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R V Haendchen

Publications and source records attributed to R V Haendchen.

29 records · Page 2Linked to original sources
PubMed1984

Increased regional end-diastolic wall thickness early after reperfusion: a sign of irreversibly damaged myocardium.

Two-dimensional echocardiographic measurements of regional left ventricular end-diastolic wall thickness and systolic wall thickening were studied during coronary artery occlusion and early after reperfusion and compared with measurements of regional myocardial infarct size. In 25 closed chest anesthetized dogs with left anterior descending coronary artery occlusion followed by reperfusion, the occlusion period was 3 minutes in group I (n = 4), 20 minutes in group II (n = 4), 60 minutes in group III (n = 5) and 180 minutes in group IV (n = 12). Infarct size in groups III and IV was quantitated using the triphenyltetrazolium chloride technique. After coronary occlusion, wall thickening was replaced by thinning in the center of the ischemic region at the midpapillary echographic short-axis section, and no improvement in function occurred up to 60 minutes after reperfusion, except in group I. Ischemic zone end-diastolic wall thickness did not change significantly from control to the end of the coronary occlusion period, except Group IV. At 60 minutes after reperfusion, end-diastolic wall thickness increased only slightly in groups I and II (by 7.2 and 0.24%, respectively), but a marked increase was observed in groups III and IV (by 41 and 50%, respectively). The percent change in ischemic zone end-diastolic wall thickness from before reperfusion to 60 minutes after reperfusion correlated well with the amount of myocardial necrosis in corresponding segments (r = 0.936, standard error of estimate = 11.4%); an increase in segmental end-diastolic wall thickness of more than 25% was generally associated with 20% or more segmental necrosis. It is concluded that significantly increased regional end-diastolic wall thickness early after reperfusion is associated with irreversibly damaged myocardium, and this might be used as an index of myocardial salvage.

Animals↗
PubMed1984

Prostaglandin E1 coronary venous retroperfusion in acute myocardial ischemia: effects on regional left ventricular function and infarct size.

Prostaglandin E1 was administered by means of coronary venous synchronized retroperfusion and the effectiveness of the combined (prostaglandin-retroperfusion) system was examined during acute myocardial ischemia in 10 closed chest anesthetized dogs. Such treatment was administered between 30 minutes and 3 hours after occlusion of the proximal left anterior descending coronary artery. An equivalent series of 10 dogs with arterial blood retroperfusion alone and 9 untreated dogs served as control subjects. Standardized two-dimensional echocardiographic measurements of global and regional left ventricular function were performed in five short-axis cross sections. The global low left ventricular section and its profoundly ischemic anterolateral region exhibited distinctly improved systolic fractional area changes as a result of the prostaglandin E1 retroperfusion treatment between 30 minutes and 3 hours after occlusion (22.9 +/- 1.5 to 41.2 +/- 4.0% and 1.8 +/- 3.6 to 29.4 +/- 5.6%, respectively). In contrast, further deterioration in function was noted during an untreated equivalent coronary occlusion period (16.3 +/- 2.7 to 10.0 +/- 3.3% and 12.6 +/- 6.1 to 4.1 +/- 6.9%). Although arterial blood retroperfusion alone provided distinct benefits in the ischemic region of a midpapillary echo section (from 13.4 +/- 3.9 to 32.1 +/- 10.4%, p less than 0.05), no improvements were observed in profoundly jeopardized segments at the low left ventricular level (5.6 +/- 6.0 to 0.9 +/- 5.7%). Triphenyltetrazolium chloride delineation of infarction revealed significant myocardial salvage with prostaglandin E1 retroperfusion as compared with findings in untreated control dogs (3.7% +/- 1.3% of the left ventricle versus 9.3 +/- 1.9%, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1984

Two-dimensional echocardiographic contrast assessment of pacing-induced mitral regurgitation: relation to altered regional left ventricular function.

Two-dimensional echocardiography during agitated saline contrast injections into the left ventricle was applied in eight closed chest dogs to examine the degree of mitral valve regurgitation encountered with pacing from two sites: 1) at the right ventricular apex and 2) within the coronary sinus at the base of the left ventricle. Pacing was at a rate of 10 beats/min above the sinus rate, and ranged from 60 to 120 beats/min. Hemodynamic variables were monitored, and data on global and regional left ventricular function were derived from a series of short- and long-axis cross-sectional echographic images. The degree of valvular regurgitation was assessed independently by two observers, and systolic appearance of echo contrast in the left atrium was graded as 0 to +4. Although no mitral regurgitation was noted in sinus rhythm, regurgitation was severe with right ventricular apical pacing (3.2 +/- 0.7, mean +/- standard deviation) and relatively mild (0.9 +/- 0.7) with basal pacing (p less than 0.01 and 0.05, respectively). Relative to sinus rhythm, thermodilution stroke volume was significantly (p less than 0.05) depressed by both apical and basal pacing (from 32.6 +/- 14.6 to 25.0 +/- 7.9 and 26.0 +/- 7.6 cc, respectively), but there was no significant difference between the two pacing sites. Mapping of regional function at six levels of the left ventricle revealed significant heterogeneities, with maximal dysfunction noted in the vicinity of the pacing site. It is concluded that significant differences in mitral regurgitation exist depending on the site of pacing, with apical pacing causing severe regurgitation and abnormal regional contraction near the pacing site.

Animals↗
PubMed1983

Assessment of quantitative methods for 2-dimensional echocardiography.

Several 2-dimensional echocardiographic (2-DE) methods were tested in vitro for accuracy of linear and cross-sectional measurements and in vivo for left ventricular (LV) volume reconstruction. With 2-DE instrument settings at low and high gains and with precise in vitro calibrations, we studied myocardial slice thickness (3.0 to 10.0 mm). The 2-DE myocardial thickness was measured by leading-trailing, trailing-leading, and leading-leading methods. Regression analysis of 2-DE versus direct measurements yielded excellent correlations for all 3 methods (r greater than 0.985), with interobserver variability less than 3%. Accuracy of measurement was satisfactory only for the leading-leading method (3 and 6% error at low and high gains, respectively); other methods substantially over- or underestimated thickness. Thin myocardial slices (less than 1 mm thick) were applied to cylinders and fixed in formalin to produce precise cavity areas (1.8 to 7.0 cm2). Regression analysis of 2-DE versus actual cavity area gave high correlations (r greater than 0.970), and low interobserver variability (less than 4%) for the inner edge and leading edge methods, but the leading edge method was the most accurate (1.3 to 2.5% error). In vivo LV volumes in 7 anesthetized dogs were compared with 2-DE and cineangiography. Good correlations (r = 0.92) were obtained, but the inner edge method underestimated angiographic volume, whereas the leading edge method reduced the magnitude of underestimation. Thus, the leading edge method for 2-DE is most accurate not only for linear and cross-sectional measurements of the myocardium, but also for application to in vivo LV volumes.

Animals↗
PubMed1983

Prevention of ischemic injury and early reperfusion derangements by hypothermic retroperfusion.

Hypothermic synchronized retroperfusion was applied during coronary artery occlusion to determine its ability to alleviate junctional derangements of reperfusion and to reduce infarct size. The proximal left anterior descending coronary artery was occluded in 25 closed chest dogs for 3 hours and then reperfused for 7 days. Thirteen dogs with no reperfusion pretreatment served as a control group (Group A). In 12 dogs, hypothermic retroperfusion was applied from 30 minutes up to 3 hours of the occlusion period (Group B). Sequential two-dimensional echocardiographic and hemodynamic as well as metabolic measurements were performed. Compared with untreated control dogs, dogs with hypothermic synchronized retroperfusion had significantly reduced heart rate and rate-pressure product, decreased left ventricular volumes and improved ejection fraction during the occlusion period. Two-dimensional echocardiographically-derived ischemic zone systolic fractional area change and systolic wall thickening indicated significantly improved function as a result of retroperfusion. During the reperfusion period, untreated control dogs (group A) had more severe derangements in hemodynamics and wall motion than dogs treated by hypothermic retroperfusion (group B). Mortality was 30.7% in group A, 16.7% in group B and 7th day infarct size as percent of the left ventricle was 12.0 +/- 6.5 (mean +/- standard deviation) and 4.2 +/- 5.9, respectively (p less than 0.02). It is concluded that hypothermic synchronized retroperfusion applied after coronary occlusion and before reperfusion significantly improves cardiac function during occlusion, minimizes complications of reperfusion and reduces the ultimate infarct size. Because this form of circulatory assistance helps maintain cardiac function and delays the evolution of myocardial necrosis, its application may be beneficial during an evolving acute myocardial infarction before achievement of surgical or nonsurgical reperfusion.

Animals↗
PubMed1983

Retrograde lysis of coronary artery thrombus by coronary venous streptokinase administration.

This study examined whether an occlusive thrombus within a coronary artery can be lysed by streptokinase retroperfusion into the associated regional coronary vein. Experimental coronary artery thrombosis was induced in 15 closed chest dogs by placing a small copper coil at a proximal site of the left anterior descending coronary artery. Total thrombotic obstruction of this artery was verified within 10 to 60 minutes (38.0 +/- 15.8, mean +/- standard deviation) and streptokinase was administered within 94.0 +/- 17.4 minutes from coil insertion at an average rate of 42 IU/kg per minute by one of three modes: 1) intermittent 10 minute direct coronary venous retroinfusion (five dogs); 2) continuous infusion into the pumping circuit of synchronized phased retroperfusion of the great cardiac vein with arterial blood (five dogs); and 3) for comparison, streptokinase administered intravenously (five dogs). The intracoronary thrombus was fully lysed and anterograde reperfusion established within 51.0 +/- 18.7 minutes by intermittent streptokinase retroinfusion, and in 50.0 +/- 6.1 minutes by streptokinase supplemented synchronized retroperfusion (50.5 +/- 13.2 minutes for pooled retrograde coronary venous delivery). Lysis was also induced by systemic streptokinase, but the time to lysis was significantly longer and more variable (131.6 +/- 60.6 minutes) than with retrograde administration (p less than 0.01). The retroperfusion modality appears the preferable technique because it provides early thrombolysis and, at the same time, improves cardiac function and maintains myocardial viability of the jeopardized ischemic zone pending achievement of full reflow. Thus, streptokinase retroperfusion, if promptly instituted, may be a useful complemental nonsurgical treatment of evolving acute myocardial infarction after thrombotic coronary artery occlusion.

Animals↗
PubMed1983

Quantitation of regional cardiac function by two-dimensional echocardiography. I. Patterns of contraction in the normal left ventricle.

Regional differences in wall motion and wall thickening were quantitated in the normal left ventricle using two-dimensional echocardiography (2-D echo). Using a computer-aided system, the left ventricle was subdivided in a standardized manner into 40 segments of five 2-D echo short-axis cross sections from the mitral valve level to the low left ventricle or apex. Measurements of sectional and segmental cavity areas, muscle areas and endocardial as well as epicardial perimeters, allowed assessment of contractile function using such indexes as endocardial systolic fractional area change (FAC), wall thickening (WTh), and circumferential fiber shortening (shortening). In 50 normal anesthetized, closed-chest dogs (including 10 studies in the conscious state) and in 32 normal humans, left ventricular contractile function increased significantly from base to apex. Thus, in anesthetized dogs, sectional FAC, WTh and shortening increased from left ventricular base to apex as follows: 39.4 +/- 5.1% to 61.6 +/- 7.2%, 20.5 +/- 6.6% to 46.7 +/- 11.5% and 22.7 +/- 3.4% to 35.4 +/- 5.9%, respectively. Similar trends were noted in conscious dogs. In man, sectional FAC, WTh and shortening also increased from the mitral valve to the low left ventricular level: 38.8 +/- 3.3% to 60.7 +/- 4.5%, 23.9 +/- 5.6% to 28.9 +/- 7.6% and 21.4 +/- 5.0% to 30.6 +/- 5.6%, respectively. Detailed segmental analysis in individual cross sections also revealed regional differences in contraction. Generally, contraction was most vigorous in posterior regions of the left ventricle. The septal regions exhibited lowest contraction at the base, but also the greatest increase from base to apex, both in the canine and human. Lateral regions did not show significant changes along the length of the left ventricle. Diastolic wall thickness also varied. We conclude that contraction in the normal left ventricle cannot be assumed to be uniform or symmetrical. These normal regional differences in function should be taken into account when evaluating altered physiologic states and in studying effects of therapeutic interventions.

Adult↗
PubMed1983

Validation of a computerized edge detection algorithm for quantitative two-dimensional echocardiography.

An edge detection algorithm used in conjunction with digitized two-dimensional echocardiograms was applied to validate computerized two-dimensional echocardiographic (2DE) quantitation of cross-sectional areas of canine left ventricular chambers. Images were enhanced by space-time smoothing and dynamic range expansion, after which automatic edge detection was performed by convolving a Laplacian operator with the enhanced image. In an in vitro study of 29 myocardial slabs, computer-derived 2DE measurements of short-axis sections of the left ventricle were compared with manually derived 2DE data and validated against direct measurements of intraluminal areas of myocardial slabs. Correlations of both manually and computer-derived 2D echocardiograms vs direct measurements were equally satisfactory (r = .95 for both). Computer-derived measurements of perimeters tended to underestimate actual perimeters of the endocardial outlines of left ventricular sections. In 13 closed-chest anesthetized dogs, manually and computer-derived left ventricular short-axis areas measured by 2DE techniques showed a good correlation at both end-diastole (r = .91) and end-systole (r = .92). Left ventricular volumes reconstructed from 2DE images were compared with angiographically determined volumes. The computer-enhanced 2DE method correlated against angiography, with r = .93 for end-diastolic and r = .93 for end-systolic volumes. Left ventricular volume correlations between manually and computer-derived 2D echocardiograms were satisfactory, with r = .87 for end-diastole and r = .87 for end systole. We conclude that computerized enhancement and edge detection of 2D echocardiograms obtained in dogs provided accurate analysis of actual left ventricular cross-sectional areas and left ventricular volumes.

Animals↗
PubMed1982

Evaluation of changes in left ventricular end-diastolic pressure by left atrial two-dimensional echocardiography.

Two-dimensional echocardiography (2DE) measurements of left atrial (LA) cross-sectional areas were compared in closed-chest dogs with concurrent high-fidelity recordings of left ventricular end-diastolic pressure (LVEDP) measurements. One hundred forty-three simultaneous determinations of LVEDP and end-diastolic as well as end-systolic LA cross-sectional areas were obtained in eight dogs during control, after coronary artery occlusion, and following alterations in LV preload and afterload. Correlation coefficients for LVEDP versus LA end-diastolic cross-sectional area ranged from 0.85 to 0.97 in the eight dogs, with standard errors of estimate from 1.89 to 5.43 mm Hg. These findings suggest that 2DE measurements of changes in LA size may facilitate noninvasive evaluation of alterations in LVEDP in patients with LV failure or undergoing interventions.

Animals↗
PubMed1982

Hypothermic coronary venous phased retroperfusion: a closed-chest treatment of acute regional myocardial ischemia.

Hypothermic synchronized retroperfusion (HSRP) was applied in closed-chest dogs after acute coronary occlusion to determine whether this intervention can significantly retard the otherwise rapidly developing irreversible ischemic injury. The left anterior descending coronary artery (LAD) was occluded for 3 hours in 22 dogs and for 6 hours in 16 dogs. Starting 30 minutes after occlusion, HSRP was applied during maintained coronary occlusion in 21 dogs. The remaining dogs served as untreated controls. Arterial blood was cooled to 20 degrees C and retroperfused in diastole into the regional coronary veins. Hemodynamics, contrast cineangiography and two-dimensional echocardiography were measured sequentially. Glycogen-depleted ischemic areas and necrotic zones were delineated in transverse slices of the left ventricle. Untreated controls dogs further deteriorated; in contrast, HSRP between 30 minutes and 3- and 6-hour LAD occlusion significantly reduced the rate-pressure product (21.3 +/- 4.0% or 26.8 +/- 8.2%) and left ventricular end-diastolic pressure (39.5 +/- 9.5% or 51.4 +/- 7.7%) and increased ejection fraction (28 +/- 17% and 33 +/- 2.0%). HSRP caused no arrhythmias and led to much less necrosis of ischemic myocardium in the treated 3- or 6-hour occlusion series (7.4 +/- 2.7% or 28.9 +/- 12.6%) than in respective untreated controls (47.1 +/- 8.9% and 72.3 +/- 5.9%). Moderately hypothermic closed-chest phased retroperfusion appears to protect reversibly injured ischemic myocardium and improve cardiac function. Such treatment may be particularly suitable in the earliest stages of evolving myocardial infarction, when maintenance of myocardial viability is essential for preservation of jeopardized myocardium while awaiting coronary bypass revascularization or nonsurgical thrombolytic reperfusion.

Animals↗