bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of left ventricular ejection fraction and volumes by real-time, two-dimensional echocardiography. A comparison of cineangiographic and radionuclide techniques.
Authors: Folland E D , Parisi A F , Moynihan P F , Jones D R , Feldman C L , Tow D E
Published: June 2012

Five different algorithms for determining left ventricular (LV) ejection fraction (EF) and volumes from two-dimensional echocardiographic examination (TDE) were compared with standard methods for obtaining EF and volume from x-ray cineangiography (cine) and EF from radionuclide ventriculography (RVG) in 35 patients. Although all methods correlated positively, the degree of correlation varied with the algorithm used. For EF determination, TDE algorithms (especially those using multiple planes of section) were superior to unidimensional algorithms commonly used with M-mode echocardiography. The best algorithm (modified Simpson's rule) correlated well enough with cine EF (r = 0.78; SEE 0.097) and RVG EF (r = 0.75; SEE 0.087) to make clinically useful estimates. TDE volumes also correlated meaningfully with cine end-diastolic and end-systole volumes (r = 084; n = 70) but were associated with a large standard error of the estimate (43 ml) and offered less advantage over unidimensional volume estimates. Quantitative application of TDE appears to be a useful noninvasive method of evaluating LVEF, but is not as useful for estimating LV volumes.
Evaluation of the echocardiogram as an epidemiologic tool in an asymptomatic population.
Authors: Valdez R S , Motta J A , London E , Martin R P , Haskell W L , Farquhar J W , Popp R L , Horlick L
Published: June 2012

An asymptomatic adult population of 196 men and women was studied with the echocardiogram to derive age- and sex-specific "normal" values for a number of clinically used echocardiograhic variables. The results are in general agreement with previously published normal values. Body position during the examination, age and sex influence the echocardiographic results; body surface area correction normalized most of these effects. The prevalence of occult abnormalities determined by the echocardiogram is 7%; the most common finding was mitral valve prolapse. Inter- and intraobserver variability was assessed. The interobserver differences found on analysis are statistically, but not clinically , significant. The echocardiogram appears to be a suitable tool to use in epidemiologic studies to detect selected cardiac abnormalities, but is limited for this purpose because some subjects in such a population cannot be adequately examined.
Exercise-induced U-wave inversion as a marker of stenosis of the left anterior descending coronary artery.
Authors: Gerson M C , Phillips J F , Morris S N , McHenry P L
Published: June 2012

The prevalence and cineangiographic correlates of exercise-induced inversion of U waves were studied in 248 patients. Exercise-induced U-wave inversion was observed in 36 patients (15%), of whom 35 had greater than or equal to 75% stenosis in one or more of the major coronary arteries. The proximal left anterior descending or left main coronary artery was involved in 33 of these patients, including 24 patients with no electrocardiographic evidence of anterior myocardial infarction. Exercise-induced U-wave inversion was observed in the absence of an abnormal resting 12-lead ECG. Only one of the 82 patients (1.2%) without significant coronary artery disease demonstrated exercise-induced U-wave inversion, and this patient had a primary cardiomyopathy. We conclude that exercise-induced inversion of the U-wave is highly predictiveof significant coronary artery disease and, more specifically, of disease of the proximal left anterior descending coronary artery.
Adverse hemodynamic effects of intravenous disopyramide compared with quinidine in conscious dogs.
Authors: Walsh R A , Horwitz L D
Published: June 2012

Disopyramide resembles quinidine electrophysiologically, but its effect on left ventricular function has not been clarified. Twelve awake dogs were instrumented for measurement of cardiac output, left ventricular pressure and its maximal first derivative (dP/dt max), and left atrial and aortic pressures. Disopyramide or quinidine at identical, clinically relevant doses (1 and 5 mg/kg i.v.) was infused over 5 minutes at each level. Peak changes after disopyramide 1 mg/kg included increases in heart rate (34%), mean aortic pressure (24%) and systemic vascular resistance (33%), and decreases in stroke volume (16%) and dP/dt max (19%). With disopyramide at 5 mg/kg these changes were of greater magnitude (e.g., dP/dt -- 36%). Quinidine at both doses caused no changes except a 13% decrease in vascular resistance at 5 mg/kg. Heart rate with disopyramide increased after propranolol (1 mg/kg i.v.), was unchanged after atropine (0.1 mg/kg i.v.), and slowed after propranolol and atropine. Phenoxybenzamine (2 mg/kg i.v.) did not prevent the rise in systemic vascular resistance produced by disopyramide. Thus, disopyramide in clinical dosages exerts opposing direct and indirect effects on cardiac pacemakers and, unlike quinidine, is a potent myocardial depressant and vasoconstrictor in the conscious dog.
Assessment of left ventricular function in secundum atrial septal defect by computer analysis of the M-mode echocardiogram.
Authors: St John Sutton M G , Tajik A J , Mercier L A , Seward J B , Giuliani E R , Ritman E L
Published: June 2012

Left ventricular function in 53 patients with secundum atrial septal defect was assessed by computer-assisted analysis of the left ventricular echocardiogram and by cardiac catheterization. The patients were divided into two groups, those younger and those older than 60 years, to investigate the effect of aging on left ventricular function. Cavity size was significantly smaller than normal (p less than 0.01) and septal motion was abnormal in 86%, but values for cardiac index, left ventricular end-diastolic pressure, velocity of circumferential fiber shortening, left ventricular filling rate, and duration of rapid filling were normal in both groups. Regional dynamics assessed in terms of peak rates of systolic thickening and diastolic thinning of the septum and posterior wall were also normal in both groups. We concluded that, although left ventricular minor dimensions are small, and septal motion is reversed in the majority of patients with atrial septal defect, left ventricular function is normal, and it does not appear to deteriorate with increased age, pulmonary hypertension, or the presence of right ventricular failure. The abnormal septal motion appears to be compensated for by enhanced septal and posterior wall percentage thickening.
Noninvasive assessment of atrioventricular pressure half-time by Doppler ultrasound.
Authors: Hatle L , Angelsen B , Tromsdal A
Published: June 2012

The mean pressure drop across the mitral valve and atrioventricular pressure half-time were measured noninvasively by Doppler ultrasound in 40 normal subjects, in 17 patients with mitral regurgitation, 32 patients with mitral stenosis and 12 with combined stenosis and regurgitation. In normal subjects pressure half-times were 20--60 msec, in patients with isolated mitral regurgitation 35--80 msec and in patients with mitral stenosis 90--383 msec. There was no significant change in pressure half-time with exercise or on repeat examinations, indicating relative independence of mitral flow. In 25 patients with mitral stenosis and seven with combined stenosis and regurgitation, pressure half-time was related to mitral valve area calculated from catheterization data. Increasing pressure half-times occurred with decreasing mitral valve area, and this relationship was not influenced by additional mitral regurgitation. Noninvasive measurement of pressure half-time together with mean pressure drop was useful for evaluating patients with mitral valve disease.
Ventricular tachycardia and ventricular fibrillation in a young population.
Authors: Pedersen D H , Zipes D P , Foster P R , Troup P J
Published: June 2012

In this study, we describe the findings in 18 young patients (age range 4 days to 24 years, mean 16.6 years) who had ventricular tachycardia and/or ventricular fibrillation and were followed for 4--70 months (mean 22.4 months). Patients had a variety of problems associated with their arrhythmia, including mitral valve prolapse, cardiomyopathy, myocarditis, prolonged QT syndrome and hypokalemia. Six patients had no clinically recognizable cardiac abnormality. The ventricular tachycardia showed a left bundle branch block contour in 10 of 17 patients, right bundle branch block in four, was multiform in two and had an indeterminate contour in one. Sustained ventricular tachycardia was initiated and terminated reproducibly by atrial and ventricular stimulation in three of seven patients who did not have spontaneous episodes of ventricular tachycardia during the electrophysiologic study. In one other patient, short bursts of ventricular tachycardia were induced. Patients who had ventricular fibrillation, those who died, and those who are still symptomatic with poorly controlled ventricular arrhythmias had significant heart disease. In one patient, a ventricular tachyarrhythmia that had required more than 100 electrical cardioversions spontaneously disappeared after requiring 1 year of antiarrhythmic therapy.
Ventricular ectopic beats and their relation to sudden and nonsudden cardiac death after myocardial infarction.
Authors: Moss A J , Davis H T , DeCamilla J , Bayer L W
Published: June 2012

The role of ventricular ectopic beats (VEBs) in identifying patients who die of cardiac cause in the posthospital phase of myocardial infarction was evaluated in 940 patients who survived an acute coronary event. Six-hour Holter ECG recordings were obtained before hospital discharge, and VEBs were classified as complex (bigeminal, multiform, repetitive or R on T), simple (one or more VEBs that did not have complex patterns), or not present. Patients were followed 1-60 months (average 36 months) and cardiac mortality was categorized as sudden (less than or equal to 1 hour) or nonsudden (greater than 1 hour) among 98 witnessed cardiac deaths. Complex VEBs were associated with a significantly increased cardiac death rate, but did not discriminate between sudden and nonsudden death. Simple VEBs were associated with a 3-year cardiac mortality rate intermediate between those with complex and those with no VEBs. The relationship between complex VEBs and cardiac mortality was independent of 10 relevant clinical variables.
Verapamil therapy: a new approach to the pharmacologic treatment of hypertrophic cardiomyopathy. I. Hemodynamic effects.
Authors: Rosing D R , Kent K M , Borer J S , Seides S F , Maron B J , Epstein S E
Published: June 2012

The hemodynamic effects of intravenous verapamil administration were examined in 27 patients with hypertrophic cardiomyopathy. Increasing doses of verapamil produced small increases in heart rate and cardiac output and a significant decrease in systolic blood pressure, but had no significance effect on mean pulmonary artery wedge pressure or left ventricular end-diastolic pressure. The highest dose of verapamil increased heart rate from 72 +/- 3 to 81 +/- 6 beats/min and reduced systolic blood pressure from 118 +/- 8 to 99 +/- 5 mm Hg (p less than 0.005). This dose decreased the basal left ventricular outflow tract gradient from 94 +/- 14 to 49 +/- 14 mm Hg and the average left ventricular outflow tract gradient during the Valsalva maneuver from 76 +/- 5 to 63 +/- 13 mm Hg, during amyl nitrite inhalation from 69 +/- 15 to 39 +/- 13 mm Hg, and during isoproterenol infusion from 108 +/- 29 to 70 +/- 21 mm Hg (p less than 0.01). These results indicate that verapamil can significantly decrease left ventricular outflow obstruction in patients with hypertrophic cardiomyopathy and thus may provide an important new therapeutic agent in the treatment of this disorder.
Analysis of regional ischemic left ventricular dysfunction by quantitative cineangiography.
Authors: Tzivoni D , Diamond G , Pichler M , Stankus K , Vas R , Forrester J
Published: June 2012

The ability of left ventricular angiography to detect regional ischemic dysfunction was assessed in 10 closed-chest dogs during the course of acute balloon occlusion of the anterior descending coronary artery. During the 2-minute period of occlusion, serial cineangiography revealed a sequence of wall motion abnormalities over the anteroapical region almost identical to that observed using directly implanted gauges. This sequence consisted of progressive reduction in regional systolic shortening with eventual replacement by systolic expansion. These changes preceded both electrocardiographic ST-segment and hemodynamic alterations, and were readily observed by gross subjective inspection of the cineangiograms, but with an intraobserver variability of 22%. Frame-by-frame motional analysis of the ventricular perimeter relative to its centroid of mass allowed more precise characterization of regional dysfunction. These data are consistent with previous studies demonstrating that regional wall motion abnormalities are both sensitive and specific markers of acute ischemia, and support the use of computerized left ventricular angiography for the quantitative assessment of clinical ischemic dysfunction.
Atypical patterns of retrograde conduction over accessory atrioventricular pathways in the Wolff-Parkinson-White syndrome.
Authors: Klein G J , Prystowsky E N , Pritchett E L , Davis D , Gallagher J J
Published: June 2012

Patterns of ventriculoatrial conduction have been used to distinguish retrograde conduction over an accessory atrioventricular pathway from that over the normal atrioventricular conduction system. Ventriculoatrial conduction at a constant interval during incremental ventricular pacing and during progressive prematurity of ventricular extrastimuli has been considered characteristic of conduction over an accessory pathway. We describe three patients with the Wolff-Parkinson-White syndrome who had progressive or sudden increments in ventriculoatrial conduction over an accessory pathway during fixed-rate ventricular pacing or during introduction of ventricular extrastimuli. Such properties have been considered characteristic of conduction over the normal atrioventricular conduction system. We conclude that retrograde conduction over accessory pathways may resemble conduction over the normal atrioventricular conduction system.
Exercise can promote coronary collateral development without improving perfusion of ischemic myocardium.
Authors: Neill W A , Oxendine J M
Published: June 2012

We studied the effect of exercise training on the coronary collaterals that developed in response to gradual coronary occlusion in dogs. After their proximal left circumflex coronary artery occlusion, 33 dogs were randomly assigned to exercise or sedentary groups. Coronary collateral function was evaluted 5 weeks or 8 weeks later. The exercised dogs developed better epicardial collateral connections to the occluded left circumflex as judged by higher retrograde blood flow from the distal left circumflex and lower pressure drop across the collaterals. No difference in collaterals was apparent angiographically. Microsphere data indicated that exercise dogs were not better protected against tachycardia provoked subendocardial ischenia in the myocardium supplied by the collaterals.
Research contributions toward prevention of cardiovascular disease. Research related to the underlying mechanisms in hypertension.
Authors: Dustan H P
Published: June 2012

The pathogenesis and basic mechanisms of hypertension are not understood. Hypertension is now considered to reflect abnormality in one or more of the biologic systems that regulate flow and resistance. Its complications result from high intra-arterial pressure, and drug treatment substantially lessens these complications. The death rate from hypertension has dropped strikingly. Although current knowledge is not sufficient to develop predictably successful prevention programs, there is growing interest in applying available information. Epidemiologic studies have identified obesity as a major risk factor for hypertension; they have also been interpreted as showing that high dietary sodium intake causes hypertension in industrialized societies. Evidence on the role of obesity seems firm and can provide the basis for prevention programs. The role of sodium intake requires further study.
Research related to noninvasive instrumentation.
Authors: Harrison D C
Published: June 2012

In the past three decades, techniques that permit noninvasive quantitation of the function of the heart have been developed. Exercise electrocardiography has been widely used to determine the presence or absence of ischemic heart disease. Echocardiography permits detection of valvular, congenital and arteriosclerotic disease and quantitation of its severity. Selective use of isotopes allows nuclear angiogarphy, myocardial perfusion studies and detection of damage to cellular myocardium. New techniques such as computerized axial tomography, magnetometry, focused pulsed Doppler, and wider application of computer-enhanced image processing are important future directions for noninvasive monitoring.
Research related to surgical treatment of coronary artery disease.
Authors: Kirklin J W , Kouchoukos N T , Blackstone E H , Oberman A
Published: June 2012

In the past 20 years, basic and clinical research have provided new information on coronary artery surgery. For example, several studies have shown that coronary artery bypass grafting is more effective than medical treatment in relieving the symptoms of chronic disabling angina pectoris. However, we still do not have definitive answers to many questions. What factors in the patient, in the operation and in the care after operation determine success in surgical treatment? Does the operation prolong useful life? Is the operation affordable? These questions are difficult. Further research is needed to solve complex problems relating to surgical vs medical treatment of coronary artery disease.
Research related to surgical treatment of aortic and peripheral vascular disease.
Authors: DeBakey M E
Published: June 2012

The history of vascular surgery and the developments that made it possible are briefly traced. Approaches to the treatment of arterial lesions are considered in terms of the characteristic anatomic, pathologic and clinical patterns of arteriosclerosis or atherosclerosis, the basic underlying lesion in most aneurysmal and occlusive diseases of the aorta and major arteries. The importance of appreciating the various patterns and rates of progression of atherosclerosis is emphasized.
Diagnosis and management of postoperative pulmonary hypertensive crisis.
Authors: Wheller J , George B L , Mulder D G , Jarmakani J M
Published: June 2012

In this paper we discuss two infants and one child who experienced a previously unreported complication after complete correction of a large, unrestrictive ventricular septal defect. Two patients had documented pulmonary hypertensive crises and severe right-heart failure secondary to hypoxia and pulmonary vasoconstriction. These crises were associated with significantly increased right ventricular (RV) peak systolic and end-diastolic pressures and right-to-left shunting via a foramen ovale which, in turn, exaggerated the hypoxis. The crises were treated successfully with tolazoline in the second and third patients. RV pressure returned to normal values and have remained normal up to 12 months postoperatively in the second patient. Although the RV pressures decreased with tolazoline in the third patient, they never reached normal values. Postoperative monitoring of pulmonary artery and RV pressures in infants with large ventricular septal defects is essential when unexplained complications are encountered. Tolazoline proved to be very effective in the treatment of two patients with pulmonary vasoconstriction secondary to hypoxia.
Pulmonary vascular disease in total anomalous pulmonary venous drainage.
Authors: Newfeld E A , Wilson A , Paul M H , Reisch J S
Published: June 2012

Pulmonary vascular disease (PVD) was assessed by a qualitative and quantitative histopathologic analysis of lung specimens of 40 patients (age at autopsy 5 days to 12 years, median 3 months) with total anomalous pulmonary venous drainage. A PVD index was derived by counting the number of vessels with each Heath-Edwards grade of PVD (PVD index = [0 (Normal) +1 (N grade 1) +2 (N grade 2)....+6 (N grade 6)]/number of vessels graded, where N = the number of patients) in randomly selected pulmonary resistance vessels 30-300 mu in diameter. Patients with pulmonary venous obstruction died earlier and had a higher PVD index as a group than patients with unobstructed venous drainage. A remarkable degree of advanced pulmonary vascular changes was found in the entire group, even young infants. Pulmonary vascular obstructive disease is an important factor in the pathophysiology of this lesion. Careful attention to the prevention and management of increased pulmonary vascular resistance in the postoperative period may improve survival.
Detection and estimation of the degree of mitral regurgitation by range-gated pulsed doppler echocardiography.
Authors: Abbasi A S , Allen M W , DeCristofaro D , Ungar I
Published: June 2012

Sensitivity and specificity of detection of mitral regurgitation was assessed by range-gated Doppler echocardiography. The degree of mitral regurgitation was also estimated by the depth and width of the regurgitant jet detected with Doppler and compared with that assessed by left ventriculography. Of 47 patients with an adequate Doppler study, 24 had no mitral regurgitation by ventriculography. All but one were also negative for mitral regurgitation by Doppler, for a specificity of 96%. Of 23 cases with mitral regurgitation documented by ventriculography, Doppler detected mitral regurgitation in 21, for a sensitivity of 92%. Two cases with mitral regurgitation undiagnosed by Doppler had mild mitral regurgitation due to papillary muscle dysfunction. All cases with rheumatic mitral regurgitation were detected. The degree of mitral regurgitation estimated with Doppler had a high correlation with that determined by ventriculography (r = 0.88, p less than 0.01).
The Belgian heart disease prevention project. Modification of the coronary risk profile in an industrial population.
Authors: Kornitzer M , De Backer G , Dramaix M , Thilly C
Published: June 2012

The Belgian Heart Disease Prevention Project is a controlled, multifactorial prevention trial involving 19,390 males aged 40-59 years employed by 30 Belgian industries. These industries were paired and randomized into a control or intervention unit. In each intervention factory, the subjects from the two highest deciles of a coronary risk-score distribution curve were given individual advice twice a year. A health education campaign was also organized in each intervention factory. In the control group, 10% of randomly chosen subjects had the same baseline examination as the whole of the intervention group. After 2 years, high-risk subjects and random samples of the control and intervention group were compared regarding the coronary risk profile by means of a multiple logistic function (MLF). In the intervention high-risk group, the MLF showed a decrease of 20%, and in the control group there was an increment of 12.5% (p less than 0.001). Comparing the random samples an increment of 25% was found in the control group vs a drop of 2.26 in the intervention group (p less than 0.001). The coronary risk profile can be altered in a middle-aged male working population through mass media health education supplemented by face-to-face counseling in high-risk subjects.
Recurrent myocardial infarction in a young man due to coronary arterial spasm demonstrated at autopsy.
Authors: El-Maraghi N R , Sealey B J
Published: June 2012

A case is presented, believed to be the first reported, describing recurrent myocardial infarction in an athletic 25-year-old man due to coronary arterial spasm, which was demonstrated at autopsy. A previous angiogram performed during life, after the first myocardial infarction, showed normal coronary arteries. The findings in this case are discussed with a review of the current knowledge pertaining to coronary arterial spasm.
The effect of timolol vs placebo on angina pectoris.
Authors: Aronow W S , Turbow M , Van Camp S , Lurie M , Whittaker K
Published: June 2012

The effect of timolol vs placebo on the frequency of anginal episodes, nitroglycerin consumption and exercise performance was investigated in a double-blind, randomized, crossover study in 23 patients with angina pectoris. The optimal dose of timolol (10-30 mg twice daily) for each patient was titrated by exercise studies. Compared with placebo, timolol decreased the weekly number of anginal attacks and the weekly number of nitroglycerin tablets consumed, reduced the resting heart rate, systolic and diastolic blood pressure, and product of systolic blood pressure times heart rate, decreased the heart rate, systolic and diastolic blood pressure, and product of systolic blood pressure times heart rate at the onset of angina pectoris or marked fatigue, prolonged exercise duration, and diminished electrocardiographic evidence of myocardial ischemia. Timolol is an excellent antianginal agent when prescribed twice daily, with the optimal dose titrated by exercise studies.
Cryosurgical ablation of the atrioventricular node-His bundle: long-term follow-up and properties of the junctional pacemaker.
Authors: Klein G J , Sealy W C , Pritchett E L , Harrison L , Hackel D B , Davis D , Kasell J , Wallace A G , Gallagher J J
Published: June 2012

We used a cryosurgical technique to ablate the atrioventricular (AV) node-His bundle in twenty-two selected patients with disabling supraventricular tachyarrhythmias unresponsive to medical management. Successful AV block was achieved in seventeen. There was no intraoperative mortality and significant surgical complications were not encountered. Electrophysiologic studies performed 7-10 days after surgery revealed that the subsidiary pacemaker had a narrow QRS complex morphology and a mean cycle length of 1244 msec. Isoproterenol (1-4 microgram/min i.v.) significantly increased (p less than 0.01) the rate of the subsidiary pacemaker (mean maximum response 1008.3 msec); atropine (2 mg i.v.) had no effect on its rate. The cycle length of the subsidiary pacemaker during long-term follow-up (mean 14.8 months) showed a small but significant (p = 0.024) increase (mean cycle length 1430 msec). Treadmill exercise in seven patients did not result in the subsidiary pacemaker exceeding the rate of the implanted demand pacemaker set at 70 beats/min. The properties of the subsidiary pacemaker suggest an intra-Hisian site of impulse formation.
The effect of the pericardium on ventricular systolic function in man.
Authors: Mangano D T
Published: June 2012

To determine the role of the pericardium in man, ventricular function was studied in 20 patients who underwent pericardiotomy during coronary artery bypass surgery. Left and right ventricular function curves were generated before and after pericardiotomy by changing body position to alter venous pressure. Central venous (0--14 mm Hg) and pulmonary wedge pressures (1--25 mm Hg) ranged over normal and moderately elevated values. Pericardiotomy did not alter the relationship between left ventricular stroke work index and pulmonary wedge pressure, between right ventricular stroke work index and central venous pressure, or between pulmonary wedge pressure and central venous pressure. These data suggest that in patients with normal and moderately elevated filling pressures, the pericardium does not influence right or left ventricular systolic function or the coupling between the right and left ventricles.
Characterization of the cardiomyopathy in infants of diabetic mothers.
Authors: Gutgesell H P , Speer M E , Rosenberg H S
Published: June 2012

A transient form of hypertrophic cardiomyopathy has been previously described in infants of diabetic mothers (IDMs). The purpose of this study was to determine the incidence, natural history and pathologic features of this cardiomyopathy in symptomatic and asymptomatic IDMs. We studied 47 IDMs for evidence of cardiomyopathy. Among 24 symptomatic IDMs, five had marked septal hypertrophy with echocardiographic features suggesting left ventricular outflow obstruction and five had hypertrophy of the right ventricular free wall. With the exception of mild septal hypertrophy, these abnormalities resolved during the first 6 months of life, and echocardiograms in the first-degree family members were normal. Of 23 asymptomatic IDMs, three had septal hypertrophy and two had right ventricular free wall hypertrophy; none of the asymptomatic IDMs had evidence of outflow obstruction. One symptomatic IDM died, and autopsy revealed a hypertrophic septum that distorted both ventricular cavities. Microscopic examination revealed hypertrophic fibers and occasional areas of cellular disarray in the septum. Despite the clinical and pathologic similarities of the cardiomyopathy in IDMs to the hypertropic cardiomyopathies in older children and adults, its transient and nonfamilial nature suggest that it is a separate disease. We speculate that it is a manifestation of the generalized organomegaly in IDMs.
Clinical judgment and statistics. Lessons from a simulated randomized trial in coronary artery disease.
Authors: Lee K L , McNeer J F , Starmer C F , Harris P J , Rosati R A
Published: June 2012

A simulated randomized clinical trial in coronary artery disease was conducted to illustrate the need for clinical judgment and modern statistical methods in assessing therapeutic claims in studies of complex diseases. Clinicians should be aware of problems that occur when a patient sample is subdivided and treatment effects are assessed within multiple prognostic categories. In this example, 1073 consecutive, medically treated coronary artery disease patients from the Duke University data bank were randomized into two groups. The groups were reasonably comparable and, as expected, there was no overall difference in survival. In a subgroup of 397 patients characterized by three-vessel disease and an abnormal left ventricular contraction, however, survival of group 1 patients was significantly different from that of group 2 patients. Multivariable adjustment procedures revealed that the difference resulted from the combined effect of small imbalances in the distribution of several prognostic factors. Another subgroup was identified in which a significant survival difference was not explained by multivariable methods. These are not unlikely examples in trials of a complex disease. Clinicians must exercise careful judgment in attributing such results to an efficacious therapy, as they may be due to chance or to inadequate baseline comparability of the groups.
Atenolol: once-daily cardioselective beta blockade for angina pectoris.
Authors: Jackson G , Schwartz J , Kates R E , Winchester M , Harrison D C
Published: June 2012

The physiology, pharmacokinetics and efficacy of atenolol, a cardioselective beta-adrenergic blocking agent, were evaluated in 10 patients with stable angina pectoris in a single-blind, dose-ranging study. After a 1-month control placebo period, atenolol was administered once daily at dosages of 25, 50, 100 and 200 mg for 2-week periods. All patients had fewer anginal attacks and consumed fewer nitroglycerin tablets than mg for 2-week periods. All patients had fewer anginal attacks and consumed fewer nitroglycerin tablets than during the placebo period. Twenty-four-hour ambulatory ECG recordings showed a decrease in mean hourly heart rate throughout the dosing period, with preservation of diurnal variation. Maximal, symptom-limited, treadmill exercise tests performed 3 hours after drug ingestion showed significantly increased exercise time and decreased double products for all doses, but especially with 100-mg and 200-mg doses. Exercise time 24 hours after drug ingestion continued to show a decrease in maximum heart rate and double product, with 100-mg and 200-mg doses again being most effective. Atenolol serum levels correlated with percent reduction in exercise heart rate and increased exercise time. Serum levels rose linearly, with an average elimination half-life of about 10 hours after chronic oral dosing. Thus, atenolol was an effective antianginal agent and suppressed resting and exercise-stressed heart rate for 24 hours after ingestion when given in a 100-mg or 200-mg dose once daily.
Thallium-201 myocardial perfusion imaging in infants and children. Value in distinguishing anomalous left coronary artery from congestive cardiomyopathy.
Authors: Gutgesell H P , Pinsky W W , DePuey E G
Published: June 2012

In infants and children, anomalous origin of the left coronary artery (ALCA) from the pulmonary artery may be difficult to distinguish from congestive cardiomyopathy (CCM) of other causes. We performed thallium-201 myocardial perfusion imaging in seven children with ALCA and in nine with CCM to study the usefulness of this technique in distinguishing between these lesions. Localized abnormalities of thallium uptake were present in each of the seven patients with ALCA, including two asymptomatic 4-year-old children. Thallium distribution was normal in five patients with CCM, diffusely irregular in three, and was absent in the lateral and posterobasal portions of the left ventricle in one patient. We conclude that thallium-201 imaging is a sensitive noninvasive method of detecting ALCA. However, perfusion abnormalities are not limited to patients with coronary artery abnormalities, and may be present in patients with myocardial ischemia or infarction of other causes.
Evidence for additional blood pressure correlates in adults 20-56 years old.
Authors: Havlik R J , Garrison R J , Feinleib M , Padgett S , Castelli W P , McNamara P M
Published: June 2012

The offspring of parents belonging to the original Framingham Heart Study cohort, and spouses of these offspring, were examined beginning in 1971. Cardiovascular examinations similar to those performed on the parents in 1952-1953 were given to offspring and their spouses. The mean blood pressure (BP) appeared to be lower in the female offspring-spouses than in the cohort mothers. Comparable multivariate analyses on 3588 offspring and spouses of both sexes, ages 20-49 years, and 1842 parents, ages 30-49 years, confirmed the frequently reported importance of weight, heart rate, alcohol consumption, glucose and hematocrit or hemoglobin as independent positive correlates and smoking as an inverse correlate of botsured variables of total serum proteins and plasma triglycerides added significantly to prediction of BP in both sex groups, and a less striking negative association was found for serum phosphorus. The findings for serum proteins and triglycerides were supported in a separate population of middle-aged twin men. Even with the additional measured variables, only 28-34% of the total BP variance is explained in these populations.
Rest and exercise hemodynamic effects of oral hydralazine in patients with coronary artery disease and left ventricular dysfunction.
Authors: Hindman M C , Slosky D A , Peter R H , Newman G E , Jones R H , Wallace A G
Published: June 2012

To determine the hemodynamic effects of afterload reduction at rest and during upright exercise in patients with coronary artery disease and left ventricular dysfunction, 12 patients were studied before and after taking 50-75 mg of oral hydralazine every 6 hours for 48 hours. Oxygen consumption and heart rate were unchanged from control both at rest and during two work loads on a bicycle ergometer. Cardiac output was significantly increased at rest and during both workloads. The arteriovenous oxygen difference was significantly reduced at rest and during exercise. Pulmonary capillary wedge pressure was also significantly lower at rest and during exercise. Systemic vascular resistance was reduced at rest, and exercise-induced vasodilation was augmented by the administration of hydralazine. Left ventricular end-diastolic volume and ejection fraction assessed by radionuclide angiocardiography were not significantly changed at rest or during exercise after hydralazine. Seven of the 12 patients have maintained clinical improvement during a follow-up of 6-12 months. Hemodynamic improvement provided by oral hydralazine at rest is maintained during moderate exertion in patients with coronary artery disease and left ventricular dysfunction. In selected patients, chronic afterload reduction with oral hydralazine may result in increased cardiac reserve, decreased pulmonary congestion or decreased myocardial oxygen demands, thereby improving or abolishing resting or exertional dyspnea or angina.
Effect of acute coronary artery occlusion on local myocardial extracellular K+ activity in swine.
Authors: Hill J L , Gettes L S
Published: June 2012

We studied the time course, magnitude and homogeneity of the change in extracellular myocardial potassium activity after acute ligation of the left anterior descending coronary artery in pigs using potassium-sensitive electrodes made from a valinomycin-polyvinyl chloride matrix membrane. We also studied the relationship between the changes in potassium activity and the simultaneous changes in ventricular activation using the reference barrel of the K+ electrode to record ventricular electrograms. We found that the K+ rose sooner, more rapidly and to higher levels than previously reported. The K+ changes occurred in three phases: a phase of rapidly rising K+ that began within seconds of the ligation and lasted 5-15 minutes, a plateau phase that lasted approximately 15 minutes and a phase of slowly rising K+ that extended throughout the longest occlusion (60 minutes) used in this study. The K+ changes were reversed by release of the occlusion during the rapidly rising and plateau phases, but were not reversed by release of the occlusion during the phase of slowly rising K+. Inhomogeneities in the K+ rise appeared between the center and lateral margins of the midmyocardial ischemic zone, between the subendocardium and the subepicardium in the center of the ischemic zone, and between closely spaced electrodes located in the midmyocardial center of the ischemic zone. Thus, the change in K+ activity, as recorded by our electrodes, can be considered an excellent marker of ischemia. Changes in ventricular activation paralleled the K+ rise, the inhomogeneities of K+ rise and the reversal of the K+ rise after release but could not be entirely explained by the change in K+.
Technetium-99m pyrophosphate uptake in experimental viral perimyocarditis. Sequential study of myocardial uptake and pathologic correlates.
Authors: Matsumori A , Kadota K , Kawai C
Published: June 2012

The myocardial uptake of technetium-99m pyrophosphate (99mTc-PYP) in perimyocarditis induced by coxsackievirus B3 in BALB/c mice was studied. 99mTc-PYP uptake ratio, measured by the ratio of counts/min per gram for the heart to counts/min per gram for the skull, began to increase 5 days after virus inoculation when myocardial necrosis was evident. On the seventh day after the inoculation, 99mTc-PYP ratio reached a maximum. Histologically, fine, dystrophic calcification appeared in the necrotic fibers. 99mTc-PYP uptake was in proportion to the extent of the myocardial lesions. Thereafter, cellular infiltrations increased with time and were most severe on the fourteenth day, but 99mTc-PYP ratio had begun to fade. On the twenty-eighth day, perimyocardial fibrosis increased and calcification was still present, but 99mTc-PYP ratio had decreased. Myocardial uptake with severe pathologic lesions was visualized on a whole-body image on the seventh day after inoculation with the virus. The findings may provide a basis upon which 99mTc-pyp imaging may be applied to viral perimyocarditis in humans.
Congenital left ventricular inflow obstruction evaluated by two-dimensional echocardiography.
Authors: Snider A R , Roge C L , Schiller N B , Silverman N H
Published: June 2012

Several forms of congenital heart disease that cause left ventricular inflow obstruction have similar M-mode findings, and frequently the exact anatomic diagnosis cannot be made by M-mode echocardiography alone. We examined five children with various forms of left ventricular inflow obstruction using two-dimensional echocardiography. The diagnosis was confirmed by cardiac catheterization and surgery in all five patients. In one patient with congenital mitral valve stenosis, a thick mitral valve with two papillary muscles was imaged. This patient was easily distinguished from a second child with parachute deformity of the mitral valve in whom a single papillary muscle arising from the left ventricular apex was seen. These two patients with mitral valve stenosis were easily differentiated from the three patients in whom the left ventricular inflow obstruction was caused by a membrane within the left atrium. The membrane could be seen in several spatial planes; however, we could not distinguish by two-dimensional echocardiography one child who had cor triatriatum from the other two patients who had a supravalvar mitral ring. Because of its spatial anatomic display, the two-dimensional echocardiogram provides information for a more detailed anatomic diagnosis in children with congenital left ventricular inflow obstruction.
Two-dimensional echocardiographic findings in right-sided infective endocarditis.
Authors: Berger M , Delfin L A , Jelveh M , Goldberg E
Published: June 2012

M-mode and two-dimensional echocardiograms were recorded in 12 narcotic addicts who had right-sided infective endocarditis. The two-dimensional echocardiogram showed vegetations in 10 patients (nine tricuspid and one pulmonic), while the M-mode echocardiogram was positive in six (five tricuspid and one pulmonic). The use of multiple transducer positions resulted in better visualization of the valves and appeared to be an important reason for the large number of positive two-dimensional echocardiograms. Echocardiographic findings were also available after completion of antibiotic therapy in seven of 10 patients. Of these seven patients, the vegetation appeared unchanged in three, diminished in size in three and was no longer visualized in one. No patient required valve replacement. Two-dimensional echocardiography using a wide-angle sector scanner appears to offer distinct advantages over the standard M-mode technique in evaluating patients with right-sided infective endocarditis.
Methods for recording electrograms of the sinoatrial node during cardiac surgery in man.
Authors: Hariman R J , Krongrad E , Boxer R A , Bowman F O , Malm J R , Hoffman B F
Published: June 2012

Recent reports have shown that it is possible to record extracellular electrograms from the rabbit and dog sinoatrial (SA) node. We applied similar techniques to record SA nodal activity in 23 patients who underwent cardiac surgery for various forms of heart disease. Both a bipolar technique, using pairs of electrodes at various interelectrode distances, and a unipolar technique, using an exploring and an indifferent electrode, were used. To record SA nodal electrograms, polarity was reversed from the conventional electrocardiographic recording; high amplification (100 microV/cm) and low-pass filters (0.15-20 Hz) were used. SA nodal electrograms were recorded from eight of 12 patients using the bipolar method and from nine of 11 patients using the unipolar method. There were no significant differences in the success rate or quality of the recording between the two methods. However, the unipolar method allowed a more accurate localization of the SA node. Human SA nodal electrograms resembled those of the dog and rabbit and showed two distinct slopes: a diastolic slope and an upstroke slope preceding the P wave of the ECG, SA conduction times were 32.4 +/- 2.8 msec (mean +/- SEM) at sinus (PP) cycle lengths of 587.6 +/- 35.6 msec for the bipolar method, and 38.2 +/- 3.2 msec at sinus (PP) cycle lengths of 712.2 +/- 50.7 msec for the unipolar method. These methods for recording of extracellular SA nodal electrograms in man may prove useful in 1) localization of the SA node during open heart surgery and 2) assessment of SA nodal function in health and disease.
Scintigraphic detection of carotid atherosclerosis with indium-111-labeled autologous platelets.
Authors: Davis H H , Siegel B A , Sherman L A , Heaton W A , Naidich T P , Joist J H , Welch M J
Published: June 2012

Using autologous platelets labeled with indium-111-oxine, we studied the localization of platelets on arterial lesions by radionuclide scintigraphy in 34 patients with suspected cerebrovascular disease. The imaging results were compared with the findings of contrast angiography in 23 patients, 16 of whom were receiving antiplatelet and/or anticoagulant drugs during the platelet imaging study. Angiography demonstrated atherosclerotic lesions at 33 sites in the extracranial arteries of 16 of these patients. There was accumulation of 111In-platelets at 20 of these sites (61%) and at three other sites without definite angiographic abnormalities. Lesions with stenoses less than 50% were slightly more frequent than those with greater stenosis (68% vs 45%). The frequency of true-positive scintigraphic results was slightly higher in patients not treated with antithrombotic agents than in those on such drugs (70% vs 57%). Our results suggest that imaging with 111In-labeled autologous platelets may be useful for evaluating the pathophysiologic characteristics of atherosclerotic lesions in patients with cerebrovascular disease.
Straddling right atrioventricular valves in atrioventricular discordance.
Authors: Becker A E , Ho S Y , Caruso G , Milo S , Anderson R H
Published: June 2012

Four hearts are described in which the right atrioventricular valve, draining a morphologically right atrium, straddled and overrode a septum between a right-sided chamber of left ventricular morphology and a left-sided chamber of right ventricular morphology. The degree of override varied between the straddling valve and was committed by 20-45% to the morphologically right ventricle. The ventriculoarterial connections in the hearts were discordant in one, double outlet from the morphologically right ventricle in two and single outlet via an aorta from the morphologically right ventricle with pulmonary atresia in the other. The straddling valve in one of the cases with double outlet had a dual orifice. Pulmonary stenosis was present in three cases, and pulmonary atresia in the fourth. Study of the conduction system in three of the hearts revealed subtle but important differences from the pattern expected in atrioventricular discordance. Each case had an anterior atrioventricular node and penetrating bundle, but the connection thus formed was more lateral than usual, and in the case with ventriculoarterial discordance, the nonbranching bundle was unrelated to the pulmonary outflow tract. A sling of conduction tissue between the anterior node and the regular node was found in the case with single outlet and pulmonary atresia.