bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional contractility. Selective depression of ischemic myocardium by verapamil.
Authors: Smith H J , Goldstein R A , Griffith J M , Kent K M , Epstein S E
Published: June 2012

The effects of verapamil (0.02-0.2 mg/kg) on contractility in normal and partially ischemic myocardium were compared with the changes following propranolol (0.01-1.0 mg/kg). Regional contractile function was studied in open-chest dogs with ultrasonic crystals and ischemia was controlled by graded occlusion of a carotid-to-coronary artery shunt. Reduction in shunt perfusion pressure (40-55 mm Hg) resulted in hypokinesia. Verapamil depressed contractility in ischemic myocardium in 5/5 dogs, but did not alter the maximum velocity of shortening (max V) or end-diastolic segment length in normal myocardium. Propranolol in doses sufficient to depress ischemic myocardium also depressed contractile function in normal myocardium. In two dogs without coronary occlusion, verapamil (up to 1.0 mg/kg) increased end-diastolic segment length but did not reduce max V. We conclude that verapamil selectively depresses ischemic myocardium, a finding that may have clinical implication since ischemic injury can be decreased by reducing contractility (and thereby MVO2).
Relationships between myocardial perfusion, myocardial necrosis, and technetium--99m pyrophosphate uptake in dogs subjected to sudden coronary occlusion.
Authors: Marcus M L , Tomanek R J , Ehrhardt J C , Kerber R E , Brown D D , Abboud F M
Published: June 2012

The quantitative relationship between abnormalities seen on technetium-99m pyrophosphate (99mTc-PYP) infarct scintigrams and the size of the myocardial infarction is unclear. We evaluated two possible determinants of 99mTc-PYP accumulation: myocardial perfusion measured with 7-10 mu microspheres and the extent of necrosis determined histologically. Hemodynamics and myocardial perfusion to small segments of the left ventricle were measured prior to, 5-10 min, and 44-48 hours following sudden occlusion of the left anterior descending coronary artery in ten awake dogs. 99mTc-PYP was injected i.v. following the third injection of microspheres and the animals were killed 2 hours later. The important findings were as follows: 1) there is a close relationship between the extent of myocardial necrosis observed and the perfusion of segments 5-10 min following coronary occlusion; and 2) that segmental myocardial perfusion is an important determinant of 99mTc-PYP accumulation by myocardial segments which contain areas of necrosis. Although the present data preclude statistical analysis of the relationship between the level of necrosis in a segment and the accumulation of 99mTc-PYP by that segment, the two do not appear to be related, a finding which would discourage use of intensity of 99mTc-PYP images for infarct size. The distribution of an abnormality on the scintigram may provide an estimate of infarct size. However, the geometry of the infarct and the resolving power of the scanning equipment will significantly limit this in many clinical situations.
Effect of coronary thrombus age on fibrinogen uptake.
Authors: Moschos C B , Oldewurtel H A , Haider B , Regan T J
Published: June 2012

A study was carried out to define the time limits during which an experimental coronary thrombus remains capable of incorporating fibrinogen. 131I-fibrinogen was given to intact anesthetized dogs at different time intervals, up to 67 hours, following the formation of a coronary thrombus by catheter-electrode. Radioactivity of the recovered thrombi as a whole and segmentally divided, was determined following variable time intervals of exposure to circulating fibrinogen and was expressed as thrombus/blood ratio. The results indicate that coronary thrombi formed in a normal coronary vessel remain capable of incorporating fibrinogen for at least eighteen hours, with no significant differences in the segmental distribution of radioactivity. These findings do not support the view that the recovery of isotopic fibrinogen, which was given after the onset of coronary symptoms, in thrombi from patients with myocardial infarction establishes that the thrombus was initiated after the ischemic process.
Noninvasive assessment of mitral insufficiency by transcutaneous Doppler ultrasound.
Authors: Nichol P M , Boughner D R , Persaud J A
Published: June 2012

Instantaneous aortic arch blood velocity was recorded transcutaneously from the suprasternal notch, using a 2.2 MHz Doppler ultrasound unit, in 18 normals and 16 patients undergoing cardiac catheterization who had murmurs of mitral regurgitation. In normals aortic blood velocity rose rapidly in early systole to a midsystolic peak then fell to zero velocity. These roughly parabolic patterns had area ratios beneath the first and second halves of the curves measuring 52:48 +/- 3 (SD). With increasingly severe mitral regurgitation the pattern became skewed leftward such that the percent in the first half of systole ranged from 53-79%. From the angiograms of our sixteen patients an estimate of true percent regurgitation was made using the Fick cardiac output and ventricular volume measurements. When compared with the area under the first half of the velocity curve a strong correlation was found (r = 0.84) indicating that this Doppler technique can be used to evaluate mitral insufficiency.
Acute hemodynamic interventions shift the diastolic pressure-volume curve in man.
Authors: Alderman E L , Glantz S A
Published: June 2012

Frame-by-frame analysis of angiograms in 16 patients revealed that hemodynamic interventions are capable of producing substantial shifts in the diastolic pressure-volume curve. Angiotensin raises blood pressure and shifts the entire pressure-volume curve up, and nitroprusside lowers blood pressure and shifts the curve down. Indirect measurements of pleural pressure in seven patients (via esophageal pressure) showed that pleural pressure changes were too small to account for these shifts. Analyzing our results in terms of a theoretical pressure-volume equation previously validated in dog studies did not show the observed shifts to be the product of acute changes in the elasticity of the myocardium itself. This same analysis suggested that indirect changes in the external mechanical constraints acting on the left ventricle such as the right ventricular pressure, the pericardium, and perhaps viscoelastic effects related to changes in filling rate account for the pressure-volume curve shifts with intervention. The fact that one cannot in general relate a specific volume to a given pressure in the face of hemodynamic interventions calls into question the use of end-diastolic pressure interchangeably with end-diastolic fiber length when interpreting systolic events in terms of the Frank-Starling mechanism.
Response to exercise in patients after total surgical correction of Tetralogy of Fallot.
Authors: James F W , Kaplan S , Schwartz D C , Chou T C , Sandker M J , Naylor V
Published: June 2012

Heart rate, blood pressure, physical working capacity, and electrocardiographic changes were evaluated during upright bicycle exercise in 43 asymptomatic patients, aged seven to 41 years, one to 14 years after total surgical correction of tetralogy of Fallot (TF). One hundred and nine normal subjects between the ages of five and 42 years served as controls. The patient and control groups, subdivided by sex and body surface area (BSA), were similar in height and weight. When comparing males to males and females to females with BSA greater than or equal to 1.2 m2, maximal heart rates and working capacities were lower in the patient groups than in the control groups. An inverse relationship was observed between maximal working capacity and age at surgery in both male and female patient groups. By contrast, especially in the males with BSA less than 1.2 m2, the mean maximal heart rates and working capacities did not differ significantly between the patient and control groups. Premature atrial or ventricular contractions were recorded in ten of 43 patients (23%) after exercise. Five of these ten patients had multifocal premature ventricular contractions (PVC) and four had unifocal PVC. In the five patients with multifocal PVC, a short burst of ventricular tachycardia occurred in two, coupling in one, and bigeminal rhythm in two. Cardiac arrhythmia was not observed in the control group. Although our current surgical results are excellent, this study suggests that impaired cardiovascular function persists after corrective surgery and that early surgical treatment may be more desirable. Furthermore, additional data suggest that the exercise procedure may be useful in detecting and managing patients who may develop life-threatening arrhythmias following intraventricular surgery.
Idiopathic prolapsed mitral leaflet syndrome. Angiographic-clinical correlations.
Authors: Ranganathan N , Silver M D , Robinson T I , Wilson J K
Published: June 2012

Angiographic clinical correlations were made in 59 patients with prolapsed mitral leaflet syndrome. Eight had nonejection systolic clicks (group I), 20 had early, mid or late systolic murmurs with or without a systolic click (group II), and 31 had pansystolic murmurs (group III). Isolated prolapse of posterior leaflet (PL) scallops occurred in 42 and 17 had combined leaflet prolapse. The study demonstrated the following: (I) Group II patients usually had isolated PL prolapse with a predominant biscallop involvement while a high incidence of triple scallop prolapse and combined mitral leaflet prolapse occurred in group III. (II) Severe mitral regurgitation and a greater incidence of atrial fibrillation were seen in patients with triscallop prolapse and combined mitral leaflet prolapse. Mitral regurgitation was milder in patients with single and biscallop prolapse and, when severe, was associated with ruptured chordae. (III) ST-T wave abnormalities in the inferior leads were most frequent in patients with isolated PL prolapse. (IV) Systolic and diastolic asynergy occurred in 41 patients, most frequently in group II but also relatively frequently in group III (19 of 31). Segmental anterior dysfunction with normal ejection fraction was found in 18 patients, of whom 13 had early anterior wall relaxation. (V) Patients without asynergy were slightly older than those with it. More in the former group had severe mitral regurgitation and were clinically disabled from it.
Mitral valve prolapse. Two-dimensional echocardiographic and angiographic correlation.
Authors: Gilbert B W , Schatz R A , VonRamm O T , Behar V S , Kisslo J A
Published: June 2012

In order to define baseline descriptive criteria for the diagnosis of mitral valve prolapse with cross-sectional echocardiography, 49 patients undergoing catheterization were examined by a real-time, two-dimensional phased array echocardiographic imaging system. Angiography was used to separate patients into two distinct groups: 15 with normal mitral valve function and 34 with definite mitral valve prolapse. Systolic mitral leaflet and annulus motion were then observed in each patient and similarities and differences were noted between the two groups of patients. Correlative M-mode echocardiographic data were available in 37 patients. Certain two-dimensional echocardiographic findings restricted to the angiographically proven mitral valve prolapse group were defined: 1) posteriorly displaced coaptation of the leaflets, 2) systolic superior movement of one or both mitral leaflets above the level of the mitral ring, and 3) a systolic curling motion of the posterior mitral ring on its adjacent myocardium. One or more of these abnormalities were found in all 34 patients with angiographic mitral valve prolapse. When mitral valve prolapse does occur, the results of two-dimensional echocardiography would suggest that both leaflets are usually involved.
Distribution of coronary artery disease. Prediction by echocardiography.
Authors: Dortimer A C , DeJoseph R L , Shiroff R A , Liedtke A J , Zelis R
Published: June 2012

To assess the sensitivity of standard echocardiography in detecting ventricular motion abnormalities in patients with coronary artery disease (CAD) without prior myocardial infarction, 56 consecutive patients with a history of angina pectoris were studied during an angina-free period. In the 48 patients with adequate echocardiograms, the amplitude of septal and posterior wall motion in the high, mid, and low left ventricle was determined and used to predict prospectively in a blinded fashion the sites of angiographically-determined CAD. Twenty-eight of 35 patients (80%) with disease of the left anterior descending artery (LAD) had diminished interventricular septal motion (P less than 0.001) and 14 of 27 patients (52%) with disease of posterior vessels had diminished posterior wall motion on echocardiogram. When abnormalties of echocardiographic wall motion were compared with left ventriculography, the results were similar. Echocardiography may aid in predicting the presence and distribution of CAD, especially LAD disease.
Echocardiographic measurement of cardiac output using the mitral valve and aortic root echo.
Authors: Lalani A V , Lee S J
Published: June 2012

The current echo method for measuring cardiac output (CO) has various technical limitations and is based on the assumptions that the left ventricle is not dilated and that it contracts uniformly. We have taken a different approach to measuring CO by echo: CO = cross-sectional area of aortic root X left ventricular ejection time X mean aortic flow velocity X heart rate. Using the Fick method, 34 measurements of CO were made in patients with normal aortic and mitral valves, with simultaneous echo recordings from the aortic and mitral valves. The systolic closure slope of the anterior mitral valve leaflet was assumed to represent the mean aortic flow velocity. CO by Fick and the proposed echo method correlated well, both in patients with (r = 0.94) and those without (r = 0.87) asynergy and the overall correlation was strong (r = 0.90). Using the conventional echo and Fick methods, a much weaker association was found between the two measurements in those patients with asynergy (r = 0.44) as opposed to those without asynergy (r = 0.77).
Reduction of ischemic injury by sublingual nitroglycerin in patients with acute myocardial infarction.
Authors: Awan N A , Amsterdam E A , Vera Z , DeMaria A N , Miller R R , Mason D T
Published: June 2012

The effect of sublingual nitroglycerin (NTG) on myocardial ischemic injury was evaluated in eleven patients with acute anterior myocardial infarction. Precordial 35-lead ST-segment maps were obtained in each patient immediately before and 3-10 minutes after 0.4 mg sublingual NTG. The following measurements were made from each ST map: N-ST (number of leads showing ST elevation greater than 1mm), sigmaST (total ST elevation in all leads), ST (average ST-segment elevation in those leads with less than 1mm elevation). Following 0.4 mg sublingual NTG evidence of myocardial ischemic injury as assessed by ST-segment mapping decreased in association with reduction of heart rate X systolic blood pressure product (10.80 X 10(3) to 9.49 X 10(3), P less than 0.001). Group mean values diminished significantly for N-ST (18.1 to 14.4, P less than 0.001), sigma ST (37.9 to 30.1 P less than 0.005) and ST (1.7 to 1.4, P less than 0.001). Evaluation performed by the technique of precordial ST-segment mapping suggests that sublingual nitroglycerin in a commonly employed clinical dose is associated with evidence of reduced ischemic cardiac injury in patients with acute myocardial infarction. This effect appears to be related to reduction of myocardial oxygen demand by the nitrate.
Electrophysiologic properties and response to pharmacologic agents of fibers from diseased human atria.
Authors: Hordof A J , Edie R , Malm J R , Hoffman B F , Rosen M R
Published: June 2012

We used standard microelectrode techniques to record action potentials of human right atrial fibers obtained during cardiac surgery, and correlated these potentials with clinical and preoperative ECG data. Human atrial fibers were classified as follows: Group A (ten patients) had a maximum diastolic potential (MDP) of -71.4 +/- 5.1mV (mean +/- SD), and action potentials that were primarily fast responses. These atria were normal or slightly dilated. In group B (12 patients) MDP was 50.3 +/- 5.7 mV; action potentials were slow responses and the atria were moderately to markedly dilated. Atrial arrhythmias occurred in four group B and no group A patients. The ECG revealed a signficant difference (P less than 0.005) in P wave duration: group A, 89 +/- 3.0 msec; group B, 111 +/- 6.0 msec. Verapamil, 0.1 mg/L, markedly depressed only the action potential plateau of group A. Procainamide 1-100 mg/L had equivalent effects on fibers of both groups A and B, effects which were small at dosages of less than 40 mg/L. Procainamide did not depress slow response automaticity, but verapamil (0.1-1 mg/L) did.
The natural history of trifascicular disease following permanent pacemaker implantation. Significance of continuing changes in atrioventricular conduction.
Authors: Lichstein E , Ribas-Meneclier C , Naik D , Chadda K D , Gupta P K , Smith H
Published: June 2012

Seventy-two patients with trifasicular disease were followed for an average of 40 months following permanent pacemaker insertion. The indications for pacemaker insertion were either electrocardiographic evidence of complete heart block with a wide QRS escape complex or a pattern of bifasicular block with either periods of Mobitz type II atrioventricular (A-V) block or a documented history of syncope. The patients were then divided into three groups depending on subsequent change in A-V conduction. There were 31 (43%) patients with no change in A-V conduction, 17 (24%) with increasing A-V block, and 24 (33%) with decreasing A-V block. The characteristics of these three groups, including age and sex distribution, were compared and found to be similar. The incidence of previous transmural myocardial infarction as determined by electrocardiographic criteria was higher in the group with decreasing block. Survival curves showed a significantly decreased probablity of surviving for those with decreasing block compared to both those with increasing block and those with no charge in conduction (P less than 0.03). We conclude that the probability of long-term survival was less in the group with decreasing block. This finding may be related to the greater prevalence of coronary heart disease in the patients.
Thallium 201 myocardial imaging in patients with pulmonary hypertension.
Authors: Cohen H A , Baird M G , Rouleau J R , Fuhrmann C F , Bailey I K , Summer W R , Strauss H W , Pitt B
Published: June 2012

The appearance of the right ventricular myocardium on thallium 201 myocardial perfusion images was evaluated in patients with chronic pulmonary hypertension and compared to patients without pulmonary hypertension. Four groups of patients were studied: 1) eight normals, 2) five patients with angiographically documented coronary artery disease and normal pulmonary artery pressures, 3) ten patients with moderate to severe pulmonary parenchymal or vascular disease and documented pulmonary hypertension and 4) eight patients with chronic left ventricular dysfunction and pulmonary hypertension discovered during cardiac catheterization. The right ventricular free wall was visualized on the thallium 201 myocardial perfusion image in only one of eight normals (group 1) and in only one of the five patients with coronary artery disease (group 2) and measured 0.5 cm and 0.9 cm in thickness, respectively. In patients with documented pulmonary hypertension the right ventricle was visualized on low contrast thallium 201 myocardial perfusion image in all patients. The apparent right ventricular free wall thickness measured from the ungated thallium 201 myocardial perfusion images was 1.7 +/- 0.3 cm in group 3 and 1.5 +/- 0.2 cm in group 4. Right ventricular hypertrophy was detected by electrocardiography in only five of ten patients in group 3 and only one of eight patients in group 4. Thallium 201 myocardial perfusion imaging appears to be a useful technique for assessing the effects of chronic pulmonary hypertension on the right ventricular myocardium.
Right ventricular volume characteristics in ventricular septal defect.
Authors: Graham T P , Atwood G F , Boucek R J , Cordell D , Boerth R C
Published: June 2012

Right and left ventricular volume characteristics were determined from biplane cineangiocardiography in 37 patients with isolated ventricular septal defects. Patients were divided into three categories as determined by the degree of left-to-right shunt: small shunt-less than 35% of pulmonary blood flow (N=9); moderate shunt-35-49% (N=8), and large shunt-greater than 50% (N=20). Right ventricular (RV) end-diastolic volume was increased above normal in 15 of 20 studies performed in patients with large left-to-right shunts and averaged 159 +/- 10% of normal (P less than 0.001). In contrast, only one of the patients in the small shunt group and only half of the patients in the moderate shunt group showed increases in RV end-diastolic volume. The increase in RV volume was proportional to the corresponding increase in left ventricular end-diastolic volume, with the right ventricle ranging from 48 to 116% of LV end-diastolic volume (average 83%). Right ventricular ejection fraction was normal in all patient groups. Right ventricular outpur was increased commensurate with the increases in the RV end-diastolic volume. These data indicate that substantial augmentation in RV end-diastolic volume does occur in patients with isolated ventricular septal defects and large left-to-right shunts. These data can be explained by the significant diastolic and "isovolumic" shunting from left ventricle to right ventricle which occurs in these patients.
Results of a two-year health education campaign on dietary behavior. The Stanford Three Community Study.
Authors: Stern M P , Farquhar J W , McCoby N , Russell S H
Published: June 2012

A two-year, bilingual mass-media health education campaign was carried out in two communities with a third serving as control. In one of the two treated communities, personal couseling of high risk individuals ("intensive instruction") took place. Dietary behavior, before and after the campaigns, was assessed using a dietary questionnaire which estimated the average daily consumption by participants of cholesterol, saturated fat, and polyunsaturated fat. Both intensive instruction and the mass-media campaigns led to significant reductions (20-40%) in cholesterol and saturated fat consumption in both men and women, with intensively instructed men tending to outperform men exposed to mass-media alone. In general, the improvements in the treated communities were maintained over the two years of the study, whereas the initial small drops in the control community at the end of the first year were followed by recidivism during the second year. Polyunsaturated fat consumption fell slightly in all three communities so that increases in P/S ratios in the two treated communities were of only modest degree. Mean changes in plasma cholesterol concentration for the various cohorts under study were higly correlated with those which would have been predicted on the basis of the self-reported changes in dietary behavior. The results indicate that mass-media health education campaigns can lead to significant changes in dietary practices in the general population with potentially important public health implications.
Reduced cholinergic sinus node restraint in hyperthyroidism.
Authors: White C W , Zimmerman T J
Published: June 2012

The role of the cholinergic nervous system in the tachycardia of hyperthyroidism was investigated in this study of dogs made severely thyrotoxic by the administration of Na-L-thyroxine over a six to nine month period. Differences in heart rate between control and thyrotoxic unanesthetized dogs could be abolished by cumulative doses of intravenous atropine both before and after beta-adrenergic blockade with propranolol, and at submaximal as well as maximal heart rates. There were no differences in the heart rate response of control and thyrotoxic anesthetized dogs to vagal stimulation or to the selective injection of hypertonic saline or acetylcholine into the perfused sinus node artery. The results indicate that in addition to the direct effects of thyroid hormone on sinus node automaticity there is an abnormality in parasympathetic control of heart rate in hyperthyroidism. The data suggest that this abnormality is not due to a decreased responsiveness of the sinus node or an impaired release of the cholinergic neurotransmitter, but may reflect a reduction in cholinergic efferent activity in the thyrotoxic state.
The expression of normal ventricular repolarization in the body surface distribution of T potentials.
Authors: Abildskov J A , Burgess M J , Lux R L , Wyatt R , Vincent G M
Published: June 2012

Isopotential maps from 120 normal subjects were obtained from 192 simultaneously recorded electrocardiographic leads. Maps were plotted at 1 msec intervals during the QRS and 5 msec intervals during the ST-T deflection. Repetition of QRS features was evident during all but the first few msec of the initial half of serial T maps. This suggests similarities of the normal sequence of ventricular excitation and recovery. Such similarities have been demonstrated by direct studies but are not evident from other electrocardiographic examinations. Serial maps during later portions of the T wave showed decreasing intensity of potentials with little change of body surface locations. This also correlates with an established feature of ventricular repolarization, namely that potential difference boundaries with stable locations are widely distributed during part of that process. Findings suggest isopotential maps show features of ventricular recovery not apparent from less extensive examinations.
Echophonocardiographic studies of the contribution of the atrioventricular valves to the first heart sound.
Authors: Mills P G , Chamusco R F , Moos S , Craige E
Published: June 2012

The movements of the mitral, tricuspid and aortic valves have been recorded echocardiographically and related to the first heart sound (S1) in patients with various hemodynamic and conduction abnormalities. Closure of the mitral and tricuspid valves has been studied with respect to the corresponding atrioventricular pressure crossover and it is clear that both valves finish closing about 50 msec after pressure crossover. In order to clarify the relative contribution of tricuspid valve closure and aortic root events to the second high frequency component of S1, a new simultaneous dual echophonocardiographic technique was employed. This permitted the simultaneous registration of tricuspid and aortic valve movements and demonstrated that in certain circumstances the second high frequency component of S1, could be attributed to tricuspid closure, aortic root events being excluded from the genesis of this sound. These observations suggest that the two high frequency components of S1 are related to closure of the mitral and tricuspid valves. The results do not however, exclude a contribution to S1 of aortic root events, which may be of lower frequency vibrations.
Hemodynamics after surgical repair with right ventricle to pulmonary artery conduit.
Authors: Rocchini A P , Rosenthal A , Keane J F , Castaneda A R , Nadas A S
Published: June 2012

To assess the results of cardiac repair utilizing a right ventricular to pulmonary artery conduit, we reviewed postoperative hemodynamic data in 16 patients catheterized 0.5 to 5 years after repair. In 12 patients, a Hancock conduit (dacron conduit with porcine valve) was used; the conduit in the remaining four patients was made with an aortic homograft. All patients in whom an aortic homograft was utilized developed severe obstruction and calcification of their graft. The majority of patients, 9/12, with a Hancock conduit, had only mild to moderate conduit obstruction; the remaining three had severe obstruction (gradients greater than 70 mm Hg). The sites of Hancock conduit obstruction were at the distal end of the conduit in 8/12, proximal end of conduit in 6/12, and at the porcine valve in 4/12 patients. The data suggest that repair with a Hancock conduit is hemodynamically more satisfactory than with aortic homograft.
Subaortic obstruction after the use of an intracardiac baffle to tunnel the left ventricle to the aorta.
Authors: Rocchini A P , Rosenthal A , Castaneda A R , Keane J F , Jeresaty R
Published: June 2012

Postoperative hemodynamic studies in five patients document subaortic obstruction after surgical repair utilizing an intracardiac baffle to establish continuity between the left ventricle and the aorta. Four of the patients had a Rastelli procedure for D-transposition of the great arteries with a ventricular septal defect and pulmonary stenosis; one patient had repair of double outlet right ventricle with a ventricular septal defect and pulmonary stenosis. The left ventricular outflow was shown to be a long narrow tunnel by angiography in four of five patients and by echocardiography in one patient. Resting aortic peak systolic pressure gradient ranged from 10 to 42 mm Hg (mean 24). The obstruction was localized to the proximal end of the left ventricule to aorta tunnel (i.e., at the site of ventricular septal defect) in five patients. One patient with a gradient of 42 mm Hg has angina and decreased exercise tolerance. Subaortic obstruction is a newly described sequelae after the Rastelli procedure for transposition or repair of double outlet right ventricle. The obstruction may be hemodynamically significant and should be searched for at postoperative cardiac catheterization.
Blood pressure in tenth-grade students: results from the Chicago Heart Association Pediatric Heart Screening Project.
Authors: Miller R A , Shekelle R B
Published: June 2012

This report is based on 13,231 tenth-grade students who participated in the Chicago Heart Association Pediatric Heart Screening Project. The blood pressures of these fifteen and sixteen-year-olds were analyzed with respect to sex, race, adiposity, pulse rate, and father's educational attainment. The mean systolic blood pressure was higher in boys than girls by nearly 5 mm Hg, but mean diastolic blood pressure was lower by less than 1 mm Hg. Black tenth-graders had higher mean diastolic blood pressure than whites; the difference in systolic blood pressure was not statistically significant. Adiposity and resting pulse rate were positively correlated with systolic blood pressure and, to a lesser degree, with diastolic blood pressure. After taking adiposity and pulse rate into account, father's educational attainment had a small but statistically significant negative association with diastolic blood pressure in white but not in black students. Nearly 5 percent of students were recalled for a second test because the initial screening blood pressures equaled or exceeded 150 mm Hg systolic or 90 mm Hg diastolic, and almost half of students at the recall examination continued to have pressures of 145/85 or greater.
A quantitative echocardiographic study of champion childhood swimmers.
Authors: Allen H D , Goldberg S J , Sahn D J , Schy N , Wojcik R
Published: June 2012

An echocardiographic evaluation of 77 members of a championship childhood swim team showed dimensional variations from normal in most athletes. Cardiac walls were thicker than the 95th percentile of normal: right ventricular anterior wall exceeded the 95th percentile in 100%, interventricular septum in 83% and left ventricular posterior wall in 91%. The left ventricular and left atrial cavities in diastole had mean values at the 50th percentile of normal but showed considerable scatter. The left ventricular cavity in systole had a mean value less than the 5th percentile of normal and also showed wide scatter. The aortic root and the aortic intercusp dimension exceeded the 95th percentile of normal in most subjects, 74% and 77%, respectively. No correlation existed between the coach's estimate of championship ability and echocardiographic wall or chamber sizes. Children who participate extensively in athletic training programs such as swimming may have echocardiograms which are quantitatively different from those of nonathletic younsters.
Mid-diastolic aortic valve opening in severe acute aortic regurgitation.
Authors: Weaver W F , Wilson C S , Rourke T , Caudill C C
Published: June 2012

A case of severe acute aortic regurgitation is reported. Echocardiographic findings included mid-diastolic opening of the aortic valve, premature closure of the mitral valve, diastolic shuddering of the anterior mitral leaflet, probable demonstration of the flail aortic cusp in the left ventricular outflow tract, and increased left atrial and left ventricular dimensions. Correlation with hemodynamic, angiographic and surgical evidence is made.
The response of healthy men to treadmill exercise.
Authors: Wolthuis R A , Froelicher V F , Fischer J , Triebwasser J H
Published: June 2012

Heart rates, blood pressures, and functional responses to submaximal, maximal and postexertional treadmill testing are presented for a group of 704 healthy, asymptomatic aircrewmen referred to the USAF School of Aerospace Medicine. The indicated measurements are individually described by the use of percentiles. These data provide the practicing clinician with an accurate and complete description of the response of healthy men to treadmill exercise.
Effects of operation on left atrial size and the occurence of atrial fibrillation in patients with hypertrophic subaortic stenosis.
Authors: Watson D C , Henry W L , Epstein S E , Morrow A G
Published: June 2012

The relation between left atrial size and atrial fibrillation was examined in 37 patients who had left ventriculomyotomy and myectomy at the National Heart and Lung Institute. Atrial fibrillation was present in 11 of 27 (41%) patients with an echocardiographically measured left atrial dimension greater than 45 mm. No patient with a left atrial dimension less than 45 mm had atrial fibrillation pre or postoperatively. Eleven of 13 patients less than 40 years of age with an abnormal preoperative left atrial dimension had a 10% or greater reduction in left atrial dimension postoperatively. A group of 21 patients 40 years of age or older had an abnormal left atrial dimension preoperatively, and no significant change postoperatively. These results indicate that left ventriculomyotomy and myectomy can produce a significant decrease in left atrial size in younger patients with idiopathic hypertrophic subaortic stenosis. It is hoped that the decrease in atrial size may reduce the risk of atrial fibrillation in these patients.
Left ventricular performance in the critically ill premature infant with patent ductus arteriosus and pulmonary disease.
Authors: Baylen B , Meyer R A , Korfhagen J , Benzing G , Bubb M E , Kaplan S
Published: June 2012

Left cardiac dimensions and an index of left ventricular performance, the percent shortening of the internal diameter (%SID) of the left ventricle, were evaluated in premature infants who were asymptomatic, others with pulmonary disease and others with patent ductus arteriosus (PDA). In contrast to controls, left atrial and/or left ventricular end-diastolic dimensions were increased in all infants with clinical criteria of significant PDA. Postoperative dimensions decreased significantly. Percent SID values for normal premature infants (m=33.5%; SD=3.5%) and those with pulmonary disease alone did not differ significantly. In those with clinical criteria of PDA, who were subsequently found to have echocardiographic evidence of left cardiac enlargement, values for %SID were increased. As expected %SID values for individual patients represented a wider range of left ventricular function and/or afterload than for controls. Upon spontaneous or surgical closure of the PDA, %SID returned to normal. A PDA which is associated with left cardiac enlargement exhibits increased %SID, whereas decreasing %SID in the presence of increased dimensions suggests deteriorating myocardial performance. Echocardiography provides valuable insight into the cardiac status of these infants and may contribute to their medical and/or surgical management.
Coarctation of the aorta with ventricular septal defect.
Authors: Neches W H , Park S C , Lenox C C , Zuberbuhler J R , Siewers R D , Hardesty R L
Published: June 2012

From 1965 to 1974, 53 children with coarctation of the aorta (COA) and an associated ventricular septal defect (VSD) underwent cardiac catheterization. Thirty-one patients presented with congestive heart failure. Twenty-five of 27 patients (92%) who underwent cardiac catheterization under age 3 months had either systemic hypertension, a systolic gradient across the coarctation greater than 20 mm Hg or both. Pulmonary hypertension was present in all 25 patients. COA repair was performed in 39 patients and there were seven deaths. Of the 32 survivors, 23 have no residual gradient; six are normotensive but have a mild residual gradient; three are hypertensive or have a gradient greater than 20 mm Hg. Repair of the VSD or pulmonary artery banding has been performed in 11 of 44 patients who survived infancy. Spontaneous closure of the VSD has occurred in three cases and 25 patients have a small VSD that does not warrant surgical repair. Surgical repair of COA during infancy may be unavoidable but conservative medical management of the associated VSD is often successful.
Development of pulmonary arteriovenous shunt after superior vena cava-right pulmonary artery (Glenn) anastomosis. Report of four cases.
Authors: McFaul R C , Tajik A J , Mair D D , Danielson G K , Seward J B
Published: June 2012

Four patients with cyanotic congenital heart disease who had previously undergone superior vena cava-right pulmonary artery (Glenn) anastomosis developed pulmonary arteriovenous malformations that resulted in significant intrapulmonary right-to-left shunting. This abnormality was documented by selective angiography, oximetry, and contrast echocardiogrphy. It may be a major cause of late clinical deterioration in patients treated with the Glenn anastomosis.
Diagnosis of trifasicular damage following tetralogy of fallot and ventricular septal defect repair.
Authors: Yabek S M , Jarmakani J M , Roberts N K
Published: June 2012

We evaluated the usefulness of the surface electrocardiogram to predict the presence of postoperative trifascicular damage. We used the pre and postoperative electrocardiograms and postoperative His bundle electrograms from 50 patients an average of 3.8 years following tetralogy of Fallot (TF) and ventricular septal defect (VSD) repair. Right bundle branch block (RBBB) and RBBB with left anterior hemiblock (LAH) developed in 88% and 18% respectively, and 22% had transient postoperative complete heart block (CHB). Mean P-A and A-H conduction times were 16.6 and 84.9 msec and were not different from 37 are-matched normal patients and 61 patients with unoperated TF and VSD. The mean H-V conduction time of 48.5 msec was significantly increased compared to the other two groups. Ten postoperative patients had H-V times of 55 msec or greater, indicating trifasicular damage. Of these, five had electrocardiographic bifascicular block (RBBB with LAH) with or without additional 1 degrees A-V block. The remaining five patients' electrocardiograms did not suggest trifascicular damage. Since postsurgical trifascicular damage may progress to late onset CHB, conduction studies are indicated to identify patients at risk, despite surface electrocardiographic findings.
Thallium-201 myocardial perfusion imaging at rest and during exercise. Comparative sensitivity to electrocardiography in coronary artery disease.
Authors: Bailey I K , Griffith L S , Rouleau J , Strauss W , Pitt B
Published: June 2012

The sensitivity of myocardial perfusion imaging (MPI) using thallium-201 injected both at rest and during peak exercise was compared to simultaneously recorded 12 lead electrocardiography (ECG) for the detection of transient ischemia in 20 normal subjects and 63 patients with coronary artery disease (CAD). No significant perfusion defects or ECG changes were seen on either the rest or exercise studies in any of the normal subjects. Fifty-six percent of patients with CAD developed new perfusion defects with exercise compared to 38% who developed ischemic ST-segment depression (P less than 0.02). However, when chest pain and/or ST depression were considered indices of ischemia, the sensitivity of exercise testing and thallium-201 MPI was similar. The increased sensitivity of MPI compared to ST-segment depression on the ECG was due to patients with baseline ECG abnormalities and those who failed to achieve 85% of predicted maximum heart rate with exercise. Analysis of the exercise results according to the extent of coronary artery disease revealed a progressive increase in both positive ECGs and MPI with the number of vessels involved. In patients with single vessel disease the MPI was more sensitive than the ECG (P less than 0.02). The combination of the rest and exercise ECG, MPI and chest pain during exercise failed to identify 11% of patients with CAD. Exercise thallium-201 MPI is a useful adjunct to conventional exercise testing particularly when evaluating patients with abnormal resting ECGs, those who develop ventricular conduction defects of arrhythmias during exercise, and those who fail to achieve their predicted heart rate because of fatigue or breathlessness.
Detection of left atrial myxoma by gated radionuclide cardiac imaging.
Authors: Pohost G M , Pastore J O , McKusick K A , Chiotellis P N , Kapellakis G Z , Myers G S , Dinsmore R E , Block P C
Published: June 2012

Gated radionuclide cardiac blood pool scans (GCS) of end-systole and end-diastole or eight images subtending the entire cardiac cycle were performed on seven patients with left atrial myxomas documented by pulmonary cineangiography with left atrial follow-through. The ethocardiogram was either suggestive or diagnostic in all patients. In addition to demonstration of the tumor (6 patients), the GCS detected three patterns of tumor motion: 1) a defect which moved from the left atrium in end systole to the left ventricle in end diastole (2 patients); 2) a defect which remained within the region of the left atrium but decreased in size between end diastole and end systole (3); and 3) a defect which was observed within the region of the left ventricle in end diastole but disappeared in end systole (1). Thus, the GCS is a noninvasive method for detection and evaluation of motion of left atrial myxomas.
Multiple arrhythmias detected during nocturnal monitoring in patients with congenital complete heart block.
Authors: Levy A M , Camm A J , Keane J F
Published: June 2012

Twenty patients with congenital complete heart block (CHB) were monitored with ECG tape recordings while awake and asleep. Episodes of marked ventricular slowing during sleep (R-R greater than 3000 msec., i.e. less than 20 beats/min) were noted in 35% (7/20). Most of these sudden R-R prolongations were 2:1 or 3:1 exit block of the junctional focus. Atrial and ventricular rate changes were mostly concordant in 2/3 but the remainder demonstrated fixed ventricular rates while atrial rates varied normally, suggesting a "sick" or "lazy" junctional focus. Other arrhythmias were found in 60% (12/20), including several types of rhythms in three patients. One child with previously unsuspected superimposed multiple arrhythmias later had a syncopal episode despite proven supra-Hisian block. The multiple patterns of atrial and ventricular rate changes found indicate complex feedback mechanisms, suggesting that congenital CHB is not a single entity. Since a significant number of patients demonstrated one or another of these unexpected and potentially hazardous findings, we recommend that congenital block patients be carefully studied, including Holter monitoring done on a regular basis.
Intracardiac conduction intervals in children with congenital heart disease: comparison of His bundle studies in 41 normal children and 307 patients with congenital cardiac defects.
Authors: Levin A R , Haft J I , Engle M A , Ehlers K H , Klein A A
Published: June 2012

His bundle electrograms were recorded in 348 patients aged 2 months to 24 years following routine diagnostic cardiac catheterization. Among 41 children found to be free of anatomic or hemodynamic abnormality the following mean values were obtained: P-H interval, 93.4 +/- 15.3 msec; P-A time, 21.2 +/- 7.1 msec; A-H interval, 72.2 +/- 15.9 msec; and H-V interval, 39.8 +/- 5.2 msec. The remaining 307 patients were analyzed by diagnosis of congenital heart disease. The mean P-H interval was found to be significantly increased in both ostium primum and secundum atrial septal defect (ASD) with A-H prolongation in primum ASD and P-A prolongation in secundum ASD. The mean H-V interval was significantly prolonged in ostium primum ASD and in patients with severe aortic stenosis, aortic insufficiency. and mitral regurgitation. Grouping of the patients physiologically revealed that patients with moderate-to-severe right ventricular volume overload had P-H prolongation, and patients with severe left ventricular volume or pressure overload had H-V prolongation. The clinical implications of these findings are discussed.
Differentiation of transiently ischemic from infarcted myocardium by serial imaging after a single dose of thallium-201.
Authors: Pohost G M , Zir L M , Moore R H , McKusick K A , Guiney T E , Beller G A
Published: June 2012

Myocardial 201Tl uptake and regional blood flow by the microsphere technique were determined in anesthetized dogs undergoing either 20 min of coronary occlusion and 100 min of reperfusion (N = 10) or 120 min of occlusion (N = 4). In both groups, 201Tl was injected intravenously after 10 min of occlusion. In transiently occluded dogs, regional flow at the time of 201Tl administration was reduced to 8 +/- 3% of normal flow in endocardial layers of the central ischemic zone. After 100 min of reperfusion, flow values were not significantly different from normal. 201Tl activity after reperfusion rose to 56 +/- 5% of normal, demonstrating that redistribution of the radionuclide occurred during the reflow period. In animals with persistent occlusion, there was a significant relationship between 201Tl uptake and flow (r = 0.95) and no evidence of redistribution of 201Tl during the two hour occlusion period. In another five dogs receiving 201Tl, serial gamma camera images obtained during reperfusion showed increasing uptake of the tracer in apical defects which returned to normal by 4 hours of reflow. Thirteen patients with stable angina received 2 mCi of 201Tl intravenously at peak exercise, and multiple gamma camera images obtained serially. All demonstrated zones of diminished 201Tl uptake 10 min after exercise. Defects which partially or completely disappeared within 1-6 hours postexercise corresponded to areas supplied by coronary arteries with significant stenoses. Persistent defects were present in regions of old myocardial infarction. Six additional patients with acute myocardial infarction demonstrated 201Tl myocardial defects which showed no significant change over 6 hours. Thus, redistribution of 201Tl into ischemic myocardium was demonstrated during transient coronary occlusion in dogs and after exercise stress in man. Sequential imaging after a single dose of 201Tl at the time of exercise may provide a means for distinguishing between transient perfusion abnormalities or ischemia and myocardial infarction of scar.