bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relationship of Stroke to Other Cardiovascular Disease
Authors: FRIEDMAN GARY D. , LOVELAND DONALD B. , EHRLICH S. PAUL 
Published: June 2012

The frequencies of prior cardiovascular abnormalities were compared in 117 stroke patients and 234 control subjects. All were residents of a retirement community who had been examined initially and followed in the local medical clinic before the strokes occurred. Cases and controls were matched for age, sex, length of residence, and blood pressure.
Prior coronary, rheumatic, and hypertensive heart disease were all more frequent in cases than in controls, as were cardiac enlargement, congestive heart failure, and digitalis therapy. There was a stronger association of stroke with atrial fibrillation than with other cardiac abnormalities, suggesting that atrial fibrillation in the elderly is an important precursor of stroke and should not be regarded lightly.
Aortic calcification and intermittent claudication were also more frequent among the stroke cases than the controls. Since the blood pressures of cases and controls were matched, the association of both cardiac disease and noncerebral atherosclerosis with stroke is independent of blood pressure and is not attributable to the fact that hypertension predisposes to all of these conditions.
Guanethidine-Resistant Hypertension
Authors: SANDLER G. , LEISHMAN A. W. D. , HUMBERSTONE P. M. 
Published: June 2012

Resistance of hypertensive patients to large doses of guanethidine is seldom due to defective absorption of the drug, since the existence of adrenergic blockade can be demonstrated in these cases.
The effect on the blood pressure of intravenous phenoxybenzamine and norepinephrine, respectively, has been compared in groups of hypertensive patients resistant and responsive to guanethidine.
As both the hypotensive action of intravenous phenoxybenzamine, a peripheral antagonist of norepinephrine, and the pressor effect of norepinephrine infusion were more marked in patients resistant to guanethidine it seems likely that the maintenance of high blood pressure in these cases is due to enhanced sensitivity of the arterioles to endogenous norepinephrine. To combat this effect the therapeutic use of phenoxybenzamine appeared logical.
Phenoxybenzamine taken by mouth has been found by itself to be an unsatisfactory hypotensive agent but when used in combination with guanethidine has proved highly effective. The blood pressure of 13 out of 16 hypertensive cases previously resistant to guanethidine in high dosage has been controlled for periods of from 3 to 30 months after the addition of phenoxybenzamine.
When used in combination with guanethidine, phenoxybenzamine caused no side effects.
Electromechanical Correlations in Hypertrophic Subaortic Stenosis
Authors: KLEIN MICHAEL D. , MATHUR VIRENDRA , LEVINE HAROLD D. , GORLIN RICHARD 
Published: June 2012

Six of 14 patients with hemodynamically proven subaortic stenosis (SAS) showed electrocardiographic patterns consistent with myocardial infarction. Analysis of the 0.02-sec horizontal plane vector allowed discrimination between true myocardial infarction and SAS. In SAS this vector was shifted anteriorly and to the right consistent with septal hypertrophy and increased left-to-right early septal forces.
Cineangiographic studies of left ventricular contraction revealed a unique pattern also consistent with septal hypertrophy disproportionately greater than that of the ventricular free wall.
No correlation existed between maximal instantaneous vectorial voltage, and either the peak left ventricular pressure or the pressure gradient within the left ventricular outflow tract. Striking increases in vectorial forces in SAS may be related to dystrophic changes within the myocardial mass and may not be attributable to simple hypertrophy secondary to hemodynamic obstruction.
Treatment of Supraventricular Tachycardias by Rapid Atrial Stimulation
Authors: LISTER JOHN W. , COHEN LAWRENCE S. , BERNSTEIN WILLIAM H. , SAMET PHILIP 
Published: June 2012

In 10 patients, 24 episodes of supraventricular tachycardia were treated by rapid electrical stimulation of the right atrium. One episode of sinus tachycardia, eight episodes of atrial tachycardia, two episodes of atrial flutter, and 13 episodes of A-V junctional tachycardia occurred. In each case the diagnosis of the arrhythmia was documented by obtaining unipolar and bipolar intra-atrial electrograms.
In three cases of supraventricular tachycardia the ventricular rate was slowed as a result of an increased atrial rate. The increased atrial rate caused an increase of the functional refractory period of the A-V junction, and thus, fewer atrial impulses were transmitted to the ventricles.
In seven cases, 21 episodes of supraventricular tachycardia were terminated by rapid atrial stimulation. In six of these cases the tachycardia was converted to normal sinus rhythm either during or shortly after atrial stimulation. In one case, 12 episodes of A-V junctional tachycardia were converted to rhythms varying between normal sinus rhythm and a slow A-V junctional rhythm. In this case, after termination of the last episode of A-V junctional tachycardia, the rhythm was stabilized by atrial pacing.
Possible X-Linked Congenital Heart Disease
Authors: MONTELEONE PATRICIA L. , FAGAN LEONARD F. 
Published: June 2012

Four male members of a family are known to have congenital mitral and aortic insufficiency, a fifth male has congenital mitral insufficiency only, and a sixth male had congenital heart disease by history. The involved males comprised all males in three generations of this family. Chromosomal and dermatoglyphic studies of the two living affected males are normal.
The involvement of males in this family is best explained on the basis of X-linked recessive inheritance. To our knowledge, this is the first report of possible X-linked inheritance of isolated congenital heart disease.
Quantitative Methods for the Recognition of Atrioventricular Junctional Rhythms in Atrial Fibrillation
Authors: URBACH JOHN R. , GRAUMAN JACOB J. , STRAUS SANDOR H. 
Published: June 2012

This paper describes a method of analyzing electrocardiograms that detects and identifies nonfibrillatory atrial, A-V junctional, and ventricular pacemakers in atrial fibrillation, measures the ventricular beat intervals produced by the detected pacemaker, and estimates the block between pacemaker and ventricle. The identification and measurements are made with a known degree of assurance which may be increased or diminished since it depends entirely upon the number of heart beats analyzed. By applying the method to 61 recordings of 31 patients, we detected 18 instances of A-V junctional tachycardia and escape rhythm of which only three had been identified by ordinary electrocardiographic interpretation. The procedure consists of recording the electrocardiogram on magnetic tape, reducing the contained information to certain displays, and testing statistically the hypotheses suggested by them.
The displays employed are: (1) A plot of the duration or the reciprocal of the duration of successive electrocardiographic R-R intervals against elapsed time (tachogram); (2) a plot of the number of R-R intervals in the recording within each duration class against the duration of the class (interval histogram); (3) a plot of the number of beat-to-beat interval sequences formed by intervals with equal durations, successively diminishing durations, and durations representing multiples of a common time segment against the duration of the identifying interval of each sequence (sequence histogram); and (4) a graphic presentation of the averaged electrocardiographic presystolic potential.
The paper also presents evidence that A-V junctional escape rhythm in atrial fibrillation is due to pathological A-V block and should be considered to be the result of digitalis excess when this drug is exhibited.
Stress Electrocardiography in the Evaluation of Surgical Revascularization of the Heart
Authors: KASSEBAUM DONALD G. , JUDKINS MELVIN P. , GRISWOLD HERBERT E. 
Published: June 2012

Electrocardiography was carried out during hypoxemia and graded exercise tests before and at intervals between 2 and 20 months after attempts to revascularize the heart by internal mammary artery implantation in 44 patients with angiographically documented coronary disease and angina pectoris. Eleven patients had single vessel disease; the right coronary was involved in seven of these patients. Thirteen patients had single vessel implants, employing the left internal mammary artery in 11 patients and a saphenous vein graft from the aorta in two. Thirty-one patients had double internal mammary artery implantation accompanied by gastroepiploic arterial implantation in four.
Fifty per cent of the patients were symptomatically improved after surgery, the best results occurring in two patients with isolated anterior descending coronary disease. Of the 34 patients having postoperative coronary and mammary arteriography, 15% showed improvement which could be ascribed to mammary revascularization; 24% had limited myocardial revascularization and no symptomatic improvement; 29% had patent implants without development of collateral vessels, and the implanted vessels were occluded in 32%. Eleven of the 34 (32%) had fair or good symptomatic improvement in the absence of revascularization.
The results of postoperative stress electrocardiography correlated closely with the findings on postoperative coronary and mammary angiography. The stress tests were persistently positive after operation in 83% of the patients having angiographically confirmed implant occlusion or nonrevascularization. The stress ECG response was reversed, becoming negative postoperatively, in five cases of angiographically proved significant revascularization. Thus, stress electrocardiography provided objective evidence of improvement in a small number of patients with limited coronary disease who developed good collateral circulation and correlated with the lack of revascularization in the majority even in those subjectively improved.
Hemodynamic Performance of a Transplanted Human Heart
Authors: CARLETON RICHARD A. , HELLER STANLEY J. , NAJAFI HASSAN , CLARK JAMES G. 
Published: June 2012

Cardiac catheterization studies, performed 3 weeks after cardiac homotransplantation, revealed nearly normal cardiac performance. Alteration in heart rate by right atrial pacing, passive elevation of the legs, and exercise modified cardiac performance predominantly by variation in ventricular filling. Isoproterenol infusion increased stroke volume above the level predicted from the ventricular end-diastolic pressure.
The heart was hypersensitive to beta-adrenergic stimulation with isoproterenol as judged by a greater responsiveness of the donor sinus node than the recipient sinus node, by prolongation of ventricular filling time, and by shortening the P-R interval for any given paced heart rate. These measures permitted tests for endogenous catecholamine effects during passive leg elevation and during exercise. Only after the 3 minutes of exercise was a small beta-adrenergic effect detectable.
These data demonstrate the dependence of the denervated human heart upon variation in ventricular filling as the predominant mode of regulation of cardiac performance.
Use of the Dipole Moment in the Assessment of Left Ventricular Hypertrophy
Authors: ELLISON R. CURTIS , FISCHMANN EUGENE J. , MIETTINEN OLLI S. , HUGENHOLTZ PAUL G. 
Published: June 2012

A multi-electrode grid lead system, suited for the measurement of the total outward electromotive force of the heart expressed as a dipole moment, was tested in 64 subjects without heart disease and in 44 patients with left ventricular overload. The normal group showed the maximum dipole moment to the left (L-MDM) to be proportional to body weight, and by inference to left ventricular weight. For the patients with heart disease, the degree of hypertrophy was assessed in terms of LV weight derived from biplane angiocardiograms; for these patients, L-MDM was found to be proportional to LV weight (r = 0.85). The grid allowed for a more accurate assessment of LV weight than parameters obtained from the Frank lead system in the same patients.
A substantially improved estimation of LV weight was achieved with both systems when body weight was considered in addition to the electrocardiographic measurements.
Among the reasons for the better performance of the grid system are surface potential integration instead of sampling, consideration of individual torso dimensions, and as a result of distributed multiple electrodes, absence of distortion in the local field.
Aortic Homograft Valve Replacement
Authors: BARRATT-BOYES B. G. , ROCHE A. H. G. , BRANDT P. W. T. , SMITH J. C. , LOWE J. B. 
Published: June 2012

An initial series of 101 patients with a homograft aortic valve has been reviewed from 4 to 6 years postoperatively. There were six hospital and 24 late deaths, eight of which were due to homograft valve failure. The 71 surviving patients were all symptomatically improved. Anticoagulants were not used, and emboli were thought not to originate from the valve.
Important incompetence occurred in 27 patients and reoperation was undertaken in 17 of these. The causes were peripheral leaking of the suture line, cusp rupture, bacterial endocarditis, and valve misplacement.
Leaflet calcification produced stenosis, requiring reoperation in two patients, and was significant in eight other valves. Precipitating causes, present in eight of the 10 cases, were imperfections in the original homograft, valve misplacement, or endocarditis.
Both cusp rupture and leaflet calcification were related to the method of valve preparation as neither was encountered in untreated valves. For this reason, chemical sterilization and freeze drying have been replaced by sterilization and storage in an antibiotic Hank's solution.
Acute Pulmonary Edema in the Absence of Left Ventricular Failure
Authors: RITTENHOUSE EDWARD A. , MERENDINO K. ALVIN 
Published: June 2012

Two patients have been observed to develop acute repetitive pulmonary edema in the absence of left ventricular failure as evidenced by a normal or near normal left atrial pressure recorded during these periods. Continuous monitoring of the left atrial pressure was made possible by a catheter inserted during open-heart surgery. Both patients suffered brain damage, presumably secondary to cerebral air embolism, and eventually succumbed.
Although the authors think that a causal relationship between cerebral damage and pulmonary edema best explains the mechanism in these two patients, this must remain conjectural. Neurogenic pulmonary edema, however, has been assumed to be secondary to elevated left atrial and left ventricular end-diastolic pressures. If a specific relation exists in these patients, the findings herein described strongly suggest that this may not be the mechanism.
The Accuracy of Pulmonary Angiography in Assessing Resolution of Experimental Thromboemboli
Authors: WOLF PHILLIP S. , GENTON EDWARD 
Published: June 2012

Quantification of pulmonary emboli has become important in assessing the results of thrombolytic therapy and in following the natural history of thromboemboli. This study evaluated angiography as a quantitative procedure by comparing sequential changes in emboli of known size and weight with alterations on angiograms.
Twenty-four aged thrombi formed in vivo were embolized intact into 12 recipient dogs. Serial angiograms showed the location of each thrombus and allowed evaluation of its changes. Urokinase was administered to some animals to produce a spectrum of lysis.
Quantification proved accurate when thrombolysis exceeded 80%. When less, angiograms over or underestimated lysis in 11 of 18 instances (61%). Postmortem dissection suggested four reasons for these discrepancies: (1) downstream movement impacted emboli and increased obstruction; (2) coiling of an embolus compromised more vessel area and increased obstruction; (3) circumferential flow of contrast material obscured some emboli; and (4) second emboli redistributed flow to an area with prior embolus, producing apparent improvement.
These data suggest that quantifying changes in emboli by angiography are frequently misleading when less than 80% lysis occurs. The discrepancy, when present, usually results in overestimation of the amount of embolus remaining.
Evidence for Propagation of Activation Across an Accessory Atrioventricular Connection in Types A and B Pre-excitation
Authors: BOINEAU JOHN P. , MOORE E. NEIL 
Published: June 2012

The sequence of atrioventricular activation was studied in two human subjects with type B Wolff-Parkinson-White syndrome (WPW) and in a dog with spontaneous type A WPW. In all three subjects a focal spot of pre-excitation was demonstrated at the A-V margin of the right ventricle (RV). In the two human subjects with type B WPW, the area of pre-excitation was located on the anterior aspect of the RV and in the dog with type A the pre-excited area was located on the posterior aspect of the RV. A probable Kent bundle electrogram was recorded from the A-V margin in one of the human patients. Serial sections (7 µ) of a block taken from the region of pre-excitation in the dog revealed an anomalous A-V communication (Kent bundle). Propagation velocity across this pathway was estimated to be 0.3 mm/msec. Electrophysiologic data recorded from one of the human subjects at the onset and during an episode of supraventricular tachycardia demonstrated an atrioventricular-atrial sequence of excitation. The mechanism of initiation of the tachycardia was a ventriculo-atrial echo following a premature atrial contraction blocked in the anomalous pathway. Surgical separation of right atrium and RV at the site of pre-excitation normalized the activation and ECG and abolished the tachycardia in both patients.
Ventricular fibrillation occurred repeatedly in the dog as a direct result of the rapid ventricular rate permitted by the Kent bundle subsequent to induced atrial fibrillation. Correlation of the activation sequence with the body surface potentials suggests an updated conceptual model for electrocardiographic typing of WPW. In a third patient, who demonstrated an atypical form of WPW, the region of pre-excitation could not be precisely defined and interruption of an accessory pathway was unsuccessful.
The Prognosis of an Abnormal Electrocardiographic Stress Test
Authors: DOYLE JOSEPH T. , KINCH SANDRA H. 
Published: June 2012

Treadmill walking for 10 min at 3 mph against a 5% grade has been used as an electrocardiographic (ECG) stress test as part of a prospective epidemiologic study of 2,437 men. From 1953 through 1966, 22,223 tests have been done without untoward event.
The criteria of an abnormal postexercise ECG were ischemic flattening or coving of the S-T segment, T-wave changes consistent with focal left ventricular epicardial ischemia, and paroxysmal left bundle-branch block.
Of the 2,003 men exercised two or more times, 264 developed some manifestation of ischemic heart disease (IHD) and in 75 (30%) this was an abnormal ECG response to exercise. They had higher blood pressures and were more often heavy smokers than normal responders. Body weight and serum cholesterol were similar in the two groups. Over the next 5 years there was an 85% probability that these abnormal responders would develop angina pectoris or experience a myocardial infarction.
These relatively insensitive but highly specific and reproducible ECG criteria accurately identify men with clinically silent but far-advanced coronary atherosclerosis, attested by the poor prognosis of an abnormal response. An abnormal postexercise ECG is valid evidence of IHD. A submaximal ECG stress test is useful in clinical and epidemiologic studies and might be useful in assessing the effectiveness of efforts to reduce the risk of IHD.
Ultrasonic Evaluation of Prosthetic Valve Motion
Authors: JOHNSON MICHAEL L. , PATON BRUCE C. , HOLMES JOSEPH H. 
Published: June 2012

1. Ultrasound echo tracing is a simple, atraumatic method for examining prosthetic valve function.
2. In vitro experiments have elucidated the meaning of traces obtained from various types of caged balls.
3. By the use of this method ball diameter, poppet excursion, and opening and closing velocities can be measured in patients.
4. Both in vitro and in vivo experience has demonstrated that the measurements obtained are accurate and reproducible.
Double-Outlet Right Ventricle Without Pulmonic Stenosis
Authors: GOMES MANUEL M. R. , WEIDMAN WILLIAM H. , MCGOON DWIGHT C. , DANIELSON GORDON K. 
Published: June 2012

The results of complete repair of double-outlet right ventricle without pulmonic stenosis in 18 Mayo Clinic patients are analyzed; the over-all operative mortality rate was 22%. Pulmonary vascular obstructive disease and a second ventricular septal defect of the atrioventricular canal type were associated with a higher mortality rate. The difficulties in the diagnosis of this uncommon condition are emphasized.
Patients with double-outlet right ventricle without pulmonic stenosis should have complete repair early in life before the onset of severe pulmonary vascular obstructive disease-the only specific contraindication to operation. Pulmonary artery banding may be preferable as a first-stage palliative procedure in infants less than six months old who do not respond to medical therapy.
Physiological Evaluation of Chronic Right Ventricular Bypass
Authors: LAFARGE C. GRANT , BANKOLE MICHAEL , BERNHARD WILLIAM F. 
Published: June 2012

Investigations with an implantable left ventricular (LV) assist pump indicated inadequate circulatory support in the presence of induced ventricular fibrillation (VF). Consequently, a right ventricular (RV) bypass pump was developed to provide a stable pulmonary blood flow. This report evaluates the physiological effects of the RV pump alone and in conjunction with an LV pump.
Eleven calves have been evaluated by standard cardiac catheterization techniques during chronic pumping (1 to 85 days, mean 30 days, and continuing). Pressures, flows, and RV and LV function were monitored with transducer-tipped catheters and angiography. Effective pulmonary compliance was also measured. The RV bypass studies revealed (1) pump capability up to 8 L/min, reducing RV pressure and work to zero, (2) pulmonary artery pressure not significantly increased (20 to 40 mm Hg), (3) pulmonary compliance identical with sham-operated calves, and (4) no pathological changes noted in lungs. Data suggest that biventricular bypass pumps will provide chronic circulatory support during VF or biventricular failure.
Fate of Orally Administered
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H-Digitoxin in Man with Special Reference to the Absorption
Authors: BEERMANN BJÖRN , HELLSTRÖM KJELL , ROSÉN ANDERS 
Published: June 2012

3
H-digitoxin and polyethylene glycol (nonabsorbable marker) were given orally to five subjects provided with a gastrointestinal tube. Of the radioactivity administered, approximately 15, 30, and 70% had been absorbed when the test solution was passing the stomach, the duodenum, and the upper jejunum, respectively. The absorption was rapid, and the plasma contained detectable amounts of radioactivity after 5 minutes. There was no evidence of a disposition of
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H-digitoxin in intestinal aspirates. On a sixth subject labeled digitoxin was instilled in the mid-jejunum. The concentration of label in the plasma and the pattern of elimination of radioactivity in the urine and the feces in this subject indicated that the absorption of digitoxin was effective also in the more distal part of the gut. The combined results from the present study indicate that the absorption of orally administered digitoxin is complete.

The biliary excretion of label 4 to 24 hours after the start of the experiments was calculated from the bilirubin turnover and the mean radioactivity per mg bilirubin in duodenal aspirates obtained after intravenous injections of cholecystokinin. Less than 10% of the administered dose appeared to be excreted with the bile.
The radioactivity recovered in plasma showed less decomposition than that found in duodenal bile and urine.