Phase analysis of gated blood pool scintigraphic images to localize bypass tracts in Wolff-Parkinson-White syndrome.

The ability of radionuclide techniques to localize bypass tracts in patients with Wolff-Parkinson-White syndrome to sites around the atrioventricular (AV) ring using a three view triangulation method was investigated. In 17 patients with Wolff-Parkinson-White syndrome, phase images were generated from gated blood pool scans using the first Fourier harmonic of the time-activity curve of each pixel. In addition, the difference between left and right ventricular mean phase angles was calculated for each patient and for 13 control subjects. Bypass tracts were localized to one or more sites on a 10 site grid schematically superimposed on the AV ring (Duke grid) by electrophysiologic study in all patients and by intraoperative mapping in 7 of the 17 patients. These same 10 anatomic sites were projected onto three scintigraphic views and the site of earliest ventricular phase angle was located in each view. The 10 sites around the AV ring were divided into two anatomic groups: free wall and septal/paraseptal. Phase image locations correlated with electrophysiologic locations within one grid site in 11 of 11 patients with free wall tracts and were confirmed at surgery in 5 of the 11. In five of six patients with septal/paraseptal tracts, electrophysiologic study could not localize the bypass tract to one site, whereas phase images localized two of the five as free wall adjacent to the septum, one as paraseptal and two as true posteroseptal. One posteroseptal site was confirmed at surgery. In one patient, in whom phase image analysis and electrophysiologic study showed different sites, existence of both tracts was confirmed at surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of right ventricular contractile state with the conductance catheter technique in the pig.

OBJECTIVE: Since the conductance catheter method has facilitated evaluation of left ventricular contractile state in both laboratory and clinical studies, the aim of this study was to determine whether the technique is similarly useful for the right ventricle. METHODS: A series of right ventricular pressure-volume loops was obtained in seven open chest pigs during transient vena caval occlusion using a 12-electrode conductance catheter. End systolic pressure-volume relationships, stroke work-end diastolic volume relationships, and dP/dt-end diastolic volume relationships were compared at control and during infusion of dobutamine and esmolol. RESULTS: Right ventricular pressure-volume loops generated with the conductance catheter were of a shape consistent with those previously reported by other volume measurement techniques, and responded to changes in inotropic state in a predictable fashion. Dobutamine shifted the three contractile relationships leftward, whereas esmolol shifted them rightward. Comparisons of stroke volume derived with the conductance catheter and with a pulmonary artery flow probe demonstrated the ability of the conductance technique to measure relative volume changes. CONCLUSIONS: The conductance catheter provides a continuous measure of right ventricular volume that was used to detect changes in right ventricular contractile state in pigs. This represents a promising and much needed method for the evaluation of right ventricular function.

Systolic and diastolic properties of the human left ventricle during valve replacement for chronic mitral regurgitation.

M mode and two dimensional echocardiography were combined with pressure-flow data to analyze systolic mechanics and diastolic compliance in nine patients during valve replacement for chronic mitral regurgitation. Both M mode (six patients) and two dimensional (four patients) echographic analyses revealed large decreases in early postoperative shortening fraction (-24 +/- 17 [standard deviation] percent M mode study, p < 0.01: -30 +/- 12 percent two dimensional study, p < 0.02), which were significantly different from small changes observed in control subjects (M mode study, +7 +/- 10 percent, 25 subjects and two dimensional study, -7 +/- 14 percent, 8 subjects). Additional data suggest that ventricular compliance is increased in chronic mitral regurgitation and that elimination of the low impedance left atrial pathway by valve replacement is associated with a significant increase in wall stress (five patients, p < 0.02) that appears to be responsible for the decreased ejection fraction postoperatively. Analysis of hemodynamic variables other than ejection fraction and rate of circumferential shortening revealed no difference between five postoperative patients with chronic mitral regurgitation and five with coronary artery disease. These results in human subjects confirm predictions from studies in animal models and suggest that unique properties of chronic mitral regurgitation and demand special attention when patients with this condition are being evaluated for surgery.

Intraoperative 2-dimensional echocardiography: ejection of microbubbles from the left ventricle after cardiac surgery.

Although the presence of entrapped air in the left ventricle at surgery has long been a concern, its prevalence and clinical significance are unknown. Two-dimensional echocardiography provides a unique means for observing intracardiac microbubbles intraoperatively. Accordingly, intraoperative 2-dimensional echocardiograms obtained in 79 patients immediately after cardiopulmonary bypass were examined for the presence of microbubbles. Left ventricular microbubbles were detected in 14% of coronary artery bypass operations (n = 22), 50% of multiple valve replacements (n = 8), 67% of single valve replacements (n = 58), and 100% of atrial septal defect closures (n = 4), left atrial myxoma resections (n = 2), and mitral commissurotomies (n = 2). Microbubbles were not observed in patients undergoing coronary artery bypass with valve replacement (n = 4) or with removal of left ventricular aneurysm (n = 1). Continuous ejection of microbubbles from the left ventricle was frequently noted for extended periods of time and, although no patient in this study showed evidence of gross neurologic dysfunction, the possibility of subclinical organ damage exists. We conclude that 2-dimensional echocardiography is useful for detection of intracardiac microbubbles and therefore may be instrumental in their elimination.

Two-dimensional ultrasound and cardiac operations.

Two-dimensional ultrasound was employed for qualitative and quantitative studies during cardiac operations in 74 patients. A gas-sterilized phased-array transducer applied directly to the anterior surface of the heart produced high-quality images without a water path or other special manipulations. The techniques employed were successful in demonstrating alterations in cardiac anatomy associated with valve disease and cardiac tumors. Continuous clouds of microbubbles ejected from the left ventricle immediately following cardiopulmonary bypass were detected in 42% of 45 patients studied. Measurement of short-axis area change during systole proved useful for evaluation of intraoperative changes in left ventricular function. In the perioperative period, with the chest closed, the method detected increasing left ventricular mass during transplant rejection and was useful for monitoring changes in left ventricular performance when image quality was sufficient. The capabilities and limitations of this technique for special studies during cardiac operations should be familiar to surgeons with access to the method.

Effect of nitroprusside on end-diastolic pressure-diameter relations of the human left ventricle after pericardiotomy.

Although studies in human beings have suggested that sodium nitroprusside may increase the diastolic compliance of the left ventricle, animal models have provided contradictory evidence following pericardiotomy. The effect of nitroprusside on the human left ventricle after pericardiotomy has not been reported. Accordingly, we studied the effects of intravenous sodium nitroprusside in eight patients during cardiac operations. Curves relating left ventricular end-diastolic pressure (EDP) to echocardiographically determined end-diastolic diameter (EDD) were determined during the transfusion of volume from the reservoir of the heart-lung machine (EDP varied from 5 to 35 mm Hg) before and during nitroprusside administration (1 to 4 mcg/kg/min). An average relation (EDP = 0.41 +/- 0.40 [SD] e1.18 +/- 0.58 EDD was obtained for eight patients by exponential curve fitting (r = 0.80 +/-08). Nitroprusside decreased systolic left ventricular pressure (118 +/- 16 to 100 +/- 13 mm Hg, p less than 0.001, paired t test) but did not alter the control curve relating EDP to EDD. We conclude that EDD-EDP relations of the human left ventricle are not altered by nitroprusside administration in the absence of the restraining influence of the pericardium. This suggests that nitroprusside has no significant direct effect on diastolic properties of the human myocardium.

Left ventricular mechanics of counterpulsation and left heart bypass, individually and in combination.

Counterpulsation and left heart bypass devices have been successfully used to salvage patients with severe left ventricular power failure following cardiopulmonary bypass. Each of these techniques is believed to reduce or minimize myocardial work, yet the effects of these devices on the force of myocardial contraction have not been defined. In the present investigation the effects of counterpulsation produced by intravascular (intra-aortic balloon pumping) and extravascular (pulsatile assist device) balloon devices, partial left atrial-aortic bypass, and total bypass on left ventricular mechanics were examined. The devices were studied individually and in combination in 10 anesthetized open-chest dogs. Left ventricular wall stress, external work, and contractility indices were calculated by computer using a changing volume spherical model of the left ventricle. Results indicate that although all currently available circulatory assist devices reduced peak left ventricular wall stress, a spectrum of relative effectiveness progressed from intra-aortic balloon pumping or pulsatile assist device alone through the combination intra-aortic balloon pumping plus the pulsatile assist device. Partial left heart bypass was more effective than intra-aortic balloon pumping plus the pulsatile assist device in reducing peak wall stress, but the difference was small. Total left heart bypass was vastly superior to any of the other modalities tested in its effects on peak wall stress as well as external work. The addition of counterpulsation to partial or total left heart bypass produced minimal changes in left ventricular systolic mechanics.

Heart reduction surgery: an analysis of the impact on cardiac function.

OBJECTIVES: Reports of improved ejection fraction, coupled with decreased filling pressures, have prompted a number of centers to begin evaluating the efficacy of heart reduction surgery to ameliorate symptoms of heart failure. However, the impact of this operation on cardiac mechanics is unknown. We applied a multiple compartment elastance model to simulate the effects of excising cardiac mass on heart function. METHODS: The left ventricle was divided into two functional compartments to simulate excision of part of the wall. At multiple increments of mass reduction, the resulting end-systolic elastance, ejection fraction, stroke volume, end-diastolic pressure and volume, and diastolic stiffness were determined. RESULTS: Changes in systolic function were accompanied by offsetting changes in diastolic function; consequently, overall pump function (the Frank-Starling Relationship) was found to be depressed. The geometric rearrangement associated with this operation leads to a reduction in wall stress for a given level of pressure generation, thus implying an increase in the efficiency with which wall stress is transduced into intraventricular pressure. CONCLUSIONS: Overall pump function is depressed in the short run after heart reduction surgery. However, on the basis of theoretic arguments, heart reduction surgery may have long-term beneficial implications. Importantly, this analysis revealed that changes in parameters of ventricular function have different implications during heart reduction surgery than when such changes are observed with inotropism caused by acute pharmacologic therapy.

Mechanical circulatory support via the left ventricular vent: the concept of left ventricular copulsation.

Left ventricular copulsation was evaluated as a means of circulatory support in an experimental canine cardiogenic shock preparation. Copulsation was effected by a commercially available pulsatile assist device which was attached to an apical left ventricular vent cannula. The hemodynamic effects were compared with those of intra-aortic balloon pumping (IABP) in the same animals. Copulsation produced a 35.6% increase in mean aortic blood pressure, a 32.3% reduction in mean left atrial pressure, a 66.7% increase in cardiac output, and a 76.2% increase in coronary blood flow. The improvement in these variables was significantly greater during left ventricular copulsation than during IABP (p less than 0.05). The method is simple, uses equipment that is readily available, and is potentially a powerful intermediate circulatory support modality between IABP and more complex techniques.

The absence of temperature effects on end-diastolic pressure-volume relations in the canine left ventricle determined by two-dimensional echocardiography.

Because of divergent conclusions in the literature regarding the effects of temperature on end-diastolic compliance in the canine left ventricle (LV), pressure-volume relationships at normothermia and hypothermia (28 degrees C) were studied with two-dimensional ultrasound in nine dogs on cardiopulmonary bypass (open pericardium) over a range of left ventricular end-diastolic pressure (LVEDP) from 0 to 22 mm Hg. Three perpendicular echocardiographic sections were used with Simpson's rule to measure LV volume and mass at end-diastole for each level of LVEDP. Temperature was varied between 37 degrees and 28 degrees C by systemic cooling, and heart rate was allowed to slow spontaneously with temperature reduction. There was no change in left ventricular end-diastole pressure-volume (LVEDP-LVEDV) relationships at lower temperature provided that ventricular relaxation was complete at end-diastole. In addition, serial postmortem pressure-volume curves carried out by direct saline infusion into sealed ventricles at 38 degrees and 28 degrees C in three additional dogs demonstrated no temperature effects on postmortem LV compliance. Postmortem mass correlated well with echocardiographically determined LV mass, which showed a significant increase during the period of cardiopulmonary bypass, correlating with the development of myocardial edema. In summary, there appears to be no effect of moderate hypothermia on LVEDP-LVEDV relationships, provided the heart is in true diastasis at end-diastole. In addition, echocardiographic techniques can be used to study LV mass change on cardiopulmonary bypass.

Pharmacologic antagonism of beta-adrenergic blockade in dogs. I. Hemodynamic effects of isoproterenol, dopamine, and epinephrine in acute propranolol administration.

Hemodynamic effects of isoproterenol, dopamine, and epinephrine were studied before and after acute beta-adrenergic blockade in 16 open-chest, anesthetized mongrel dogs. Beta blockade was induced with 1 mg. per kilogram of intravenous propranolol. Cardiac output measurements were obtained by thermal dilution, and pressure recordings were obtained in the right ventricle, pulmonary artery, left atrium, left ventricle, and aorta. Derived parameters included stroke volume, pulmonary and systemic vascular resistances, and peak left ventricular dP/dt. In the presence of propranolol, epinephrine became a lethal drug in large doses and did not increase cardiac output in standard doses. Dopamine, in 25 to 50 mcg. per kilogram per minute doses, increased arterial pressure and systemic resistance; cardiac output was diminished compared with dopamine, 10 mcg. per kilogram per minute, prior to propranolol, as a result of increased resistance and decreased LV contractility. Isoproterenol, 0.6 to 0.9 mcg. per kilogram per minute, 15 to 20 times standard dosages, had moderately positive inotropic effects and increased cardiac output. Left ventricular systolic pressure with isoproterenol after propranolol was reduced when compared with effects of smaller doses prior to propranolol. These observations suggest that none of the catecholamines studied would be optimal for circulatory support in heart failure in the presence of propranolol. The present results define a pharmacologic basis for design of appropriate drug combinations for circulatory support in beta-blocked animals.

Simulated left ventricular aneurysm and aneurysm repair in swine.

Patch reconstruction of left ventricular aneurysm may be superior to linear closure, but this hypothesis has not been tested experimentally. Accordingly, six anesthetized domestic pigs were instrumented to measure regional left ventricular wall thickening, stroke volume, systolic left ventricular pressure, and myocardial oxygen consumption. With total bypass and cardioplegia, a 6 by 8 cm Dacron patch was inserted into the anteroapical left ventricle. Simulations were as follows: left ventricular aneurysm, patch open; patch reconstruction, 50% patch plication; standard repair, ventriculotomy edges approximated. Global function, from stroke work (stroke volume x integral of left ventricular pressure)-left ventricular end-diastolic pressure curves, was depressed in all three simulations compared with control. A tendency for stroke work to be greater for standard repair than for left ventricular aneurysm and patch reconstruction at higher preloads was not statistically significant. Mechanical efficiency, from stroke work/myocardial oxygen consumption (joules per milliliter oxygen per beat), was 2.43 +/- 0.52 (mean +/- standard error of the mean) (control), 2.22 +/- 0.94 (standard repair), 1.27 +/- 0.39 (patch reconstruction), and 1.09 +/- 0.37 (left ventricular aneurysm) (no significant differences). Regional work was calculated as regional left ventricular wall thickening x integral of left ventricular pressure. The slope of the regional work-end-diastolic wall thickness relation decreased in the posterior wall 14.0 +/- 2.9 (control) versus 8.4 +/- 2.0 (left ventricular aneurysm), 6.9 +/- 1.4 (patch reconstruction), and 7.4 +/- 1.4 (standard repair) (p less than 0.05). In the anterior wall, contractility did not change significantly (7.4 +/- 1.2, control; 7.8 +/- 2.7, left ventricular aneurysm; 5.0 +/- 0.4, patch reconstruction; and 5.3 +/- 0.4, standard repair). Decreased end-diastolic wall thinning anteriorly suggested tethering. These results in the normal left ventricle suggest that patch ventriculoplasty is of no greater benefit than linear repair. Either repair may impede function of adjacent myocardium through restriction of regional diastolic lengthening.

Effects of perfusion-induced edema on diastolic stress-strain relations in intact swine papillary muscle.

The mechanism through which edema reduces left ventricular compliance has not been defined. Accordingly, diastolic properties of in situ left ventricular swine papillary muscles were studied in three groups: control (n = 6, 4 degrees to 6 degrees C), edematous (150 mOsm/L coronary perfusion, n = 6, 4 degrees to 6 degrees C), and ischemic contracture (n = 8, 28 degrees C). Lagrangian stress (sigma) and strain (epsilon) were calculated from slow stretch data and approximated by sigma = alpha(e beta epsilon-1). The natural logarithm of stress versus strain was linear over the physiologic range of 0.05 < strain < 0.40. Hypotonic perfusions (1 L x 3) progressively shifted the stress-strain relationship upward and to the left. Compared to baseline, alpha increased significantly (p < 0.05) after perfusion 3 (6.7 +/- 2.1 baseline, 12.2 +/- 6.6 perfusion 1, 12.7 +/- 3.5 perfusion 2, and 42.9 +/- 16.3 gm/cm2 perfusion 3). The constant beta did not change significantly (13.0 +/- 1.5 baseline, 13.1 +/- 1.6 perfusion 1, 13.2 +/- 1.6 perfusion 2, and 14.1 +/- 1.4 perfusion 3). Right ventricular water content increased after each perfusion (77.1% +/- 1.4% baseline, 81.6% +/- 1.3%, 84.7% +/- 1.5%, and 86.9% +/- 1.7%, p < 0.05). With ischemic contracture, alpha increased from 61.9 +/- 17.8 to 173.1 +/- 61.5 gm/cm2 (p > 0.05) and beta increased insignificantly from 6.5 +/- 0.6 to 10.6 +/- 1.8 (p = NS). In the control group all variables were unchanged after 210 minutes. We conclude that myocardial stiffness increases with myocardial edema. This may explain decreased compliance in the edematous left ventricle.

Permanent pacing following cardiac transplantation.

Permanent pacemakers were inserted in 20 of 439 patients who had received 453 orthotopic cardiac allografts since 1980 at the Columbia-Presbyterian Medical Center. Mean age at transplantation was 45 +/- 4 (SEM) years (range 10 to 64). Pacemakers were inserted an average of 2.4 +/- 1 months after transplantation (range 0.4 to 29), 16 of 20 (80%) within the first month. Indications included sinus bradycardia or sinus arrest in 15 (75%), third-degree heart block in 2 (10%), and both sinus node and atrioventricular node dysfunction in 3 (15%). Rejection episodes and pacemaker insertion were associated in 8 patients (40%). Pacing modes included DDD (7 patients, 35%), AAI,R (7 patients, 35%), VVI,R (3 patients, 15%), DDD,R (2 patients, 10%), and VVI (1 patient, 5%). There was no pacing-related morbidity or mortality. Fourteen of 20 patients (70%) are alive and well 3 to 48 months (mean 24 +/- 4) after transplantation. Late follow-up indicated that atrioventricular node dysfunction resolved in one of two patients, sinoatrial node dysfunction improved or resolved in 7/13 patients, and no atrioventricular block developed in 11 (8 to 37 months, mean 22 +/- 3). Permanent pacing can be safely performed following orthotopic cardiac transplantation, predominantly for sinus node dysfunction. The requirement for pacing may reflect ongoing or new onset rejection and patients should therefore be evaluated accordingly. Dual-chamber pacing is probably not necessary unless atrioventricular node dysfunction is coexistent. Further, as most transplant recipients return to an active life-style, AAI,R may be the preferred mode of pacing.

Retrograde cardioplegia preserves myocardial function after induced coronary air embolism.

Coronary air embolism is a potential complication of cardiopulmonary bypass. We compared left ventricular function before and after the administration of antegrade or retrograde cardioplegic solution in a porcine model of coronary air embolism. Nineteen pigs were placed on cardiopulmonary bypass support and cooled to 32 degrees C. The heart was initially arrested with antegrade cold blood cardioplegic solution. The aortic crossclamp was released at 30 minutes and 0.02 cc/kg body weight of air was injected into the left anterior descending artery distal to the first diagonal branch. After 5 minutes the aorta was reclamped and the animals treated with 15 ml/kg body weight of 1:4 blood cardioplegic solution delivered by the antegrade (n = 6) or retrograde (n = 7) method. Control animals (n = 6) were not treated. Changes in regional preload recruitable stroke work were used to assess left ventricular performance before and after cardiopulmonary bypass. Two control animals could not be weaned from cardiopulmonary bypass. Left ventricular function was best preserved after treatment of induced coronary air embolism with retrograde cardioplegia (90% of baseline). Coronary air embolism treatment with antegrade cardioplegia resulted in diminished left ventricular performance (68% of baseline). In control animals left ventricular contractility was significantly impaired (39% of baseline). We conclude that administration of retrograde cardioplegic solution may be an effective method of treating coronary air embolism. The favorable outcome seen with cardioplegia may be in part because of its ability to protect the ischemic myocardium while the solution mechanically dislodges air from the vascular bed.

Pharmacologic antagonism of beta adrenergic blockade in dogs. II. Hemodynamic effects of simultaneous intravenous infusion of isoproterenol and dopamine during chronic propranolol administration.

Chronic beta adrenergic blockade was induced in eight dogs with 240 to 360 mg of oral propranolol dailty for 2 to 6 weeks. Beta blockade was confirmed by a minimal heart rate response to isoproterenol, 0.06 micrograms/kg/min, in a pentobarbital-anesthetized, open-chest preparation. Subsequent to confirmation of beta blockade, hemodynamic effects of isoproterenol and dopamine were examined individually and in combination. A desirable balance of arterial pressure and cardiac output was achieved by combining isoproterenol, 0.2 to 2.0 micrograms/kg/min, with dopamine, 5 to 20 micrograms/kg/min. This combination increased mean arterial pressure (109 +/- 9 versus 81 +/- 7), cardiac output (4.3 +/- .5 versus 2.8 +/- .3 L/min) and heart rate 156 +/- 4 versus 120 +/- 7) (p less than 0.05). The hemodynamic effects of combined isoproterenol-dopamine were superior to the effects of either drug alone and suggest a method for effective circulatory support of man during chronic beta adrenergic blockade.

Two-dimensional echocardiography in dogs. Variation of left ventricular mass, geometry, volume, and ejection fraction on cardiopulmonary bypass.

Quantitative two-dimensional echocardiography was evaluated in 39 open-chest dogs placed on cardiopulmonary bypass. The correlation coefficient of left ventricular end-diastolic volume against postmortem pressure-volume curves was r = 0.89 to 0.93 (347 measurements in 15 dogs, 0 to 24 mm Hg). Ejection fraction was validated against roller pump flow and echo left ventricular end-diastolic volume (r = 0.83, n = 13). Left ventricular mass in vivo was compared with postmortem left ventricular mass (r = 0.81 in 21 early studies, r = 0.91 in 10 later studies with updated equipment) and was found to increase with ischemic injury as well as cardiopulmonary bypass with hemodilution. Left ventricular mass increased (p less than 0.001) from 119 +/- 5 (standard error of the mean) to 138 +/- 6 gm (n = 23) after 2 1/2 hours on cardiopulmonary bypass and moderate hemodilution. With the addition of ischemic arrest, left ventricular mass increased from 119 +/- 7 to 148 +/- 11 gm (p less than 0.01, n = 8), and myocardial water content increased by 2.0% +/- 0.4%, which accounted for at least 65% of the observed mass change. Mean left ventricular wall thickness increased from 13.8 to 15.5 mm (p = 0.02) after ischemia. Ventricular shape became more spherical with increasing left ventricular end-diastolic pressure. We conclude that two-dimensional echocardiography can be reliably used for accurate, serial measurements in physiological studies. The demonstrated variability in left ventricular mass is important, yet frequently ignored. Recognizing left ventricular mass changes may facilitate the detection of myocardial injury reflected as edema.

Diastolic function in the heterotopic rat heart transplant model. Effects of edema, ischemia, and rejection.

Decreased systolic ventricular function and compliance and increased left ventricular edema and mass have been demonstrated in cardiac allograft rejection. Whether decreased left ventricular compliance in rejection is caused by myocardial edema has not been examined, and compliance in the Ono-Lindsey model has not been reported. Heterotopic rat abdominal cardiac transplantation was performed in ACI isografts (n = 24) and in ACI to Lewis allografts (n = 24). Subgroups were studied on posttransplantation days 0, 1, 3, and 5 (each n = 6). Both transplanted hearts and native hearts were arrested with potassium for the assessment of myocardial water content, heart weight, and the left ventricular pressure-volume relation. In transplanted hearts, myocardial water content did not change in isografts but increased on posttransplantation day 5 in allografts (81.1% on posttransplantation day 5 versus 76.1% on day 0, 77.2% on day 1, and 77.5% on day 3, p < 0.05). Wet and dry heart weight also increased on posttransplantation day 5 in allografts (p < 0.05). The left ventricular pressure-volume relation in transplanted hearts shifted to the left when compared with that in native hearts in all subgroups; these volume differences were statistically significant (p < 0.01) for all pressures above 7.5 mm Hg. This pattern was similar in isografts and allografts on posttransplantation days 0, 1, and 3, and no significant differences between isografts and allografts were demonstrated. On posttransplantation day 5, however, the pressure after a 0.05 ml injection in allografts was greater in transplanted hearts than in native hearts (24 +/- 3 versus 3 +/- 1 mm Hg, p < 0.01). The pressure difference between transplanted and native hearts was also significantly greater in allografts than in isografts (22 +/- 2 versus 6 +/- 1 mm Hg, p < 0.01), indicating an increase in stiffness of allografts. Thus edema and impaired diastolic properties occur concurrently with allograft rejection. Left ventricular volume is abnormal from posttransplantation days 0 to 5 in transplanted hearts but not native hearts in the Ono-Lindsey model with current methods, apparently because of ischemic injury during transplantation.

Effects of crystalloid, blood, and University of Wisconsin perfusates on weight, water content, and left ventricular compliance in an edema-prone, isolated porcine heart model.

Coronary perfusion with blood and cardioplegic solutions was examined in isolated, arrested, hypothermic porcine hearts. Myocardial water content, heart weight, and left ventricular diastolic pressure-volume curves were measured before and after coronary perfusion. Statistics were based on exponential curve fitting to pressure-volume data and analysis of variance. Thirty-two pig hearts were divided into five experimental groups and a control group; after control measurements, each experimental group underwent three successive coronary perfusions with 1 L of unmodified blood or a solution of controlled osmolarity, 150 mOsm/L (diluted Plegisol solution), 280 mOsm/L (Plegisol solution and albumin), 334 mOsm/L (University of Wisconsin solution), or 380 mOsm/L (Stanford solution). After each perfusion, measurements were repeated. All experiments were completed within 90 minutes. The first perfusion was delayed 20 minutes after excision of the heart to allow for instrumentation. Each experimental group demonstrated a statistically significant increase in heart weight and myocardial water content and a significant decrease in left ventricular compliance after perfusion. Changes were less pronounced with blood than crystalloids. Edema effects were minimized but not prevented by hyperosmolarity. University of Wisconsin solution appeared unique in minimizing progressive edema after the first perfusion. Over the 81 perfusions studied, changes in left ventricular compliance were linearly related to heart weight and water content. We conclude that in this model, in which edema sensitivity is increased by delayed perfusion and venous occlusion, edema is minimized but not eliminated by whole blood and University of Wisconsin solution. The model appears useful in assessing properties of cardioplegia vehicles intended for use in the injured myocardium.

Long-term function of human cardiac allografts assessed by two-dimensional echocardiography.

Previous studies from our laboratory demonstrated increasing left ventricular mass in cyclosporine-treated cardiac allograft recipients over 30 days after transplantation, but the long-term evolution of this process and possible effects on allograft function are unknown. Accordingly, quantitative two-dimensional echocardiography was performed 2 and 23 days and 15 months postoperatively in 14 recipients treated with cyclosporine and prednisone. Changes in left ventricular ejection fraction, end-diastolic volume, mass, and end-systolic wall stress were analyzed. Comparison of studies at 2 and 23 days revealed significant (p less than 0.01) increases in ejection fraction (54% +/- 8% [standard deviation] to 62% +/- 4%), end-diastolic volume (84% +/- 32 ml to 96 +/- 31 ml), and left ventricular mass (118 +/- 45 gm to 136 +/- 41 gm). Comparison of studies at 23 days and 15 months revealed no significant change in end-diastolic volume or left ventricular mass, whereas ejection fraction decreased slightly (62% +/- 4% to 57% +/- 4%, p less than 0.01). End-systolic wall stress decreased when data at 2 days and 15 months were compared (83 +/- 24 gm/cm2 versus 66 +/- 18 gm/cm2, p less than 0.05), but no change in contractility was apparent from the ejection fraction/end-systolic stress relation. We conclude that left ventricular mass and end-diastolic volume increase early after transplantation in cyclosporine-treated cardiac allograft recipients, but these changes are not predictive of long-term results, which are characterized by no significant late variation in left ventricular mass, end-diastolic volume, or contractility.