Depressed myocardial contractility in mitral stenosis--an analysis by force-length and stress-shortening relationships

To determine whether low ejection fraction (EF) in mitral stenosis (MS) is the result of depressed contractility or is mediated by other factors, left ventricular (LV) function was analyzed by force-length and stress-shortening relationships. Thirty patients without heart disease served as normal controls (Group 1). Forty-three patients with MS were divided into 2 subgroups: Group 2 (n = 19) had EF within one standard deviation of the mean of Group 1, and Group 3 (n = 24) had EF below it. Normal EF (Group 2) was associated with low preload (end-diastolic stress) and low afterload (end-systolic stress), and preload and afterload were in the normal range in patients with low EF (Group 3). A significant negative correlation was observed in the whole group of patients with MS between EF and end-systolic stress (Y = -0.14X + 72.8, r = -0.61, p less than 0.001), and a positive correlation between end-systolic stress and volume (Y = 1.39X + 65.4, r = 0.45, p less than 0.01). These observations suggest that systolic shortening and end-systolic volume of the left ventricle are in part governed by afterload in this disease. It is concluded that low EF of MS is not mediated by reduced preload or inappropriately elevated afterload, and contractility of the ventricle is mildly depressed in MS.     

Novel techniques for assessment of left ventricular systolic function

The evaluation of left ventricular systolic function is one of the most common reasons for referral for a non-invasive cardiac imaging study. In addition to its diagnostic and prognostic value, an assessment of ejection fraction can also be used to guide medical and device therapy. Thus, obtaining an accurate and reproducible assessment of LVEF is essential for patient management. This review will focus on novel multi-modality techniques used for the quantification of left ventricular systolic function. Emerging echocardiography techniques such as three-dimensional echocardiography and strain imaging and their incremental role over traditional 2D imaging will be discussed. In addition, new developments expanding nuclear imaging techniques’ evaluation of left ventricular systolic function will be reviewed. Finally, an overview of advances in imaging techniques such as cardiac magnetic resonance and cardiac computed tomography, which now allow for an accurate and highly reproducible assessment of LVEF, will be presented.     

Non-invasive assessment of systolic left ventricular function in systemic sclerosis

Systemic sclerosis is a multisystemic disorder, also affecting the heart. To evaluate its influence on systolic left ventricular (LV) function, we investigated 30 consecutive patients (age 54.5 +/- 2.4 years, 15 men and 15 women) and 48 controls matched for age and sex. All subjects were investigated by phonocardiography, pulse curve recordings, M-mode echocardiography, and by pulsed and continuous wave Doppler. Heart rate, blood pressure and peripheral resistance did not differ, but patients weighed less than controls (P less than 0.01). Systolic time intervals indicated systolic impairment, with an increased pre-ejection period to LV ejection time (LVET) ratio (0.37 +/- 0.02 vs 0.30 +/- 0.01 P less than 0.001), and also an increased isovolumic contraction time to LVET ratio (0.17 +/- 0.02 vs 0.12 +/- 0.01, P less than 0.02). The latter difference remained when LVET was adjusted for heart rate. Echocardiographic E-point to septal separation was increased in patients (8.3 +/- 1.3 vs 4.8 +/- 0.3 mm, P = 0.001), also after adjustment for LV dimension (P = 0.0001), while septal fractional thickening was decreased (P less than 0.01). End systolic wall stress (P = 0.0002) and stress to volume ratio (P = 0.03) were lower in systemic sclerosis. Peak LV emptying rate was also lower in the patient group when measured by echocardiography (P = 0.03). There was no difference between groups regarding LV dimensions, fractional shortening or mean velocity of circumferential fibre shortening. While aortic Doppler peak emptying rate did not differ between groups, it occurred later in systole in the patient group (P less than 0.01) as did peak velocity (P = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)     

应用二维整体收缩期应变评价左室收缩功能

目的应用超声二维斑点追踪技术评价二维整体收缩期峰值应变在判断左室收缩功能中的价值。方法心功能不全患者52例和健康对照者30例,应用二维斑点追踪技术分别测量左室各节段收缩期纵向峰值应变、径向峰值应变和圆周峰值应变,并分别取其平均值做为左室收缩期整体纵向应变(GLS)、整体径向应变(GRS)和整体圆周应变(GCS),同时应用Simpson双面法计算左室射血分数(LVEF)。对各指标绘制受试者工作特性曲线(ROC)并获得界值。结果心功能不全患者GLS、GRS和GCS均显著低于正常对照组(P0.05);ROC评价显示GLS、GCS的曲线偏左上角,其曲线下面积分别为0.950、0.939,对应的界值分别为-13.12%、-13.86%,其诊断心功能不全的灵敏度和特异度分别为90.0%/94.4%,93.3%/83.3%,GRS的曲线下面积0.170.5,诊断左室收缩功能不全意义不显著。结论二维整体收缩期应变可较好地评价左室的收缩功能,其中GLS和GCS具有较高的诊断心功能不全的价值。     

Quantitative assessment of left ventricular systolic function using 3-dimensional echocardiography

Assessment of left ventricular systolic function is the commonest and one of the most important indications for performance of echocardiography. It is important for prognostication, determination of treatment plan, for decisions related to expensive device therapies and for assessing response to treatment. The current methods based on two-dimensional echocardiography are not reliable, have high degree of inter-observer and intra-observer variability and are based on presumptions about the geometry of left ventricle (LV). Real-time three-dimensional echocardiography (RT3DE) on the other hand is fast, easy, accurate, relatively operator independent and is not based on any assumptions related to the shape of LV. Owing to these advantages, it is the Echocardiographic modality of choice for assessment of systolic function of the LV. We describe here a step by step approach to evaluation of LV volumes, ejection fraction, regional systolic function and Dyssynchrony analysis based on RT3DE. It has been well validated in clinical studies and is rapidly being incorporated in routine clinical practice.     

Noninvasive assessment of systolic and diastolic left ventricular function in female runners

Nine female runners and 9 matched control subjects were investigatedwith echocardiography and Doppler velocimetry to assess cardiacstructure and systolic and diastolic left ventricular (LV) functionat rest. LV mass was considerably larger in the athletes (171vs 123 g; P <001). Minute distance, the Doppler index cardiacoutput, was similar in runners and controls; the lower heartrate (P<0.01) of the athletes was associated with a higherstroke distance (P<0.05). The latter could be attributedto a larger end-diastolic LV internal diameter (46 vs 43 mm;P<0.05); wall stress and the various indices of systolicLV function were not different between runners and controls.Early diastolic LV function, estimated from the velocity ofLV relaxation and the LV inflow pattern, and late diastolicfunction, assessed by Doppler velocimetry, were similar in runnersand controls. The unchanged ratio of the peak velocities ofLV filling during atrial contraction and early filling (0.49vs 0.44; NS) indicates that LV distensibility is unaltered inthe athletes.In conclusion, the higher left ventricular massof female runners is not associated with changes of systolicand diastolic LV function.     

Noninvasive assessment of systolic and diastolic left ventricular function in female runners

Nine female runners and 9 matched control subjects were investigatedwith echocardiography and Doppler velocimetry to assess cardiacstructure and systolic and diastolic left ventricular (LV) functionat rest. LV mass was considerably larger in the athletes (171vs 123 g; P <001). Minute distance, the Doppler index cardiacoutput, was similar in runners and controls; the lower heartrate (P<0.01) of the athletes was associated with a higherstroke distance (P<0.05). The latter could be attributedto a larger end-diastolic LV internal diameter (46 vs 43 mm;P<0.05); wall stress and the various indices of systolicLV function were not different between runners and controls.Early diastolic LV function, estimated from the velocity ofLV relaxation and the LV inflow pattern, and late diastolicfunction, assessed by Doppler velocimetry, were similar in runnersand controls. The unchanged ratio of the peak velocities ofLV filling during atrial contraction and early filling (0.49vs 0.44; NS) indicates that LV distensibility is unaltered inthe athletes.In conclusion, the higher left ventricular massof female runners is not associated with changes of systolicand diastolic LV function.     

Efficient utilization of echocardiography for the assessment of left ventricular systolic function

BACKGROUND: We hypothesized that patients could be selected for echocardiographic evaluation of left ventricular (LV) systolic function on the basis of historic, clinical, radiographic, and electrocardiographic criteria. METHODS AND RESULTS: We prospectively evaluated 300 consecutive inpatients referred for the echocardiographic assessment of LV function, of whom 124 (41%) had LV systolic dysfunction (LVSD) (LV ejection fraction <0.45). Among the historic variables, male sex was the only predictor of LVSD, whereas of the abnormal physical and radiographic findings, cardiomegaly on chest radiography was the only predictor. Among the electrocardiographic findings, the presence of left bundle branch block was positively correlated with the presence of LVSD, whereas a normal electrocardiogram was negatively correlated with this finding. Only 2 patients with LVSD had a normal electrocardiogram. The addition of significant predictors on physical examination and chest radiography doubled the predictive value of the historic variables for determining LVSD. The addition of electrocardiographic findings further doubled the predictive value of the model. Almost 45% of the predictive power of the final multivariate model (chi-square of 48 of the total chi-square of 108) was based on the absence of normal electrocardiogram in patients with LVSD. When chest radiographic findings were excluded from the model, the overall predictive power of the model did not change, with the normal electrocardiogram gaining greater prominence: Full 56% of the predictive power of the model (chi-square of 60 of the total chi-square of 108) resided in the ability of a normal electrocardiogram to discriminate between patients with and those without LVSD. CONCLUSIONS: Historic, chest radiographic, and electrocardiographic variables can be used to predict low likelihood of LVSD on echocardiography. In particular, when the electrocardiogram is normal, it is extremely unlikely to have LVSD. It can be argued that such patients should not be referred for echocardiography.     

Importance of left ventricular systolic function in the assessment of left ventricular diastolic function with Doppler transmitral flow velocity recording

To study the effect of left ventricular systolic function on the Doppler transmitral flow velocity pattern, Doppler echocardiographic variables were correlated with hemodynamic indexes in 11 control subjects and 58 patients with heart disease. All underwent cardiac catheterization performed with use of a Millar micromanometer. The time constant of left ventricular isovolumetric pressure decrease and left ventricular end-diastolic myocardial stiffness was calculated. The 58 patients were classified into two groups according to ejection fraction: group I (n = 30; ejection fraction greater than 55%) and group II (n = 28; ejection fraction less than 50%). Compared with the control subjects, patients in group I had impairment only of left ventricular relaxation (time constant 47 +/- 9 vs. 38 +/- 3 ms; p less than 0.01), whereas patients in group II had, in addition to impaired left ventricular relaxation (time constant 52 +/- 11 vs. 38 +/- 3 ms; p less than 0.01), increased preload, increased pulmonary capillary pressure (12 +/- 8 vs. 5 +/- 3 mm Hg; p less than 0.01) and increased myocardial stiffness (2,018 +/- 980 vs. 1,050 +/- 218 g/cm2; p less than 0.01). In group I, there was a significant partial correlation coefficient between the time constant and deceleration half-time (r = 0.54). In group II, a strong correlation existed between myocardial stiffness and peak atrial filling velocity (r = -0.71) and between myocardial stiffness and the ratio of peak atrial to peak rapid filling velocity (r = -0.71).(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of left ventricular systolic function by velocity vector imaging

ObjectivesTo study the usefulness of a novel echocardiographic technique, velocity vector imaging (VVI) in the measurement of left ventricular ejection fraction (LVEF).BackgroundEjection fraction measured by echocardiography forms the cornerstone in the assessment of LV systolic function. Errors in measurement of EF by routine two-dimensional echocardiography (2D ECHO) limit its utility. The VVI is a new technology which uses speckle tracking and other algorithms to track the endocardial border. This may help in more accurate assessment of EF.MethodsGlobal and regional LVEF was measured in 49 patients using VVI, 2D ECHO and radionuclide-gated single photon emission computed tomography (SPECT). Results were categorised as normal, mild, moderate, or severe LV systolic dysfunction based on American Society of ECHO classification. The results were analysed by appropriate statistical tests for correlations.ResultsThe mean EF was 35 ± 12.08% by VVI, 54.2 ± 19.51% by SPECT (P< 0.001 vs VVI) and 50.3 ± 8.92% by 2D ECHO (P < 0.001 vs VVI). There was weak linear positive correlation between EF measured by VVI and the other modalities (Pearson's correlation coefficient 0.577 for SPECT and 0.573 for 2D; P=0.01). The VVI systematically underestimated the EF compared to SPECT. Greater number of patients had moderate or severe LV systolic dysfunction by VVI (37; 74.5%) than by SPECT (17; 34.7%; P=0.037). We derived a correction factor to calculate SPECT EF from VVI EF as follows: EF (SPECT) = EF (VVI) × 0.9 + 21 or approximately VVI (EF) + 20.ConclusionMeasurement of EF by VVI is feasible. The VVI underestimated the EF when compared to nuclear-gated SPECT in this study. The accuracy of this technology and the need for a correction factor needs to be assessed in future studies.     

Quantitative evaluation of left ventricular systolic function by Doppler echocardiographic techniques

Doppler echocardiography provides the ability to measure blood flow velocities noninvasively. These blood flow velocities can be used to obtain powerful hemodynamic information about systolic contractility of the left ventricle, which in the past could only be determined from invasive cardiac catheterization or cumbersome pulse recordings. Volumetric flow rates can be measured using the hydraulic principle of flow through a rigid tube, providing a measurement of stroke volume and cardiac output. The rate of the left ventricular pressure rise derived from a mitral regurgitation velocity curve provides a nonejection phase index of systolic contractility. Acceleration time can be obtained from an ascending aortic velocity and is an indicator of maximum myocardial force. Systolic time intervals can now be quickly and accurately obtained from the standard Doppler tracings. These quantitative measurements of the status of the left ventricle are accurate, reproducible, and should be incorporated into the routine noninvasive assessment of patients with cardiac disease.     

Heart failure and diabetes: left ventricular systolic function

AIM: Heart failure is the main cause of mortality and morbidity in general population, annual mortality rate is 20%, in spite of pharmacological treatments or other therapies. Cardio-vascular events and diabetes tight correlation is well known, while it is less evaluated diabetes and heart failure correlation is less studied, heart failure as left ventricular systolic function impairment. Cardiovascular disease rate is decreasing, systolic heart failure rate is raising. Our study goal is to evaluate which role diabetes plays in determining systolic heart failure, diagnosed by echocardiographical examination. METHODS: Four hundred and fifty consecutive patients, systolic heart failure prone, diagnosed by left ventricular ejection fraction less than 40%, were included. Exclusion criteria were rheumatic or congenital valve diseases. Mean age was 78.3 years (53-93 years), 286 were women and 164 men. Statistical analysis were performed by parametric t-Student test and not parametric chi2 test. High significant difference was assessed for P<0.05. RESULTS: Seventy six (16.9%) patients were diabetes prone (D), 374 (83.1%) were diabetes free, so not diabetic (ND). Forty three men were D (56.5%), 131 ND (35%). Diabetic mean age was 74.7 years (52-88), not diabetic was 79.3 (53-93). Six D (7.8%) and 21 ND patients (5.6%) were hypercholesterolemia prone. Eight D (10.5%) and 18 ND (10.1%) patients were smokers. Twenty eight D (36.8%) and 107 ND patients (28.6%) were hypertensive. Thirty three D (43.4%) and 88 ND (26.4%) patients were coronary artery disease prone, 3 of 33 (3.9%) D and 28 of 88 (7.4%) ND ischemic patients were myocardial infarction prone. Twenty one D (27.6%) and 106 ND (28.3%) patients were atrial fibrillation prone. There were not statistical significant difference among D and ND patients for following variables: sex, smoke, total cholesterolemia, hypertension and atrial fibrillation. We found an high significant difference for mean age (P<0.005) and coronary artery disease prone patients (P<0.007), but not for myocardial infarction prone subjects (P<0.1). CONCLUSIONS: Diabetes, not depending by other common cardiovascular risk factors, causes systolic heart failure, in prone patients, on an younger age, and in the same time an higher coronary artery disease rate, but not an higher myocardial infarction rate, because the coronary artery disease is often a microvascular one, and it leads to heart failure rather than myocardial necrosis.