The angiotensin infusion test as a method of evaluating left ventricular function

Fifteen patients had left ventricular function measured by the angiotensin infusion method. Seven patients had no evidence of heart disease, and eight patients had angina pectoris and coronary arteriographic evidence of coronary disease without congestive heart failure. During angiotensin infusion, those patients without heart disease had a decrease in cardiac index (average, 0.63 L. per minute per square meter) and a decrease in heart rate (average, 12 beats per minute). The ventricular function curve had a poor SWI response in four of the seven subjects. The patients with coronary artery disease also had a reduction in cardiac index during angiotensin (average, 0.44 L. per minute per square meter) and the heart rate was unchanged in four subjects, increased in two subjects, and decreased in two subjects. Six of the subjects had flat or descending slopes on the function curve, and in one subject there was only a very gradual ascending slope. Many of the curves of both groups looked similar so that the function curves did not differentiate between those patients with or without heart disease.The mechanism for production of bradycardia, reduction of cardiac output, and depressed function curves with angiotensin is multifactorial, but is probably due to the baroreceptor reflex response, the increase in coronary artery resistance, and possibly to the direct effect of increased left ventricular afterload itself.The ventricular response to angiotensin is so variable that the angiotensin infusion method of evaluating ventricular function is not reliable.     

Anomalous ventricular contractile performance in experimental chronic aortic insufficiency in the dog]

Hemodynamics and right (RV) and left (LV) ventricular performances of anaesthetized, closed-chest animals were studied in normal control dogs (N) and in dogs with aortic insufficiency (AI), the latter intervention being performed 33 months before verification. In dogs with AI, LV was hypertrophied (N = 49.6 +/- 6.3 g; AI = 98.7 +/- 10.1, p less than 0.001); forward stroke volume was slightly decreased (N = 20.0 +/- 2.2 ml; IA = 14.6 +/- 5.4 ml, p = NS);LV and diastolic pressure was increased (N = 9.4 +/- 1.4 mmHg; IA = 16.7 +/- 2.9, p less than 0.05); both RV and LV myocardial performace index (e.g. dP/dt max, peak VCE, Vmax) were normals. Relative pressure/velocity of shortening and wall stress/velocity of shortening relationships, however, were decreased, when measured during L.V. isovolumetric beats. LV stiffness of arrested heart was increased in proportions with hypertrophy extent. Thus, myocardial performance of chronically volume-overloaded heart appears to be depressed before the stage of the circulatory failure.     

Treatment of chronic left ventricular insufficiency

Left ventricular failure results from many myocardial diseases: the symptoms of left ventricular failure are the consequence of adaptations which the left ventricle and circulatory system activate to counteract the initial myocardial disease. The aims of treatment of cardiac failure are diverse depending on whether treatment is directed to correct the initial myocardial disease, its myocardial consequences, its circulatory consequences or, more simply, the patient's symptoms. The ideal treatment of cardiac failure would include a drug acting on the cause, a drug restoring left ventricular contraction and relaxation adapted to the conditions of cardiac load, a drug correcting regional blood flow disturbances and a drug relieving symptoms related to salt retention. An ideal drug for chronic left ventricular failure does not exist, and so treatment is a composite effort. Should it be in first intention? This is the current trend.     

Mild mitral insufficiency is a marker of impaired left ventricular performance in aortic stenosis

Whether mitral insufficiency is a marker of decreased left ventricular function in patients undergoing aortic valve replacement for sever aortic stenosis was examined. Hemodynamic measurements in 26 patients with pure aortic stenosis (Group 1), 17 patients with aortic stenosis and grade 1 or 2 mitral insufficiency (Group 2) and 19 control patients were compared. All patients were free of significant coronary artery disease. Ventriculograms were digitized for calculation of ejection fraction, ventricular volumes and wall stress. Despite similar aortic valve areas, Group 2 patients had more advanced symptoms. Cardiac index was comparably decreased in Group 1 (2.6 +/- 0.4 liters/min per m2) and Group 2 (2.7 +/- 0.8 liters/min per m2) compared with the control group (3.8 +/- 0.6 liters/min per m2). Left ventricular end-diastolic and end-systolic volume indexes were increased only in Group 2 (119 +/- 35 and 73 +/- 36 ml/m2, respectively). Likewise, end-systolic wall stress was increased only in Group 2 (149 +/- 54 kdynes/cm2). Ejection fraction was decreased to a greater extent in Group 2 (42 +/- 17%) than in Group 1 (59 +/- 13%) as compared with values in the control group (68 +/- 5%). Although an inverse relation existed between ejection fraction and end-systolic stress in all groups, the ejection fraction (extrapolated to end-systolic stress = 0) was decreased in Group 2, and the slope of the relation was increased in Groups 1 and 2. The end-systolic stress/end-systolic volume index ratio, an index of ventricular performance, was also decreased to a greater extent in Group 2.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prognostic indices of the normalization of left ventricular function in chronic aortic insufficiency following valve replacement

The aim of this study of 31 patients was to identify M mode echocardiographic parameters predictive of normalisation of left ventricular function after valvular replacement for chronic aortic incompetence in order to determine the optimal time for surgery. Only patients with chronic, pure aortic incompetence (ventriculo-aortic pressure gradient less than or equal to 30 mmHG) were considered. At the time of investigation 4 patients were in functional Class I, 6 in Class II, 10 in Class III and 11 in Class IV (NYHA). M mode echocardiography was performed on an Echovideorex or an Irex System II echocardiograph. The following measurements were made and corrected for body surface area according to the recommendations of the American Society of Echocardiography; end systolic and end diastolic dimensions (mm), fractional shortening (%), end systolic and end diastolic wall thickness (mm), diastolic radius to wall thickness ratio, short axis myocardial surface area (cme), wall stress, end systolic stress (mmHg). The study comprised pre and postoperative studies with an interval of 22.7 +/- 12.5 months (range 5 to 46 months); the data obtained was compared with a control group of 10 normal subjects. The results showed that preoperative fractional shortening less than 28% was associated with an increased risk of persistent postoperative left ventricular dysfunction.     

Echocardiography in chronic aortic insufficiency. Prediction of the reversibility of left ventricular dysfunction following surgical correction

The long term outcome of patients undergoing aortic valve replacement (AVR) for chronic aortic regurgitation (AR) is mainly determined by the reversibility or permanence of left ventricular dysfunction. We analysed the echocardiogram of 49 patients before and after surgery to identify the patients whose left ventricular dysfunction regressed completely after AVR. The patients were divided into 2 groups according to the results of the last postoperative echocardiogram: Group I: 25 patients whose left ventricular dimensions and wall motion reverted to normal; Group II: 24 patients with dilated and/or hypokinetic left ventricles. The two groups of patients were comparable for sex (Group I: 19 men, 6 women; Group II: 20 men, 4 women), age (Group I: 50,8 years, Group II: 53,9 years) and length of postoperative follow-up (Group I: 32 months, Group II: 34 months). The following parameters were measured and compared: diastolic and systolic left ventricular dimensions, myocardial mass and ventricular wall motion. Results: Patients in Group I had less left ventricular dilatation than those in Group II (+35% vs +60%, p less than 0,001) and left ventricular contraction was better (FE: 62% vs 45%, p less than 0,001; %FS: 35% vs 23%, p less than 0,001). This study establishes that patients with chronic AR and % delta Dd less than 60%, an EF greater than 50% or %FS greater than 25%, have about a 90% probability of normalisation of LV function after AVR. If one of the indices exceeds these threshold values, the probability of permanent LV dilatation and/or hypokinesia after AVR is also about 90%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reversibility of left ventricular functional damage after valve replacement in patients with chronic aortic valve insufficiency

The authors study retrospectively some preoperative echocardiographic findings and their importance as predictors of reversible myocardial dysfunction. The functional status of 57 survivors after isolated aortic valve replacement was evaluated with exercise testing and on this ground the patients, were divided into three groups: A (28 pts) greater than 60%; C (10 pts) less than 40%; B (19 pts) from 40% to 60%. The authors conclude that the postoperative improvement in functional status is strictly correlated with some preoperative echocardiographic indexes (end-diastolic dimension, end-systolic dimension, shortening fraction, mean end-systolic radius/thickness ratio, end-systolic wall stress, myocardial mass, ejection fraction) with are also predictive of operative mortality. The authors consider the principal values of beginning left ventricular impairment: a) end-systolic dimension greater than or equal to 5.5 cm; b) shortening fraction less than 27%; c) mean end-systolic radius/thickness ratio greater than 2.5; d) end-systolic wall stress greater than 240 mmHg.     

Study of left ventricular function in valvular cardiopathies (mitral insufficiency and aortic insufficiency

A study of the left ventricular function based on the haemodynamic data combined with those provided by biplane cineangiography was performed in 35 cases with left ventricular volume overload (20 cases of mitral incompetence and 15 of aortic insufficiency). The importance of the haemodynamic changes and of the adaptation mechanisms set up were described. The more intense dilatation-hypertrophy of aortic incompetence than of mitral incompetence plays an essential part. The role of Starling's mechanism is underlined. Estimation of the contractile value of the myocardium, taken into account the mechanical overload and the conditions of late-diastolic lengthening of the fibre and of impedance to left ventricular ejection was determined. An obvious myocardial failure, demonstrated in approximately one third of the cases, by determination of some contractility indices estimated in the ejection phase, Vf sigma max in particular, the only one valid in the presence of valvular regurgitation. In the other cases, the moderate decrease of myocardial contractility was masked by compensatory mechanisms.     

Apical left ventricular asynergy in chronic aortic regurgitation

Apical left ventricular (LV) wall motion abnormalities have been described in chronic volume overload. To evaluate if these abnormalities are due to an actual hypokinesia we analyzed the percent shortening of apical LV radiants (PS%) by an angiographic computerized method and the endocardial systolic movement (ESM) and thickening (%Th) of the same region using M-mode echocardiographic technique in 11 patients affected by pure aortic regurgitation (AR). In these patients mean apical radii shortening was reduced with respect to normal values. Both %Th and ESM were significantly reduced in AR when compared to normal subjects (24.5 +/- 31.7% vs. 63.8 +/- 35.8%, p less than 0.01 and 4 +/- 7 vs. 10 +/- 3 mm, p less than 0.01, respectively). In addition, %Th and ESM directly correlated with PS% (r = 0.79, p less than 0.01 and r = 0.77, p less than 0.01, respectively). PS% correlated positively with systolic eccentricity and inversely with end-systolic volume index (r = 0.64, p less than 0.05 and r = 0.57, p less than 0.05, respectively). Finally, in AR %Th was related to a normalized peak rate of systolic wall thickening (r = 0.85, p less than 0.01) and to a normalized peak rate of diastolic wall thinning (r = 0.68, p less than 0.05). These results showed that in AR a reduced apical radii percent shortening was associated with a reduced normalized peak rate of systolic wall thickening and of diastolic wall thinning, thus indicating an actual hypokinesis and an impaired contractility. Moreover, the observed abnormalities correlated with an altered LV dynamic geometry linked to chronic volume overload.     

Role of hemodynamic studies in evaluating left ventricular insufficiency in acute myocardial infarct

Left ventricle (LV) disfunction is the main cause of death in patients suffering from acute myocardial infarction (AMI) who are admitted to Coronary Care Units. Therefore, it is easily understandable that the study of LV performance is of paramount importance in the choice and evaluation of the efficacy of therapy, as well as in the prognosis of patients with AMI. In the first section of this paper, the authors analyze the physiopathology of LV disfunction during AMI; in the second section, based upon a study of 480 patients, they value the contribution of hemodynamic examination with the Swan-Ganz catheter in the evaluation of the cardiac function and in the prognosis of patients with AMI.     

A noninvasive comparison of left ventricular performance in sickle cell anemia and chronic aortic regurgitation

Abnormalities of the cardiovascular system are common in patients with sickle cell anemia (SS). Noninvasive testing to document left ventricular dysfunction has yielded conflicting results. Left ventricular performance was evaluated in 27 patients with SS by M-mode and 2-D echocardiography, and systolic time intervals. Comparisons were made to 25 normal controls, and to 22 patients with chronic aortic regurgitation. Left ventricular diastolic diameter (LVDD) and cardiac index (CI) were significantly greater in the patients with SS than in controls (LVDD 5.3 +/- 0.4 vs. 4.7 +/- 0.5 cm; CI 4.2 +/- 1.3 vs. 3.1 +/- 0.8 liters/min/m2; both p less than 0.001). Left ventricular ejection fraction (EF) was slightly, but significantly less (62.9 +/- 7.3 vs. 67.0 +/- 5.4; p less than 0.05). In comparison to the patients with chronic aortic regurgitation, the LVDD in the patients with SS was slightly, but significantly lower (LVDD 5.3 +/- 0.4 vs. 5.9 +/- 0.6 cm; p less than 0.05). There was no significant difference between the patients in EF or CI (EF 62.9 +/- 7.3 vs. 63.3 +/- 4.4; CI 4.2 +/- 1.3 vs. 5.0 +/- 1.0 liters/min/m2; NS). Left ventricular EF was below 55 in three patients who also had hypertension at the time of examination. We conclude that patients with SS have resting left ventricular performance consistent with a high output state. Significant left ventricular dysfunction related to sickle cell disease alone was not demonstrated in this population, although the addition of hypertension appears to deleteriously affect resting left ventricular performance.     

Importance of preoperative hypertrophy, wall stress and end-systolic dimension as echocardiographic predictors of normalization of left ventricular dilatation after valve replacement in chronic aortic insufficiency

To define and compare predictors of postoperative normalization of diastolic left ventricular dimension after aortic valve replacement, echocardiographic indexes of left ventricular size, function, degree of hypertrophy and systolic wall stress were examined in 43 patients with chronic and 14 with acute aortic insufficiency. In all of the latter 14 patients, left ventricular diastolic dimension returned to normal (mean 5.2 +/- 0.4 cm) in the postoperative follow-up period (mean 8.0 months). In contrast, of those with chronic insufficiency, 28 (group A) had postoperative normalization of diastolic dimension whereas the remaining 15 (group B) had persistent enlarged diastolic dimension. Preoperative end-systolic dimension, diastolic radius/thickness ratio, mean radius/thickness ratio, mean wall stress and end-systolic stress were 84 to 93 percent accurate in predicting normalization versus persistence of left ventricular dilatation postoperatively, and were superior to preoperative end-diastolic dimension and shortening fraction. Postoperatively, group A had complete normalization of end-systolic dimension and of mean and end-systolic wall stresses with persistence of a normal shortening fraction. Group B continued to have increases in end-systolic dimension, mean wall stress and end-systolic stress with a reduction in shortening fraction. Postoperatively there was a 43 and 29 percent incidence rate of heart failure and death by heart failure, respectively, in group B versus none in group A (p less than 0.01). These findings support the concept that inappropriate hypertrophy in chronic aortic insufficiency is associated with progressive increases in wall stress and end-systolic dimension and a reduction in shortening fraction that eventually result in irreversible cardiac dilatation and failure. Accurate and clinically relevant determination of reversible and irreversible alterations in left ventricular size and function may be obtained with these echocardiographic indexes.     

Indices of left venticular performance and evaluation myocardial quality in mitral valve insufficiency, chronic aortic valve insufficiency and stenosis]

132 patients with pure mono-valvular cardiopathies (mitral incompetence, aortic stenosis and aortic incompetence) were classified into two groups according to the values of the systolic work index/myocardial mass ratio (SWI/MLV). Normal values of the ejection function (EF) and mean velocity of circumferential fibre shortening (VCF) for each cardiopathy were so obtained. Only patients with aortic stenosis of group I (SWI/MLV greater than or equal to 0.75 gm . g-1) had normal EF. All the other patients had EF and VCF values below normal although this did not always imply impaired myocardial function. Therefore the myocardial mass should also be considered in the evaluation of myocardial function and it would seem desirable to take this parameter into account in the management of these patients.