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PubMed1988

Effect of mild hyperthermia on recovery of metabolic function after global cerebral ischemia in cats.

We investigated the effect of mild whole-body hyperthermia before and after 16 minutes of global cerebral ischemia on metabolic recovery during recirculation in cats using in vivo phosphorus-31 nuclear magnetic resonance spectroscopy. Hyperthermia (temperature 40.6 +/- 0.2 degrees C) was induced greater than or equal to 1 hour before ischemia and was maintained during 1.5-2 hours of recirculation in nine cats; four cats were subjected to hyperthermia without cerebral ischemia, six to hyperthermia during recirculation (after return of intracellular pH to preischemic values), and 14 to normothermic ischemia and recirculation. Our data indicate that preischemic hyperthermia results in an intracellular cerebral pH during recirculation significantly lower than that in normothermic cats. In hyperthermic cats beta-ATP and phosphocreatine (PCr) concentrations and the ratio of PCr to inorganic phosphate failed to return to preischemic levels during recirculation in contrast to normothermic cats. Hyperthermia without ischemia and hyperthermia during recirculation had no significant effect on intracellular pH. Thus, preischemic hyperthermia has a detrimental effect on metabolic recovery after transient global cerebral ischemia.

Acidosis↗
PubMed1984

[Left ventricular global and segmental function in pure mitral valve prolapse with poor tolerance for exertion].

Poor effort tolerance is observed in a small percentage of cases of idiopathic mitral valve prolapse (IMVP). The aim of this study was to assess the possible left ventricular dysfunction in such cases, responsible for poor effort tolerance. Left ventricular function and segmental wall motion were studied retrospectively in a group of 17 patients with IMVP. The patients, average age 53 +/- 12 years, had poor effort tolerance (ST segment depression of 2 to 4 mm in 15 cases, drop in blood pressure in 6 cases) justifying catheter and angiographic studies. All patients had IMVP confirmed on RAO left ventriculography. There was no associated mitral regurgitation or coronary artery disease. Left ventricular function was studied by parameters of global function (systolic and diastolic parameters, volume measurements) and by a quantitative study of segmental wall contraction. The method used for studying regional wall motion was an application of the Stanford method in which segmental shortening is studied over all the endocavitary contour of the LV during an angiographic cycle filmed at 50 frames/second in the RAO projection. The time and velocity amplitudes of wall motion were measured during systole and diastole. The same methodology was applied to 21 normal control subjects. The results showed abnormal volumic compliance and wall motion in the IMVP group. Asynergy was mainly confined to the antero-lateral wall of the LV. The amplitude of contraction was generally normal but the contraction was slower and finished earlier. In the same zone, relaxation was abnormally early and lasted longer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Global ventricular function and synchronism of contraction during and after exertion].

Phase analysis and ejection fraction (EF) of the left ventricle were obtained by radionuclide angiography in 53 patients at rest, during submaximal exercise and 3-8 minutes after exercise. The standard deviation of the peak of the histogram of phases (SDP) was used as an index of the synchronicity of regional contraction. The material comprised 13 sportsmen and 40 patients who underwent coronarography, 12 of whom had normal coronaries and 28 significant lesions. EF, while comparable in the three groups at rest, increased significantly on effort in normals and did not change in patients with coronary disease. At rest SDP was higher in coronary patients than in normals (p less than 0.01), and during exercise, it increased, but decreased in normals (p less than 0.01). After exercise, mean EF decreased in comparison with exercise in normals (p less than 0.01), while the opposite was the case in coronary patients. Normals had lower SDP values in the post-exercise period than at rest; on the other hand, SDP of coronary patients was significantly higher in the post-exercise period than at rest (p less than 0.001). Phase analysis during, and particularly after, exercise was found to be superior to EF in detecting ischemic left-ventricular dysfunction, and should be used in conjunction with EF to evaluate patients suspect for coronary disease.

Adult↗
PubMed1978

[Radionuclide ventriculography. II. Clinical results--parameters of global ventricular function (author's transl)].

The ejection fraction as determined by gated blood pool studies was compared with the ejection fraction as evaluated by the following conventional methods: 1) biplane cineangiography employing the Simpson rule. Correlation was r = 0.805 (n = 25); 2) the same patients using the area-length method (r = 0.88, n = 25); 3) monoplane cineangiography using the method of Greene et al. (5) (r = 0.86, n = 35). In 20 patients the maximal contraction velocity as evaluated by radionuclide ventriculography was compared with the mean systolic ejection rate. The observed correlation was weak (r = 0.62, n = 20); however, it should be noted that the radionuclide method determines the maximum contraction velocity whereas cinceangiography measures an average value over the whole systole.

Cineangiography↗
PubMed1980

[Motion of the posterior wall in the m-mode echocardiogram - a parameter of global left function (author's transl)].

The cardiac output was determined by thermodilution in 42 patients during heart catheterization and compared to the amplitude of the posterior aortic wall in the m-mode echocardiogram. The amplitude of the posterior aortic wall was measured at the time of the closure of the aortic cusps (KS) and at the time the maximal excursion of the posterior aortic wall occurred (GA). Both parameters correlated strongly to the cardia output (r = 0.84, KS; r = 0.76, GA) and to the forward stroke volume (r = 0.81, KS; r = 0.73, GA). Thus, the amplitude of the posterior aortic wall in the m-mode echocardiogram is a useful parameter in predicting left ventricular function especially in those patients, in whom determination of left ventricular function from the m-mode echocardiogram is limited due to left ventricular asynergy.

Aorta↗
PubMed1983

Alterations in regional myocardial function after heterogeneous cardioplegia.

Coronary stenoses lead to heterogeneous delivery of cardioplegic solution during cardiac operations. This situation was simulated by occlusion of the circumflex artery during cardioplegic infusion in canine right heart bypass preparations. Regional myocardial function (systolic shortening by sonomicrometer) was often diminished, despite preservation of global function. The correlation between recovery of circumflex regional function and recovery of stroke work or dP/dt (at constant aortic pressure, heart rate, and left atrial pressure) was poor (r = 0.17 and 0.07). The response of damaged regions to hemodynamic manipulations was studied. Increases in afterload after arrest did not lead to further deterioration of damaged regions. Volume loading (cardiac output 2 to 5 L/min) improved regional function even in severely damaged, bulging regions (p less than 0.05). Regional distensibility (delta length/delta left atrial pressure) decreased by 41% (p less than 0.02) in regions with poor protection and by 22% (p less than 0.01) in regions with good cardioplegic protection. There was also an increase in resting length (p less than 0.001) in both circumstances (5.2% and 3.7%). These changes in diastolic properties have not always been apparent in other experimental studies with less precise hemodynamic control. Heterogeneous cardioplegia causes heterogeneous changes in both diastolic distensibility and systolic function. These changes are poorly detected by examination of global ventricular function.

Animals↗
PubMed1990

Myocardial preservation: a comparison of oxygenated crystalloid and blood cardioplegia.

The purpose of this experiment was to compare myocardial protective effect after global ischemia using oxygenated crystalloid (CCcO2) and an oxygenated blood (BCcO2) cardioplegic solutions. Post-ischemic ventricular performance was studied in 2 equal (n = 7) groups of dogs subjected to 120 min of global ischemia induced at average myocardial temperatures of 8 degrees C in the CCcO2 group and 18 degrees C in the BCcO2 group. Left ventricular (LV) function included analysis of LV systolic function (global and regional function), LV diastolic function (chamber and myocardial stiffness) and LV relaxation was measured by sonomicrometry and Millar micrometers. Data were processed with a Dec PDP-11/23 computer. In vitro oxygen content (Vol%) measured 3.2 +/- 1.0 (CCcO2) and 9.5 +/- 0.3 (BCcO2). Percent recoveries of LV global function (LVSP, loop area, % shortening, LV dp/dt, mean VCF and E max) in the CCcO2 group were approximately the same as those in the BCcO2 group. There were no significant differences in LV regional function (loop area and % shortening) after ischemia between the two groups. The chamber and myocardial stiffness after ischemia in the CCcO2 group were almost the same as the baseline values. Values in the BCcO2 group were reduced significantly compared to the baseline level. There were significant differences in post-ischemic chamber and myocardial stiffness between the two groups. Post-ischemic maximum negative LV dp/dt in both groups decreased significantly compared to the baseline values. However, the time constant and diastolic interval after ischemia in both groups were approximately the same as the baseline values. We conclude that there were no significant differences in myocardial protective effect between the CCcO2 and BCcO2 groups, and both methods preserved the ischemic myocardium well.

Animals↗
PubMed1993

Preservation of regional and global left ventricular function by intracoronary infusion with oxygenated fluorocarbon emulsion Therox in dogs.

We tested the oxygen transport and delivery capacity of the novel perfluorocarbon emulsion, Therox (F44E, 1,2-bis-perfluorobutyl-ethylene) by comparing left ventricular regional and global function in dogs during perfusion of the left anterior descending coronary artery (LAD) with oxygenated Krebs buffer and oxygenated Therox emulsion (20% w/v) at 20 ml/min for two separate 3 min periods. During LAD perfusion with oxygenated Krebs buffer, complete loss of systolic wall thickening in the LAD perfusion area was observed, dP/dt was significantly reduced and left ventricular end-diastolic pressure (LVEDP) was increased. In contrast, LAD perfusion with oxygenated Therox maintained regional wall thickening at 60-70% of control and completely preserved global function as measured by dP/dt and LVEDP. Thus, Therox is an effective oxygen carrier in this animal model.

Animals↗
PubMed1983

Relation of segmental wall motion to global left ventricular function in acute myocardial infarction.

The relation of left ventricular regional wall motion to global ventricular function was evaluated by radionuclide ventriculography in 127 patients within 18 hours of acute myocardial infarction. No patient had evidence of previous myocardial infarction. The following parameters were measured: (1) wall motion index; (2) percent of abnormally contracting segment; (3) ejection fraction (EF); (4) end-diastolic volume (EDV) and end-systolic volume (ESV); and (5) peak systolic cuff pressure/end-systolic volume ratio (PSP/ESV). The measurements of global function correlated well with wall motion index (r = 0.83, p less than 0.001 for EF; r = -0.69, p less than 0.001 for ESV; and r = 0.061, p less than 0.001 for PSP/ESV), but EDV correlated less well (r = -0.35, p less than 0.001). Multiple linear regression analysis revealed that EF correlated best with wall motion index, and no other parameters of global left ventricular function added significantly to the regression. The correlation of motion in each segment with EF was determined by multiple linear regression analysis. Ejection fraction correlated best with motion in the anterobasal, then in order of correlation, in the apical-septal, inferoapical, anterolateral, and superlateral walls. The relation of EDV, ESV, and degree of percent abnormally contracting segments was as follows: EDV did not increase with a mild regional wall motion abnormality; however, ESV did increase and reduced stroke volume. As percent abnormally contracting segments worsened, enlargement of both EDV and ESV was seen and was associated with further reduction in systolic volume. These data suggest that EF is the best global left ventricular function correlate of the severity of the regional wall motion abnormality, and that abnormal motion in the territory of the left anterior descending coronary best predicts reduction in global left ventricular function. Radionuclide ventriculography is useful in characterizing global and regional left ventricular function in the early hours of acute myocardial infarction.

Aged↗
PubMed1992

Evaluation of right ventricular function by regional wall motion analysis in patients after correction of tetralogy of Fallot. Comparison of transventricular and nontransventricular repairs.

Right ventricular function was assessed by regional wall motion analysis and by global function in 62 patients after repair for tetralogy of Fallot. Its relation to surgical procedures, with special attention to right ventriculotomy, was investigated. Patients were classified as follows: group Ia (n = 17), transpulmonary-transatrial repair without right ventriculotomy; group Ib (n = 22), transpulmonary-transatrial repair with minimal right ventriculotomy and small transannular patch; and group II (n = 23), transventricular repair with or without transannular patch. For regional wall motion analysis, fractional area change was used for three anterior parts obtained from hemiaxis area analysis of the lateral right ventriculogram. Ejection fractions were used for global right ventricular function. Functional assessment was done both at rest and during isoproterenol infusion, which is a stress test to evaluate cardiac functional reserve. At rest, group Ia showed better right ventricular anterior wall motion as well as global ejection fraction than did group II. Group Ib showed a global ejection fraction comparable to group Ia, with better regional wall motion in the middle anterior part of the right ventricle despite the depressed upper and lower anterior parts of the right ventricle. Group II showed depressed wall motion of the middle anterior part and the resultant impaired global ejection fraction. During isoproterenol infusion, group Ia showed significant increase in fractional area change of all anterior parts and in global ejection fraction. Group Ib showed significant increases in fractional area change at the middle and lower parts and in global ejection fraction comparable with group Ia. Otherwise, group II showed no significant change in fractional area change, or in global ejection fraction, at the upper and middle parts. These results indicated that transpulmonary-transatrial repair for tetralogy of Fallot provided better postoperative global right ventricular function and its reserve, with less impaired regional wall motion, than did the transventricular repair.

Cardiac Catheterization↗
PubMed1992

Quantitative gated blood pool tomographic assessment of regional ejection fraction: definition of normal limits.

OBJECTIVE: Our aim was to select a method of analysis for gated blood pool tomography that reduced variability in a group of normal subjects, allowed comparison with normal limit files and displayed results in the bull's-eye format. BACKGROUND: Abnormalities in left ventricular function may not be accurately detected by measures of global function because hyperkinesia in normal regions may compensate for abnormal regional function. Gated blood pool tomography acquires three-dimensional data and offers advantages over other noninvasive modalities for quantitative assessment of global and regional function. METHODS: Alternative methods for selecting the ventricular axis, calculating regional ejection fraction and choosing the number of ventricular divisions were studied in 15 normal volunteers to select the combination of parameters that produced the lowest variability in quantitative regional ejection fraction. Methods for quantitative comparison of regional ejection fraction with normal limit files and for display in the bull's-eye format were also examined. RESULTS: A fixed axis (the geometric center of the ventricle defined for end-diastole and used for end-systole) gave ejection fractions that were significantly higher in the lateral wall versus in the septum, 82 +/- 8 (mean +/- 1 SD) versus 39 +/- 17 (p less than 0.001) at the midcavity and 66 +/- 11 versus 21 +/- 20 (p less than 0.001) at the base. A floating axis system (axis defined individually for end-diastole and end-systole and realigned at the center) gave more uniform regional ejection fraction: 63 +/- 6 versus 64 +/- 8 (p = NS) at the midcavity and 44 +/- 16 versus 45 +/- 15 (p = NS) at the base. The coefficient of variability for regional ejection fraction was consistently lower using a floating axis. Calculating regional ejection fraction by dividing the regional stroke volume by the end-diastolic volume of the region gave a lower coefficient of variability and a more easily understood value than dividing the regional stroke volume by the total end-diastolic volume of the ventricle. Although the variability was lower using five versus nine ventricular divisions, nine regions offer greater spatial resolution. Comparison of regional ejection fraction with normal data identified regions greater than 2.5 SD below the mean as abnormal. We described the two-dimensional bull's-eye format as a method for displaying the regional three-dimensional data and illustrated abnormalities in patients with prior myocardial infarction. CONCLUSIONS: Gated blood pool tomography performed using a floating axis system, regional stroke volume calculation of ejection fraction and nine regions uses all the three-dimensional blood pool data to calculate regional ejection fraction, allow quantitative comparison with normal limit files, display the functional data in the two-dimensional bull's-eye format and demonstrate abnormalities in patients with myocardial infarction.

Adult↗