bluuebunny/crossref_metadata_2025 huggingface dataset:
The cellular electrophysiologic effects of digitalis on human atrial fibers.
Authors: Hordof A J , Spotnitz A , Mary-Rabine L , Edie R N , Rosen M R
Published: June 2012

We used microelectrode techniques to study the indirect and direct actions of ouabain on human atrial fibers (HAF) obtained from patients with congenital heart disease undergoing open heart surgery. At 15 min of superfusion ouabain, 2 X 10(-7) M, induced an increase in maximum diastolic potential (MDP), action potential (AP) amplitude and upstroke velocity of phase 0 depolarization (Vmax) and a decrease in AP duration. Spontaneously beating HAF showed a decrease in automaticity. Acetylcholine (3 X 10(-6) M) induced identical effects on AP characteristics and automaticity. Prior treatment with atropine (1 X 10 (-6) M) blocked these effects of ouabain and acetylcholine. Superfusion with ouabain (2 X 10 (-7) M) for 30 to 90 min resulted in decreased MDP, AP amplitude and Vmax, and a further decrease in AP duration. Phase 4 depolarization and spontaneous rate increased and delayed afterdepolarization and tachyarrythmia occurred. The ACh-like effects of digitalis decrease automaticity and increase MDP of HAF; the direct effects decrease MDP, increase automaticity, and induce tachyarrythmias.
Electrophysiologic and hemodynamic effects of verapamin. Correlation with plasma drug concentrations.
Authors: Mangiardi L M , Hariman R J , McAllister R G , Bhargava V , Surawicz B , Shabetai R
Published: June 2012

Verapamil was administered intravenously to 30 open-chest dogs and the electrophysiologic and hemodynamic effects of the drug were correlated with the corresponding plasma concentrations. At concentrations below 152 ng/ml, verapamil prolonged the A-H interval, abolished ventriculoatrial conduction, but did not significantly change sinus rate, cardiac output, left ventricular dp/dt, of systemic vascular resistance. Concentrations above 200 ng/ml were associated with slowing of the sinus rat, high degree atrioventricular block during atrial pacing, 24% decrease in mean aortic pressure, and decreased cardiac output and left ventricular dp/dt. Sinus arrest, high degree atrioventicular block during sinus rhythm, decreased systemic vascular resistance and increased left ventricular end-diastolic pressure occurred when plasma verapamil concentrations exceeded 400 ng/ml. These results show that plasma verapamil concentrations reliably reflect the electrophysiologic and hemodynamic actions of the drug, and that "therapeutic" drug effects can be achieved at plasma concentrations at which myocardial depressant effects are unlikely.
The rate-pressure product as an index of myocardial oxygen consumption during exercise in patients with angina pectoris.
Authors: Gobel F L , Norstrom L A , Nelson R R , Jorgensen C R , Wang Y
Published: June 2012

In order to evaluate hemodynamic predictors of myocardial oxygen consumption (MVO2), 27 normotensive men with angina pectoris were studied at rest and during a steady state at sympton-tolerated maximal exercise (STME). Myocardial blood flow (MBF) was measured by the nitrous oxide method using gas chromatography. MBF increased by 71% from a resting value of 57.4 +/- 10.2 to 98.3 +/- 15.6 ml/100 g LV/min (P less than 0.001) during STME while MVO2 increased by 81% from a resting value of 6.7 +/- 1.3 to 12.1 +/- 2.8 ml O2/100 g LV/min (P less than 0.001). MVO2 correlated well with heart rate (HR) (r = 0.79), with HR x blood pressure (BP) (r = 0.83), and, adding end-diastolic pressure and peak LV dp/dt as independent variables, slightly improved this correlation (r = .86). Including the ejection period (tension-time index) did not improve the correlation (r = 0.80). Thus, HR and HR x BP, both easily measured hemodynamic variables, are good predictors of MVO2 during exercise in normotensive patients with ischemic heart disease. Including variables reflecting the contractile state of the heart and ventricular volume may further improve the predictability.
Exploration of the cause of the low intensity aortic component of the second sound in nonhypotensive patients with poor ventricular performance.
Authors: Stein P D , Sabbah H N , Khaja F , Anbe D T
Published: June 2012

This investigation was undertaken to explore the cause of the diminished second sound (S2) that may occur in normotensive patients with poorly performing ventricles. Intra-aortic sound and pressure were measured in 16 patients with angina; eight had normal ventricular performance (ejection fraction greater than or equal to 60%) and eight had poor performance (ejection fraction less than 50%). The amplitude of S2 was lower in patients with poor ventricular performance as was negative d/dt. Aortic pressure was conparable in both groups. The ampitude of S2 was linearly related to the rate of change of the pressure gradient that developed across the aortic valve during diastole (r = 0.82). The latter also correlated with negative dp/dt (r = 0.82). These observations indicate that in patients with poor ventricular performance, isovolumic relaxation may be compromised. This would cause a reduction of the rate of development of the diastolic pressure gradient, which would result in a diminished S2.
Dissecting aortic aneurysm associated with congenital bicuspid aortic valve.
Authors: Edwards W D , Leaf D S , Edwards J E
Published: June 2012

Among 119 cases of fatal dissecting aneurysm of the aorta, exclusive of those iatrogenically caused or associated with arachnodactyly or aortic stenosis, there were observed 11 cases of congenital bicuspid aortic valve (9%). The ages ranged from 17 to 69 years, five of the patients being 29 years old or younger. Among the latter, three had coarctation of the aorta and one had Turner's syndrome without coarctation. In one of the older patients, aortic insufficiency was present. Hypertension was either established or inferred from cardiac weight in 73% of the cases. In each case, cystic medial necrosis of the aorta was present. Prolapse of valves other than the aortic was observed in 45% of the cases with bicuspid aortic valve. Compared to an estimated incidence of bicuspid aortic valve of about 1 to 2% in the population, the high incidence among subjects with dissecting aneurysm suggests a causative relationship between bicuspid aortic valve and aortic dissecting aneurysm.
Unexplained in-hospital fever following cardiac surgery. Natural history, relationship to postpericardiotomy syndrome, and a prospective study of therapy with indomethacin versus placebo.
Authors: Livelli F D , Johnson R A , McEnany M T , Sherman E , Newell J , Block P C , DeSanctis R W
Published: June 2012

In Part I of this study, the in-hospital course of 219 patients who had undergone a cardiac operation is analyzed. Fever (greater than or equal to 37.8 degrees C, rectal) was present after postoperative day 6 in 159 patients (73%) and was of unexplained cause in 118. Fever decay in the population of unexplained fever patients was exponential. All patients with unexplained postoperative fever were afebrile by postoperative day 19. In-hospital pericardial rub and pleuritic chest pain, widening of the mediastinum on chest film, and pleural effusion were not specifically associated with unexplained postoperative fever. In Part II, 67 patients with unexplained postoperative fever were given indomethacin (100 mg per day) or placebo for 7 days by a randomized, double-blind protocol. Indomethacin resulted in a shorter duration of fever (2.4 vs 3.5 days, P is less than 0.01) and in a shorter duration of chest pain, malaise, and myalgias compared to placebo. Sixty-seven percent of the patients in Part I and all of the patients in Part II were contacted 2-8 months following hospital discharge. Five percent had experienced an illness that we considered to be acute pericarditis, but its occurrence was unrelated to whether the patient had had in-hospital unexplained postoperative fever, in-hospital rub or chest pain, or in-hospital administration of indomethacin.
Echocardiographic differentiation of partial and complete atrioventricular canal.
Authors: Bass J L , Bessinger F B , Lawrence C
Published: June 2012

Retrospective examination of echocardiograms was performed in 34 patients with persistent atrioventricular (A-V) canal who had undergone cardiac catheterization. Characteristic findings in 16 patients with partial A-V canal were lack of continuity of mitral and tricuspid valves, paradoxical interventricular septal motion, definite E and A waves of the mitral valve anterior leaflet (MVAL) echoes and late systolic anterior motion of the mitral valve. Eighteen patients with persistent A-V canal had an interventricular communication and were classified as having the complete form. They characteristically had continuous mitral and tricuspid valves, normal interventricular septal motion, disorganized MVAL echoes, and normal systolic mitral valve motion. Combining these findings allowed differentiation of 31 of the 34 patients (91%) as having partial or complete A-V canal. Determining the presence of a VSD from loss of interventricular septal echoes was unsatisfactory. The severity of mitral insufficiency could not be estimated from echocardiograms of our patients with partial A-V canal.
Hemodynamic effects of intravenous phentolamine in low output cardiac failu;e. Dose-response relationships.
Authors: Stern M A , Gohlke H K , Loeb H S , Croke R P , Gunnar R M
Published: June 2012

Nineteen patients with chronic low output cardiac failure were studied before, during and after infusion of phentolamine in doses of 10, 20, 30 and 40 microgram/kg/min. Significant reduction of left- and right-sided pressures and increases in cardiac index and heart rate (HR) were present within 15 minutes of starting phentolamine at the 10 microgram/kg/min dose. Minimal additional effect was observed at 30 minutes. Increased dose from 10 to 20 mu/kg/min resulted in small but significant (P less than 0.05) additional reduction in pressures and increases in HR. No additional significant changes occurred at doses of 30 or 40 microgram/kg/min. Significant hemodynamic changes persisted for at least an hour (53 +/- 3 min) after the phentolamine infusion was discontinued. Near maximal ;emodynamic effects occur within 15 minutes of starting phentolamine infusion and can be achieved at doses of 10 to 20 microgram/kg/min. Increased HR during phentolamine infusion may limit its usefulness in patients with ischemic heart disease.
The development of pulmonary vascular obstructive disease after successful Mustard operation in early infancy.
Authors: Berman W , Whitman V , Pierce W S , Waldhausen J A
Published: June 2012

Pulmonary vascular obstructive disease developed postoperatively in an infant with aortopulmonary transposition and intact ventricular septum who underwent a Mustard operation in 3 months of age. Preoperative catheterization had shown normal pulmonary artery pressures. Four months after surgery, catheterization showed pulmonary artery systolic pressure above the systemic level and a tortuous, attenuated pulmonary vascular tree visualized angiographically. Early corrective surgery may not preclude the development of pulmonary vascular obstructive disease in patients with aortopulmonary transposition.
A chronically implanted system for automatic defibrillation in active conscious dogs. Experimental model for treatment of sudden death from ventricular fibrillation.
Authors: Mirowski M , Mower M M , Langer A , Heilman M S , Schreibman J
Published: June 2012

Ventricular defibrillation was acheived in active conscious dogs with a chronically implanted automatic system composed of a defibrillator and an alternating current fibrillator. The hermetically sealed defibrillator is encased in titanium, weighs 250 g and has a volume of 145 ml. The sensor continuously monitors ventricular electircal activity and recognizes fibrillation by the absence of isoelectric potential segments. Fibrillation is induced by placing a magnet over the implanted fibrillator. The resulting syncope closely resembles the clinical entity of sudden death, while the defibrillator automatically restores normal rhythm with a truncated exponential pulse of 30 J, 15 seconds after the onset of the arrhythmia. The operational status of the defibrillator can be tested in vitro and noninvasively in vivo with an external analyzer. This experimental model allows for the first time a long-term study of the automatic implantable defibrillator approach to prevent sudden death from ventricular fibrillation under a variety of physiopathologic conditions.
Severe aortic stenosis with impaired left ventricular function and clinical heart failure: results of valve replacement.
Authors: Smith N , McAnulty J H , Rahimtoola S H
Published: June 2012

Nineteen patients, aged 58-80 years, with severe isolated aortic valve stenosis, severely reduced ejection fraction and clinical heart failure underwent aortic valve replacement between January 1970 and April 1977. Ten had concomitant coronary artery disease (all underwent additional coronary bypass surgery), 17 had angina pectoris and four had syncope. Aortic valve area index was 0.32 +/- 0.03 cm2/m2 (mean +/- SEM); left ventricular (LV) end-diastolic volume index was 117 +/- 9 ml/m2 and LV ejection fraction was 0.37 +/- 0.02. There were four operative deaths and one late death. The follow-up time ranged from six to 74 months (38 +/- 6 months). Actuarially determined three-year survival is 74 +/- 10%; the expected five-year survival is the same. One patient had a serious cerebrovascular accident. Of the remaining survivors, seven were initially Functional Class IV and six Class III; currently, six are Class I and seven Class II (New York Heart Association classifications). The cardiothoracic ratio has decreased from 0.54 +/- 0.03 to 0.49 +/- 0.03. Repeat hemodynamic evaluation has been performed in 10 patients, 22 +/- 6 months after surgery. In these 10 patients, the aortic valve gradient decreased from 55 +/- 7 11 +/- 1.3 mm Hg; LV end-diastolic pressure from 22 +/- 2.4 to 9 +/- 1.9 mm Hg; LV end-diastolic volume index from 119 +/- 16 ml/m2 to 107 +/- 11 ml/m2. LV ejection fraction has increased dramatically from 0.34 +/- 0.03 to 0.63 +/- 0.05 and mean velocity of circumferential fiber shortening from 0.57 +/- 0.08 to 1.3 +/- 0.18 circ/sec. The encouraging long-term survival, improved functional class and the marked improvement in left ventricular function that occurred in our patients indicate that all patients with severe aortic stenosis in clinical heart failure should be offered aortic valve replacement.
The effect of digitalis on refractoriness of the intact canine His-Purkinje system.
Authors: Gomes J A , Damato A N , Bobb G A , Lau S H
Published: June 2012

The effect of therapeutic doses of digitalis on functional (F), relative (R) and effective (E) refractory periods (RP) of the His-Purkinje system (HPS) was studied in 12 open-chested, innervated adult mongrel dogs (10-20 kg) during control and 15, 30 and 45-60 min after 0.016 mg/kg of intravenous ouabain. To determine the stability of the preparation and to assess time-dependent changes in His-Purkinje refractoriness, another six dogs (Group II) had similar studies, but without drug administration. In all dogs, the His bundle was paced by using the plunge wire technique at a predetermined cycle length (CL) and a premature stimulus (S2) to the His bundle was introduced at decreasing S1 S2 intervals. Following ouabain, in Group I dogs, at the longest Cls tested (458 +/- 125 msec; +/- SD) there was significant increase in the FRP (+4.34%; P less than 0.05), RRP (S2 V2 (+6.57%, P less than 0.05), RRP (Ab) (+6%, P less than 0.05) and ERP (52%, P less than 0.05) of the HPS. These significant changes were generally observed 30 minutes after drug administration. Changes in RPs were of greater magnitude at longer CLs (greater than 400 msec), but insignificant at shorter CLs (less than 400 msec). The H-V interval during sinus rhythm and the S1 V1 interval during His bundle pacing at all CLs did not change after ouabain. In Group II dogs there were no significant change in His-Purkinje refractoriness over 60 minutes. These findings suggest that therapeutic doses of digitalis 1) tend to increase refractoriness within the HPS to a very small degree, 2) have no appreciable effect on His-Purkinje conduction, and 3) affect CL-dependent changes in refractoriness. The His bundle extrastimulus method is useful in studying the HPS in the intact heart.
Treatment of infective endocarditis: a 10-year comparative analysis.
Authors: Richardson J V , Karp R B , Kirklin J W , Dismukes W E
Published: June 2012

The results of surgical and non-surgical treatment of active infective endocarditis in 182 patients over a 10-year period were analyzed. Heart failure, annular and myocardial abscesses, heart block, and coronary embolism, seen most frequently with staphylococcal and fungal endocarditis, were the primary causes of death in both native valve endocarditis (NVE) and prosthetic valve endocarditis (PVE). In NVE, surgery significantly improved the survival in patients with moderate or severe heart failure (P less than 0.05) and in all patients with staphylococcal endocarditis (P less than 0.03). In PVE, surgery significantly influenced survival in patients with moderate or severe heart failure (P less than 0.05) and in the entire group with late PVE (P less than 0.01). Early surgery is recommended for patients with native valve endocarditis and moderate or severe heart failure; those patients with staphylococcal NVE, regardless of hemodynamic state, should undergo early valve replacement. Early surgery is recommended for PVE patients with moderate or severe heart failure. We also recommend early valve replacement for early and late staphylococcal PVE.
Aortic infarction following dissecting aortic aneurysm.
Authors: Barsky S H , Rosen S
Published: June 2012

Aortic infarction was observed in 21 of 34 cases of dissecting aortic aneurysm. This lesion occurred as a central zone of necrosis with preserved elastic laminae, sparing media adjacent to the true and false lumens. In cases where the false lumen was occluded, the central infarction extended to this lumen. The infarction followed rather than preceded dissection, took approximately 48 hours to develop, and did not organize with time. The lesion occurred exclusively in the thoracic aorta, and bore no relationship to medial cystic necrosis. Present surgical therapy does not extirpate these areas, and the implication of these lesions in terms of management remains to be determined.
Similarities of ergonovine-induced and spontaneous attacks of variant angina.
Authors: Curry R C , Pepine C J , Sabom M B , Conti C R
Published: June 2012

Ergonovine has been shown to provoke attacks of variant angina, but a question remains whether spontaneous and ergonovine-induced attacks of variant angina are similar. Seven patients with variant angina undergoing cardiac catheterization were studied during transient episodes of spontaneous and ergonovine-induced rest angina with ST-segment elevation. Clinical, electrocardiographic, left ventricular hemodynamic and coronary angiographic observations were made before and repeated after ergonovine (0.05-0.2 mg I.V.). The character and duration of chest pain were similar during both spontaneous and ergonovine-induced episodes. ST-segment elevation (greater than 1 mm) was present inferiorly in three patients, anteriorly in three patients, and both inferiorly and anteriorly in one patient during both episodes. Mean heart rate and systolic arterial pressure changed little, while left ventricular end-diastolic pressure increased significantly during spontaneous or ergonovine-induced attacks. We observed subtotal or total dynamic obstruction in the left anterior descending (three patients), right coronary arteries (three patients) and both arteries in one patient during both attacks. Thus, in selected patients ergonovine-induced attacks of variant angina were remarkably similar to spontaneous episodes.
Effect of prazosin vs placebo on chronic left ventricular heart failure.
Authors: Aronow W S , Lurie M , Turbow M , Whittaker K , Van Camp S , Hughes D
Published: June 2012

The effect of the vasodilator prazosin vs placebo on exercise duration until marked dyspnea, and on left ventricular function measured by echocardiography, was evaluated in a double-blind, randomized study in 24 patients with chronic left ventricular failure despite digitalis and diuretic therapy. Compared with the double-blind placebo, prazosin reduced resting systolic and diastolic blood pressure and systolic blood pressure times heart rate, improved clinical symptoms, decreased cardiothoracic ratio measured by chest roentgenography, decreased left ventricular and left atrial dimensions, improved ejection fraction and Vcf measured by echocardiography, and improved treadmill exercise duration. All 12 patients taking prazosin had greater than or equal to 20% improved treadmill exercise duration; none of 12 receiving placebo improved. In six of 12 patients taking prazosin, roentgenographic evidence of pulmonary venous congestion disappeared compared with none of the patients on placebo. These data suggest that prazosin may be effective in treating chronic left ventricular failure.
Evidence from a nonrandomized study that coronary surgery prolongs survival in patients with two-vessel coronary disease.
Authors: Hammermeister K E , DeRouen T A , Dodge H T
Published: June 2012

Within the larger Seattle Heart Watch arteriography registry, surgically treated patients non randomly selected for direct myocardial revascularization were matched to medically treated patients such that each of the 287 pairs was identical in seven variables (ejection fraction, ventricular arrhythmia on resting electrocardiogram, age, heart murmur, stenosis of left main coronary artery greater than or equal to 50%, number of vessels with stenosis greater than or equal to 70%, and use of diuretics) previously demonstrated to be independently predictive of survival. Actuarial survival analyses based on cardiovascular deaths (average follow-up 3.5 years) indicate improved survival for the entire surgical matched pair cohort (p = 0.008) and for the surgically treated subgroup with two-vessel disease (p = 0.0002) when compared to the medical cohort. These results were confirmed by examination of the entire arteriography registry (n = 1524) in which these seven variables were known, using Cox's model for survival analysis. This multivariate, statistical technique indicated that the surgical mode of therapy was significantly predictive of improved survival in surgically treated patients for the entire registry (p = 0.008) and for the subgroup with two-vessel disease (p = 0.0005).
Congenital abnormalities of the conduction system in two patients with tachyarrhythmias.
Authors: Bharati S , Bauernfiend R , Scheinman M , Massie B , Cheitlin M , Denes P , Wu D , Lev M , Rosen K M
Published: June 2012

Serial sections of the conduction system (CS) were performed in two patients with recurrent tachyarrhythmias. Case 1, a 34-year-old female who had dual atrioventricular (AV) nodal pathways with recurrent paroxysmal supraventricular tachycardia, committed suicide. Autopsy revealed an abnormally formed atrial septum with insertion of eustachian valve on the AV part of the pars membranacea. The intercuspid portion of the pars membranacea was muscular. The AV node was located adjacent to the membranous part of the ventricular septum rather than the central fibrous body. In addition, there was an accessory anterior AV node on the parietal wall of the right atrium. Case 2, a 13-year-old boy with history of recurrent ventricular tachycardia, died suddenly. CS revealed a right-sided, markedly septated bundle. The first part of right bundle branch was divided into three parts, which later joined together. Both cases showed fatty infiltration of the atrial septum, more than normal for the age of the patients. The relationship of the recurrent tachyarrhythmias to the congenital abnormalities in the CS in the two cases and the fatty infiltration is reviewed.
Treatment of hypertension with nifedipine, a calcium antagonistic agent.
Authors: Olivari M T , Bartorelli C , Polese A , Fiorentini C , Moruzzi P , Guazzi M D
Published: June 2012

Hemodynamic monitoring after a single dose (10 mg) of nifedipine in 27 primary hypertensive subjects (diastolic pressure greater than 110 mm Hg) documented that this calcium antagonistic agent exerts a potent arteriolar vasodilating action, which results in prompt (-21% of control at 30 minutes) and persistent (-16% of control at 120 minutes) fall in mean arterial pressure associated with a rise in cardiac output and pulse rate. The same patients received oral treatment for 3 weeks. Hourly pressure readings showed that 1) the antihypertensive response to each dose lasts 8--12 hours; and 2) nifedipine every 6 hours significantly reduced blood pressure throughout the 24 hours, without postural hypotension. Side effect were short-lasting (headache in five patients, palpitation without arrhythmias in eight patients, burning sensation in the face and legs in five patients and sporadic extrasystoles in five patients) and tended to disappear with continued treatment. Development of drug resistance, sodium retention, plasma volume expansion, renin release or angina pectoris were not observed during the study. Although these findings seem to differentiate nifedipine from other vasodilators currently used in the treatment of hypertension, broader experience and more prolonged trials with nifedipine as an antihypertensive agent will be needed before conclusions can be drawn on these particular aspects.
Right atrial myxoma: unusual clinical presentation and atypical glandular histology.
Authors: Frishman W , Factor S , Jordan A , Hellman C , Elkayam U , LeJemtel T , Strom J , Unschuld H , Becker R
Published: June 2012

A 57-year-old black female presented with a 1-month of right-sided congestive heart failure and clinical evidence of pulmonic and tricuspid valvular stenosis and insufficiency. The echocardiographic examination and ventriculography demonstrated a large right atrial tumor interfering with the function of both right-sided valves. The patient underwent successful surgical resection of the tumor. Histologically, the tumor had cellular areas typical of myxoma, as well as glandular areas, a feature which has been described very rarely in this lesion. Electron microscopy of the glandular zones, which has never been reported previously, shown cells having essential homology with the usual myxoma elements. The atypical histopathology of this lesion supports the theory that atrial myxomas are true neoplasms, and are not derived from unusually organized mural thrombi.
Hemodynamic factors influencing arterial hypoxemia in massive pulmonary embolism with circulatory failure.
Authors: Jardin F , Gurdjian F , Desfonds P , Fouilladieu J L , Margairaz A
Published: June 2012

Arterial hypoxemia is a common finding in acute pulmonary embolism, and its severity is generally assumed to be proportional to the extent of pulmonary artery obstruction. We studied blood gases (during room air breathing and 100% oxygen breathing) and hemodynamic data is seven patients with massive pulmonary embolism and circulatory failure. All measurements were made before and 30 minutes after medical therapy of shock. We observed that a low cardiac output state can result in a misleading improvement in arterial oxygenation during massive pulmonary embolism, and that an improved circulatory status resulting from medical therapy (including inotropic drug infusion with or without blood volume expansion) can paradoxically increase arterial hypoxemia. We conclude that severity of arterial hypoxemia may not reflect the severity of pulmonary artery obstruction in acute pulmonary embolism if shock is present.
Effect of Cholesterol Feeding during Pregnancy on Blood Cholesterol Levels and Placental Vascular Lesions
Authors: MOSES CAMPBELL , RHODES GRACE L. , LEATHAM EVELYN , GEORGE ROBERT S.
Published: June 2012

After establishing the normal variations in blood cholesterol levels on a recorded dietary regimen during pregnancy, 2 Gm. of cholesterol in chocolate candy were fed daily without significant alteration in blood cholesterol levels or placental vascular lesions.
Orthostatic Hypotension, Anhidrosis, and Impotence
Authors: ROSECAN MARVIN , GLASER ROBERT J. , GOLDMAN MELVIN L.
Published: June 2012

Anhidrosis and impotence occur frequently with idiopathic orthostatic hypotension. Two new cases of this syndrome, which occurs chiefly in males over 40 years of age, are herewith described. Postural vertigo and/or syncope, weakness, and anhidrosis or hypohidrosis are common symptoms, and a marked fall in systolic and diastolic blood pressure is noted when the patients stand. The pathologic physiology of the syndrome is discussed and various forms of therapy, none of them especially satisfactory, are reviewed.
The Atrial Border Electrokymogram in Mitral Regurgitation
Authors: SOLOFF LOUIS A. , ZATUCHNI JACOB , STAUFFER HERBERT M.
Published: June 2012

Border electrokymograms of the cardiovascular silhouette in various views were obtained at approximately 1.0 cm. intervals in 28 subjects to determine the constancy and the specificity of the atrial border motion and to determine its ability to differentiate organic from functional apical systolic murmurs. Although a "plateau" curve previously reported as pathognomonic of organic mitral regurgitation was obtained in 12 of the 13 individuals with various types of heart disease and with an apical systolic murmur, identical "plateau" curves were obtained in 10 of the 15 individuals with normal hearts and with no apical systolic murmur. Atrial curves previously reported as normal were also obtained in each of the 28 subjects studied. Some of the reasons for these results, which are at variance with those reported by others, are discussed.
The Clinical Significance of Postextrasystolic T-Wave Changes
Authors: LEVINE HAROLD D. , LOWN BERNARD , STREEPER RICHARD B.
Published: June 2012

Examination of the T wave of the beat following the pause occurring in many conditions, notably premature systoles, may show variations from the regular T waves in the same lead without concomitant change in the QRS complex. This phenomenon, when pronounced, is generally associated with evidence of myocardial impairment and is correlated with abnormal reaction to stress tests for coronary insufficiency. Inquiry is here made into the factors affecting this phenomenon, its mechanism topography, persistency and clinical significance.
Respiratory Variations in Blood Pressure
Authors: DORNHORST A. C. , HOWARD P. , LEATHART G. L.
Published: June 2012

A study of respiratory blood pressure variations in normal subjects suggests that variations in both cardiac output and peripheral resistance are involved, the latter mechanism being essentially similar to that producing the Traube waves in apnea. The interactions of the two mechanisms are compared to the known behavior of coupled electronic oscillators.
The Pathogenesis of Malignant Hypertension
Authors: PICKERING G. W.
Published: June 2012

Whether hypertension follows the benign or the malignant course depends chiefly on the severity of the hypertension. Malignant hypertension may develop in hypertension due to any cause, provided it is sufficiently severe. The evidence for this hypothesis is as follows:

1. The characteristic finding in malignant hypertension during life is albuminuric retinitis (hypertensive neuroretinopathy) which differs from the retinitis of benign hypertension (arteriosclerotic retinitis) in the presence of neuroretinal edema. This neuroretinal edema is due to raised intracranial pressure, which in turn seems to be a consequence of the high level of diastolic arterial pressure.

2. The characteristic finding in malignant hypertension after death is acute arteriolar necrosis, the occurrence of which in the kidneys is chiefly responsible for the rapid renal failure which is so often the cause of death. Evidence from animal experiments suggest that the chief factor determining these arteriolar necroses is the high level of arterial pressure.

3. Albuminuric retinitis, rapid renal failure and acute arteriolar necroses may occur in essential hypertension, acute and chronic nephritis, pyelonephritis, polycystickidney, Cushing's syndrome and toxemia of pregnancy; these conditions may terminate therefore in the malignant phase. Alternatively, the hypertension may be stable, and, provided the underlying disease is stationary, the patient's condition may remain unchanged for many years; the hypertension may thus have the characteristics of the benign type.

4. In patients whose hypertension changes from the benign to the malignant phase, it is usual to find that the arterial pressure is higher in the malignant than in the benign phase.

5. It has been proved tha thypertension can be reversed from the malignant to the benign phase by measures which reduce the arterial pressure.

It would therefore seem correct to speak of the malignant phase of hypertension and to relate this to the underlying malady whether this be essential hypertension, pyelonephritis or the like. The diagnosis of the malignant phase of hypertension carries a single and urgent therapeutic implication, namely, the prompt and persistent lowvering of arterialpressure.
The Effect of Age and Body Weight on the Electrocardiogram of Healthy Men
Authors: SIMONSON ERNST , KEYS ANCEL
Published: June 2012

It is believed that proper evaluation of the electrocardiogram of a patient should mean comparison with the electrocardiographic features in healthy individuals who are in other respects comparable. Among the "other respects," age and body weight are important constitutional variables. The present information about the effect of these factors on the electrocardiogram is not adequate and, therefore, the differentiation between normal and abnormal is less precise than need be. In this paper, information is provided on the effect of age and body weight on the electrocardiogram, on the basis of a statistical analysis of various electrocardiographic items in numerically adequate samples of normal male population. It is shown that the effect of both age and weight is statistically highly significant, so that their consideration in electrocardiographic normal standards is suggested.
The Clinical Diagnosis of Anomalous Pulmonary Venous Drainage
Authors: SNELLEN H. A. , ALBERS F. H.
Published: June 2012

Clinical studies are presented in: (
a
) One case of partial anomalous pulmonary venous drainage (right common pulmonary vein into inferior vena cava), and (
b
) four cases of total abnormal pulmonary venous drainage (via "left vena cava" and left innominate vein into the superior vena cava on the right side). One of the latter four cases was verified on exploratory thoracotomy. The diagnosis was based on angiocardiography and heart catheterization, but the conventional chest roentgenogram proved to be quite characteristic of both conditions. The relatively slight impairment of health is stressed in the cases reported here.
Quantitative coronary angiography: measurement of the "critical" stenosis in patients with unstable angina and single-vessel disease without collaterals.
Authors: McMahon M M , Brown B G , Cukingnan R , Rolett E L , Bolson E , Frimer M , Dodge H T
Published: June 2012

Quantitative angiographic assessment of proximal coronary artery stenosis was performed in 15 patients with consecutive presentations in two categories defined by clinical and angiographic criteria. Group 1 consisted of 10 patients who had new onset of refractory rest angina and ischemic ST-T changes, but no infarction, single-vessel coronary disease without collateralization, and normal left ventricular (LV) angiograms. Group 2 consisted of five patients who were similar to patients in group 1, but had subendocardial infarction (SEI). Quantitative coronary arteriography, using paired perpendicular angiographic views and digital computation, yielded statistically different lesion dimensions and hemodynamic predictions for the two groups. Minimum stenosis diameters were 0.88 +/- 0.14 (SD) and 0.64 +/- 0.08 mm, respectively, for groups 1 and 2. This corresponded to 72% and 78% diameter reduction and 92% and 95% cross-sectional area reduction for the two groups. These small dimensional differences among lesions in the two groups resulted in large differences in their hemodynamic impact as predicted from classic fluid mechanics theory. We conclude that there are characteristic lesion dimensions for the isolated "critical" stenosis in these selected patients with rest angina. Further small increases in lesions severity result in SEI. Certain practical applications and limitations of these observations are discussed.
Comparison of myocardial protection with nifedipine and potassium.
Authors: Magee P G , Flaherty J T , Bixler T J , Glower D , Gardner T J , Bukley B H , Gott V L
Published: June 2012

Nifedipine, a slow-channel calcium blocker, is thought to provide useful myocardial protection during prolonged total ischemia and reperfusion. An isolated, isovolumic, feline heart model was used to asses the effectiveness of nifedipine in both cardioplegic (100 microgram/10 ml) and noncardioplegic (10 microgram/10 ml) doses for providing myocardial preservation during 90 minutes of hypothermic ischemic arrest and 45 minutes of normothermic reperfusion. Use of nifedipine was compared to hypothermia (27 degrees C) alone and to hypothermia with potassium cardioplegia. Ventricular function was assessed by recovery of isovolumic left ventricular developed pressure and dP/dt. Myocardial carbon dioxide tension (PCO2) and myocardial oxygen tension (PO2) were measured by mass spectrometry. Potassium cardioplegia and the higher dose of nifedipine resulted in immediate asystole. The rates of rise of PCO were greatest in the group receiving 10 microgram nifedipine and in the control group. The rates of rise in the two cardioplegic groups were significantly lower. Recovery of ventricular function was significantly lower with low-dose nifedipine than with potassium cardioplegia. Higher dose nifedipine resulted in a return of function, which was no different than with potassium cardioplegia. Morphologic protection was better with higher dose nifedipine and potassium cardioplegia than with either low-dose cardioplegia or hypothermia alone. These results demonstrate that nifedipine in a cardioplegic dose results in preservation of myocardial structure and function that is similar to that obtained with potassium cardioplegia. In lower noncardioplegic dose, nifedipine does not appear to offer additional protection compared to hypothermia alone. Whether persistent depression of ventricular contractility will limit nifedipine's clinical usefulness as a myocardial protection agent will require further study.
Left ventricular volume from paired biplane two-dimensional echocardiography.
Authors: Schiller N B , Acquatella H , Ports T A , Drew D , Goerke J , Ringertz H , Silverman N H , Brundage B , Botvinick E H , Boswell R , Carlsson E , Parmley W W
Published: June 2012

To evaluate the applicability of two-dimensional echocardiography to left ventricular volume determination, 30 consecutive patients undergoing biplane left ventricular cineangiography were studied with a wide-angle (84 degrees), phased-array, two-dimensional echocardiographic system. Two echographic projections were used to obtain paired, biplane, tomographic images of the left ventricle. We used the short-axis view (from the precordial window) as an anolog of the left anterior oblique angiogram, and the long-axis, two-chamber view (from the apex impulse window) as a right anterior oblique angiographic equivalent. A modified Simpson's rule formula was used to calculate systolic and diastolic left ventricular volumes from the biplane echogram and the biplane angiogram. These methods correlated well for ejection fraction (r = 0.87) and systolic volume (r = 0.90), but only modestly for diastolic volume (r = 0.80). These correlations are noteworthy because 65% of the patients had significant segmental wall motion abnormalities. The volumes determined from the minor-axis dimensions of M-mode echograms in 23 of the same patients correlated poorly with angiography.
Noninvasive radioisotopic technique for detection of platelet deposition in coronary artery bypass grafts in dogs and its reduction with platelet inhibitors.
Authors: Fuster V , Dewanjee M K , Kaye M P , Josa M , Metke M P , Chesebro J H
Published: June 2012

At 8 and 32 hours after saphenous vein bypass graft surgery in six dogs, in vivo images of the graft were obtained with a gamma camera after intravenous injection, 2 hours postoperatively of autologous platelets labeled with indium-111. Platelet deposition in the grafts could be imaged in vivo from the scintiphotos. In vitro images of the excised heart showed saphenous vein graft uptake confirming the in vivo image. In vitro determination of radioactivity in the graft averaged 17 +/- 14 times greater than in blood and 33 +/- 26 times greater than in the lung. Under identical conditions, in eight dogs treated with dipyridamole (55 mg/day) plus aspirin (325 mg/day), the grafts appeared to have considerably less platelet deposition as estimated by imaging. In vitro determination of radioactivity in the graft averaged 5 +/- 2 times greater than in blood and 8 +/- 4 times greater than in the lung (p less than 0.01). This noninvasive technique may be a promising tool for a better understanding of the role played by platelets in the process of occlusion of saphenous vein bypass grafts in man and its prevention with platelet inhibotors.
Biostatistics: how to detect, correct and prevent errors in the medical literature.
Authors: Glantz S A
Published: June 2012

Approximately half the articles published in medical journals that use statistical methods use them incorrectly. These errors are so widespread that the present system of peer review has not been able to control them. This article presents a few rules of thumb to help readers identify questionable statistical analysis and estimate what the authors would have concluded had they used appropriate statistical methods. To prevent such errors from appearing, journals should secure review by someone knowledgeable in statistics before accepting a manuscript. In addition, human research committees should insist that an investigator define an appropriate strategy for data analysis before approving a protocol. Such policies should quickly and effectively increase the reliability of the clinical and scientific literature.
Echocardiographic documentation of vegetative lesions in infective endocarditis: clinical implications.
Authors: Stewart J A , Silimperi D , Harris P , Wise N K , Fraker T D , Kisslo J A
Published: June 2012

Eighty-seven patients with the clinical syndrome of infective endocarditis were examined by M-mode and two-dimensional echocardiography. Patients were divided into two groups based on the presence or absence of echocardiographically detected vegetative lesions. Group 1 consisted of 47 patients with one or more vegetations. Group 2 consisted of 40 patients without evidence of vegetations. Group 1 patients had a higher rate of complications: emboli, congestive heart failure and the need for surgical intervention. Analysis of morphologic characteristics of the vegetations in group 1 was of no predictive value for complications in individual patients. Two-thirds of the vegetations persisted unaltered well beyond the period of bacteriologic cure without significant complications. No characteristic alteration of the vegetations predicted the efficacy of medical therapy. Although the detection of vegetations by echocardiography in patients with the clinical syndrome of endocarditis clearly identifies a subgroup at risk for complications, decisions regarding clinical management made solely on the basis of the presence or absence of vegetative lesions are hazardous. Management of such patients must continue to be based on the clinical integration of multiple factors.
Effect of atrial septal defect repair on left ventricular geometry and degree of mitral valve prolapse.
Authors: Schreiber T L , Feigenbaum H , Weyman A E
Published: June 2012

To ascertain the effects of surgical closure of atrial septal defect on left ventricular geometry and degree of mitral prolapse, 14 patients with atrial septal defect were studied by cross-sectional and M-mode echocardiography preoperatively and 7 days postoperatively. Seven of the 14 patients (50%) had mitral valve prolapse preoperatively by cross-sectional echocardiography. To quantitate the degree of prolapse, we measured the net algebraic area subtended by the apposed mitral valve leaflets in systole (MVAS) with respect to the mitral ring. The mitral valve prolapse group had an MVAS of 0.3 +/- 3.1 units (mean +/- SEM) preoperatively, while the group without mitral valve prolapse had an MVAS of 12.5 +/- 3.1 units (p less than 0.02). Postoperatively, prolapse either decreased in degree or was abolished in six of seven patients (86%), associated with an increase in MVAS to 14.7 +/- 4.4 units (p less than 0.02). In all patients, septal curvature in diastole on short-axis view normalized either partially or completely postoperatively, resulting in decreased left ventricular eccentricity (1.34 +/- 0.06 preop vs. 1.06 +/- 0.07 postop, p less than 0.001). Atrial septal defect closure, therefore, leads to normalization of left ventricular geometry and in patients with evidence of mitral valve prolapse, is associated with a decrease in the degree of prolapse.
Left ventricular function after repair of tetralogy of fallot and its relationship to age at surgery.
Authors: Borow K M , Green L H , Castaneda A R , Keane J F
Published: June 2012

Left ventricular (LV) work-function curves were used to assess LV performance in eight postoperative tetralogy of Fallot (TOF) patients who underwent repair before 2 years of age (group 1) and 12 patients who underwent repair after 2 years of age (group 2). All patients were without significant residual shunts or pulmonary stenosis. Results were compared with those in seven control patients. Left- and right-heart hemodynamics were measured at various levels of afterload induced by methoxamine while heart rate was maintained constant. Cardiac output was serially measured. The slope (m) for each patient's LV end-diastolic pressure (EDP) vs LV minute-work index (MWI) relationship was determined. There were no significant differences in resting cardiac index, LV systolic pressure, LVEDP, aortic oxygen saturation or MWI among the groups. However, with afterload stress, group 2 patients had abnormal work-function curves with depressed slopes (m = 0.21 +/- 0.04) compared with the values for group 1 patients (m = 0.89 +/- 0.13, p less than 0.001) or the control group (m = 1.13 +/- 0.12, p less than 0.001). Thus, LV dysfunction unmasked by an afterload stress was present in the older TOF patients but not in the patients repaired during infancy. These findings raise the possibility that early, definitive repair of TOF may help preserve postoperative LV function.
Atherosclerosis-related responses to cigarette smoking in the baboon.
Authors: Rogers W R , Bass R L , Johnson D E , Kruski A W , McMahan C A , Montiel M M , Mott G E , Wilbur R L , McGill H C
Published: June 2012

Thirty-six young adult male baboons (Papio cynocephalus) were fed an atherogenic diet (40% calories from lard, 1.5 mg cholesterol/kcal) and taught to puff by operant conditioning with water rewards. Eighteen baboons (smokers) were assigned randomly to smoke 43 cigarettes a day, and 18 baboons (shams) were assigned randomly to puff air under conditions equivalent to those of the experimental group. During months 14-19 of smoking, cigarette-smoking baboons had significantly higher carbon monoxide and thiocyanate concentrations in blood and cotinine concentrations in urine. There were no significant differences in serum total cholesterol, VLDL + LDL cholesterol, HDL cholesterol or triglyceride concentrations of smokers and shams. Smoking baboons had significantly higher fasting blood glucose concentrations and lymphocyte counts. Platelet count, platelet aggregation, food and water intake, and body weight were not significantly different in the two groups.