bluuebunny/crossref_metadata_2025 huggingface dataset:
A study of the dynamic relations between the mitral valve echogram and phasic mitral flow.
Authors: Laniado S , Yellin E , Kotler M , Levy L , Stadler J , Terdiman R
Published: June 2012

Echocardiographically recorded mitral valve motion was compared with phasic transmitral flow in 17 open chest dogs. The normal mitral valve opening started with the onset of mitral flow and reached its full excursion while flow was still accelerating. Complete valve opening occurred .044 sec (plus or minus .002 sem) before peak flow, during which time an average of 17.6 percent of total mitral filling volume had passed through the valve. In contrast to the opening movement, the closing motion of the anterior mitral valve cusp lagged behind the deceleration of mitral flow. The E-F phase of the mitral valve echogram started while mitral flow was still increasing and resulted from a combined posterior motion of the cusp and the ring. The E-F slope of the normal valve was found to decrease with reduced cardiac output. The amplitude of the anterior cusp excursion did not reflect the amount of mitral flow. Prolonged P-R interval may induce a mid-diastolic reversal of mitral flow which, in turn, may be accompanied by partial or complete valve closure, occurring before the onset of ventricular contraction. Such premature closure of the mitral valve may be accompanied by a certain amount of regurgitant flow.
Pulmonary edema related to changes in colloid osmotic and pulmonary artery wedge pressure in patients after acute myocardial infarction.
Authors: Luz da P L , Shubin H , Weil M H , Jacobson E , Stein L
Published: June 2012

Pulmonary artery wedge and plasma colloid osmotic pressures and their relationship to pulmonary edema were investigated in 26 patients with acute myocardial infarction of whom 14 developed pulmonary edema. In the absence of pulmonary edema, both the pulmonary artery wedge pressure and plasma colloid osmotic pressure were in normal range; after onset pulmonary edema, a moderate increase in pulmonary wedge pressure and reduction in plasma colloid osmotic pressure were observed. When the gradient between the plasma colloid osmotic pressure and the pulmonary artery wedge pressure was calculated, highly significant differences were demonstrated (P less than 0.002). In the absence of pulmonary edema, this gradient averaged 9.7 (plus or minus 1.7 SEM) torr; following appearance of pulmonary edema, it was reduced to 1.2 (plus or minus 1.3) torr. During therapy with digoxin and furosemide, reversal of pulmonary edema was closely related to a concomitant change in the colloid osmotic-hydrostatic pressure gradient. These observations indicate that both increases in pulmonary capillary pressure and decreases in colloid osmotic pressure may follow the onset of pulmonary edema. Such decline in colloid osmotic pressure and especially the reduction in colloid osmotic-hydrostatic capillary pressure gradient may favor transudation of fluid into the lungs.
Histopathology of the conduction system in sudden death from coronary heart disease.
Authors: Lie J T
Published: June 2012

Sudden cardiac death (SCD) has been attributed to the development of lethal dysrhythmias in coronary heart disease victims, and several recent autopsy surveys showed that 10 to 50% of SCD patients had unsuspected acute myocardial infarction (AMI). The present study concerned histopathological findings of the conduction system in 49 SCD (within six hours of the onset of acute symptoms) patients; 39 with established AMI (group A) and ten without (group B). Both groups showed high incidence of cardiomegaly, significant coronary artery disease affecting one or more vessels, and acute myocardial ischemia detectable by specific histological criteria. Stenosis of nutrient vessels of the conduction system was present in about 50% of the atrioventricular (A-V) node arteries and about 25% of the sinoatrial (SA) node arteries in both groups of SCD patients. Nonspecific "degenerative" changes (fibrosis, fatty infiltration, or both) of the conduction tissue, which might or might not represent results of old ischemic injury, also occurred with similar frequencies. Acute changes (infarction, hemorrhage) of the A-V node and bundle branches were found only in two group A patients, both had massive septal infarction. Thus, the conduction tissue appeared more resistant to ischemic injury and was overtly damaged only on rare occasions in fatal AMI. The scarcity of acute lesions in the conduction system itself suggested that lethal dysrhythmia in SCD was probably due to electrical instability of the acutely ischemic contractile myocardium rather than a direct injury to the specialized tissue of the heart.
Vectorcardiographic diagnosis and electrocardiographic correlation in left ventricular asynergy due to coronary artery disease. I. Severe asynergy of the anterior and apical segments.
Authors: Young E , Cohn P F , Gorlin R , Levine H D , Herman M V
Published: June 2012

The transverse plane QRS loop vectorcardiogram (VCG) was analyzed in 102 consecutive patients, angiographically proven to have coronary artery disease (CAD), whose right anterior oblique left ventriculogram showed severe asynergy (akinesis or marked hypokinesis) of the anterior and apical segments. Eighty-four of the 102 loops were considered to be diagnostic of severe asynergy because similar loops were not found in patients with CAD with less severe asynergy of either or both segments or in normal control subjects. Eighty-two of the 84 showed a uniformly abnormal pattern. Posterior vectors exhibited partial or complete clockwise "rotation" and were much more prominent than early anterior forces. In fact, the latter were often absent. In the other two VCG's at least the early half of the loop displayed prominent anterior vectors. The ECGs showed marked variability of the QRS in leads V-2-V-6. Abnormal Q waves were present in only 63 of the 102. The numbers of these leads showing abnormal Q waves varied from one to all of these positions.
Measurement of mitral orifice area in patients with mitral valve disease by real-time, two-dimensional echocardiography.
Authors: Henry W L , Griffith J M , Michaelis L L , McIntosh C L , Morrow A G , Epstein S E
Published: June 2012

A quantitative assessment of mitral valve orifice area can be achieved in patients with pure mitral stenosis by cardiac catheterization. In the presence of mitral regurgitation, however, accurate measurement often is impossible because total diastolic flow through the mitral valve frequently is unknow. Using a recently developed real-time, two-dimensional echocardiography system, we are able to obtain cross-sectional images of the mitral valve by scanning the heart perpendicular to its long axis at the level of the tip of the mitral leaflets. Twenty consecutive patients undergoing operation for mitral valve disease were studied during the week prior to operation. In 18 of 20 (90%) the mitral orifice was imaged successfully in early diastole by two-dimensional echocardiography so that mitral valve orifice area could be measured directly in square centimeters. In 14 patients (ten with associated mitral regurgitation), mitral orifice area was measured both by echocardiography and directly at time of operation. In 12 of 14 (86%) patients, mitral orifice area by two-dimensional echocardiography was within 0.3 square centimeters of that measured at operation (correlation coefficient for all 14 patients equals 0.92). We conclude that two-dimensional echocardiography is extremely useful in the evaluation of patients with mitral valve disease because it provides a noninvasive method for directly measuring the mitral valve orifice area that is accurate even in the presence of mitral regurgitation.
Hemodynamic and prognostic findings in patients with transmural and nontransmural infarction.
Authors: Rigo P , Murray M , Taylor D R , Weisfeldt M L , Strauss H W , Pitt B
Published: June 2012

One hundred and eleven patients with transmural (TMI) and 49 with nontransmural myocardial infarction (NTMI) underwent hemodynamic investigation within 24 hours of onset of symptoms. Patients with NTMI were subdivided into those with ST-segment or T-wave changes alone with a normal QRS complex (NTMI-A) and a group with QRS abnormalities that did not satisfy the criteria for TMI (NTMI-B). Those with TMI had a significantly higher peak creatine phosphokinase (CPK) than those with NTMI: 840 plus or minus 99 and 336 plus or minus 69, respectively, P smaller than 0.05. There was not difference in peak CPK between those with NTMI-A and B. The incidence of arrhythmias and cardiac failure, and routine hemodynamic findings except for left ventricular filling pressure were similar in those with TMI and NTMI. There was not significant difference in in-hospital mortality between those with TMI (22%) and NTMI (33%). There was however a significant difference in in-hospital mortality between those with NTMI-A (0%) and NTMI-B (27%, P smaller than 0.05). The late mortality in those surviving their initial hospitalization was also not different between those with TMI (18%) and NTMI (19%) during a mean follow-up period of 20.2 months. In contrast to the in-hospital mortality those with NTMI-A had a late mortality similar to those with NTMI-B and those with TMI.
Continuous recording of direct arterial pressure in unrestricted patients. Its role in the diagnosis and management of high blood pressure.
Authors: Littler W A , Honour A J , Pugsley D J , Sleight P
Published: June 2012

We have compared casual indirect measurements of arterial pressure obtained 1) by the general practitioner (GP) and 2) in the outpatient clinic (OPC) with 24 hour continuous recording of direct arterial pressure in two selected group of unrestricted patients. 1) Eight asymptomatic, untreated patients with suspected hypertension. 2) Eight asymptomatic, treated patients whose indirect pressure readings seemed inappropriately high when considered against a general absence of target organ damage. Both groups showed that usually there was good agreement between arterial pressure recorded indirectly by GP and OPC while continuous recording showed wide variability of systolic and diastolic pressures over 24 hours and a significant fall during sleep. The first groups with suspected hypertension showed that the indirect measurements were not significantly different from the 24 hour direct recording. The second group of patients on treatment for hypertension showed a discrepancy, the direct readings being significantly lower than the indirect. This difference (approixmately 30 mm Hg mean arterial pressure) would explain the lack of target organ damage and may have been due to the effect of exercise augmenting the hypotensive action of drugs or due to a well developed defense reflex which biased the indirect readings.
Coexistence of functional Kent and Mahaim-type tracts in the pre-excitation syndrome. Demonstration by catheter techniques and epicardial mapping.
Authors: Tonkin A M , Dugan F A , Svenson R H , Sealy W C , Wallace A G , Gallagher J J
Published: June 2012

An unusual patient with Ebstein's anomaly of the tricuspid valve and the Wolff-Parkinson-White syndrome is presented. Ventricular pre-excitation related to conduction over both a right posterior Kent bundle and Mahaim fibers coursing from the atrioventricular node to the right ventricle. Two types of supraventricular tachycardia were demonstrable. These were due to re-entry involving antegrade conduction over either the normal or Mahaim paths, and retrograde retrograde conduction via the Kent bundle. Surgical division of the Kent bundle has abolished the clinically debilitating arrhythmias.
Objective and subjective analysis of left ventricular angiograms.
Authors: Chaitman B R , DeMots H , Bristow J D , Rösch J , Rahimtoola S H
Published: June 2012

In order to determine the reproducibility of analyses of left ventriculograms, 35 cineangiograms were evaluated by four observers, two using standard quantitative techniques to determine ventricular volumes and a newly devised quantitative system to evaluate wall motion and two others using only visual inspection of the angiograms. Objective analysis repeated by the same observer correlated well for end-diastolic and end-systolic volumes and ejection fraction (r = .98, .99, respectively) and only one of 105 (1%) wall segments were identified differently. Variability in assessments increased when comparisons were made with a second objective observer. Correlation coefficients for the three volumetric parameters were .93, .98, and .95 and there was disagreement in the assessment of 8% of wall segments. Wide variability was present between an objective and two subjective observers in analyses of end-diastolic volumes (r = .63, .64). Regional wall motion was assessed differently in 19% and 27% of segments, respectively. Though the correlation of objectively and subjectively determined ejection fractions was much better than the correlation for volume (r = .92, .84), it was not as good as the correlation between two objective observers. Occasional errors of clinical significance occurred. We conclude that subjective analysis has a significant error rate and that reproducibility and accuracy of analysis of left ventriculograms require objective analysis.
Gradual changes of ECG waveform during and after exercise in normal subjects.
Authors: Simoons M L , Hugenholtz P G
Published: June 2012

The directions and magnitudes of time-normalized P, QRS, and ST vectors, and other ECG parameters were analyzed during and after multistage exercise in 56 ostensibly healthy men aged 23 to 62. By selective averaging with a digital computer system a single representative beat was obtained from each stage. Measurements were taken from this beat. During exercise, the interval between the spatial maximum of the P wave and the onset of the QRS complex decreased while the magnitude of the P wave increased. The direction of the P vectors did not change. This pattern corresponds to the electrocardiographic manifestations of predominant right atrial overload. No significant changes in the QRS duration were observed. Also the magnitude and spatial orientation of the maximum QRS vectors remained constant. The interval between the QRS onset and the maximum spatial magnitude of the T wave shortened. The terminal QRS vectors and the ST vectors gradually shifted toward the right, and superiorly. The T magnitude lessened during exercise. In the first minute of the recovery period the P and T magnitudes markedly increased. Afterward all measurements gradually returned to the resting level. Mechanisms which may explain the observed ECG changes during and after exercise are discussed, including changes in the blood conductivity and intracardiac blood volume. Age did not contribute to the variance of the ECG measurements, but a significant reduction of this variance could be otained in some ST-segment measurements by relating them to heart rate with linear regression equations (P less than or equal to 0.05). Therefore it is expected that the sensitivity of the exercise ECG for detection of ischemic heart disease would be increased when heart rate dependent normal limits for ST-segment measurements are used. Different criteria should be employed for the interpretation of the ECG during and after exercise.
Left atrial appendage aneurysm: correlation of noninvasive with clinical and surgical findings: report of a case.
Authors: Krueger S K , Ferlic R M , Mooring P K
Published: June 2012

Congenital left atrial appendage aneurysm is rarely diagnosed on the basis of an abnormal cardiac silhouette. Patients with a left atrial appendage aneurysm often present with symptoms of systemic emboli or supraventricular arrhythmias. A patient with left atrial appendage aneurysm was diagnosed by correlation of two noninvasive techniques echocardiography and radionuclide scintiscanning. Angiography was confirmatory and aneurysmectomy was successfully performed.
Measurement of midwall myocardial dynamics in intact man by radiography of surgically implanted markers.
Authors: Ingels N B , Daughters G T , Stinson E B , Alderman E L
Published: June 2012

Tiny radiopaque helices (0.85 times 1.5 mm) of pure tantalum wire were implanted by means of a simple insertor instrument into the left ventricular myocardium in 24 patients at the time of cardiac surgery. The markers were positioned in such a way as to outline the profile of the left ventricle when viewed in a 30 degree right anterior oblique projection. Biplane studies showed that all markers could be placed very nearly in a plane using the surface anatomy of the heart as a guide to implantation. Implantation of markers required approximately two minutes. No intraoperative or postoperative complications ascribable to the markers have occurred. They remain firmly in place and allow acquisition of a noninvasive ventriculogram at any time after surgery. The dynamic geometry of the left ventricle was determined by analysis of cineradiograms of these markers. Utilization of a single-plane (right anterior oblique) cineradiogram to obtain measurements of major transverse ventricular diameters, mean circumferential shortening, and circumferential shortening velocity results in underestimation of lenghts by 1.4%, overestimation of shortening by 1.2% of end-diastolic length, and overestimation of velocity by 0.05 circ/sec, when compared with values obtained simultaneously from biplane cineradiograms.
Analysis of left ventricular function in response to afterload changes in patients with mitral stenosis.
Authors: Bolen J L , Lopes M G , Harrison D C , Alderman E L
Published: June 2012

In order to assess left ventricular function in patients with rheumatic mitral stenosis, left ventricular function curves (plotting stroke work index vs left ventricular end-diastolic pressure) were constructed using angiotensin to augment, and nitroprusside to reduce, afterload. Hemodynamic responses to these alterations in afterload were measured. Resting ejection fractions and qualitative assessment of left ventricular angiographic contraction abnormalities were also determined. Changes in left ventricular end-diastolic pressure following afterload interventions could be linearly related to changes in mean aortic pressure, but mitral valve gradients were unaffected. Afterload reduction with nitroprusside did not augment cardiac output. Afterload elevation with angiotensin significantly depressed both cardiac output and calculated mitral valve areas. Patients with normal resting ejection fractions evidenced normal ventricular function curves and those with depressed ejection fractions showed flat or declining function curves. Contraction abnormalities, generally in the posterobasal area, correlated well with abnormal left ventricular function curves.
Attributable risk, population attributable risk, and population attributable fraction of death associated with hypertension in a biracial population.
Authors: Deubner D C , Tyroler H A , Cassel J C , Hames C G , Becker C
Published: June 2012

In 1961, blood pressure was measured in the 40-69-year-old segment of the population of Evans County, Georgia. Mortality was monitored for up to ten years. The relationship found between hypertension and mortality is characterized in this report by four parameters: attributable risk, prevalence, population attributable risk, and population attributable fraction. Attributable risk of death, a measure of the over-all impact of hypertension on those in each race-sex group with hypertension, is high in white males, black males, and black females, and is lowest in white females. Population attributable risk, a measure of the impact of hypertension on each entire race-sex group, is highest in black males and females due to the high prevalence of hypertension in blacks. It is somewhat lower in white males and lowest in white females. The fraction of all deaths attributable to hypertension (population attributable fraction) is highest in black females and lower in the other three groups. The population attributable fraction (ranging from 0.26 to 0.54 for systolic hypertension) is of such magnitude that if the 50% reduction in mortality achieved in the Veteran Administration Cooperative Study could be repeated in the general population, life expectancy after 40 years of age could be substantially increased.
Complication rate of coronary arteriography. A review of 5250 cases studied by a percutaneous femoral technique.
Authors: Bourassa M G , Noble J
Published: June 2012

Distressing rates of embolic complications from coronary arteriography performed by the percutaneous femoral approach have been reported since 1972. From 1970-1974, 5250 patients underwent coronary arteriography in our laboratory by the same percutaneous femoral technique with preformed polyethylene catheters and no systemic heparinization. Data were recorded during and for 24 hours postcatheterization. The annual mortality rate averaged 0.23% and remained relatively stable. Our incidence of embolic complications was very low. In patients with normal coronary arteries, no fatal or serious nonfatal complications occurred. Left main coronary artery disease was present in all cases of mortality and greater than or equal to 60% stenosis was shown in nine of 12 instances. Thus major risk was proportional to the severity of disease in the left coronary system. The use of more aggressive supportive measures in these high-risk cases appears essential to reduce the total complication rate from coronary arteriography significantly.
Evaluation of potassium-43 scintillation images during early myocardial ischemia in an animal model.
Authors: Haider B , Oldewurtel H A , Moschos C B , Regan T J
Published: June 2012

To assess the validity of myocardial imaging with potassium-43 (43K) early after the onset of ischemia, the left anterior descending artery was occluded with a baloon tip catheter in 32 intact anesthetized dogs. 99mTechnetium ventriculograms localized the left ventricle. 43K was administered intravenously and serial images were obtained in four views using an Anger camera with a pinhole collimator. The heart was arrested after 60 minutes and removed for imaging and tissue counts to ascertain extracardiac and geometric factors. In normals (group 1) left ventricular images were relatively homogeneous, except for the thin walled apex, both in vivo and in the isolated heart. Equilibration with 43K prior to ischemia (group 2) gave similar images to group 1, associated with a small reduction in tissue count after one hour of ischemia. Group 3 was infused with 43K after initiation of ischemia. Despite a reduction of 43K counts in the ischemic area to less than one-fourth of the nonischemic site (P less than 0.001), demonstration of a "cold area" in vivo was inconstant, occurring in only 34% of studies. Lead shielding did not improve accuracy. In the isolated heart the ability to detect the cold area was improved to 73%. However, when the left ventricle was incised and spread flat, so that low and high activity areas were contiguous rather than superimposed, a widespread area of ischemia was present without exception in the anterior wall. Use of a rectilinear scanner in seven animals failed to improve diagnostic yield; areas of reduced radioactivity were seen at the apex in normals by both techniques. Thus, while detection of low flow areas in the isolated heart is feasible by isotopic imaging early after the onset of ischemia, both extracardiac and geometric factors can contribute to qualitative and quantitative errors in vivo.
Evaluation of left ventricular function in patients with aortic regurgitation using afterload stress.
Authors: Bolen J L , Holloway E L , Zener J C , Harrison D C , Alderman E L
Published: June 2012

Left ventricular function was assessed in 14 patients with chronic aortic regurgitation by afterload elevation with angiotensin. Seven of 14 patients maintained their resting ejection fraction with angiotensin (group A), while the remaining seven experienced a decline of greater than 0.10 in ejection fraction (group B). Six of seven group A patients showed an appropriate rise in left ventricular stroke work index in response to the angiotensin-induced rise in left ventricular end-diastolic pressure. In contrast, six of seven group B patients showed abnormal, flat, or declining stroke work indices. Included in the seven group B patients were two patients with left ventricular dysfunction secondary to coronary artery disease. The five other group B patients, who did not have coronary diseases, exhibited similar stress-induced ventricular dysfunction, despite the absence of any significant resting hemodynamic differences from patients in group A. These five stress-induced dysfunction patients were distinctive from patients who maintained their ejection fraction level in that the former all had regurgitant fractions of greater than 0.50, whereasl all gruop A patients had regurgitant fractions of less than 0.50. Similarly, these five stress-induced dysfunction patients had significantly larger left ventricular end-diastolic volumes than did the group A patients. These data suggest that patients with pronounced aortic regurgitation measured in terms of regurgitant fraction greater than 0.50 and left ventricular end-diastolic volume of greater than 160 cm3/m2 exhibit impaired ventricular function if appropriately stressed. As most of the patients with stress-induced dysfunction had a normal ejection fraction at rest, it may be that stress-induced dysfunction represents a stage before overt resting dysfunction and cardiac failure.
Left ventricular outflow tract obstruction produced by redundant mitral valve tissue in a neonate. Clinical, angiographic, and operative findings.
Authors: Mathewson J W , Riemenschneider T A , McGough E C , Condon V R
Published: June 2012

An unusual case of left ventricular outflow tract obstruction associated with severe left ventricular failure in a neonate is reported. The physical and laboratory data were consistent with the diagnosis of infantile valvular aortic stenosis. At operation, however, redundant gelatinous pedunculated tissue attached to the mitral valve annulus appeared to move through and obstruct the aortic valve during systole. The aortic valve showed only minimal thickening of the right and left coronary cusps. A distinct angiographic pattern was demonstrated during left ventricular cineangiography. In the frontal projection a large ovoid filling defect appeared to protrude through the aortic valve during systole and return to a subvalvular location during diastole. Recognition of this angiographic pattern should facilitate diagnosis and subsequent repair. Complete correction is possible by operative excision of the obstructing tissue without damaging the mitral valve. In contrast to isolated congenital infantile valvular aortic stenosis, a condition in which the valve leaflets are often primitive and deformed, aortic valvotomy and/or subsequent valve replacement are not necessary, resulting in a better long-term prognosis.
The acute hemodynamic effects of ethacrynic acid and furosemide in patients with chronic postcapillary pulmonary hypertension.
Authors: Austin S M , Schreiner B F , Kramer D H , Shah P M , Yu P N
Published: June 2012

The acute hemodynamic effects of either ethacrynic acid or furosemide were studied in 27 patients who underwent diagnostic right and transseptal left heart catheterization. Twenth-three patients had postcapillary pulmonary hypertension secondary to isolated or predominant mitral stenosis. Of these, 21 patients were in New York Heart Association functional class III, and one each in class II and IV. In the remaining four patients pulmonary artery pressures were normal. Two patients had aortic stenosis and one each coronary artery disease and nonobstructive cardiomyopathy. All four patients were in class II. Cardiac index, pressures, and pulmonary blood volume (PBV) were measured in the control state and 20, 40, and 60 min after diuretic administration. Pulmonary extravascular fluid volume (PEV) was measured in the control state and at 60 min post drug infusion. A similar hemodynamic response was observed for each drug. Significant reductions in pulmonary artery and left atrial mean pressures, cardiac index, and plasma volume occurred over the one hour observation period and were accompanied by a significant duiresis. However, despite recutions in central pressures and blood flow, PBV, ev, and PEV/PBV remained unchanged, as did systemic arterial pressure. Since 23 of the subjects had postcapillary pulmonary hypertension it is postulated that the failure of PBV to decrease significantly despite significant decreases in pulmonary artery mean pressure is related to altered pressure volume characteristics in the pulmonary vascular bed in which the lung is operating on a steep portion of its pressure volume curve. The failure of the PEV to decrease supports the concept that the pulmonary extravascular space is relatively resistant to early decreases in pulmonary capillary pressure induced acutely. The failure of the pulmonary extravascular fluid volume to decrease despite a fall in plasma volume and pressures corresponds to the well recognized delay in resolution of radiologic evidence of pulmonary congestion.
The pulmonary vascular bed in patients with complete transposition of the great arteries.
Authors: Clarkson P M , Neutze J M , Wardill J C , Barratt-Boyes B G
Published: June 2012

Histological material obtained at autopsy from 35 patients over three months of age with complete transposition of the great arteries (TGA) was examined. Two of six patients less than a year of age with an intact ventricular septum and closed ductus arteriosus were found to have pulmonary vascular changes of at least grade 3 severity; in addition, two of seven patients with a large ventricular septal defect in this age group showed changes of similar severity. The reported low incidence of marked pulmonary vascular changes in patients with only an interatrial communication dying during the first year of life would appear to be due in part to the high proportion of cases less than three months old in whom there was not sufficient time for such changes to develop. Although the incidence is not as high as that found beyond a year of age, it is sufficiently high to influence the management of infants beyond three months of age. Hemodynamic studies were performed following atrial baffle repair in 34 patients. All but one of the 16 patients operated upon prior to two years of age had a pulmonary arteriolar resistance (Rpa) less than 3 units M2 at the time of review, including three with a large communication at ventricular or great vessel level who underwent surgery before two months of age. Repair at an older age did not preclude a low Rpa on follow-up, but in 11 of the 18 patients who were two or more years of age at the time of repair it was greater than 3 units M2. None of these latter patients had a large ventricular septal defect or patent ductus arteriosus. Comparison of postoperative hemodynamic data with autopsy studies would suggest that advanced pulmonary vascular disease is associated with earlier death among patients with complete transposition of the great arteries.
Clinical conference: Rupture of right ventricle complicating closed chest cardiac massage.
Authors: Baldwin J J , Edwards J E
Published: June 2012

Two cases of rupture of the right ventricle following closed chest cardiac massage are presented. This is believed to result from trapping of blood in the right ventricle at levels of systemic arterial pressure. In one case there was massive pulmonary embolism which interfered with egress of blood from the right ventricle. In the other case, application of pressure during a closed chest resuscitative attempt might have closed the right ventricular outflow tract.
Myocardial LDH isozyme distribution in the ischemic and hypoxic heart.
Authors: Hammond G L , Nadal-Ginard B , Talner N S , Markert C L
Published: June 2012

Small myocardial specimens were obtained from 12 patients undergoing coronary reconstructive surgery and from 12 patients undergoing surgical correction for cyanotic congenital heart defects. The specimens were analyzed for LDH isozyme distribution. A control analysis was performed on myocardial specimens obtained at the time of surgical correction for acyanotic congenital heart defects in seven patients with normal coronary arteries. There was a 42% increase in the proportion of A subunits in the hearts of coronary patients as compared to controls. This represented a shift toward an anaerobic isozyme distribution. There was no change in the percentage of A units from the hearts of cyanotic patients as compared to acyanotic hearts of the same age. Cardiac muscle from patients with coronary vascular disease had an altered LDH subunit composition. Such an alteration was not present with chronic systemic hypoxia. These deficiencies may or may not be related to differing local metabolic responses to the two conditions. However, in the clinical situations, ischemic heart muscle may be oxygen deprived to the point of lactic acid production while hypoxic heart muscle usually is not. Consequently, these findings may represent a compensatory cellular mechanism which provides for continued energy production during chronic ischemia by enhancing glycolysis.
Autoregulation of cerebral blood flow in hypertensive patients. The modifying influence of prolonged antihypertensive treatment on the tolerance to acute, drug-induced hypotension.
Authors: Strandgaard S
Published: June 2012

Autoregulation of cerebral blood flow (CBF) was studied by the arteriovenous oxygen difference method in 13 patients with untreated or ineffectively treated severe hypertension, nine patients with effectively treated, formerly severe hypertension, and ten normotensive controls. Resting mean blood pressure in these three groups was 145 +/- 17 (1 SD) mm Hg, 116 +/- 18 mm Hg, and 98 +/- 10 mm Hg, respectively. Blood pressure was decreased by trimethaphan infusion combined with head-up tilt. The lower limit of CBF autoregulation in the three groups was 113 +/- 17 mm Hg, 96 +/- 17 mm Hg, and 73 +/- 9 mm Hg, and the lowest tolerated blood pressure where mild symptoms of brain hypoperfusion were encountered was 65 +/- 10 mm Hg, 53 +/- 18 mm Hg, and 43 +/- 8 mm Hg. These pressures were all significantly higher (P less than 0.01) in the group of untreated or ineffectively treated hypertensive patients than in the normotensive group demonstrating a shift of CBF autoregulation in the former. The observations in effectively treated hypertensive patients strongly suggested a readaptation of CBF autoregulation toward normal in some cases. In four hypertensive patients studied twice it was found that 8-12 months of antihypertensive treatment on average did not influence the lower limit of CBF autoregulation.
Real-time observation of ruptured right sinus of Valsalva aneurysm by high speed ultrasono-cardiotomography. Report of a case.
Authors: Nishimura K , Hibi N , Kato T , Fukui Y , Arakawa T
Published: June 2012

A two-dimensional echocardiographic manifestation of a ruptured right sinus of Valsalva aneurysm is described in this case report. The ultrasono-cardiotomograms demonstrated the aneurysm cut longitudinally and protruding into the outflow tract of the right ventricle. The configuration of the aneurysm was consistent with the contrast medium-filled sinus demonstrated by angiocardiography. In systole, the aneurysmal sinus moved anteroinferiorly together with the aortic wall. The echocardiogram revealed an abnormal two-layered horizontal echo in the right ventricle which showed the aneurysm when the ultrasonic beam passed through the interventricular septum near the aortic root and mitral leaflets. During the operation, the protruding sinus and a small interventricular septal defect in the membranous septum under it were observed through the opened right ventricle. After the closure of the aneurysm, the two-dimensional echocardiogram no longer showed an abnormal configuration.
Electrophysiologic evaluation of sinus node function in patients with sinus node dysfunction.
Authors: Strauss H C , Bigger J T , Saroff A L , Giardina E G
Published: June 2012

Twenty patients of mean age 66.2 years, with suspected sinus node dysfunction, underwent extensive electrophysiologic study. Sinus bradycardia (18), sinus pauses (3), and sinoatrial block (1) were identified in their ECGs prior to study. Also 11 patients had some abnormality of atrioventricular nodal and/or intraventricular conduction prior to study. At the time of electrophysiological study, 10/20 patients (50%) had a mean cycle length exceeding 1000 msec, and mean P-V interval exceeded 210 msec in 7/20 (35%). The estimated "sinoatrial conduction time" exceeded 215 msec in 6/16 (38%) patients. The maximum first escape cycle following pacing at six different rates exceeded a value equal 1.3 X the mean value of the control cycle length + 101 msec (slope of regression line + Y intercept + 1 SD) in 13/9 (68%) patients. Nineteen patients received 1 mg atropine intravenously and mean cycle length decreased by 19%, from 891 +/- 175.8 msec to 718 +/- 182.9 msec. Graded infusion of isoproterenol was employed in 19 patients; four patients required an infusion rate greater than 28.3 ng/kg/min to produce a 20% decrease in spontaneous sinus cycle length. These data would indicate that a variety of interventions are required to characterize the disturbance of sinus node automaticiy and sinoatrial conduction in patients with sinus node dysfunction.
Concealed intraventricular conduction in the His bundle electrogram.
Authors: Cohen H C , D'Cruz I , Pick A
Published: June 2012

Multiple areas of concealed intraventricular conduction are deduced on the basis of aftereffects observed in His bundle recordings. Electrocardiograms and His bundle recordings are presented from two patients with unstable bilateral bundle branch block, the instability of which depended on the interval at which ventricular depolarization was initiated by sinus or paced impulses. This circumstance allows postulation of 1) concealed transseptal retrograde penetration of the left bundle branch system; 2) concealed transseptal retrograde penetration of the right bundle branch system; 3) alternate beat Wenckebach phenomenon with two areas of block in the bundle branch system with concealed penetration of the proximal area; 4) concealed re-entry in the right bundle branch system during an H-V Wenckebach cycle with resetting of the sequence of 2:1 H-V block and return of the re-entry wave to the A-V node causing subsequent A-H block; 5) proximal 2:1 block and distal Wenckebach block producing only two consecutively blocked beats; and 6) infrahisian Wenckebach block with changes both in A-V conduction and QRS contour.
Effects of vasodilator therapy for severe pump failure in acute myocardial infarction on short-term and late prognosis.
Authors: Chatterjee K , Swan H J , Kaushik V S , Jobin G , Magnusson P , Forrester J S
Published: June 2012

Forty-three patients with severe pump failure complicating acute myocardial infarction were treated with vasodilators (nitroprusside (40) and phentolamine (3)) for four hours to 27 days. Cardiac index, stroke volume index, and stroke work index (SWI) increased while the left ventricular filling pressure (LVFP) decreased during vasodilator therapy. Twenty-four of the 43 patients (56%) survived. Of patients with initial SWI between 11-20 gm-m/m2 and LVFP less than 15 mm Hg, 68% survived. In contrast only 18% of patients with SWI of 10 gm-m/m2 or less and LVFP greater than 15 mm Hg survived. Of the 17 patients with clinical shock, 8 (47%) survived. All 24 patients discharged from the hospital were followed for at least 12 months. Fourteen patients died one to 25 months (average 9.2 months) after discharge and the cause of death was pump failure in ten of them (71%). The ten survivors at last follow-up had been followed for 15 to 32 months (average 24 months). The cumulative survival at 24 months was 28%. Thus, despite improvement in short-term prognosis with vasodilator therapy in patients with severe pump failure complicating acute myocardial infarction, the prognosis for long term survival remains unfavorable, possibly due to severe intrinsic cardiac damage.
Prophylactic digitalization for coronary artery bypass surgery.
Authors: Johnson L W , Dickstein R A , Fruehan C T , Kane P , Potts J L , Smulyan H , Webb W R , Eich R H
Published: June 2012

One hundred and twenty patients undergoing aortocoronary bypass procedures were randomly placed into control and digitalized groups. All were initially in normal sinus rhythm and without evidence of congestive heart failure. Supraventricular arrhythmias occurred in 17 of 66 controls and in only three of 54 digitalized patients (P less than 0.01). There was no evidence of digitals toxicity. Based on this evidence we recommend prophylactic digitalization for patients having aortocoronary bypass operations.
Technetium 99m stannous pyrophosphate myocardial imaging in patients with and without left ventricular aneurysm.
Authors: Ahmad M , Dubiel J P , Verdon T A , Martin R H
Published: June 2012

To further explore the usefulness of technetium 99m pyrophosphate (99mTc-PYP) myocardial imaging and test its validity in the diagnosis of acute myocardial infarction, 99mTc-PYP myocardial scintigrams were performed in 50 patients. Out of 28 patients with acute myocardial infarction, myocardial scintigrams demonstrated localized activity in the 15 patients with transmural, and diffuse activity in the 13 patients with subendocardial myocardial infarction. Twenty-two patients with significant coronary artery disease documented by coronary angiography but without acute myocardial infarction were also studied. Nine of ten patients with clinical evidence of left ventricular aneurysm from previous myocardial infarction and definite left ventricular dyskinesis had positive scintigrams with activity localized to the site of the wall motion abnormality. Two of five patients without definite aneurysm but with left ventricular akinesis also had localized uptake in the involved area of the left ventricle. Seven patients with normal left ventricular wall motion had negative scintigrams. These findings suggest caution in interpreting positive 99mTc-PYP scintigrams as being indicative of acute myocardial infarction when evidence of a left ventricular aneurysm is also present.
Patient acceptance of guanethidine as therapy for mild to moderate hypertension. A comparison with reserpine.
Authors: Ferguson R K , Rothenberg R J , Nies A S
Published: June 2012

The relative benefits and risks of reserpine and guanethidine were compared in patients with thiazide-treated mild to moderate hypertension (diastolic pressure 95-115 mm Hg). Forty-nine ambulant patients )30 men, 19 women) were treated throughout the study with hydrochlorothiazide, 50 mg/day. In this double blind crossover study each drug was added in graded increments until a predetermined therapeutic response was obtained, blood pressure measurements and side effect scores were evaluated biweekly. Major conclusions of the study were: 1) guanethidine, as well as reserpine, will reduce mild to moderate blood pressures to normal; 2) in most cases, side effects which did occur while taking guanethidine or reserpine were well tolerated and neither drug was clearly superior. Side effects associated with larger doses of guanethidine employed in severe hypertension were absent or only slightly bothersome. Thus, guanethidine apppears to have a good benefit-to-risk ratio in the therapy of mild to moderate hypertension and offers a number of advantages over drugs commonly used in this syndrome. This study refutes the common belief that guanethidine must be reserved only for the treatment of more severe degrees of hypertension.
The protective effect of glucose-insulin-potassium on the response to atrial pacing.
Authors: Chiong M A , West R , Parker J O
Published: June 2012

The effects of glucose-insulin-potassium infusion (GIK) on atrial pacing-induced angina, ST depression, abnormal left ventricular end-diastolic pressure during pacing interruption (LVEDPi) and lactate metabolism (L), were studied in 18 patients: ten had angina during pacing = Ischemic group, and eight (5 normals and 3 with coronary artery disease) remained asymptomatic = Nonischemic group. The study consisted of 8-10 minute periods of control, pacing and recovery, before and after GIK. No untoward effects were observed. Comparison of the pacing responses (GIK vs pre-GIK states) showed that during GIK, angina occurred in only 4 patients, while significantly less severe changes were observed in ST depression (1.4 +/-0.5 vs 2.4 +/- 0.4 mm) and LVEDPi (16 +/- 3 vs 23 +/- 3 mm Hg). Lactate extraction was also higher (8.1 +/- 10.9 vs -5.2 +/- 11.1%), but not significantly so, although L became normal in 4 subjects and improved in another. These results indicate that GIK infusion was well tolerated and had a beneficial effect on pacing-induced myocardial ischemia.
The association of increased plasma MB CPK activity and irreversible ischemic myocardial injury in the dog.
Authors: Ahmed S A , Williamson J R , Roberts R , Clark R E , Sobel B E
Published: June 2012

To evaluate the concordance between elevated plasma MB CPK and irreversible myocardial ischemic injury, coronary occlusion was induced for 10 minutes to 48 hours in 21 open chest dogs and 13 conscious animals. Results of plasma CPK and MB CPK assayed in samples obtained serially ofr 24 hours were compared to microscopic changes in hearts from the same animals examined 48 hours after occlusion. Twelve of the 34 dogs died within two hours after coronary occlusion. Among the surviving 22 dogs, one failed to exhibit gross of electrocardiographic evidence of ischemia and was therefore excluded. Twelve had coronary occlusion maintained for 30 minutes or longer and in 11 of these peak plasma MB CPK activity exceeded thenormal range (mean +/- 2 SD) and baseline values by at least 100%. Necrosis was present in the hearts from each manifested by nuclear pyknosis, eosinophilia, shrinkage of cytoplasm, and leukocytic infiltration. In the remaining nine dogs with occlusion for less than 30 minutes, peak plasma MB CPK activity was not elevated and necrosis was not detected. The close concordance between plasma MB CPK elevations and myocardial necrosis was significant (chi2 = 14.5, P less than 0.001), and thus, increased plasma MB CPK activity reflected irreversible myocardial ischemic injury.
Body-surface maps of heart potentials: tentative localization of pre-excited areas in forty-two Wolff-Parkinson-White patients.
Authors: De Ambroggi L , Taccardi B , Macchi E
Published: June 2012

Heart potentials were recorded from the entire chest surface in 42 patients suffering from Wolff-Parkinson-White syndrome. We were able to identify six types of surface maps, according to the location of the potential maximum and minimum during the delta wave. For each of these types we suggested the most likely location of the pre-excited region around the A-V rings (types 1 to 5) or in the interventricular septum (type 6). In 13 patients belonging to Types 1, 2, 3, 5 and 6 our hypotheses were in agreement with intracardiac recordings, epicardial maps or surgical results obtained by others. Isopotential surface maps provide more information on the location of the pre-excited area than conventional ECGs, particularly when these exhibit intermediate features between Types A and B.