bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diminution and Closure of Large Ventricular Septal Defects After Pulmonary Artery Banding
Authors: MESKO ZOLTAN G. , JONES JIMMY E. , NADAS ALEXANDER S. 
Published: June 2012

In a period of 15 years (1957-1972), 114 infants (51 males, 63 females) with the diagnosis of ventricular septal defect and congestive heart failure underwent pulmonary artery banding at The Children's Hospital Medical Center in Boston. A second study performed in 55 of these revealed the left-to-right shunt through the ventricular septal defect to be greatly diminished in seven and completely closed in three.
Pulmonary artery banding proved clinically beneficial to all patients restudied. Important hemodynamic changes, documented at the second study in all ten patients, included a significant decrease in left-to-right shunt and a drop in pulmonary arteriolar resistance to normal range. The right ventricular pressure, post banding, ranged from suprasystemic levels in those with muscular defects to half systemic levels in the majority of those with membranous defect.
The muscular ventricular septal defects closed by muscular tissue, the membranous defects by aneurysm formation at the "exit" of the left-to-right shunt on the right ventricular septal surface.
There is a surprisingly high closure rate (19%) in these large ventricular septal defects after pulmonary artery banding noted. Hemodynamic mechanisms to account for closure are proposed.
Communication of Mitral Valve with Both Ventricles Associated with Double Outlet Right Ventricle
Authors: TANDON RAJENDRA , MOLLER JAMES H. , EDWARDS JESSE E. 
Published: June 2012

A rare case of an infant with "double inlet right ventricle" (straddling mitral valve) and double outlet right ventricle is described. Coarctation of the aorta was associated.
A left-to-right shunt resulted from part of the mitral valve opening into the right ventricle and also from the presence of a ventricular septal defect. The infant's clinical features reflected the shunt, although the valvular abnormality had not been suspected clinically. It is anticipated that left atriography might have identified this rare type of straddling atrioventricular valve.
Noninvasive Technique for Detection of Electrical Activity During the P-R Segment
Authors: BERBARI EDWARD J. , LAZZARA RALPH , SAMET PHILIP , SCHERLAG BENJAMIN J. 
Published: June 2012

Many recent clinical studies of the His-Purkinje system have utilized intracardiac catheter recordings. This study describes a technique for recording activity of the ventricular specialized conduction system from the body surface. Unlike the standard electrocardiographic signals, approximately one mV at the body surface, the electrical activity of the His-Purkinje system is in the microvolt range at the body surface.
In 15 anesthetized dogs, His bundle electrograms, standard ECG recordings, and a highly amplified, filtered bipolar lead across the chest were recorded. The application of signal averaging to the surface leads allows for extraction of the periodic signal (His-Purkinje activity) from random electrical noise. The heart was paced from the right atrium to insure periodicity of the heart rate and to obtain a valid average. By pacing at progressively higher rates, there was a progressive increase in the P-R segment, so that a series of potentials (defined here as the C complex) could be observed occurring prior to ventricular activity. The morphology and temporal relationships of His bundle (H) activity and the G complex to ventricular activity remained constant at all paced rates. H-V times averaged 29 ± 2 msec; correspondingly, the onset of G to V was 29 ± 2 msec. Procainamide was used to alter His-Purkinje conduction times. Comparison of the preventricular activity with the His bundle electrogram showed almost identical time intervals in the control and after drug administration, H-V = 37 ± 3 msec. Thus by using the signal averaging technique, signals that are associated with the His-Purkinje system can be detected on the body surface and validated in various experimental situations.
The Electrophysiologic Time-Course of Acute Myocardial Ischemia and the Effects of Early Coronary Artery Reperfusion
Authors: COX JIMMY L. , DANIEL THOMAS M. , BOINEAU JOHN P. 
Published: June 2012

Bipolar potentials were recorded from intramural electrodes located within areas of acute myocardial ischemia in dogs. Alterations in bipolar potential electromotive force (EMF) and local activation times were measured at predetermined intervals up to 12 hours after coronary occlusion. Histochemical stains were used to correlate structural-biochemical changes with sites of electrophysiologic changes. In severely ischemic areas, bipolar potentials lost 50% of their preocclusion EMF within 30 min and 95% within six hours at which time all parameters stabilized. Lesser decreases in bipolar potential EMF were recorded in the peripheral areas of the infarct. Bipolar potential EMF increased at the junction of ischemic and normal myocardium. Activation time was delayed in ischemic areas but no correlation between the magnitude of delay and the degree of tissue ischemia could be established. Coronary reperfusion after 30 min, one hr, two hr and six hr of occlusion resulted in some return in bipolar potential EMF, decreasing as a function of duration between occlusion and reperfusion.
Variation in the degree of ischemia of different zones of injury within an acute myocardial infarction, as well as a different response of those zones to the return of blood flow, was shown.
Diagnosis of Obstructive Coronary Disease by Maximal Exercise and Atrial Pacing
Authors: KELEMEN MICHAEL H. , GILLILAN RONALD E. , BOUCHARD RICHARD J. , HEPPNER RICHARD L. , WARBASSE J. RICHARD 
Published: June 2012

The reliability of graded maximal exercise treadmill testing and right atrial pacing in diagnosing significant obstructive coronary artery disease was evaluated in 74 consecutive patients referred to a cardiac unit with chest pain consistent with angina pectoris. The results of maximal exercise testing and right atrial pacing, with regard to the presence or absence of the patient's characteristic chest pain or discomfort and ischemic ST segment depression, were compared with the findings determined by selective coronary arteriography. Ischemic ST segment depression was defined as a downward displacement of one full mm or more of a horizontal or downward sagging ST segment.
Forty-nine of the 74 patients studied were found to have significant coronary arteriographic obstruction, i.e., greater than 75% obstruction of one major coronary artery. The occurrence of the patient's characteristic chest pain or discomfort during maximal exercise testing or right atrial pacing is an excellent indicator of the presence of obstructive coronary artery disease, since all of the 41 patients developing their characteristic pain on maximal exercise testing had coronary arteriograms positive for obstructive coronary disease (no false positives), and 46 of 47 patients with characteristic chest pain on right atrial pacing had selective coronary arteriograms positive for obstructive coronary disease. When present, one mm ST depression during maximal exercise treadmill testing also reliably indicates arteriographic obstructive coronary disease (26 of 27 patients). However, the presence or absence of ischemic ST depression during right atrial pacing is a particularly unreliable indication of the presence or absence of arteriographic obstructive coronary disease: 15 of 25 false positive tests, and 13 of 49 false negative tests.
Myocardial Fibrosis in Constrictive Pericarditis
Authors: LEVINE HAROLD D. 
Published: June 2012

It has been suggested that a tentative preoperative decision favoring a pericardial lesion, on the one hand, or a myocardial lesion, on the other, may be made from certain noninvasive procedures, including the electrocardiogram. An attempt was therefore made to detect associated myocardial fibrosis by electrocardiogram in 67 patients with constrictive pericarditis as proven at catheterization (63 patients), surgery (64 patients) or postmortem examination (12 patients). Seven of the 67 had electrocardiograms characteristic of, and 16 compatible with, old myocardial infarct. The electrocardiographic experience was otherwise typical of the literature with non-specific changes in the T waves or RS-T segments and/or low voltage in the remaining 44. All three autopsied patients whose electrocardiograms were interpreted as diagnostic of an old myocardial infarct and both autopsied patients with electrocardiograms compatible with that diagnosis showed myocardial fibrosis. In seven autopsied cases with non-specific T waves or low voltage, the myocardium was normal in three while four showed myocardial fibrosis. It appears that in a few cases right ventricular hypertrophy might have simulated infarct by inducing tall R waves over the right precordium, or R waves which decreased in amplitude as the electrode was passed from the right to the left precordium.
Pathologic evidence related myocardial fibrosis to: (1) direct subepicardial penetration by the inflammatory process or deposit of fat in the subepicardial myocardium; (2) compromise of coronary blood flow, as by (a) direct throttling of coronary arteries by scar tissue or (b) deficient irrigation of subendocardial layers due to rigidity of the pericardium; or (3) a concomitant myocardial and pericardial process (lupus, radiation fibrosis, rheumatoid). Independent pericarditis and coronary disease was surprisingly rare. This limited experience (1) suggests that, though myocardial fibrosis may be predicted in constrictive pericarditis if the electrocardiogram shows characteristic changes of myocardial infarction, non-specific T wave changes or low voltage may likewise be associated with myocardial fibrosis, and (2) emphasizes that the difficulty in determining the site of a constrictive process may be compounded by the co-existence in the same heart of both a pericardial and a myocardial process.
Echocardiographic Features of Endocardial Cushion Defects
Authors: WILLIAMS ROBERTA G. , RUDD MICHAEL 
Published: June 2012

The echocardiographic features of endocardial cushion defects were defined in 28 patients. Two basic characteristics, common to both complete and incomplete forms of endocardial cushion defects, were found. First, the mitral valve excursion was not seen best in the usual location as defined by intraventricular landmarks. Secondly, the mitral valve echoes in cases where there are dense attachments of the mitral leaflet to the crest of the interventricular septum may be traced to the rightward and anterior border of the left ventricular outflow tract. This is the echocardiographic representation of the characteristic "goose-neck" deformity seen angiographically.
Two additional paterns were recognized in patients with complete atrioventricular (A-V) canal. In Pattern I, a large, single, A-V valve was found occupying a central location between the two ventricles. During diastole, the superior segment moved anteriorly into the right ventricle and the inferior segment posteriorly into the left ventricle. In Pattern II, a large single A-V valve moved from the left ventricle in systole into the right ventricle in diastole. This pattern was specific to patients with common A-V valve leaflets.
Vectorcardiographic Criteria for the Diagnosis of Inferior Myocardial Infarction
Authors: STARR JOHN W. , WAGNER GALEN S. , BEHAR VICTOR S. , WALSTON ABE , GREENFIELD JOSEPH C. 
Published: June 2012

Vectorcardiograms (VCG) from two patient groups were analyzed to develop and test quantitative criteria for the diagnosis of inferior myocardial infarction. The first group (219 patients) consisted of four subgroups and was used to develop the criteria. Patients were placed in the normal and infarct subgroups by clinical descriptors including history, course in the coronary care unit, and cardiac catheterization findings. The criteria which were found to give the fewest false positive results with acceptable sensitivity were as follows:
In the frontal plane, generally clockwise early superior QRS forces must be present, i.e., forces which are initially either a) superior (rightward or leftward) or b) inferior and completely rightward for not more than 10 msec prior to becoming superior, and which subsequently cross the X axis to the left of the 0 point (or less commonly, the entire efferent limb remaining superior to the X axis). One of the following conditions must also be present: 1) Time from the 0 point to leftward X intercept of at least 25 msec and distance from the 0 point to leftward X intercept of at least 0.30 mV; 2) A maximal frontal plane QRS vector less than 15°; 3) A maximal superior deviation of at least 0.1 mV and a ratio of maximal superior deviation to maximal inferior deviation of at least 1:5.

The performance of these proposed criteria were then tested prospectively using a second group (255 patients) which was similar to the criteria group. The proposed criteria were found to be statistically superior to both ECG Q wave criteria and to the VCG initial force criteria of Young and Williams.
2
The incidence of false positive diagnosis in the test group was less than 3%.
Cardiac Responses to Isometric Exercise
Authors: QUARRY VERONICA M. , SPODICK DAVID H. 
Published: June 2012

The time course of cardiocirculatory responses to different levels of isometric handgrip (IHG) in sitting position were studied noninvasively in normal males and compared to supine IHG results in the same subjects.
Control Comparisons.
Resting postural differences were as expected: sitting heart rates (HR), pre-ejection phase (PEP) and PEP/LVET were higher while left ventricular ejection time (LVET) and ejection time index (ETI) were lower than those supine (P < 0.05 to P < 0.001). The following trends, while not statistically significant, were also noted: systolic and diastolic blood pressure were lower while pressure-rate product (PRP), the interval from appearance of the Q wave to the first major "mitral" component of the first heart sound (Q-I
M
), and isovolumic contraction time (IVCT) tended to be higher than those supine.
Isometric Exercise.
The supine IHG results are consistent with data reported in the literature. During sitting IHG at 15% maximum voluntary contraction (MVC) there was no statistical change in any parameter measured. At 30%, 50%, and 100% MVC there were increases in HR, systolic and diastolic pressures, and PRP. At 30% MVC, Q-I
M
and pulse transmission time (PTT) decreased, ETI increased and IVCT, PEP, LVET, and PEP/LVET did not change significantly. At 50% MCV, Q-I
M
, IVCT, PEP, LVET, PEP/LVET and PTT shortened while ETI increased. At 100% MCV, Q-I
M
, IVCT, PEP, and LVET shortened but no significant changes occurred in PEP/LVET or ETI.

When sitting IHG was compared to supine IHG the end points of exercise yielded statistically similar values for systolic and diastolic pressures, PRP, Q-I
M
, IVCT, PEP, and PTT. LVET and ETI were consistently lower (
P
< 0.02) while HR and PEP/LVET were higher for sitting vs supine IHG. Standard errors were smaller supine, a finding that indicates greater homogeneity of response in this posture and probably explains why some changes in cardiac parameters at lower levels of IHG reached statistical significance in the supine but not the sitting position.

The changes in systolic intervals are consistent with the increased contractility resulting from IHG. Lack of uniform decreases in PEP/LVET with higher levels of IHG, however, were believed to reflect decreased myocardial adaptability to higher pressure (vs volume) loads. Decreases in pulse transmission time appeared to be influenced by diastolic pressure increases which were directly related to the levels of IHG.
Once resting postural differences are accounted for, however, the effect of posture on IHG is not very great and certainly does not present the disparity which exists between sitting and supine rhythmic exercise. Most responses were directly related to the level of exertion, with greater changes occurring at the higher levels of IHG. For noninvasive studies, 50% or 100% MVC are the recommended levels of exertion since significant cardiocirculatory responses are greater than at 15% and 30% MVC and occur within one minute.
Single Ventricle with Transposition
Authors: MARÍN-GARCÍA JOSÉ , TANDON RAJENDRA , MOLLER JAMES H. , EDWARDS JESSE E. 
Published: June 2012

Fifty-seven cases of single (common) ventricle with transposition of the great vessels are reviewed. The diagnosis had been confirmed by necropsy in 25 and by angiocardiography in 32 cases.
Single (common) ventricle is defined as that condition in which both atrioventricular valves separately enter a single ventricular cavity. According to this definition, cases presenting with common atrioventricular valve, atresia of one atrioventricular valve, or straddling valves have been excluded. Two structural types of common ventricle are identified: the left ventricular type and the primitive type of single ventricle. The former showed anatomic features similar to a left ventricle, whereas in the latter, features characteristic of a left ventricle were not present. The latter was considered a more primitive condition than the former.

A classification based upon the type of single ventricle and its outflow tract and upon the relationship of the great vessels is presented. Of the 25 cases of single ventricle with transposition studied pathologically, 21 were of the left ventricular type and four of the primitive type. Of the four cases with double conus three were among the four examples of primitive ventricle. Among the 21 cases with a single conus, the type of transposition was about equally divided between the
d
-type (ten cases) and the
l
-type (11 cases).

Pulmonary stenosis or atresia was observed in seven of the 21 cases with a single conus and in one of the four cases with double conus.
In the clinical cases, only angiocardiography could establish the diagnosis and delineate the different types of great vessel-ventricular relationships.
Ineffectiveness of Glucose, Potassium, and Insulin Infusion During Pacing Stress in Chronic Ischemic Heart Disease
Authors: LESCH MICHAEL , TEICHHOLZ LOUIS E. , SOELDNER J. STUART , GORLIN RICHARD 
Published: June 2012

Eight patients with coronary artery disease and positive exercise electrocardiograms undergoing cardiac catheterization were subjected to periods of atrial pacing-induced tachycardia at identical rates, before and during a glucose, potassium, and insulin (GKI) infusion. Steady state elevation of glucose and insulin was obtained prior to repeating the atrial pacing test in the GKI state. With each patient serving as his own control, five developed augmented clinical signs of acute ischemia during the paced GKI state, two no change, and one subjective improvement. Left ventricular end-diastolic pressure (LVEDP) was elevated in all patients (1-8 mm Hg) at rest during GKI infusion as compared to the rest control state. LVEDP during pacing was greater during the GKI paced state as compared to the control paced state in three of the eight patients whereas after pacing LVEDP was higher in four of eight patients during GKI. ST-segment depression was less during pacing in the GKI as compared to control state in four patients. A decrease in ST-segment depression was noted in two patients after pacing in the GKI state as compared to this measure after pacing in the control state. Augmented myocardial glucose uptake was demonstrated in the paced GKI state but lactate analysis failed to demonstrate a stoichiometric relationship between enhanced glucose uptake and lactate production.
It is concluded that tolerance to ischemia is not extended and in the majority of cases may be adversely affected by GKI.
Pre- and Postoperative Rest and Exercise Hemodynamics in Children with Pulmonary Stenosis
Authors: STONE FREDERIC M. , BESSINGER F. BLANTON , LUCAS RUSSELL V. , MOLLER JAMES H. 
Published: June 2012

Twenty children with pulmonary valvular stenosis were studied by cardiac catheterization both at rest and during submaximal supine exercise, prior to and following pulmonary valvotomy. The resting and exercise states were comparable preoperatively and postoperatively since cardiac output, heart rate, A - V O
2
difference and oxygen consumption were similar. Evidence of improved cardiac function was found postoperatively.

Both the rest and the exercise right ventricular end-diastolic pressure (RVEDP) decreased significantly following pulmonary valvotomy. Preoperatively, 12 of 20 patients showed an increase in RVEDP with exercise; in six of these there was a simultaneous fall in stroke index, indicating impaired myocardial function. No patient showed this response postoperatively.
This indicates that although altered cardiac function can be demonstrated in some children with pulmonary valvular stenosis, it is reversible by pulmonary valvotomy. This is in contrast to studies in adults, and suggests that a factor in the natural history of pulmonary valvular stenosis is the impact of chronically elevated afterload on the right ventricle. Hemodynamic measurements made during exercise provide a useful means of assessing patients with pulmonary stenosis before and after pulmonary valvotomy.
Electrophysiological Delineation of the Specialized A-V Conduction System in Patients with Congenital Heart Disease
Authors: KRONGRAD EHUD , MALM JAMES R. , BOWMAN FREDERICK O. , HOFFMAN BRIAN F. , WALDO ALBERT L. 
Published: June 2012

The course of the distal His bundle and the right bundle branch was electrophysiologically delineated during open heart surgery in nine patients with tetralogy of Fallot and in six other patients with various forms of congenital heart disease. In patients with tetralogy of Fallot, right bundle branch electrograms were usually recorded up to 25 mm from the plane of the tricuspid valve annulus and only rarely beyond this site, indicating that the electrical activity in the right bundle branch was isolated from right ventricular myocardium to a site 25 mm away from the tricuspid annulus in the patients studied. In one patient with right bundle branch block pattern on the electrocardiogram induced by a ventriculotomy, the right bundle branch was traced to the Purkinje fiber-ventricular muscle junction, supporting the observation that a right bundle branch block pattern induced by ventriculotomy does not indicate that injury to the proximal part of the right bundle branch occurred.
In five patients with various forms of congenital heart disease we did not record electrical activity from the distal His and right bundle branch. The anatomic and functional reasons for this failure are discussed. In one patient with a common ventricle, the identification of the specialized atrioventricular (A-V) conduction system allowed for total surgical correction of this anomaly without injury to the conduction system. The electrophysiological delineation of the specialized atrioventricular conduction system is suggested for all patients undergoing open heart surgery who have complicated congenital heart disease on which no data are available regarding the exact location of the specialized atrioventricular conduction system, for patients with unusual ventricular anatomy, and for patients in whom the hemodynamic and angiographic studies do not correlate well with the electrocardiogram.