the bipolar electrode offered the advantage of a superior signal-to-noise ratio for sensing depolarization. In one case, however, the bipolar signal was so small as to cause a clinical sensing failure.
Right ventricular compression as a sign of cardiac tamponade: an analysis of echocardiographic ventricular dimensions and their clinical implications.
Authors: Schiller N B , Botvinick E H
Published: June 2012

We have identified pericardial effusion by echocardiography in 174 patients. Seventeen had cardiac tamponade which was not always clinically obvious. Right ventricular narrowing or compression, occurring in the minor axis at end diastole and end expiration, to 7 +/- 2 mm or less, was strongly associated with tamponade in patients with effusion. Right ventricular compression and signs of tamponade abated with pericardiocentesis. One patient was in tamponade without obvious right ventricular narrowing. Nonetheless, he demonstrated serial increases in right ventricular dimensions which paralleled hemodynamic improvement. Diminished left ventricular end-diastolic dimension, "swinging heart," electrical alternans, reciprocal respiratory variations in right and left ventricular end-diastolic dimensions and variation in amplitude of the mitral D-E slope were nonspecific for tamponade. Evaluation of right ventricular dimensions may be clinically useful to diagnose and monitor cardiac tamponade.
Infarct size reduction by propranolol before and after coronary ligation in dogs.
Authors: Rasmussen M M , Reimer K A , Kloner R A , Jennings R B
Published: June 2012

Coronary occlusion in the dog results in irreversible myocardial cell injury which develops first in subendocardial areas of severe ischemica and subsequently spreads into mid and subepicardial areas of moderate ischemia. The effect of propranolol on this progression of ischemic injury was evaluated. Three groups of dogs were studied: 1) untreated, 2) treated with propranolol before and throughout coronary ligation, and 3) treated with propranolol beginning three hours after ligation. Dogs were sacrificed 24 hours after coronary ligation and necrosis was quantitated from histologic sections of transmural slices through the posterior papillary muscle. Propranolol reduced infarct size by preventing necrosis in peripheral (subepicardial) areas of moderately ischemic myocardium. Pretreatment with propranolol reduced necrosis from 85 +/- 3% (untreated) to 52 +/- 4% (P less than 0.05). Delayed propranolol therapy was about half as effective as pre-treatment and reduced necrosis to 71 +/- 3% (P less than 0.05). Propranolol also limited microvascular injury so that perfusion defects, detected with the dye thioflavin S, were smaller in treated dogs.
"Reverse coronary steal" induced by coronary vasoconstriction following coronary artery occlusion in dogs.
Authors: Chiariello M , Ribeiro L G , Davis M A , Maroko P R
Published: June 2012

The phenomenon of "coronary steal," i.e., the shunting of blood from ischemic to normally perfused areas of myocardium, has been described as an effect of the administration of several vasodilating agents. This study was performed to ascertain whether the reverse situation can be induced, i.e., whether vasoconstriction of the vessels supplying the nonischemic zone could increase the collateral flow to the ischemic area. In 16 open chest dogs, 15 and 30 min after occlusion of the left anterior descending coronary artery, epicardial electrograms were recorded and regional myocardial blood flow (RMBF) was measured with radiolabeled microspheres. Methoxamine was infused intravenously between 17 and 30 min, the mean arterial pressure being kept constant. The results indicate that while the coronary arterial flow to the normal myocardium fell from 90.6 +/- 4.3 to 77.7 +/- 3.2 ml/min/100 g (P less than 0.01), the collateral blood flow to the ischemic area increased from 21.4 +/- 3.5 to 41.0 +/- 4.2 ml/min/100 g (P less than 0.01), and thereby reduced acute myocardial ischemic injury. This favorable redistribution of blood flow might be considered a "reverse coronary steal."
Thallium-201 myocardial imaging before and after coronary revascularization: assessment of regional myocardial blood flow and graft patency.
Authors: Ritchie J L , Narahara K A , Trobaugh G B , Williams D L , Hamilton G W
Published: June 2012

Twenty patients underwent myocardial imaging with Thallium-201 (201Tl) before and subsequent to coronary artery bypass grafting. All patients had rest and maximal treadmill exercise imaging postoperatively. Eleven of the 20 patients had rest and exercise 201Tl images preoperatively; 9/20 only had rest imaging preoperatively. Postoperative regional exercise perfusion was improved in seven of the 11 patients who had preoperative exercise images, and was associated with regional graft patency in each case. Thirteen of 20 patients showed no new defect with postoperative exercise imaging. The remaining seven patients developed or had an increased defect with exercise. The patients with no new perfusion defects during postoperative study has 26/30 grafts patent (87%). Patients developing a new perfusion defect with exercise had fewer grafts patent (7 of 13 [54%]; P less than 0.03). In these seven cases, a new exercise-induced defect was associated with regional graft closure or residual nonoperated disease. Knowledge of the preoperative coronary anatomy allowed the distinction between ungrafted areas and regional graft dysfunction. We conclude that preoperative and postoperative 201Tl imaging may noninvasively predict graft closure and/or improved regional perfusion with patent grafts.
The use of "fresh" unstented homograft valves for replacement of the aortic valve: analysis of 6 1/2 years experience.
Authors: Thompson R , Knight E , Ahmed M , Somerville W , Towers M , Yacoub M
Published: June 2012

Between August 1969 and January 1976, 561 patients underwent homograft replacement of the aortic valve (AVR). Isolated AVR was performed in 339 patients, ranging in age between 18 months and 74 years. The valves were sterilized in antibiotic solution and preserved at 4 degrees C in tissue culture medium. There were 11 early deaths (3.2%) and 23 late deaths (6.8%). Actuarial analysis showed 88% survival at 5 years and 85% at 6 years. Valve failure occurred in 13 patients (3.8%) due to prolapse of one cusp in five patients (1.5%), infective endocarditis in three and degeneration of the graft in five (1.5%). Degenerative valve failure was encountered after the fourth year with an incidence of 3.5% of patients at risk, and occurred only in grafts from donors over the age of 70 years. Diastolic murmurs were present in 22% of patients followed up for more than one month and increased very slightly with time. The clinical result was judged to be good or excellent in approximately 90% of the surviving patients.
Hemodynamic results of aortic valvular replacement with the porcine xenograft valve.
Authors: Morris D C , King S B , Douglas J S , Wickliffe C W , Jones E L
Published: June 2012

Twenty-three patients were evaluated by cardiac catheterization two to 12 months following aortic valve replacement with the porcine xenograft valve. These hemodynamic studies established a mean peak-to-peak systolic gradient across the prosthesis of 23 mm Hg with a range of 6-58 mm Hg. The mean effective orifice area was calculated to be 1.25 cm2. The effective orifice area increased with increasing valve size from 0.99 cm2 for the 19 mm prosthesis to 1.44 cm2 for the 25 mm prosthesis. While in general the hemodynamics of the porcine xenograft valve are comparable to other available prostheses, the exceedingly small orifice areas (0.99 cm2 and 1.03 cm2) calculated for the 19 mm and 21 mm prostheses render their use inadvisable.
Contractile state of the left ventricle in man as evaluated from end-systolic pressure-volume relations.
Authors: Grossman W , Braunwald E , Mann T , McLaurin L P , Green L H
Published: June 2012

End-systolic pressure (PES), volume (VES), wall tension (TES) and circumference (CES) of the human left ventricle were studied at cardiac catheterization in 24 subjects with varying degrees of left ventricular dysfunction. Acute alterations in systolic load consistently resulted in changes in VES and CES, with a smaller volume and circumference characterizing the lower systolic load in each subject. End systolic pressure-volume lines were constructed by plotting PES against VES at the higher and lower systolic load in each subject. The slope of the resultant lines was considerably steeper for normal than for poorly contractile left ventricles. Vo, the volume axis intercept of the line (i.e., the theoretical VES at PES = O) was significantly smaller for normal than for poorly contractile ventricles. Similar findings were noted for Co, the theoretic end-systolic circumference at zero end-systolic ventricular wall tension. Post-extrasystolic potentiation resulted in decreased VES and CES with no change in PES and only a slight fall in TES. In conclusion, end-systolic pressure-volume and tension-circumference relations reflect the contractile state of left ventricular myocardium. Quantitation of these relationships may provide a useful new approach to the assessment of myocardial function in man.
Cardiac size and function in acromegaly.
Authors: Martins J B , Kerber R E , Sherman B M , Marcus M L , Ehrhardt J C
Published: June 2012

Sixteen acromegalic patients underwent echocardiography, phonocardiography, stress electrocardiography with Thallium perfusion scanning and gated radioisotope left ventricular angiocardiograms. Abnormalities consisting of increased echo left ventricular mass index, low velocity of circumferential fiber shortening or elevated pre-ejection period to left ventricular ejection time ratio were found in six patients with coexistent hypertension or coronary disease. Concentric left ventricular hypertrophy was also found in three patients with no known etiology other than acromegaly of greater than thirteen years' duration or with fasting growth hormone concentrations greater than 100 ng/ml. One of these three also had left ventricular dysfunction. Neither hypertrophy nor ventricular dysfunction was found in other acromegalics with shorter duration of disease or lower growth hormone concentrations or with normal growth hormone concentrations after therapy. A high prevalence of coronary artery and hypertensive heart disease is associated with acromegaly. A few patients with acromegaly have a specific, potentially reversible cardiomyopathy probably related to prolonged acromegaly or very high growth hormone concentrations.
The effect of mannitol following permanent coronary occlusion.
Authors: Hirzel H O , Kirk E S
Published: June 2012

Quantitative comparisons of infarcts 24 hours after ligation of the left anterior descending coronary artery (LAD) via thoracotomy were made in 13 control and 13 dogs treated with i.v. 25% mannitol, 2 ml/min for 4 hours following occlusion. Mannitol increased serum osmolarity by 44+/-4 mOsm/L (mean +/- 1 SE) with hemodynamic effects limited to a small increase in left ventricular dP/dt. Nonperfusible tissue measured by planimetry at 24 hours was similar in both groups (46+/-4% of area defined with dye injected into the distal LAD for control versus 48+/-5% for mannitol treated dogs, P = NS). Creatine phosphokinase activity in infarcted tissues was also similar in both groups. Myocardial blood flows measured with radioactive microspheres were also similar in both groups. Collateral conductance calcultaed from retrograde flow and aortic pressure increased with the 24 hour period by 146+/-23% in the control dogs; in the mannitol treated dogs, collateral increased only 38+/-14% (P less than 0.001). Thus mannitol had no effect on ultimate infarct size. Moreover, mannitol appeared to hinder the development of collateral vessels.
Effect of methylprednisolone upon technetium-99m pyrophosphate assessment myocardial necrosis in the canine countershock model.
Authors: Schneider R M , Hayslett J P , Downing S E , Berger H J , Donabedian R K , Zaret B L
Published: June 2012

Repeat DC countershock reproducibly results in myocardial necrosis in dogs. In this model, myocardial technetium-99m pyrophosphate (PYP) uptake correlates linearly with tissue creatine kinase depletion (r = -0.83). The effect of pretreatment with methylprednisolone (MP) was studied with PYP in 25 dogs. In myocardium damaged by countershock, 12 MP dogs had higher tissue radioactivity sample:normal (S:N) ratios than control (P less than 0.05), suggesting increased tissue injury. However, by several other measures of tissue damage, the two groups did not differ. MP-elevated PYP S:N ratios were explained by reduced PYP activity in normal myocardium of MP dogs. Further experiments in 21 dogs revealed that renal PYP clearance, which correlated with glomerular filtration rate (GFR) as measured by creatinine clearance, was increased in Mp dogs, resulting in accelerated urinary excretion of PYP (46.9+/-3.6 vs 35.8+/-2.4 percent injected dose in one hour, P less than 0.01), and reduced blood PYP. Thus MP does not modify countershock-induced myocardial injury. However, by increasing GFR, MP increased PYP excretion, resulting in lowered blood and normal zone myocardial PYP, thereby spuriously affecting myocardial PYP tissue uptake data.
Congenital mitral stenosis. A review of 20 years' experience.
Authors: Collins-Nakai R L , Rosenthal A , Castaneda A R , Bernhard W F , Nadas A S
Published: June 2012

The clinical course of 38 patients with congenital mitral stenosis (MS) is reviewed. Associated cardiac defects were present in 28 patients, including tetralogy of Fallot in five. In all but one of the eight patients with supravalvar mitral ring (SVR), there were concomitant abnormalities of the mitral valve. Delay in the diagnosis of MS was common. Serial cardiac catheterizations and pulmonary pathologic examination indicated that pulmonary vascular obstructive disease develops during childhood. Mitral valve surgery was performed in 19 of 38 patients: valvotomy alone in eight, excision of SVR in five (two ofwhom also had valvotomy) and mitral valve replacemtnt in seven. Additional non-mitral cardiac surgery was performed in 18 patients. Overall surgical mortality was 49%; mortality for surgery on the mitral valve was 26%. Only patients having mitral valve replacement or with isolated SVR which was then resected became asymptomatic and had normal hemodynamics on postoperative catheterization.
Dose-response relation of diazoxide in children with hypertension.
Authors: Boerth R C , Long W R
Published: June 2012

Diazoxide was administered to sixteen pediatric patients (ages 10 months to 13 years) with secondary forms of hypertension. Admission BP was 178+/-8/130+/-5 mm Hg (mean +/- SEM). Diazoxide was administered rapidly intravenously in doses ranging from 2 to 7.5 mg/kg. A significant (P less than 0.001), linear log dose-response relation was obtained which showed that a 3 mg/kg dose of diazoxide lowered diastolic BP by an average of 30 mm Hg. In five patients reduction of idastolic BP by a single injection of diazoxide was no different than when the same total dose was given as two or three small injections repeated at fifteen to twenty minute intervals. It is concluded that 1) many hypertensive children respons significantly to doses of diazoxide smaller than the usually recommended 5 mg/kg; 2) diazoxide has a significant dose-response relation in hypertensive pediatric patients; and 3) the desired blood pressure response in hypertensive children can be titrated using repeated small injections of diazoxide.
Alcohol consumption, cardiovascular risk factors, and mortality in two Chicago epidemiologic studies.
Authors: Dyer A R , Stamler J , Paul O , Berkson D M , Lepper M H , McKean H , Shekelle R B , Lindberg H A , Garside D
Published: June 2012

Multivariate analysis of the association at baseline between problem drinking and cardiovascular risk factors among 1,233 white male employees of the Chicago Peoples Gas Company age 40-59 showed the 38 problem drinkers with significantly higher blood pressures and cigarette consumption and significantly lower relative weights than the others. Similar analysis among 1,899 white male employees of the Hawthorne Works of the Western Electric Company in Chicago age 40-55 showed the 117 men consuming 5 or more drinks per day with significantly higher blood pressures and cigarette use than the others. No significant differences were recorded between heavy drinkers and the others in serum cholesterol level. The gas company problem drinkers had significantly higher 15-year mortality rates from all causes, cardiovascular diseases, coronary heart disease, and sudden death. These differences could not be entirely explained by their blood pressure, smoking, and relative weight status. The Western Electric heavy drinkers had increased 10-year mortality rates both for all causes and noncardiovascular causes.
Axial cineangiography in congenital heart disease. Section I. Concept, technical and anatomic considerations.
Authors: Bargeron L M , Elliott L P , Soto B , Bream P R , Curry G C
Published: June 2012

Cineangiographic axial techniques were designed to overcome the limitations of conventional angiography in the diagnosis of congenital heart disease. Two basic patient (or equipment) maneuvers are involved; 1) long axis of the heart is aligned perpendicular to the X-ray beam, and 2) rotation of patient results in the heart being radiographically sectioned at 30 degree angles. To accomplish this with fixed vertical and horizontal X-ray tubes, three positions were developed: 1) "hepato-clavicular," "4 chamber," 2) "long axial oblique," 3) "anterior-posterior axial." A fourth, the "sitting-up" projection is discussed. The hepato-clavicular position profiles the posterior ventricular septum and atrial septum, separates the A-V valves, places the four cardiac chambers en face, and clarifies mitral valve-semilunar valve and outflow tract relationships. The long axial oblique profiles the anterior ventricular septum, left ventricular outflow tract, aortic valve-anterior mitral valve leaflet. The sitting-up view visualizes the bifurcation of the pulmonary trunk and separates true pulmonary arteries from systemic collaterals.
Improved outcome for prehospital cardiopulmonary collapse with resuscitation by bystanders.
Authors: Copley D P , Mantle J A , Rogers W J , Russell R O , Rackley C E
Published: June 2012

Despite the development of trained mobile rescue squads, cardiopulmonary collapse outside the hospital continues to carry a poor prognosis. We examined retrospectively the clinical courses of 19 consecutive coronary unit patients who had experienced prehospital cardiopulmonary resuscitation. Seven patients received basic life support from bystanders within five minutes. Cardiopulmonary resuscitation in the other 12 patients was delayed beyond five minutes pending the arrival of rescue personnel. Six of seven early-resuscitated patients survived compared with six of 12 late-resuscitated patients (P less than 0.01). The early-resuscitated patients were more alert on admission and had lower pulmonary pressures and higher cardiac outputs compared to the late-resuscitated patients. The early-resuscitated patients also had less residual central nervous system and myocardial damage on discharge than the late-resuscitated patients. On follow-up, three early-resuscitated patients had returned to full-time work compared with none in the late group. Training laymen to initiate early basic life support can benefit the cardiopulmonary collapse victim.
Echocardiographic study of cardiac tamponade.
Authors: Settle H P , Adolph R J , Fowler N O , Engel P , Agruss N S , Levenson N I
Published: June 2012

We studied 14 patients with cardiac tamponade and pulsus paradoxus; 11 were studied after relief of tamponade by pericardiocentesis. Right ventricle diastolic diameter increased during inspiration in each of 12 patients; left ventricle diastolic diameter decreased during inspiration in each of 13. Mitral valve DE amplitude decreased with inspiration in 13 of 14 patients. Mitral valve E-F slope could be measured in eight patients, and was rounded and not measurable in six. Six of the eight showed inspiratory decrease in mitral E-F slope. Similar changes were observed in two other patients with pulsus paradoxus who had chronic obstructive airway disease. Twenty patients with large pericardial effusions and no tamponade did not show these changes. These results suggest inspiratory augmentation of right ventricular filling and inspiratory diminution of left ventricular filling, not only in cardiac tamponade, but in obstructive airway disease associated with pulsus paradoxus.
Detection of tricuspid regurgitation with two-dimensional echocardiography and peripheral vein injections.
Authors: Lieppe W , Behar V S , Scallion R , Kisslo J A
Published: June 2012

"Contrast echocardiography", utilizing a two-dimensional ultrasound system and peripheral venous injections, was used for the detection of tricuspid regurgitation in 30 patients. The appearance of contrast in the inferior vena cava and the back and forth movement of contrast across the tricuspid valve were considered evidence for tricuspid regurgitation. Echocardiographic findings were correlated with clinical and angiographic data. Patients were assigned on the basis of clinical data to one of three groups. Group I included five patients whose clinical findings were diagnostic for tricuspid regurgitation. Group II included patients (15) whose clinical findings were equivocal for tricuspid regurgitation and patients whose recognized primary problem is frequently associated with tricuspid regurgitation. Group III contained ten patients serving as controls. All group I patients had positive echocardiographic studies for tricuspid regurgitation, while all group III patients had negative studies, suggesting that this technique may be specific for tricuspid regurgitation. Among the group II patients were three who had positive echocardiographic studies despite the absence of specific clinical findings of tricuspid regurgitation, suggesting that this technique may be more sensitive than the methods in common use.
Hemodynamic, reflexive, and metabolic alterations induced by acute and chronic timolol therapy in hypertensive man.
Authors: Dunn F G , de Carvalho J G , Frohlich E D
Published: June 2012

The hemodynamic, cardiovascular, and metabolic effects of acute (intravenous) and prolonged (four weeks oral) timolol treatment were assessed in 16 patients with mild or moderate essential hypertension. Fifteen patients completed the outpatient study and ten showed a fall in mean arterial pressure of at least 10 mm Hg. They also demonstrated a significant fall in supine systolic (7%), diastolic (9%), and mean arterial pressure. Hemodynamic evaluation was performed in 13 patients and cardiac index was found to be reduced with both intravenous (20%) and oral timolol (13%). There was no correlation between the decrease in cardiac index and arterial pressure. Calculated total peripheral resistance rose with intravenous timolol and returned toward, but not below, pretreatment values with the oral therapy. Left ventricular ejection rate also fell significantly with intravenous timolol but returned toward pretreatment levels with oral therapy. Plasma renin activity was reduced similarly with both modes of administration and its reduction also did not correlate with the fall in arterial pressure. Plasma volume fell in eight of 13 patients. Reflexive responses to the Valsalva maneuver were considerably modified by both intravenous and oral timolol but responses to 50 degrees upright tilt and handgrip were not. Timolol is an effective oral antihypertensive agent with similar hemodynamic and metabolic effects to propranolol.
Hemodynamic effects of intravenous sodium nitroprusside in the conscious dog.
Authors: Pagani M , Vatner S F , Braunwald E
Published: June 2012

The hemodynamic effects of 7 min i.v. sodium nitroprusside (NP) were studied in conscious dogs previously instrumented for measurement of arterial pressure, cardiac output, regional blood flow distribution, left ventricular (LV) pressure, and internal dimensions. Nitroprusside, 25 microgram/kg/min, reduced mean arterial pressure by 23 +/- 3%. Cardiac output increased initially by 39 +/- 7% and returned toward control by the end of the infusion. Regional blood flows increased initially; the relative rise was greatest in the coronary (+ 225 +/- 39%), intermediate in the mesenteric (+ 98 +/- 23%) and iliac (+ 38 +/- 6%), and least in the renal (+ 10 +/- 3%) bed. By the end of the infusion period the vasodilation was unchanged in the iliac bed, less intense in the coronary and mesenteric, while in the iliac bed, blood flow was reduced and resistance was actually increased by 33 +/- 11% above control. A generalized vasonconstriction ensued after cessation of infusion. In contrast, when the drug was administered intra-arterially to the iliac bed, arterial pressure did not fall and only iliac vasodilation was observed. Peak cardiac effects were characterized by increases in heart rate and LV dP/dt, along with marked reduction in LV end-systolic diameter (- 13 +/- 2%), and in end-diastolic diameter (-17 +/- 2%) and pressure. LV end-diastolic diameter fell even heart rate was maintained at a constant rate by pacing. Thus, in the conscious dog, NP reduced LV dimensions substantially, while inducing changes in peripheral beds. The differences in these effects depend on interactions between the direct effects of NP and the opposing effects of reflex adjustments which appear sufficiently powerful to result in net constriction of the iliac bed late during the infusion.
The course of the conduction system in dextrocardia.
Authors: Bharati S , Lev M
Published: June 2012

This is a serial section examination of the conduction system of five hearts of various types of dextrocardia. In one case of dextroversion the conduction system was found to be normal. In one case of mirror-image dextrocardia the conduction system was normal but in the opposite spatial position. In one heart of mixed (discordant) dextrocardia, the sinoatrial node was in correct morphologic position. There were two atrioventricular nodes - a posterior node close to the coronary sinus and an anterior node in the roof of the morphologic right atrium. They formed two separate bundles which joined in the left ventricle to form a "sling". In two cases of presumptive mirror-image dextrocardia, with a common atrium in situs inversus according to the morphology of the atrial appendages, with common atrioventricular orifice (CAVO), the sinoatrial node was situated in wrong positions. Two atrioventricular nodes and bundles again formed a sling. There are various types of slings in discordant dextrocardia.
Effectiveness of unsupervised and supervised high intensity physical training in normalizing serum lipids in men with type iv hyperlipoproteinemia.
Authors: Lampman R M , Santinga J T , Bassett D R , Mercer N , Block W O , Flora J D , Foss M L , Thorland W G
Published: June 2012

The effect of high intensity physical training (HIPT), conducted in an unsupervised (group A) or supervised (group B) setting, was studied in 23 middle-aged men with Type IV hyperlipoproteinemia (HLP). Following 10 weeks of HIPT intervention, significant metabolic changes were observed such as reductions in both fasting triglyceride and insulin levels, but no changes in fasting serum cholesterol or glucagon levels were found. Other favorable results noted included a significant improvement in physical fitness, as measured by increases in aerobic power, and a decrease in body fatness with only minimal weight losses. There were no significant differences in the results when groups A and B were compared. It was concluded that HIPT is an effective means of lowering fasting triglyceride and insulin levels in Type IV HLP individuals. In addition, such physical training programs can be conducted in either an unsupervised or supervised setting, provided the subjects are highly motivated.
Effects of reperfusion on the regional contraction of ischemic and nonischemic myocardium following partial coronary obstruction.
Authors: Ramanathan K B , Raina S , Banka V S , Bodenheimer M M , Helfant R H
Published: June 2012

In 14 dogs the effects on regional tension (Walton-Brodie gauges) and length (mercury-in-silastic) following 50% reduction (52.9 +/- 2.1) in coronary flow for two hours and reperfusion afterwards for one hour were addressed. Within five minutes of partial coronary occlusion, ejection tension in the ischemic zone decreased to 36.3 +/- 7.2% (P less than 0.001) and total tension to 64.4 +/- 5.7% of control (P less than 0.001) while phasic segment length increased to 165.2 +/- 16.3% control. No further significant changes in regional tension or length were observed throughout the two hour period of partial occlusion. Ejection tension remained positive and segment length maintained systolic shortening during the ejection phase throughout the period of occlusion. Following reperfusion, ejection tension in the ischemic zone increased from 35.1 +/- 5.9 to 87.0 +/- 22.0% (P less than 0.05) and total tension increased from 56.6 +/- 5.4 to 70.2 +/- 7.2% (P less than 0.02) while segment length decreased from 149.3 +/- 6.5 to 105.7 +/- 5.7% (P less than 0.001) within five to 15 min of reperfusion. The improvement in both regional tension development and segment length shortening was maintained throughout the one hour period of reperfusion. No significant changes were seen in the nonischemic zone. The present experimental study suggests that partial coronary occlusion producing a 50% reduction in coronary blood flow results in regional contractile changes. These changes are reversible at least twice as long as those following complete occlusion.