bluuebunny/crossref_metadata_2025 huggingface dataset:
Abnormal blood pressure response and marked ischemic ST-segment depression as predictors of severe coronary artery disease.
Authors: Sanmarco M E , Pontius S , Selvester R H
Published: June 2012

The usefulness of an abnormal blood pressure response and a marked ischemic ST-segment depression during exercise testing as predictors of severe coronary artery disease was assessed in 378 consecutive patients who had a maximal symptom-limited exercise test before coronary arteriography. An abnormal blood pressure response occurred in 90 patients. The sensitivity of this response for three-vessel or left main disease was 38.6%, the specificity 87.4% and the predictive value 70%. A marked ischemic ST-segment abnormality (MIST) appeared in 85 patients. The sensitivity of MIST for three-vessel or left main disease was 38.6%, the specificity 89.8% and the predictive value 74.1%. One hundred thirty-eight patients had either an abnormal blood pressure response or a marked ST-segment change. The sensitivity of either response for three-vessel or left main disease was 56.4%, the specificity 78.6%, and the predictive value 66.7%. Exercise duration and ejection fraction were not significantly different in patients with normal or abnormal blood pressure. We conclude that abnormal blood pressure and marked ischemic ST-segment depression during exercise testing are helpful in identifying a subset of patients with advanced coronary artery disease. The physiologic mechanism for these responses is probably exercise-induced ischemia.
Intraventricular reentry with narrow QRS complex.
Authors: Reddy C P , Khorasanchian A
Published: June 2012

Reentry within the His-Purkinje System (V3 phenomenon) where the reentry pathway incorporates both bundle branches and the bundle of His is a frequent phenomenon during ventricular refractory period studies. In this form of reentry, both divisions of the left bundle branch function as a single limb and the reentrant beats (V3) have either left bundle branch block or right bundle branch block pattern. In this report, we describe in three patients the occurrence of a new type of reentrant beat (V3) whose characteristics suggested reentry within a circuit in which the retrograde limb of the reentrant circuit was constituted by one of the two divisions of the left bundle branch and the antegrade limb(s) by right bundle branch and the remaining division of the left bundle branch; i.e., the two divisions of the left bundle branch functioned as two separate limbs. We reached this conclusion because 1) reentry occurred within a narrow range of V1V2 intervals and was dependent upon critical retrograde His-Purkinje conduction (V2H2) delays; 2) reentry did not occur when the V2 impulse blocked retrogradely within the His-Purkinje system below the site of His bundle recording; 3) the QRS duration of V3 was less than 90 msec; and 4) in two-thirds of the patients, the HV interval of V3 was the same as that of sinus beats.
Alternate ventriculoatrial Wenckebach conduction.
Authors: Levy S , Roudaut R , Bouvier E , Obel I W , Clementy J , Bricaud H
Published: June 2012

Three cases are presented showing retrograde alternate Wenckebach periods. Retrograde alternate Wenckebach periods were defined as 2:1 ventriculoatrial (VA) block in which the conducted beats showed progressive prolongation of conduction (VA) time. The sequence terminates with two or three successively blocked ventricular beats. In one of the three cases the level of block was identified as being in the atrioventricular (AV) node. In the other two the level of block could not be clearly identified. This report provides further evidence for the concept of multilevel block within the AV node. Retrograde alternate Wenckebach periods may explain some instances of variation of atrial depolarization intervals during episodes of ventricular tachycardia and may be clinically significant.
Influence of left ventricular dimensions on endocardial and epicardial QRS amplitude and ST-segment elevations during acute myocardial ischemia.
Authors: Lekven J , Chatterjee K , Tyberg J V , Parmley W W
Published: June 2012

The influence of acute myocardial ischemia and changes in ventricular dimensions on endocardial and epicardial electrograms were evaluated in 17 anesthetized open-chest dogs before and after left ventricular volume expansion and before and after coronary artery ligation. In eight dogs, regional myocardial blood flow was determined by the labeled microsphere technique. Endocardial QRS (endo-QRS) amplitude in ischemic and nonischemic zones, and epicardial QRS (epi-QRS) in nonischemic zones maintained a negative linear relation with left ventricular end-diastolic dimension before and after coronary artery ligation, although acute ischemia decreased endo-QRS independently. Epi-QRS amplitude in the ischemic zone decreased after coronary artery ligation but changed inconsistently during volume expansion. Ischemia-induced epicardial ST-segment elevation decreased during volume expansion and was associated with improved epicardial blood flow. Changes in epi-QRS in ischemic zones, however, were not related to epicardial blood flow during volume expansion. These findings indicate the potential problems of using changes in QRS amplitude for determining the extent of myocardial ischemic injury.
Spontaneous variability of complex ventricular arrhythmias detected by long-term electrocardiographic recording.
Authors: Michelson E L , Morganroth J
Published: June 2012

Variations in the frequency of complex ventricular arrhythmias were evaluated by consecutive 24-hour long-term electrocardiographic recordings over 4 days using a two-channel recorder and computer-assisted analysis system with a weighted relative mean error of 7.5 +/ 5% (SD). Twenty patients (mean age 58 +/- 9 years [SD] with various cardiac disorders were selected if they had a daily average of more than 30 ventricular ectopic complexes per hour. Twenty patients had ventricular couplets and 14 patients had ventricular tachycardia (at least triplets). The mean daily number of either couplets or ventricular tachycardia was subjected a four-factor nested analysis of variance to determine the sources of variation in ectopic frequency. Differences in hourly rates accounted for 30% of the variation in the frequency of ectopic complexes. Statistical methods were applied to determine the change in frequency of complex arrhythmias necessary to exceed that attributable to spontaneous variation alone at the p less than 0.05 level. Using a typical protocol, for example, comparing a 24-hour test period with a 24-hour control period would require a 65% decrease in mean hourly frequency of ventricular tachycardia and 75% reduction in the frequency of couplets to demonstrate therapeutic efficacy rather than a reduction due to spontaneous variation alone.
Development of a bladder-free cuff for measuring the blood pressure of the fingers and toes.
Authors: Hirai M , Ohta T , Shionoya S
Published: June 2012

In the present study, we investigated the technique and reliability of measuring digital blood pressure by means of a rigid, airtight container (a bladder-free cuff) and a photocell placed on the digit. As cuff pressure increased, the position of digits in the cuff was maintained in the hand by fixing one or two fingers inside the cuff and, in the foot, by using a supporting stick to keep the distance from the cuff to the bed constant. An airtight seal inside the cuff was achieved using a thin rubber sleeve and adhesive tape. Blood pressures determined by the bladder-free cuff correlated well with those obtained by the conventional cuff with bladder. By using the bladder-free cuff, blood pressure could be measured at the distal phalanx of the fingers and in all toes.
Changes after quitting cigarette smoking.
Authors: Friedman G D , Siegelaub A B
Published: June 2012

Changes in cardiorespiratory symptoms and coronary disease risk indicators over an average 1 1/2-year period were assessed in 9392 persistent cigarette smokers and 3825 persons who quit smoking between two multiphasic checkups. The prevalence of questionnaire-reported chronic cough fell markedly in subjects who quit a one-or-more-pack/day habit (e.g., from 11.2% to 1.8% in white men, p less than 0.001). However, chest pain, shortness of breath and exertional leg pain showed no consistent improvement in quitters compared with persistent smokers. Weight gain was about 2-3 lbs greater in quitters, but changes in blood pressure were small and not consistent across race-sex groups, nor were there consistent differences between persistent smokers and quitters in trends in trends in vital capacity, cholesterol or prevalence of ECG abnormality. Quitting was associated with increase in serum uric acid levels of about 0.2-0.5 mg/dl and relative falls in hemoglobin, leukocyte count and serum glucose levels, all consistent with smoker-nonsmoker differences previously found in cross-sectional studies. Except for the small increases in weight and uric acid levels, quitting smoking did not appear to increase risk of coronary heart disease by other mechanisms.
Symptom-limited vs heart-rate-limited exercise testing soon after myocardial infarction.
Authors: DeBusk R F , Haskell W
Published: June 2012

To develop guidelines for exercise testing soon after uncomplicated myocardial infarction, 93 men completed a heart-rate-limited (HRL) protocol and 107 completed a symptom-limited (SXL) protocol 3 weeks after the acute event. In the HRL protocol, effort terminated at a heart rate of 130 beats/min in the absence of a limiting symptom, exertional hypotension or ventricular tachycardia. Peak heart rate was not an end point in the SXL protocol. Despite a higher peak heart rate and work load in patients who completed the SXL protocol, the prevalence of exercise-induced ischemic ST-segment depression and ventricular ectopic activity was similar in the two groups. No complications occurred with either protocol. Twelve patients (6%) had cardiac events within the next 2 months. Regardless of the test protocol used, early events were more common in patients with ischemic ST-segment responses (15%) than in patients without ischemic responses (3%) (p less than 0.01). In contrast, exercise-induced ventricular arrhythmias were not predictive of early events. Eleven weeks after infarction, when all tests were SXL, the prevalence of exercise-induced ischemic ST-segment depression and premature ventricular complexes was similar to that at 3 weeks. We conclude that SXL and HRL exercise test protocols reveal a similar prevalence of ischemic ST-segment depression and ventricular ectopic activity soon after uncomplicated myocardial infarction.
Sequence of events in angina at rest: primary reduction in coronary flow.
Authors: Chierchia S , Brunelli C , Simonetti I , Lazzari M , Maseri A
Published: June 2012

To investigate the events that lead to acute myocardial ischemia we monitored continuously the ECG, the left ventricular (four patients) or aortic (two patients) pressure and the great cardiac vein oxygen saturation (CSO2S) by a fiberoptic catheter in six patients with frequent anginal attacks at rest. We recorded 137 transient ischemic episodes (10 with chest pain) characterized by ST-segment elevation in 28 episodes, depression in three episodes and by pseudonormalization of previously inverted or flat T waves in 106 episodes. The onset of electrocardiographic and hemodynamic changes was preceded by a large drop in CSO2S in all 135 episodes with ST-T changes in the anterior leads but not in two episodes with ST elevation on inferior leads. The fall in CSO2S, consistently followed by signs of left ventricular function impairment and never preceded by any detectable increase in the hemodynamic determinants of myocardial oxygen consumption, probably reflects a reduction in regional perfusion. Thus, a reduction in coronary flow may cause transient ischemia in patients with angina at rest. These episodes may be associated with variable, often minor electrocardiographic changes and occasionally with anginal pain.
Transluminal angioplasty: correlation of morphologic and angiographic findings in an experimental model.
Authors: Block P C , Baughman K L , Pasternak R C , Fallon J T
Published: June 2012

The morphologic consequences of transluminal angioplasty of stenotic atherosclerotic coronary arteries are unknown. This study describes the production of aortoiliac atherosclerosis in rabbits and reports the morphologic changes after transluminal angioplasty of stenotic arterial lesions. Atherosclerotic lesions were evaluated angiographically before and after transluminal angioplasty and were studied histologically and by electron microscopy after angioplasty. Moderatley stenotic aortic segments showed denudation of endothelial cells and deposition of a carpet of platelets enmeshed in fibrin. Medial and intimal compression were not seen. Intimal plaque disruption and splitting of atheromatous plaques were observed in more stenotic vessels where dilatation during angioplasty is relatively greater. Transluminal angioplasty, therefore, acutely causes desquamation of endothelial cells and superficial plaque elements, splitting of atheroma and subsequent deposition of platelets and fibrin in the area of angioplasty. This experimental model may be useful to evaluate the morphologic changes after angioplasty and might be used in further studies to determine the long-term pathophysiologic changes after transluminal angioplasty.
Quantification of coronary arterial narrowing at necropsy in acute transmural myocardial infarction. Analysis and comparison of findings in 27 patients and 22 controls.
Authors: Roberts W C , Jones A A
Published: June 2012

We quantitatively analyzed the degree and extent of coronary arterial narrowing by atherosclerotic plaques in the entire length of each of the four major coronary arteries in 27 necropsy patients with transmural acute myocardial infarction (AMI) and compared the findings with those in 22 control subjects. Of the 1403 5-mm segments examined in the 27 AMI patients, 484 (34%; controls 3%) were 76-100% narrowed in cross-sectional area by atherosclerotic plaques, 528 (38%; controls 25%) were 51-75% narrowed, 319 (23%; controls 44%) were 26-50% narrowed, and only 72 segments (5%; controls 28%) were less than or equal to 25% narrowed. The amount of severe (greater than 75%) narrowing of the right, left anterior descending and left circumflex coronary arteries by atherosclerotic plaques was similar, as was the amount of severe narrowing in the distal and proximal halves of these three arteries. The number of severely narrowed 5-mm segments did not correlate significantly with the patient's age at death, the presence or absence of a history of angina pectoris or healed myocardial infarction, or with heart weight. The men, however, had a significantly greater number of severely narrowed 5-mm segments of coronary artery than the women (p less than 0.05), and the patients with associated transmural left ventricular scars had significantly more severely narrowed segments than did patients without transmural scars.
Evaluation of aortic valve replacement in patients with valvular aortic stenosis.
Authors: Henry W L , Bonow R O , Borer J S , Kent K M , Ware J H , Redwood D R , Itscoitz S B , McIntosh C L , Morrow A G , Epstein S E
Published: June 2012

Echocardiographic and hemodynamic studies were obtained in 42 consecutive patients undergoing aortic valve replacement for isolated aortic stenosis. Concentric left ventricular (LV) wall thickening, the most common preoperative abnormality, occurred in 95% of patients. LV dilation with reduced fractional shortening was noted in approximately 25% of patients but was severe in only one patient. Six months after operation, LV wall thickness had decreased on average but had not returned to normal and fractional shortening was unchanged. Repeat measurements in 13 patients an average of 37 months after operation were unchanged compared with measurements made 6 months after operation. When patients were subdivided into those with LV dilatation and those without, we found that patients with dilated ventricles preoperatively had a greater decrease in LV internal dimension and mass than those without preoperative dilatation. The patient data also were examined for possible association with mortality. One operative (2%) and five late cardiac (13%) deaths occurred. No preoperative or 6-month postoperative echocardiographic or hemodynamic measurement was strongly associated with these deaths, nor were any late deaths due to congestive heart failure. Compared with preoperative measurements in symptomatic patients who were operated for isolated aortic regurgitation, patients with aortic stenosis had smaller left ventricles with less depression of systolic function, as well as less aortic root and left atrial dilatation. Our data do not support the concept that the aortic valve should be replaced before the onset of symptoms to prevent irreversible LV damage in patients with isolated aortic stenosis.
Detection of patent coronary bypass grafts by computed tomography. A preliminary report.
Authors: Brundage B H , Lipton M J , Herfkens R J , Berninger W H , Redington R W , Chatterjee K , Carlsson E
Published: June 2012

Twenty-three coronary bypass graft patients were evaluated by a contrast-enhanced computed tomography (CT) technique to determine graft patency. Four to six 4.8-second sequenced scans with a 1-second interscan interval were obtained in each patient during the hand injection of 25-30 ml of contrast medium in a peripheral vein. Patency of grafts was determined by a characteristic contrast enhancement. The CT technique correlated with angiographic assessment of graft patency in 59 of 62 grafts (95%). We conclude that this relatively noninvasive technique shows promise as a method for determining coronary bypass graft patency.
Range-gated pulsed Doppler echocardiographic diagnosis of supracardiac total anomalous pulmonary venous drainage.
Authors: Skovránek J , Tůma S , Urbancová D , Samánek M
Published: June 2012

Three patients with total anomalous pulmonary venous drainage (TAPVD) into the innominate vein were studied by using M-mode and pulsed Doppler echocardiography. An abnormal continuous flow towards the transducer in a suprasternal notch position detected by pulsed Doppler echocardiography in the left hemithorax leftward of the aortic echo is a sign of blood flow through the left vertical vein into the innominate vein. This finding is highly specific for TAPVD. High-velocity flow across the tricuspid valve, disturbed flow in the right pulmonary artery and abnormal flow in the left atrium are additional important pulsed Doppler echocardiographic findings in TAPVD. Right ventricular enlargement and paradoxical interventricular septal motion by M-mode echocardiography were not specific enough to distinguish TAPVD from other right ventricular volume overload lesions. An echo-free space posterior to the left atrium was not recorded.
Origin of the atrial electrogram recorded from the esophagus.
Authors: Prystowsky E N , Pritchett E L , Gallagher J J
Published: June 2012

The purpose of this study was to ascertain the origin of the atrial electrogram recorded on the esophageal lead. The atria and esophagus were mapped during reciprocating tachycardia in 11 patients with the Wolff-Parkinson-White syndrome and one patient with atrioventricular nodal reentry, and during right ventricular pacing in four additional patients. The esophagus was mapped by recording atrial electrograms at 1-cm intervals throughout the esophagus beginning at the most distal area where atrial depolarization was seen. The retrograde atrial activation time recorded on the esophageal lead in its distal position occurred at the same time as atrial septal depolarization in all patients. In 14 of 16 patients, the distal esophageal ventriculoatrial (VA) conduction time was also the shortest esophageal VA conduction time recorded. In two of five patients with left lateral accessory pathways, the shortest esophageal VA conduction time was noted during pullback of the lead from the esophagus instead of at the most distal area. The most likely explanation for this was an unusual anatomic relationship between the esophagus and left atrium in these two patients. We conclude that 1) the most distal esophageal atrial electrogram probably records posterior paraseptal atrial depolarization; 2) it is unusual to record clearly identifiable left atrial activation in the esophagus; and 3) the esophageal lead is not useful in locating left-sided accessory pathways.
Unmasking of ventricular preexcitation by vagal stimulation or isoproterenol administration.
Authors: Przybylski J , Chiale P A , Halpern M S , Nau G J , Elizari M V , Rosenbaum M B
Published: June 2012

Twenty-one patients were studied in whom ventricular preexcitation (VP) had been recorded in the past and had later disappeared, indicating antegrade block in the accessory pathway (AP), either spontaneously (10 patients) or under the effect of chronic treatment with amiodarone (11 patients). VP reappeared in nine cases during vagal stimulation, and in five cases during an i.v. isoproterenol infusion. Retrograde conduction over the AP was studied in four of the remaining seven patients and was found to be present in three and absent in one. Although these patients differ from the ordinary patient with concealed AP in that antegrade preexcitation had been demonstrated in the past, this study suggests that concealed VP may result from the following mechanisms: 1) an extremely prolonged refractory period in the AP, causing a rate-dependent VP that can be identified during vagal stimulation; 2) a rate-independent depression of antegrade conduction that can be reversed by isoproterenol; 3) a depression of conduction that is apparently no longer reversible. Only in the latter case is a study of retrograde conduction needed to identify the concealed VP. These three mechanisms are likely to be a natural sequence of events leading to complete antegrade block in the AP.
Echocardiographic evaluation of mitral stenosis using diastolic posterior left ventricular wall motion.
Authors: Wise J R
Published: June 2012

The slope of the posterior left ventricular wall motion in diastole (LVDS) was determined by echocardiography in 25 normal subjects and 21 patients with mitral stenosis. Patients with mitral stenosis had reduced LVDS that was related to the degree of mitral stenosis determined by calculated mitral valve area (r = 0.92). The mitral valve area correlated more closely with the LVDS than with the left atrial emptying index derived from the posterior aortic wall motion. Three patients with mitral stenosis had an increased LVDS after mitral valvotomy or mitral valve replacement. One patient with a stenotic mitral valve prosthesis had reduced LVDS. The results of this study suggest that analysis of the LVDS would be useful in predicting the severity of mitral stenosis and may be beneficial in evaluating patients with suspected prosthetic mitral valve malfunction.
Isolated left anterior descending coronary atherosclerosis: long-term comparison of internal mammary artery and venous autografts.
Authors: Lytle B W , Loop F D , Thurer R L , Groves L K , Taylor P C , Cosgrove D M
Published: June 2012

A consecutive series of 100 patients receiving left internal mammary artery grafts and a consecutive series of 100 patients receiving saphenous vein grafts as treatment of isolated left anterior descending coronary artery stenosis were reviewed to determine survival, graft patency, disease progression and New York Heart Association functional class. The mean follow-up was 67 months, and the mean catheterization interval was 20 months. Recommendations for revascularization can be made selectively to patients with critical isolated left anterior descending stenoses who have limiting symptoms and large areas of viable myocardium at risk.
Myocardial perfusion as an indicator of graft patency after coronary artery bypass surgery.
Authors: Kolibash A J , Call T D , Bush C A , Tetalman M R , Lewis R P
Published: June 2012

Stress and resting myocardial perfusion were assessed in 38 patients who received 96 grafts. Stress perfusion was evaluated with thallium-201 and resting myocardial blood flow distribution with radiolabeled particles. When both stress and rest perfusion were normal, graft patency was 82% (51 of 62 grafts). Graft patency was also high (81%, 13 of 16) in areas where stress perfusion abnormalities resolved or become less apparent at rest. However, when stress perfusion defects remained unchanged at rest, the graft was likely to be occluded (73%, 11 of 15). Maintenance of normal rest perfusion or improvement of rest perfusion postoperatively was also associated with a high graft patency rate (80%, 35 of 44), whereas the development of new rest perfusion defects postoperatively implied graft occlusion (86%, six of seven).
Exercise capacity in patients with severe left ventricular dysfunction.
Authors: Benge W , Litchfield R L , Marcus M L
Published: June 2012

Normal or near-normal exercise capacity has been thought to reflect normal left ventricular function. Many compensatory mechanisms could preserve exercise capacity in patients with severe left ventricular dysfunction. We evaluated exercise capacity using a treadmill exercise test in 26 patients with severe left ventricular dysfunction defined by a left ventricular ejection fraction of 30% or less by isotope ventriculography. One half of the patients had normal exercise capacity and a normal cardiothoracic ratio on chest x-ray. This study indicates that traditional predictors of left ventricular function that have been widely used in clinical evaluation of the patients with cardiac disease (cardiothoracic ratio and exercise capacity) can be normal in a significant number of patients with severe left ventricular dysfunction. Thus, left ventricular function cannot be accurately estimated using these traditional predictors and should be assessed quantitatively. The isotope ventriculogram appears to be ideal for this purpose.
Perspectives on systolic hypertension. The Framingham study.
Authors: Kannel W B , Dawber T R , McGee D L
Published: June 2012

Diastolic hypertension has been widely and justifiably accepted as a cause of cardiovascular mortality. However, it has also been accepted that the cardiovascular sequelae of hypertension derive chiefly from the diastolic component. Because systolic and diastolic pressure are usually highly correlated it is not easy to dissociate the effects of each. Statistical analysis suggests that systolic pressure is actually the more potent contributor to cardiovascular sequelae. Even isolated systolic pressure elevation is associated witn an excess cardiovascular mortality. At low diastolic pressures (i.e., less than 95 mm Hg), risk rises with the level of systolic pressure. Also, isolated systolic hypertension is most ominous in the elderly, in whom it is highly prevalent. Isolated systolic hypertension was related to the occurrence of "direct" complications as well as to atherosclerotic sequelae. It was also associated with excess mortality, taking into account rigid vessels as judged from pulse-wave recordings. Trials to determine whether the treatment of isolated systolic hypertension is efficacious for avoiding its demonstrated excess cardiovascular morbidity and mortality are urgently needed.
The effect of stenosis of bypass grafts on coronary blood flow. A mechanical model study.
Authors: Cipriano P R , Sacks A H , Reitz B A
Published: June 2012

A mechanical model of a branched coronary artery with a graft bypassing an 80% stenosis of one branch was used to study the reduction in coronary flow due to stenosis of the bypass graft. Flow Reynolds number and ratio of aortic pressure to dynamic pressure were matched to the living system. Changes in coronary flow were measured for a range of stenoses (0-100%) of bypass grafts with graft-to-coronary-diameter ratios of 4:1, 3:1, 2:1 and 1:1 for conditions that simulated rest and exercise. The results of these studies indicate that: 1) marked stenosis of bypass grafts is needed to decrease coronary flow in the resting state, and even moderate stenosis will decrease flow during exercise when the diameter of the bypass is large relative to the coronary artery; 2) coronary flow is decreased with mild stenosis for bypass grafts of the same diameter as the coronary artery; and 3) a marked decrease in flow due to stenosis of a bypass graft occurs only when the diameter of a stenosis in a graft is less than the diameter of the coronary artery.
Digitalis and myocardial infarction in man.
Authors: Morrison J , Coromilas J , Robbins M , Ong L , Eisenberg S , Stechel R , Zema M , Reiser P , Scherr L
Published: June 2012

The use of digitalis after acute myocardial infarction is controversial. The effect of digoxin on computer-quantitated thallium-201 perfusion scintigrams (Tl-201), left ventricular (LV) ejection fraction (EF), and percentage of abnormally contracting LV regions (% ACR) was determined in 23 patients. A correlation was established between creatine kinase MB isoenzyme release and initial radionuclide-gated blood pool wall motion estimates of EF (r = -0.73) and % ACR (r = 0.71). After radionuclide assessments, 14 patients received digoxin 18 +/- 23 hours (mean +/- SD) after the rise in CK-MB from baseline, while the remaining nine patients served as controls. In the control group, the mean EF was 0.33 +/- 0.12 on the first study and 0.30 +/- 0.08 on the second study (p = NS). In the digoxin group, the EF after digoxin administration (mean 0.33 +/- 0.11) was significantly different from the initial EF (mean 0.29 +/- 0.09, p less than 0.03); however, digoxin had no apparent effect on infarct size as assessed by sequential % ACR and Tl-201 perfusion data. These data indicate that digoxin resulted in a minimal but significant improvement in EF that did not occur at the expense of LV perfusion or regional wall motion.
Fontan procedure for tricuspid atresia.
Authors: Gale A W , Danielson G K , McGoon D C , Wallace R B , Mair D D
Published: June 2012

A Fontan procedure has been performed on 29 patients for tricuspid valvular atresia. The age range was 8 months to 33 years (median 10 years), the pulmonary vascular resistance ranged from 1.8-6.1 units . m2 (mean 3.3 units . m2), and the mean pulmonary arterial pressure ranged from 13-45 mm Hg (mean 21 mm Hg). Twenty-nine previous operations had been performed in 23 patients. Fourteen other associated cardiopulmonary anomalies were present in 12 patients. There were four hospital deaths (13.8%), all in patients with complicating features. Among the last 22 consecutive patients who have undergone operation, one died (4.5%). Complete atrioventricular block necessitated pacemaker implantation in one patient. No late deaths occurred. Of the 19 patients followed 3 months or more from the time of operation, eight have no restriction of exercise capacity, nine have only mild restriction, and two have a poor result. The Fontan approach to tricuspid atresia has several theoretical advantages over previously used shunts or pulmonary artery banding, the operative mortality in patients who have suitable anatomy and hemodynamics is low, and the results have been good.
Clinical comparison of pressure-pulse and indicator-dilution cardiac output determination.
Authors: Cundick R M , Gardner R M
Published: June 2012

Two clinical studies of cardiac output determination using the pressure-pulse technique are presented. The Warner pressure-pulse method of estimating cardiac output was compared with the dye-dilution technique in 17 patients. Both the Warner and a variation of the Bourgeosis pressure-pulse methods were compared with thermodilution in 13 patients. The Warner vs dye-dilution comparison resulted in a poor correlation coefficient (r = 0.61). Values for the Warner equation calibration constant (K) were nonstationary, varying with time from --69 to 135% of the initial value in individual patients. When thermodilution was compared with the two methods, the correlation was poor (r = 0.58 for the Warner method; r = 0.50 for the modified Bourgeois method). The Warner and a variation of the Bourgeois pressure-pulse methods for monitoring the cardiac output of critically ill patients with widely varying mean arterial pressures are not sufficiently reliable for clinical decision-making.
Correlation of angiographic and autopsy right ventricular dimensions in infants and children.
Authors: Sepehri B , Fisher E A , Eckner F A , Hastreiter A R
Published: June 2012

Standard autopsy specimens from 49 infants and children, most with congenital heart disease, were prepared by controlled pressure coronary artery perfusion fixation of the heart. Autopsy measurements of tricuspid (TV) and pulmonary valve (PV) circumferences (Circ), right ventricular (RV) outflow circumference, (Circ), RV inflow and outflow tract lengths, and RV volume (Vol) were correlated with corresponding in vivo end-diastolic (D) and end-systolic (S) measurements from biplane cineangiograms (angio) in the same patients. Correlation of the dimensions studied yielded the following r values: TV 0.72, PV 0.78, D Circ 0.61, S Circ 0.56, D inflow spatial (sp) 0.83, S inflow sp 0.83, D outflow sp 0.87, S outflow sp 0.84, D Vol 0.80, and S Vol 0.80. Mean angio and autopsy values were not significantly different for spatial outflow tract measurments and S Vol. Average autopsy values were lower than all other D angio measurements: (p [diff] < 0.001) and S inflow sp, (p [diff] < 0.05), but higher than all other S angio measurements, (p [diff] < 0.05-0.001). The data show the predictability of the changes in RV morphology with this fixation method and provide a basis for meaningful comparison of quantitative autopsy and angio dimensions of the RV.
Five-year follow-up of maximal treadmill stress test in asymptomatic men and women.
Authors: Allen W H , Aronow W S , Goodman P , Stinson P
Published: June 2012

A five-year follow-up of 888 asymptomatic men and women without known coronary heart disease (CHD) who had a maximal treadmill stress test (MTST) revealed a CHD incidence of 1.1% per year. In women, exercise duration of 3 minutes or less by the Ellestad protocol correlated with subsequent development of CHD (p less than 0.001), although abnormal ST-segment and R-wave responses did not. In men 40 years of age or younger, the MTST did not correlate with subsequent CHD. In men older than 40 years, ischemic ST response (p less than 0.01), an increase or no change in R wave (p less than 0.01), and an exercise duration of 5 minutes of less (p less than 0.001) all correlated with subsequent development of CHD. Five of five men (100%) who had all three criteria developed CHD within 5 years. When men older than 40 years who had all three criteria either present or absent were considered, specificity was 100%. The sensitivity, specificity, predictive value of an abnormal test, and risk ratio for developing CHD within 5 years for the various MTST criteria alone and in combination are tabulated.
Pulsed doppler echocardiographic measurement of beat-to-beat changes in stroke volume in dogs.
Authors: Steingart R M , Meller J , Barovick J , Patterson R , Herman M V , Teichholz L E
Published: June 2012

Measurement of stroke volume by pulsed Doppler echocardiography has not been validated against a reference method in vivo. We compared Doppler systolic frequency shift integrals with electromagnetic flowmeter stroke volume in seven open-chest dogs. A pulsed Doppler echocardiographic transducer was held on the aortic arch with the sample volume in the ascending aorta. Stroke volume was varied by epinephrine or pentobarbital infusions, fluid administration or inferior vena caval construction. Linear regression analysis of stroke volume vs Doppler systolic frequency shift integrals revealed strong correlations and intercepts close to zero (tau = 0.74-0.096, rho less than 0.001). Minor changes in transducer position did not influence Doppler frequency shift integrals substantially. Therefore, pulsed Doppler echocardiography served as an excellent measurement of stroke volume changes in model. However, serious limitations are presented that may limit its clinical application.
Diastolic bulging of the interventricular septum toward the left ventricle. An echocardiographic manifestation of negative interventricular pressure gradient between left and right ventricles during diastole.
Authors: Tanaka H , Tei C , Nakao S , Tahara M , Sakurai S , Kashima T , Kanehisa T
Published: June 2012

Diastolic bulging of the interventricular septum (IVS) toward the left ventricle was observed by real-time cross-sectional echocardiography in three patients with primary pulmonary hypertension and one patient with secondary pulmonary hypertension after closure of an atrial septal defect. M-mode echocardiography showed a characteristic abnormal pattern of septal motion in diastole and in systole. In two patients, we attempted to correlate M-mode motion to the interventricular pressure gradient. During diastole, the interventricular pressure gradient between the left and right ventricles was negative and the pressure gradient curve was very similar to the M-mode echogram of the IVS. Banding studies in which acute right ventricular hypertension was produced in dogs showed similar shape changes, suggesting that the diastolic shape and motion of the septum are determined by the interventricular pressure gradient between the ventricles. Diastolic bulging of the IVS toward the left ventricle in our patients results from negative interventricular pressure gradient between the left and right ventricles during diastole.
Systolic time intervals in isolated ventricular septal defect in the adult.
Authors: Nesje O A
Published: June 2012

Little information is available on the length of the systolic time intervals in adult patients with isolated ventricular septal defects (VSD). In the present study the external carotid pulse and the phono- and electrocardiogram were recorded in 17 patients, mean age 29 years, with angiographically proved VSD. They had unidirectional left-to-right shunts with ratios of pulmonary-to-systemic blood flow (Qp/Qs) of 1-5.22. Their right ventricular pressures were normal or only moderately elevated. Left ventricular ejection time was consistently abbreviated, the degree of abbreviation relating significantly with Qp/Qs (r = -0.70, p less than 0.01). The preejection period was prolonged but the relationship between its degree of prolongation and Qp/Qs did not reach statistical significance (r = 0.4), p greater than 0.05). The relationship between the preejection period/left ventricular ejection time ratio (PEP/LVET) and Qp/Qs was statistically significant (r = 0.51, p less than 0.05). We conlcude that in adult VSD patients with normal right ventricular pressures, a hemodynamically important shunting, i.e., Qp/Qs above 1.4 or left-to-right shunt exceeding 30% of pulmonary blood flow, may be excluded in the presence of a normal left ventricular ejection time or a normal PEP/LVET ratio.
Total body surface potential mapping during exercise: QRS-T-wave changes in normal young adults.
Authors: Miller W T , Spach M S , Warren R B
Published: June 2012

Total body surface potential distributions were recorded from 20 normal young adults, 20-35 years old, during multistage maximal exercise testing on a bicycle ergometer. Using a system for measuring total body surface potential distributions from measurements at 24 locations, high-quality potential maps were obtained during exercise without requiring wave form averaging or special modes of exercise. Serial maps recorded at 1-msec intervals throughout QRS-T during exercise and during recovery from exercise were compared with corresponding maps recorded with the subjects at rest. During and after exercise, consistent changes appeared in the map patterns during early QRS and the ST segment and in the magnitude of the T-wave potentials. Increases in QRS duration (0-10 msec) also appeared during exercise. The changes in map patterns during early QRS in exercise strongly suggested changes in the initial sequence of activation in the ventricles. The results demonstrate the importance of analyses of total body surface potential distributions in understanding ECG changes during exercise.
Pulsus paradoxus in a patient with tricuspid atresia and hypoplastic right heart.
Authors: Baum V C , Tarnoff H , Hoffman J I
Published: June 2012

Increased inspiratory right ventricular filling with a consequent shift of the ventricular septum to the left, thereby decreasing left ventricular filling, has been suggested as a mechanism of pulsus paradoxus. We recently saw a patient with tricuspid atresia and hypoplastic right ventricle who developed pulsus paradoxus. His course may help clarify the contribution of this mechanism.
Restoration of normal coronary hemodynamics and myocardial metabolism after percutaneous transluminal coronary angioplasty.
Authors: Williams D O , Riley R S , Singh A K , Most A S
Published: June 2012

Regional coronary blood flow and myocardial metabolism were evaluated in a patient who underwent percutaneous transluminal coronary angioplasty (PTCA). Angioplasty increased coronary luminal diameter and reduced trans-stenotic gradient. Before PTCA, angina pectoris developed during sustained rapid atrial pacing and was associated with abnormal lactate metabolism and a mild increase in coronary flow and myocardial oxygen consumption. After PTCA, angina was absent during pacing and lactate extraction was preserved. Coronary flow and oxygen consumption were increased to a greater degree than before PTCA. The temporal response of changes in coronary blood flow due to an abrupt increase in heart rate was also evaluated. Floow reached peak value more rapidly after PTCA. These observations suggest that PTCA may result in improved regional coronary blood flow and restoration of normal flow regulatory mechanism and myocardial metabolism.
Noninvasive prediction of multivessel disease after myocardial infarction.
Authors: Dunn R F , Freedman B , Bailey I K , Uren R , Kelly D T
Published: June 2012

In 65 patients with a previous transmural myocardial infarction (anterior in 33, inferior in 32), exercise thallium scanning was compared with 12-lead exercise electrocardiography to see if multivessel disease could be detected. At coronary arteriography 40 patients were shown to have multivessel disease ( greater than or equal to 70% diameter stenosis in two or three vessels) and 25 patients had one-vessel disease. On the exercise scan thallium defects corresponding to the electrocardiographic site of infarction were present in all patients. Patients wih one-vessel and multivessel disease were separated by exercise-induced angina, perfusion defects on the exercise thallium scan in more than one specific vasculare area, and a positive exercise ECG associated with angina, but not by a positive exercise ECG alone. Of the 40 patients with multivessel disease, 85% had defects in more than one vascular area on the thallium scan and 70% had a positive exercise ECG (p = NS). Of the 37 patients with thallium defects in more than one specific vascular area, 92% had multivessel disease, compared with 72% of the 39 patients who had a positive exercise ECG (p < 0.05). periinfactional ischemia was present in 38 of the 65 patients (58%) ( 14 of 25 with one-vessel disease and 24 of 40 with multivessel disease), and did not correlate with the severity of the corresponding coronary artery disease. When thallium defects that resolved were noted in a second vascular area, they were associated with a resolving rather than a constant defect in the vascular area where the infarction had occurred ( p < 0.005). In patients after a transmural myocardial infarction, multivessel disease can be better differentiated from one-vessel disease by thallium scanning than by exercise electrocardiography.
The effect of graded coronary flow reduction in the left anterior descending and septal arteries on left ventricular function in the canine heart.
Authors: Koiwa Y , Nunokawa T , Ishide N , Isoyama S , Kitaoka S , Tamaki K , Satoh S , Suzuki H , Shimizu Y , Kakuta Y , Ino-Oka E , Takishima T
Published: June 2012

WE quantitatively analyzed the effect of graded left anterior descending and septal coronary flow (LAD + septal flow) reduction on left ventricular function with a left ventricular end-diastolic pressure (LVEDP) of 6 mm Hg and 12 mm Hg. We used an isolated, ejecting, canine heart preparation ( n = 8), the coronary flow of which could be controlled independently of the aortic pressure. We kept the other hemodynamic variables - heart rate, left circumflex coronary flow, right coronary flow and aortic input impendance - constant within their normal physiologic range. We considered this reduction in LAD + septal flow to be analogous to that of the most frequent lesion in ischemic heart disease. There was no plateau in the left ventricular work caused by this reduction of the regional coronary flow. Therefore, the plateau commonly reported in previous studies may be partially a result of the compensatory elevation of LVEDP, which is necessary to maintain the left ventricular work.
Perioperative echocardiographic evaluation of cardiovascular function: assessment of changing hemodynamic state.
Authors: Kavey R E , Krongrad E , Gersony W M
Published: June 2012

To evaluate echocardiographic assessment of ventricular function in a changing hemodynamic situation, 20 infants and children undergoing open heart surgery were examined preoperatively and 1,4 and 24 hours postoperatively by this technique. Clinical evaluation and measurements of cardiac output were obtained simultaneously with each echocardiogram. On the basis of their clinical course and cardiac output, the patients were divided into two groups: group 1 - cardiac index > 2.3 1/min/m2 without inotropic support (n = 9); and group 2 - cardiac index less than or equal to 2.3 1/min/m2 and/or need for inotropic support (n = 11). Of the echocardiographic measurements obtained, the left ventricular systolic time interval ratio (left ventricular preejection period/left ventricular ejection time ([LVPEP/LVET] correlated significantly with the clinical course, separating the two groups of patients completely at each determination. The aortic root velocity (AoV), a new index defined as the anterior excursion (in degrees) of the aortic root from the horizontal plane with systole, also correlated with the clinical course, although this was not statistically significant. Serial change in LVPEP/LVET and AoV crrrelated with changes in clinical status and cardiac output for individual patients. Using a formula based on the opening slope of the mitral valve, echocardiographic estimations of cardiac output correlated well with those determined by dye dilution. The results indicate that selected echocardiographic indexes can be used for serial assessment of cardiac performance in patients with a changing hemodynamic state.
Prospective identification of ventricular septal defects in infancy using subxiphoid two-dimensional echocardiography.
Authors: Bierman F Z , Fellows K , Williams R G
Published: June 2012

The objective of this study was to establish a dependable technique for imaging the interventricular septum and ventricular septal defects in infants. Subxiphoid two-dimensional echocardiograms were performed on 81 infants who were 1 day to 12 months (median 43 days) old and weighed 1.6-8.6 kg (median 3.4 kg). A short-focus, 5-MHz crystal with a 13-mm active element diameter was used in all studies. The interventricular septum was visualized in 80 of 81 infants. Defects in the membranous, atrioventricular canal, conoventricular and muscular segments of the sentum were identified using three standard transverse subxiphoid projections. All defects in the membranous and atrioventricular canal segments, as well as malalignment type conoventricular communications, were correctly identified when compared with selective angled cineangiocardiography. Only two of the three subpulmonic and four of 11 muscular defects were identified successfully. Limitations in imaging defects in the muscular septum reflected the varied morphology of these interventricular communications and the tangential orientation of the echo beam to the extreme apical and anterior segments of the muscular septum.