bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Furosemide in the Treatment of Left Ventricular Dysfunction Associated with Acute Myocardial Infarction
Authors: KIELY JOHN , KELLY DAVID T. , TAYLOR DEAN R. , PITT BERTRAM
Published: June 2012

Fifteen patients with acute myocardial infarction and an elevated pulmonary capillary wedge pressure were given 40 mg furosemide intravenously within 24 hr of diagnosis of infarction. We divided the patients into two groups on the basis of the diuretic response to furosemide: nine who responded with a diuresis of greater than 400 ml in two hours, and six with a lower diuresis. The nine patients who responded well had a 35% fall in pulmonary capillary wedge pressure, from 21 to 12 mm Hg (
P
< 0.01), accompanied by a small but significant decrease in arterial pressure at the end of two hours. There was no apparent increase in left ventricular function in these patients as shown by the relationship of left ventricular filling pressure and stroke work index, but all survived. The nonresponders failed to show significant hemodynamic changes, were significantly older, had a higher serum urea nitrogen (SUN) than the responders and had higher pulmonary capillary wedge pressures. Despite further therapy with much higher doses of furosemide and digitalis, five of the six nonresponders (83%) died. Furosemide is of value in relieving pulmonary congestion in patients with moderate congestive heart failure associated with myocardial infarction. It should be given cautiously, as an initial dose of 40 mg intravenously may cause a large fall in cardiac output and systemic pressure in occasional patients. Furosemide cannot, however, be recommended as the primary therapeutic agent in patients with severe left ventricular dysfunction complicating acute myocardial infarction.
Quantitation of the Normal Frank and McFee-Parungao Orthogonal Electrocardiogram in the Adolescent
Authors: LIEBMAN JEROME , LEE MOO H. , RAO P. SYAMASUNDAR , MACKAY WILMA
Published: June 2012

A detailed linear, circular and spherical quantitation of the Frank and McFee-Parungao orthogonal electrocardiograms of 166 adolescents is presented.

There are significant differences between pubescent males and females: (1) QRS and T magnitudes in the male are greater than in the female. (2) The difference in magnitudes is greater at age 11-15 than at age 16-19, presumably because females reach puberty earlier. (3) The differences in magnitudes are on the X and Z axes but
not
the Y axis. (4) Males achieve their maximal posterior QRS orientation sooner than females and are more superior as it occurs. (5) The female's T vector is less anterior than the male's. (6) The angular deviation of T from QRS is less in females than males for the horizontal and sagittal planes.

There are significant differences between the two lead systems: (1) The McFee-Parungao's voltages are greater than those of the Frank system. (2) On the X axis, the Frank leftward vector is 62% of the McFee, but the terminal rightward vector is 85% of the McFee. (3) On the Y axis, the Frank inferior vector is 76% of the McFee, but initial superior is 90% and the terminal superior 62% of the McFee. (4) On the X axis, 25% is terminally to the right in the Frank, but only 15% in the McFee. (5) The Frank system is oriented slightly more posterior than the McFee, though the T vectors are not oriented differently.

There is no evidence that the spatial QRS and T orientations are related to each other.
An Appraisal of Mitral Valve Echocardiograms Mimicking Mitral Stenosis in Conditions with Right Ventricular Pressure Overload
Authors: McLAURIN LAMBERT P. , GIBSON THOMAS C. , WAIDER WINFRIED , GROSSMAN WILLIAM , CRAIGE ERNEST
Published: June 2012

Of seven patients with pulmonary hypertension, two had marked and one had moderate retardation of the echocardiographic anterior mitral valve leaflet closing motion, suggestive of mitral stenosis. In each patient, however, mitral stenosis was excluded by hemodynamic or anatomic criteria. The reason for the abnormal mitral valve motion was considered to be a reduced rate of left ventricular diastolic filling. In the group of seven patients it was noted that the ratio of ventricular filling pressures (RVedP/LVedP) was inversely correlated with the anterior mitral valve leaflet closing slope. This observation supports the hypothesis that left ventricular diastolic filling may be secondarily altered by right ventricular overload, and that this impairment of left ventricular filling may result in alteration of the anterior mitral valve leaflet echogram mimicking mitral stenosis.
The Inotropic Effects of Digoxin in Hyperkalemia
Authors: GOLDMAN ROBERT H. , COLTART D. JOHN , FRIEDMAN JOEL P. , NOLA GAETON T. , BERKE DAVID K. , SCHWEIZER ESTHER , HARRISON DONALD C.
Published: June 2012

The effects of hyperkalemia on the inotropic properties of digoxin were studied in anesthetized mongrel dogs. With preload, afterload and heart rate maintained constant in dogs who received atropine and practolol to block cardiac reflexes, 0.08 mg/kg digoxin increased the first derivative of the left ventricular pressure curve (LV dp/dt) 53.1 ± 8.3% (SEM) in normokalemic animals but only 9.5 ± 2.5% in hyperkalemic animals at 60 min. This decrease in the inotropic effects of digoxin by hyperkalemia was accompanied by significant decreases in both total left ventricular digoxin concentration and microsomal-bound digoxin. (Na
+
, K
+
)-ATPase was inhibited 43.3 ± 2.4% in normokalemic animals but only 27.4 ± 2.5% in hyperkalemic animals (
P
< 0.01), while (Mg
++
)-ATPase levels were similar in normokalemia and hyperkalemia. In animals not given digoxin, hyperkalemia had no effect on either LV dp/dt or (Na
+
, K
+
)-ATPase. There was a good correlation between the positive inotropic effects of digoxin and percent inhibition of (Na
+
, K
+
)-ATPase.

These studies provide further support for the importance of (Na
+
, K
+
)-ATPase inhibition and microsomal-bound digoxin in determining the inotropic effects of digoxin. Hyperkalemia alters the inotropic effects of digoxin by decreasing binding of digoxin to a microsomal cell fraction containing (Na
+
, K
+
)-ATPase activity.

These studies also provide support for the importance of reflex withdrawal of sympathetic tone in modifying the inotropic properties of digoxin in normokalemic and hyperkalemic animals.
The Influence of Pericardiectomy on the Hemodynamics of Chronic Constrictive Pericarditis
Authors: VIOLA ANGEL R.
Published: June 2012

Preoperative and postoperative right heart catheterizations were performed on six patients with chronic constrictive pericarditis. Before surgery the patients characteristically showed distinct elevation of right ventricular end-diastolic, pulmonary arterial and wedge pressures. During the operation, right and left ventricular pressure curves were recorded both before and after pericardial resection. Before decortication, the average values of end-diastolic pressures for the right and left ventricles were 17 and 20 mm Hg respectively. No significant changes were observed after pericardiectomy was completed. However, all patients showed excellent clinical recoveries. Postoperative catheterizations performed two to five months after operation disclosed normal intracardiac pressures.

Persistent impairment of ventricular performance in the early period after pericardiectomy must be attributed to a reversible myocardial failure.
Unusual Evolution of Acquired Infundibular Stenosis in Patients with Ventricular Septal Defect
Authors: MARON BARRY J. , FERRANS VICTOR J. , WHITE ROBERT I.
Published: June 2012

Hemodynamic and cardiac morphologic observations were made on two patients with ventricular septal defect who showed unusual evolution of obstruction to right ventricular outflow. Both patients developed progressive infundibular stenosis, one in the presence of a spontaneously closing ventricular septal defect and the other after operative closure of the defect. Light and electron microscopic examination of resected infundibular muscle revealed hypertrophy and abnormal shapes and arrangements of cardiac muscle cells. These abnormalities resembled those found in left ventricular outflow tract muscle of patients with idiopathic hypertrophic subaortic stenosis. It is suggested that the patterns of distribution and growth of these abnormal cells in the right ventricular outflow tract may lead to localized hypertrophy and to development of progressive infundibular obstruction in some patients with ventricular septal defect.
Bicuspid Aortic Valve
Authors: WALLER BRUCE F. , CARTER JOHN B. , WILLIAMS HUGH J. , WANG KYUHYUN , EDWARDS JESSE E.
Published: June 2012

Two dominant types of congenital bicuspid valves are described. The classical type is characterized by the presence of a low ridge or raphe along the aortic aspect of the conjoined cusp. The other is characterized by a tall raphe, the upper edge of which corresponds with the upper level of the aortic cusps. Some such ridges may result from acquired fusion of the adjacent halves of two cusps (yielding an acquired bicuspid valve). In other cases, the ridge is a protrusion of the aorta and not derived from fused cuspid tissue. Such valves are considered to portray a condition which may be termed pseudoacquired congenital bicuspid aortic valve. The acquired bicuspid valve in some cases is compounded of this congenital process and acquired fusion of cuspid tissue. The ratio of classical congenital bicuspid to pseudoacquired congenital bicuspid aortic valve is 4 to 1. Exceptional forms of pseudoacquired congenital bicuspid aortic valves are also described.
Multivariate Analysis of Risk Factors for Coronary Heart Disease
Authors: WILHELMSEN LARS , WEDEL HANS , TIBBLIN GÖSTA
Published: June 2012

For a prospective study of risk factors for coronary heart disease (CHD), defined as acute nonfatal myocardial infarction and acute fatal CHD, 973 men, all aged 50 years, were recruited from a general Swedish urban population. Of the 855 who agreed to participate, 834 who showed no signs of CHD were selected and observed for nine years and four months. Autopsies were performed on all except two of the 55 patients who died during the study. Forty-four men developed clinical manifestations of CHD during this time; 19 of them died.

Using a multiple logistic model, we analyzed nine probable risk factors. The presence of high serum cholesterol, smoking, high systolic blood pressure, dyspnea, and registration by the Temperance Board increased the risk of events related to CHD significantly. The presence of high serum triglycerides, high hematocrit readings, and increased geographic mobility did not cause a significant increase in events related to CHD. Those with sedentary jobs showed a slightly increased tendency to develop manifestations of the disease.

The predictive power of the logistic function (with cholesterol, smoking, and systolic blood pressure) was tested in another randomly selected population sample of 5,146 men aged 51-55 years and found to be very accurate. The 10% (decile) of the population that had the highest risk of clinical manifestations of coronary disease and the 10% who had the lowest risk were defined. Manifestations of coronary disease occurred 29 times more frequently in the highest decile than in the lowest decile.
Visualization of Ventricular Septal Defects by Cardiac Ultrasonography
Authors: KING DONALD LATHAM , STEEG CARL N. , ELLIS KENT
Published: June 2012

Anatomically true cross-sectional ultrasonic images of the heart have demonstrated ventricular septal defects in 25 patients with this lesion as an isolated anomaly or in conjunction with other defects. In two additional patients a defect was visualized but confirmation was not obtained. Ventricular septal defects were not demonstrated in 13 other patients in whom this lesion was identified by other techniques. In these instances the lesion was not sought for, was inaccessible, or was too small to image. Defects were manifested by the septum overriding the posterior great artery, septal discontinuity immediately below the posterior semilunar valve, or a discontinuity caudal to the posterior semilunar valve. It appears that cardiac ultrasonography may be able to demonstrate most of the common larger ventricular septal defects occurring in the infracristal region of the septum.
Experimental Pulmonary Embolism
Authors: ALPERT JOSEPH S. , HAYNES FLORENCE W. , DALEN JAMES E. , DEXTER LEWIS
Published: June 2012

Autologous blood clot was used to produce pulmonary macroembolism, and lycopodium spores to produce microembolism in normal mongrel dogs. Pressures were recorded from the pulmonary artery, left atrium and femoral artery; cardiac output and pulmonary blood volume (PBV) were determined using sequential indicator dilution curves from injections into the pulmonary artery and left atrium. Macro- and microembolism caused comparable elevations of pulmonary artery pressure and total pulmonary resistance. Macroembolism with blood clots resulted in marked decreases in PBV and pulmonary vascular compliance. However, microembolism with lycopodium spores caused only small decreases in PBV despite a large reduction in pulmonary vascular compliance. Prostaglandin E
1
infusion after microembolism had no effect on pulmonary hemodynamics, but caused significant systemic hypotension. After macroembolism PGE
1
infusion decreased PBV and decreased systemic arterial pressure.
Plasma Volume Prior to and Following Volume Loading During Shock Complicating Acute Myocardial Infarction
Authors: LUZ PROTASIO L. DA , WEIL MAX HARRY , LIU VINNIE Y. , SHUBIN HERBERT
Published: June 2012

Blood volume was measured following onset of shock in 19 patients who had sustained acute myocardial infarction. The plasma volume was measured by dilution technique utilizing R
125
ISA and the red cell mass by (
51
Cr) red cell tag, at the time of admission.

The plasma volume in six survivors was 41.1 ± 3.3 ml/kg; in 13 fatal cases it was 44.7 ± 4.0 ml/kg; this difference was not significant. The red cell mass in four survivors was 27.2 ± 1.75 ml/kg and in four fatal cases, 24.7 ± 1.60 ml/kg. Since these measurements are within normal ranges, we excluded absolute hypovolemia as a significant factor in accounting for the circulatory failure. Infusion of fluids in amounts which maintained a positive fluid balance selectively increased the plasma volume (57.1 ± 4.4 ml/kg), cardiac index, stroke volume and central blood volume in survivors, and reversed arterial vasoconstriction and lactic acidosis. However, the plasma volume was unaffected in the fatal cases (44.4 ± 4.0 ml/kg) and this was associated with progressive hemodynamic and metabolic deterioration.

These observations support the hypothesis that recovery from shock is associated with expansion of plasma volume. To the contrary, during fatal progression of shock, plasma volume expansion does not occur despite volume loading.
Echocardiographic Assessment of Left Ventricular Performance in Normal Newborns
Authors: SAHN DAVID J. , DEELY WILLIAM J. , HAGAN ARTHUR D. , FRIEDMAN WILLIAM F.
Published: June 2012

Left ventricular function was assessed in 72 normal neonates (age 5-15 days, weight 6-10 lbs) using the echocardiographically determined mean velocity of circumferential fiber shortening (VCF). Comparison between mean VCF determined echocardiographically and angiocardiographically in nine infants with congenital heart disease yielded a correlation coefficient of +0.97 (
P
< 0.001). For the group of normal newborns, mean VCF averaged 1.51 ± 0.04 (
se
) circumferences/sec with a range of 0.92 to 2.2 circ/sec. Sub-group values were: <12 hrs (N = 13) 1.48 ± 0.08 circ/sec; 12-24 hrs (N = 16) 1.46 ± 0.05 circ/sec; 24-48 hrs (N = 26) 1.44 ± 0.06 circ/sec; 48-72 hrs (N = 19) 1.57 – 0.06 circ/sec; 72-150 hrs (N = 8) 1.61 ± 0.11 circ/sec. The differences between age groups were not significant statistically. In contrast, VCF was noted to be depressed significantly in the first hour of life when normal infants were evaluated serially. These studies validate ultrasound determinations of internal shortening velocity in the neonatal period, provide normal values, and attest to the reproducibility of the method. The technique will be especially valuable for the serial, noninvasive assessment of left ventricular performance in newborn infants.
Myocardial Balance of Inorganic Phosphate and Enzymes in Man
Authors: CHIONG MIGUEL A. , WEST ROXROY , PARKER JOHN O.
Published: June 2012

The effects of atrial pacing on the cardiac balance of inorganic phosphate (P
i
) were studied during control, atrial pacing, and recovery periods in 29 patients. Group A (n = 18) who had roentgenographically demonstrated coronary artery disease (CAD) developed angina during pacing, and showed mean myocardial lactate (L) production, abnormal left ventricular end-diastolic pressure (LVEDP) and ST segment depression. Group NA (n = 11), composed of six patients with CAD and five subjects with no demonstrable cardiac disease, had normal lactate metabolism, LVEDP, and ST segments during pacing. In addition, blood levels of two enzymes were determined: creatine phosphokinase (CPK) in nine patients of Group A and six patients of Group NA, and glutamic oxaloacetic transaminase (GOT) in eight patients of each group.

During control, small uptake of P
i
was observed in both groups. During pacing, Group A showed first a fall and then abolition of mean P
i
uptake, and during the early recovery period, a small loss of this ion was observed. Although there was a good correlation between L and P
i
uptakes (
r
= 0.86,
P
< 0.001) throughout the study, P
i
loss, which occurred in 55% of patients in Group A, appeared to be a less reliable index of myocardial anaerobiosis than L production, which occurred in 72%. No consistent changes in P
i
balance were observed in Group NA. The only significant enzymatic change was the small but sudden and significant rise of mean CPK levels in coronary sinus (CS) blood above the arterial levels in five patients of Group A during the first 6 min of pacing. These data show that during pacing-induced angina the human heart loses P
i
. In addition, these preliminary observations on the CS CPK levels during pacing in the angina patients suggest that the stress of tachycardia and ischemia may facilitate the escape of this enzyme from the heart.
De Subitaneis Mortibus
Authors: JAMES THOMAS N. , CARSON NINA A. J. , FROGGATT PETER
Published: June 2012

Conspicuous abnormalities of the coronary arteries and veins and of the sinus node, atrioventricular (A-V) node and His bundle are described in the heart of a boy dying with congenital homocystinuria. The unproven possibility of transient disturbances of cardiac rhythm or conduction is discussed relative to the pathogenesis of the bouts of unconsciousness with and without convulsions characteristic of the disease. Factual information on the stability or instability of electrical activity of the heart in such patients is particularly needed because of the possibility of treatable aspects of an otherwise seemingly inexorable process.
Effect of Carbon Monoxide Exposure on Intermittent Claudication
Authors: ARONOW WILBERT S. , STEMMER EDWARD A. , ISBELL MICHAEL W.
Published: June 2012

The effect of breathing 50 ppm of carbon monoxide for two hours versus compressed, purified air for two hours on intermittent claudication was evaluated in ten men in a double-blind study. The mean venous carboxyhemoglobin level insignificantly decreased from 1.12% to 0.90% after breathing compressed, purified air but significantly increased from 1.08% to 2.77% after breathing carbon monoxide (
P
< 0.001). The mean exercise time until the onset of intermittent claudication insignificantly increased from 169 sec to 173 sec after breathing compressed, purified air but significantly decreased from 174 sec to 144 sec after breathing carbon monoxide (
P
< 0.001). Breathing 50 ppm of carbon monoxide for 2 hr significantly aggravated intermittent claudication of the calf or thigh due to angiographically documented occlusive arterial disease.
A Developmental Complex Including Supravalvular Stenosis of the Aorta and Pulmonary Trunk
Authors: BLIEDEN LEONARD C. , LUCAS RUSSELL V. , CARTER JOHN B. , MILLER KENNETH , EDWARDS JESSE E.
Published: June 2012

A developmental complex is described characterized by (1) supravalvular stenosis of the aorta and pulmonary trunk, (2) dysplasia of valves and (3) stenosis of ostia of coronary arteries and branches of the aortic arch. From the four cases described, it is evident that not all of the features of the complex need be present in a given case and, when present, some lesions are not of functional significance. The variations underly the potential for differences in the hemodynamic states of affected subjects.
The Significance of Second Degree Atrioventricular Block and Bundle Branch Block
Authors: DHINGRA RAMESH C. , DENES PABLO , WU DELON , CHUQUIMIA RUBEN , ROSEN KENNETH M.
Published: June 2012

His bundle (H) electrograms were recorded in 15 patients with second degree atrioventricular (A-V) block and bundle branch block and these patients were prospectively followed. Site of block was proximal to H in four (BPH), distal to H in nine (BDH), and undetermined in two (studied during 1:1 conduction). Surface electrocardiographic features were retrospectively examined to determine the value of these recordings in predicting the site of block. Patients with type I block, with or without type II or 2:1 block, had BPH. Patients with type II block, 2:1 block, or type II combined with 2:1 block had BDH. Heart failure was more common in those with BPH (three of four patients as compared to three of nine patients with BDH). Syncope developed more commonly in patients with BDH (six of nine patients) as compared to those with BPH (one of four patients). Permanent pacing was indicated in three of four patients with BPH, nine of nine patients with BDH, and one of two patients with block at undetermined site because of syncope or heart failure. Five of nine patients with BDH required pacemakers within ten days of initial admission.

Most patients with second degree A-V block and bundle branch block will need permanent pacing. In patients with 2° BDH, pacemakers are indicated whether or not symptoms are present because of high risk of syncope and potential risk of sudden death. In asymptomatic patients with 2° BPH, careful observation is indicated.
Rest and Exercise Potassium-43 Myocardial Perfusion Imaging for the Noninvasive Evaluation of Aortocoronary Bypass Surgery
Authors: ZARET BARRY L. , MARTIN NEIL D. , MCGOWAN RONALD L. , STRAUSS H. WILLIAM , WELLS HARRY P. , FLAMM M. D.
Published: June 2012

Sixteen patients undergoing aortocoronary bypass surgery were evaluated with rest and exercise potassium-43 (
43
K) myocardial imaging and contrast angiography an average of 5.5 months postoperatively. The results of
43
K imaging allowed the division of these patients into two groups. Group 1 consisted of patients in whom there was either normalization or significant improvement in postoperative images when compared to abnormal preoperative studies (five patients), or patients in whom preoperative imaging was not accomplished but whose postoperative images both at rest and exercise showed a normal homogenous pattern of
43
K distribution (four patients). All patients in this group had at least one patent bypass graft, and 13 of 16 total grafts were patent. Group 2 consisted of seven patients in whom postoperative rest and exercise
43
K studies were either not significantly different from preoperative evaluation, or had worsened. Of these patients, three experienced intraoperative infarction, two demonstrated significant distal native coronary disease, and one had a single occluded graft. In both groups there was good correlation between the anatomic sites of graft patency or occlusion and the location of either increased perfusion or lack thereof on the
43
K image. Perfusion abnormalities occurring in the presence of occluded grafts, or improvement in perfusion occurring in the presence of patent grafts were best appreciated by comparison of exercise images. Abnormalities occurring in the presence of infarction were detected at rest as well. Thus, in this initial group of patients,
43
K rest and exercise myocardial imaging appeared to offer a sensitive noninvasive means of evaluating the results of aortocoronary bypass surgery.
Right Atrial Volume Measurements from Biplane Cineangiocardiography
Authors: GRAHAM THOMAS P. , ATWOOD GERALD F. , FAULKNER SCOTT L. , NELSON JAMES H.
Published: June 2012

Right atrial (RA) volumes were calculated from biplane cineangiocardiograms obtained during diagnostic cardiac catheterization in twenty-nine patients with normal right hearts. Validation of methodology was performed with calculations of right atrial casts of 14 human right atria. An excellent correlation of known and calculated volume was obtained either with a Simpson's rule method,
r
= 0.999, or with the area-length method assuming an ellipsoid of revolution,
r
= 0.998. The relationship between patient size and RA maximal volume (RA Max) was best fit by an exponential equation relating RA Max to body surface area: [RA Max = 54.6 (BSA)
1.233
, r = 0.979, F ratio 561.8]. RA Max normalized for body size was significantly less for infants less than one year of age than for older patients. RA Max averaged 38% greater than LA Max in the normal group. RA Max was evaluated in 14 patients with atrial septal defect or anomalous pulnonary venous return. These patients all showed increases in RA Max averaging 198% of normal. RA Max/BSA showed a significant correlation with Qp/Qs derived from O
2
data,
r
= 0.805. RA Max was increased in six of fourteen patients with moderate to severe pulmonary stenosis. The ratio of RA Max/LA Max was increased in the pulmonary stenosis group. These data provide the initial values for right atrial volume quantitation in man. RA Max can be estimated accurately from biplane cineangiograms and can aid in evaluation of alterations in right heart structure and function.
The Rate of Change of Left Ventricular Volume in Man
Authors: HAMMERMEISTER K. E. , BROOKS R. C. , WARBASSE J. R.
Published: June 2012

The rate of left ventricular volume change (dV/dt) is by definition left ventricular ejection rate during systole and filling rate during diastole, and in the absence of valvular regurgitation or intracardiac shunts, is equal to systolic aortic valve flow and diastolic mitral valve flow respectively. A computerized technique for the calculation of instantaneous left ventricular dV/dt from cineangiographically measured left ventricular volume is presented. Curve smoothing was accomplished by passing a second degree polynomial through nine consecutive volume points using the least squares technique. Validity of this technique was demonstrated by the high degree of correlation of systolic dV/dt with instantaneous ascending aortic blood velocity (flow) measured simultaneously with an electromagnetic catheter-tip velocity transducer in ten patients.

Peak left ventricular systolic ejection rate (S dV/dt) was calculated from single plane cineangiographically measured left ventricular volumes in 113 adult patients and related to other measures of cardiovascular function. Mean S dV/dt for the group of 29 normal patients was 427 ± 129 cc per second and was not significantly different in patients with coronary artery disease (21), aortic stenosis (13), mitral stenosis (11), or cardiomyopathy (9), but was increased significantly in patients with valvular regurgitation (19). S dV/dt correlates poorly with the ejection fraction and with left ventricular end-diastolic pressure (LVEDP) and is not a reliable measure of left ventricular function. The primary determinant of S dV/dt appears to be total left ventricular stroke volume. When S dV/dt is divided by end-diastolic volume (EDV), the resultant S dV/dt/EDV correlates well with peak normalized circumferential fiber shortening rate (
r
= 0.89,
P
< 0.01) and with ejection fraction (
r
= 0.69,
P
< 0.01). The correlation coefficient of S dV/dt/DV with LVEDP was
r
= 0.36 (
P
< 0.01) and with arterio-venous oxygen difference,
r
= 0.38 (
P
< 0.01). Thus, S dV/dt/EDV appears to be a measure of ventricular function. S dV/dt occurs in midsystole in normal subjects and in patients with mitral regurgitation and is not delayed in patients with aortic stenosis. The three patients with idiopathic hypertrophic subaortic stenosis appeared to have characteristic changes in the left ventricular ejection rate curve with an increase in S dV/dt (and especially S dV/dt/EDV), with S dV/dt occurring earlier in systole than normal.
An Analysis of Segmental Ischemic Dysfunction Utilizing the Pressure-Length Loop
Authors: TYBERG JOHN V. , FORRESTER JAMES S. , WYATT H. L. , GOLDNER STEVEN J. , PARMLEY WILLIAM W. , SWAN H. J. C.
Published: June 2012

Left ventricular (LV) pressure and myocardial segment length, determined by an epicardial mercury-in-silastic length gauge, were plotted simultaneously to obtain a pressure-length loop before and after left anterior descending artery (LAD) occlusion in 11 dogs. Previous studies have indicated that the area within this loop is a sensitive and reproducible means of quantitating regional myocardial performance. Immediately following ligation, systolic performance deteriorated as indicated by progressive reduction in the pressure-length loop area. Within approximately 30 sec a zero area for the pressure-length loop was observed, indicating no effective work was being performed by the ischemic segment. During the ensuing 3-5 min the pressure-length loop moved into a clockwise orientation which indicated work was being done
on
rather than
by
the segment. The magnitude was approximately 50% of that amount previously generated by the segment. In addition, during this latter period of repetitive passive stretch, the end-diastolic pressure-length relationship shifted to the right indicating increased diastolic compliance. Restoration of perfusion after 30 min produced variable results. Substantial return of function was observed in two animals, but recovery in the majority of animals was limited to the elimination of paradoxical expansion without restoration of active contraction. Therefore, the pressure-length loop method allows quantitation of regional myocardial performance, and indicates that a predictable pattern of significant changes in both systole and diastole accompanies acute myocardial ischemia.
Conduction Disorders in the Canine Proximal His-Purkinje System Following Acute Myocardial Ischemia
Authors: EL-SHERIF NABIL , SCHERLAG BENJAMIN J. , LAZZARA RALPH
Published: June 2012

An intra-His bundle lesion developed in 26 out of 38 dogs (68%) that survived the initial period of arrhythmias that followed ligation of the anterior septal artery. The lesion was isolated in the His bundle in ten experiments and was associated with bundle branch block in 16. The evolution of intra-His bundle block (IHBB) was evaluated utilizing standard ECG leads, catheter electrode, and plunge wire recordings from the His bundle and bundle branches. In all experiments the His bundle potential recorded by the catheter electrode was split into at least two distinct deflections (H
1
and H
2
). This was always associated with a progressive increase of the H
1
-V interval and represented "first degree IHBB." A "second degree IHBB," characterized by intermittent block of the atrial impulse between the two His deflections, consistently developed either spontaneously or in response to atrial pacing. The first "stage" of second degree IHBB had a Mobitz type II pattern with a constant P-R, H
1
-V, and H
1
-H
2
intervals of the beats preceding and following the block. In 20 of 26 observations, this stage merged into the second stage of second degree IHBB characterized by a progressive increment of the H
1
-H
2
intervals prior to failure of a ventricular response. The increment of conduction time, which was at first in the range of a few msec, would not be recognized in standard ECG recordings. This increment could increase up to 180 msec, giving rise to an obvious Wenckebach periodicity that would be recognized at the usual 25 mm/sec paper speed. Complete (third degree) IHBB was observed either in the form of paroxysmal or persistent block. Paroxysmal block occurred spontaneously or could be induced by a critical rate of rapid atrial pacing during early stages of second degree IHBB. Complete IHBB that developed later was persistent and usually associated with a slow idioventricular rhythm. The study suggests that Mobitz type II and the Wenckebach patterns of conduction disturbance in the His bundle are different stages of the same electrophysiological disturbance, with Mobitz type II block representing the initial stages of failure of impulse propagation.
Conduction Disorders in the Canine Proximal His-Purkinje System Following Acute Myocardial Ischemia
Authors: EL-SHERIF NABIL , SCHERLAG BENJAMIN J. , LAZZARA RALPH
Published: June 2012

The evolution of bilateral bundle branch block (BBB) was studied in ten anesthetized dogs by recording electrical activity from the bundle of His (Hb), right (Rb) and left bundles (Lb) for precise localization and characterization of the conduction disorder. Records were obtained before and at intervals up to 8 hours after ligation of the anterior septal artery. Forty to 140 min after ligation conduction was impaired in either the Rb or Lb showing complete BBB both at rapid heart rates (tachycardia-dependent) and slow rates (bradycardia-dependent) with normal QRS or incomplete BBB at control rates. Later complete BBB became constant at all heart rates. When both bundles were significantly involved, various combinations of intraventricular and atrioventricular conduction disorders occurred. Unequal delay in both bundles (unequal 1° bilateral BBB) gave rise to prolonged H-V interval and a QRS pattern of incomplete or complete bundle branch block corresponding to the branch in which the conduction delay was greater. Equal delay in both bundles gave rise to a narrow QRS with prolonged H-V interval. Second degree block in one bundle and complete (3°) block in the other manifested as 2:1, Mobitz type II, or Wenckebach A-V conduction disturbance. Unequal and asynchronous 2° bilateral BBB gave rise to complex patterns of alternating BBB associated with alteration in the H-V interval of 25-35 msec. In two experiments showing alternating BBB, longitudinal dissociation and asynchronous conduction in the distal Hb was suggested.
Patterns of Ventricular Activity During Catheter Defibrillation
Authors: MOWER MORTON M. , MIROWSKI M. , SPEAR JOSEPH F. , MOORE E. NEIL
Published: June 2012

In order to clarify the mechanism of ventricular catheter defibrillation in which the electrode distribution and the low energy requirements make a simultaneous depolarization of the entire myocardium unlikely, the electrocardiograms recorded during 120 catheter fibrillation-defibrillation episodes in 39 dogs were analyzed. Three distinct, equally distributed defibrillation patterns were observed: 1) immediate resumption of a coordinated rhythm, thought to reflect complete depolarization of the myocardium; 2) increasing coarsening of the fibrillation waveforms interpreted as progressive reduction in the number of fibrillating fibers with reversion when a critical mass of myocardium with synchronized activity is reached, and 3) production of more coordinated "flutter-like" ventricular complexes probably representing a rhythm distinct from fibrillation and convertible to sinus rhythm by a second subthreshold shock. These observations suggest that total depolarization of the entire myocardium is not a prerequisite for ventricular defibrillation.
Effects of Perhexiline on Coronary Hemodynamic and Myocardial Metabolic Responses to Tachycardia
Authors: PEPINE CARL J. , SCHANG STEVEN J. , BEMILLER CARL R.
Published: June 2012

Coronary hemodynamic and myocardial metabolic responses before and after perhexiline administration were studied in 21 patients with coronary heart disease during pacing-induced angina pectoris. Perhexiline increased the threshold to tachycardia-induced angina pectoris in 16 of the 21 patients (HR 123 ± 3 to 134 ± 3 beats/min,
P
< 0.01). Anaerobic myocardial lactate extraction was reduced by –6.1 ± 6.3 to 10.7 ± 4% after perhexiline, although lactate extraction declined in four patients and ST segment depression was not significantly changed. Myocardial oxygen extraction was enhanced, 64 ± 2 to 69 ± 2% (
P
< 0.05). Coronary flow as reflected by coronary sinus blood flow was not altered (165 ± 24 to 173 ± 26 cc/min) as left ventricular oxygen utilization was increased (18.9 ± 4 to 20.9 ± 4 ml/min,
P
< 0.05). These findings are interpreted to indicate decreased myocardial ischemia in certain patients on perhexiline.
Augmentation of Left Ventricular Contraction Pattern in Coronary Artery Disease by an Inotropic Catecholamine
Authors: HORN HOWARD R. , TEICHHOLZ LOUIS E. , COHN PETER F. , HERMAN MICHAEL V. , GORLIN RICHARD
Published: June 2012

In order to assess potential improvement in abnormal left ventricular (LV) wall motion, eighteen subjects — sixteen with obstructive coronary artery disease and LV asynergy and two with no evidence of organic heart disease — were studied by cardiac catheterization and cineangiography. Ventriculograms were performed at rest and during a constant infusion of l-epinephrine (EPI) at 1-4 µg/min after an average of nine minutes steady state. EPI infusion induced augmentation of LV contraction pattern in both normal subjects and in all normal zones in the sixteen subjects with asynergy, and in no instance was contraction in a normal zone rendered abnormal. Eleven of sixteen patients showed improved contraction in previously asynergic areas, two of whom also demonstrated paradoxical motion in an abnormal zone. Of a total of forty-four resting asynergic zones, twenty-three exhibited an improved contraction pattern with EPI, one showed depressed contraction, two demonstrated both an increase and deterioration in the same zone (paradoxical motion), and eighteen showed no change. Quantitative motion analysis generally corroborated these qualitative ventriculographic observations. Heart rate, LV systolic pressure and LV end-diastolic pressure increased slightly with EPI, but were not significantly changed from control values. While there was wide variation in end-diastolic volume in the subjects with asynergy, EPI resulted in an increase in both stroke volume and ejection fraction, the latter significantly (
P
< 0.05). In the four subjects who subsequently underwent aneurysmectomy, preoperative lack of improvement with EPI correlated with a pathologic diagnosis of fibrosis. Other than angina pectoris of brief duration in two subjects, EPI provoked no untoward reactions, arrhythmias or complications. It is concluded that LV motion abnormalities can be improved or changed in certain cases by the inotropic stimulus of EPI, suggesting residual contractile ability; the agent may differentiate between zones of potentially functional cardiac muscle and frank fibrosis.
Comparison of Isovolumic and Ejection Phase Indices of Myocardial Performance in Man
Authors: PETERSON KIRK L. , SKLOVEN DAVID , LUDBROOK PHILIP , UTHER JOHN B. , ROSS JOHN
Published: June 2012

Indices derived from both the isovolumic and ejection phases of left ventricular systole have been advocated as a means of defining the basal level of contractility, but their comparative reliability for separating patients with obvious myocardial disease from a normal population has not been documented. Accordingly, indices of myocardial function were measured and compared in 36 patients, 22 with normal and 14 with abnormal ventricular function, using optimal techniques of pressure measurements by cathetertip micromanometry, signal digitizing at 1 msec intervals with averaging of multiple beats, and left ventriculography by biplane cineangiography. Isovolumic indices derived from developed pressure (DP), including V max, dP/dt/DP at DP = 5, 10, and 40 mm Hg, demonstrated no sensitivity for identifying depressed myocardial function (
P
> 0.1 in each instance). Using total pressure (TP), V max, peak (dP/dt/TP), and peak dP/dt served to separate the two patient populations from a statistical standpoint (
P
< 0.001), but individual values in the two groups showed considerable overlap. By contrast, the simplified ejection phase velocity indices, mean velocity of circumferential fiber shortening (mean Vcf) and mean normalized systolic ejection rate (MNSER) showed superior sensitivity for identifying normal and abnormal patient groups and manifested minimal overlap of individual values (
P
< 0.001). These observations indicate that, in patients with diffuse myocardial involvement, isovolumic indices are not reliable for detecting depressed myocardial function and that ejection phase contractile indices appear to offer a preferable mode for assessing myocardial function in the basal state.
Vital Capacity and Congestive Heart Failure
Authors: KANNEL W. B. , SEIDMAN J. M. , FERCHO W. , CASTELLI W. P.
Published: June 2012

This report is concerned with an assessment of the utility of the vital capacity in
anticipating
the occurrence of congestive heart failure in susceptible persons before overt symptoms and signs. To this end, an examination of the relation of routinely measured biennial vital capacities to subsequent incidence of clinically overt myocardial decompensation over the next two years was undertaken. In 5209 persons so evaluated over an 18 year period it was found that risk of congestive heart failure varied over a 10-fold range in inverse proportion to their vital capacity (standardized for height) in persons still free of clinical evidence of myocardial decompensation. Also, among persons at high risk of failure (due to coronary disease, hypertension or rheumatic heart disease) chances of developing congestive failure were doubled in men with low vital capacities and tripled in women.

Examination of the net contribution of vital capacity to risk of congestive failure revealed that a low vital capacity was associated with development of congestive failure even after taking into account other contributing factors including blood pressure, relative weight, pulse rate, cigarette smoking, heart enlargement on X-ray, ECG-LVH, blood glucose and age. Both a persistently low and a recent fall in vital capacity were associated with increased risk of congestive failure. Obstructive lung disease was not a factor in either case since FEV
1
/total vital capacity (TVC) was unrelated to congestive heart failure incidence. The simple total vital capacity thus appears to have considerable utility as a practical, noninvasive office procedure for evaluating failing left ventricular performance.
The Significance of Coronary Calcification Detected by Fluoroscopy
Authors: BARTEL ALAN G. , CHEN JAMES T. , PETER ROBERT H. , BEHAR VICTOR S. , KONG YIHONG , LESTER RICHARD G.
Published: June 2012

Cardiac fluoroscopy to detect coronary calcification was performed on 360 patients before undergoing coronary arteriography for proven or suspected coronary artery disease. Among the 154 patients in whom coronary calcification was identified, 97% had significant coronary disease angiographically (≧ 70% stenosis). In this group, the distribution of one, two, and three vessel coronary disease was 9%, 25%, and 66% respectively. The prevalence of coronary calcification increased with age and severity of coronary disease, but no difference in males versus females was demonstrable. The angiographic severity of coronary disease increased with multiple vessel calcification; three vessel disease occurred in 45%, 66%, and 82% of patients with one, two, and three vessel calcification, respectively. Patients with hyperlipidemia or hypertension had no significant difference in the prevalence of coronary calcification. Among the 267 patients with significant coronary lesions, 56% had calcification detected by fluoroscopy.

Five of the 93 patients with no significant coronary disease angiographically had coronary calcification fluoroscopically. Four of the five had a prior history of myocardial infarction, and two showed asynergy on left ventriculography.

This study demonstrates that cardiac fluoroscopy is a valuable procedure for detecting significant coronary artery disease since this highly specific test is easily performed, inexpensive, noninvasive, and widely applicable for screening large patient populations.
The Flicker Fusion Frequency and Its Response to Nitroglycerin in Normal Subjects and in Patients with Cardiovascular Disease
Authors: KEYS ANCEL , SIMONSON ERNST
Published: June 2012

Krasno and Ivy have claimed that the change after sublingual nitroglycerin in the frequency at which a flickering light appears to fuse (f.f.f.) sharply differentiates between cardiovascular normals and patients with coronary and/or hypertensive disease and that this test may be useful in detecting and evaluating such disease. On the basis of a detailed analysis of the original publication and of data on 304 men these claims are denied. Indications for further study of flicker phenomena are discussed and fiducial norms are presented.
A Technic of Vascular Catheterization with Small Plastic Catheters
Authors: SCHNABEL TRUMAN G. , FITZPATRICK HUGH F. , PETERSON LYSLE H. , RASHKIND WILLIAM J. , TALLEY DANIEL , RAPHAEL ROBERT L.
Published: June 2012

A method of vascular catheterization is presented in which small polyvinyl catheters are introduced into peripheral vessels through 18 to 21 gage needles and then advanced into the central vascular bed. This technic has been utilized in the study of hemodynamic events occurring in the central arterial vessels in man. The results obtained from 31 arterial catheterizations done in 21 subjects are reported. Utilizing this technic, it has been impossible to catheterize the pulmonary artery in man. However, the method has proved useful in the study of right atrial and central venous pressure changes.
The Pulmonary Vascular Responses to Short-Term Hypoxia in Human Subjects
Authors: DOYLE JOSEPH T. , WILSON JOSEPH S. , WARREN JAMES V.
Published: June 2012

Using the catheter technic, the acute circulatory reactions to a brief period of hypoxia have been studied. It was found that when a normal person breathed a gas mixture containing only 10 per cent oxygen, the pulmonary arterial pressure rose but the pulmonary capillary pressure remained unchanged. This indicated pulmonary vasoconstriction, thought to be due to a direct effect on the pulmonary vascular tree. No demonstrable change in so-called pulmonary blood volume could be detected. In an additional group of patients with cardiopulmonary disease the reactions were more erratic but not significantly different in type.
The Effects of Work on the Pulmonary Circulation in Mitral Stenosis
Authors: ELIASCH HARALD , WADE GEOFFREY , WERKÖ LARS
Published: June 2012

In an attempt to understand more fully the hemodynamic effects in mitral stenosis, the vascular response to effort was studied in 12 cases. It was found that pulmonary arterial pressures rose, but did not necessarily parallel changes in the pulmonary "capillary venous" pressure (pcv), suggesting that the response pattern may be modified by secondary pulmonary vascular change. Further, in some studies, pulmonary "capillary venous" pressures were found to rise initially and then fall despite continuing work, emphasizing the necessity to choose work of such a degree and duration that a steady state may be obtained.
Dihydrogenated Ergot Alkaloids in the Treatment of Essential Hypertension
Authors: DUPUY HOMER J. , SIGNORELLI JOHN , ATTYAH ALBERT M.
Published: June 2012

The effect of the oral and intravenous administration of the dihydrogenated ergot alkaloids on 25 cases of essential hypertension in the age group of 25 to 56 is reported with reference to (1) incidence of hypotensive effect, (2) degree of hypotensive effect, (3) duration of the hypotensive effect.