Isovolumic but not Ejection Phase Doppler Tissue Indices Detect Left Ventricular Dysfunction Caused by Coronary Stenosis

Non-invasive measuring of the acceleration of contraction of the left ventricle with the Doppler echocardiography

BACKGROUND

Echocardiographically measured ejection fraction (EF) of the left ventricle (LV) is the most useful standard of the LV systolic function. Its limitations are poor delineation of the LV endocardium, pronounced regional disorders of contractility, dyssynchrony of the LV and in particular significant mitral regurgitation. The aim of this research is to evaluate the advantage of Doppler indices of left ventricular function such as index of acceleration of contraction of the LV (AccLV) over EF in patients with heart failure.

METHODS

We performed a prospective observational study. We included 45 patients with known chronic heart failure and 76 healthy subjects. We performed standard echocardiographic measurements. AccLV was calculated by the following formula: AccLV = Vmax LVOT/dt × EDV [cm/s(2) ml]. Vmax LVOT represents the maximum velocity during ejection in the left ventricular outflow tract (LVOT), dt stands for the interval from the beginning of the LV contraction to the achieved Vmax LVOT, EDV represents end-diastolic volume of the LV.

RESULTS

Between patients and healthy subjects we observed statistically significant differences in mean EF values (65.4 ± 6.7 % vs. 38.6 ± 18.0 %; p < 0.001) and of AccLV (12.1 ± 2.88 cm/s(2)ml vs. 4.4 ± 2.1 cm/s(2)ml; p < 0.001). Receiver operating characteristic (ROC) curve showed higher area under the curve values for AccLV in comparison to EF (0.996 vs. 0.897). In the patient group we observed more important correlation between AccLV index and the New York Heart Association (NYHA) functional classes (r = - 0.657; p < 0.001), than between EF and the NYHA classes (r = - 0.539; p < 0.001).

CONCLUSIONS

We could distinguish with higher accuracy between healthy subjects and patients with heart failure LV by calculated AccLV in comparison to EF. AccLV values correlated with NYHA functional classes in patients with heart failure better than EF values.

Association between right ventricular dysfunction and restrictive lung disease in childhood cancer survivors as measured by quantitative echocardiography

BACKGROUND

Restrictive lung disease is a complication in childhood cancer survivors who received lung-toxic chemotherapy and/or thoracic radiation. Left ventricular dysfunction is documented in these survivors, but less is known about right ventricular (RV) function. Quantitative echocardiography may help detect subclinical RV dysfunction. The aim of this study was to assess RV function quantitatively in childhood cancer survivors after lung-toxic therapy.

PROCEDURES

We identified records of 33 childhood cancer survivors who (1) were treated with lung-toxic therapy and/or radiation, (2) were cancer-free for ≥ one year after therapy, and (3) had pulmonary function tests and echocardiograms from their most recent follow-up visit.

RESULTS

Participants' mean age was 11.6 ± 4.5 years at cancer diagnosis and 23 ± 8.6 years at evaluation. The most common diagnosis was lymphoma/leukemia (n = 27). Twenty-nine subjects had anthracycline exposure. Eleven of the 33 subjects demonstrated restrictive pulmonary impairment (total lung capacity 3.69 ± 1.5 L [69.3 ± 22.4% predicted]). Among quantitative measures of RV function, isovolumetric acceleration (IVA), a measure of contractility, was significantly lower in the group with restrictive lung disease (2.42 ± 0.56 vs. 1.83 ± 0.78 m/sec(2); P < 0.05). There was a trend towards lower tissue Doppler derived S' and tricuspid annular plane systolic excursion in the group with restrictive lung disease. Subjects with restrictive lung disease were found to have ≥ 2 abnormal parameters (P < 0.01).

CONCLUSION

IVA may detect early RV dysfunction in childhood cancer survivors with restrictive lung disease. Our findings require confirmation in a larger study population and validation by cardiac MRI.

Left ventricular radial systolic dysfunction in diabetic patients assessed by myocardial acceleration derived from velocity vector imaging

OBJECTIVES

The purpose of this study was to determine whether left ventricular (LV) radial systolic dysfunction occurred in diabetic patients with a normal left ventricular ejection fraction (LVEF) and impaired longitudinal contraction.

METHODS

Velocity vector imaging was performed in 22 patients with type 2 diabetes without microangiopathy (12 men and 10 women; mean age ± SD, 49 ± 7 years), 21 patients with microangiopathy (12 men and 9 women; mean age, 50 ± 6 years), and 21 healthy control participants (11 men and 10 women; mean age, 49 ± 8 years). The groups were matched for age and sex. All had no clinical symptoms of heart disease, coronary artery disease, or hypertension.

RESULTS

The LVEF, fractional shortening, and end-diastolic diameter were statistically comparable in all groups. The left ventricular wall thickness was significantly greater in diabetic patients than controls (P < .05). Average peak early diastolic accelerations at all LV levels were significantly lower in diabetic patients than controls in the long-and short-axis directions (all P < .05). In the long-axis direction, a significantly lower average peak isovolumic contraction acceleration was found at the mid and apical levels in patients without microangiopathy and at all LV levels in patients with microangiopathy than controls (all P < .05). In the short-axis direction, a significantly lower average isovolumic contraction acceleration was found at the apical level in patients without microangiopathy and at the basal and apical levels in patients with microangiopathy (all P < .05).

CONCLUSIONS

In diabetic patients with a normal LVEF, myocardial systolic dysfunction occurs not only in the long-axis direction but also in the short-axis direction.

Usefulness of the evaluation of isovolumic and ejection phase myocardial signals during stress echocardiography in predicting exercise capacity in heart failure patients

AIM

To assess changes of systolic function using tissue Doppler imaging (TDI) during stress echocardiography and its impact on exercise capacity in heart failure (HF) patients (pts).

MATERIAL AND METHODS

80 pts (65 male), mean age of 59.3 +/- 10.9 years, NYHA class 1.95 +/- 0.8, left ventricle ejection fraction (LVEF) 27.2 +/- 9.5 (10-45%). The etiology of HF was ischemic (ICM) in 50 pts and dilated cardiomyopathy (DCM) in 30 pts. Peak myocardial velocity (IVV) and acceleration (IVA) during isovolumic contraction and peak myocardial velocity during ejection phase (S') were measured at baseline and peak exercise during semi-supine stress-echo (20 Watts, 2-min increments). Concurrently peak oxygen uptake (VO(2) peak) was measured.

RESULTS

Rest values of analyzed parameters were comparable in groups according to etiology of HF and physical capacity. However, peak stress parameters mainly S' were significantly higher in the DCM group and the group with better VO(2) peak. The best correlation with exercise capacity was S' at peak stress (r = 0.66; p < 0.0001). The most useful parameter for identifying severe exercise intolerance, VO(2) peak < 14 ml/kg/min, was S' with an area under ROC curve of 0.82 +/- 0.05 (95% CI 0.71-0.89). The cutoff of 5.75 cm/s for S' at peak stress showed a sensitivity of 61% with a specificity of 96%.

CONCLUSIONS

The evaluation of systolic function by means of TDI instead of LVEF shows more clearly that systolic function is at least partly responsible for exercise tolerance in HF. Assessment of echocardiographic systolic parameters at peak stress provides more accurate information about exercise capacity in HF pts.

Myocardial function in patients with Shwachman-Diamond syndrome: aspects to consider before stem cell transplantation

BACKGROUND

Early studies have suggested increased risk of fatal cardiac complications in infants with Shwachman-Diamond syndrome (SDS), an inherited bone marrow failure syndrome. Patients undergoing stem cell transplantation (STC) have appeared susceptible to organ toxicity, including cardiac involvement.

PROCEDURE

This study assessed anatomical and functional features of the heart in SDS. Eight patients (mean age 24.1 years, range 7-37 years, seven males) with SDS and confirmed SBDS mutations were prospectively assessed for cardiac anatomy, myocardial wall properties, and systolic and diastolic function. The study protocol included conventional echocardiography (n = 8) complemented by exercise Tissue-Doppler echocardiography (n = 7), and by MRI (n = 6).

RESULTS

No abnormalities in cardiac anatomy or function were observed in baseline clinical assessment, EKG, or conventional echocardiographic and MRI measurements. Myocardial structure and left ventricular (LV) mass were normal. The maximum isovolumic acceleration (IVA) value during exercise in Tissue-Doppler was significantly lower (P < 0.001), and the right ventricular (RV) ejection fraction (P = 0.02) and peak filling rate (PFR, P = 0.008) at rest in MRI were higher in patients.

CONCLUSIONS

Children and young adults with SDS and mutations in SBDS had normal cardiac anatomy and myocardial structure. Subtle RV diastolic function alterations at rest and depressed LV contractility during exercise were observed. Further studies are warranted to evaluate the clinical importance of these findings.

Longitudinal plane colour tissue-Doppler myocardial velocities and their association with left ventricular length, volume, and mass in humans

AIMS

We investigated the relationships between colour tissue-Doppler parameters of left ventricular (LV) function and indices of LV morphology.

METHODS AND RESULTS

LV length, end-diastolic volume, and mass were assessed in 40 healthy adult subjects. Further, colour tissue-Doppler scans assessed peak myocardial velocities during systole (S') and early diastole (E') as well as acceleration during isovolumic contraction (IVCa) at the mitral annulus. Non-linear allometric relationships (Y = aX(b)) were calculated to provide size exponents (b), with 95% confidence intervals, for tissue-Doppler variables (Y) and LV morphology parameters (X). The b exponents for LV length with Peaks S' and E' were not substantially different from unity (b = 0.87 and 0.95, respectively, P > 0.05). Peak E' was also associated with LV volume (b = 0.39, r = 0.53, P < 0.05). IVCa was not related to any LV morphology parameter.

CONCLUSION

Peak S' or E' divided by LV length was confirmed as a valid size-independent scaling index. Conversely, IVCa is seemingly size independent.

Quantitative echocardiographic assessment of myocardial acceleration in normal left ventricle by using velocity vector imaging

To investigate the characteristics of myocardial acceleration in normal left ventricular walls, velocity vector imaging was performed in 30 normal volunteers. Peak accelerations during early systole and early diastole and time to peak acceleration during early systole were calculated for each segment of the standard 16-segment model. A gradient of accelerations from base to apex and a homogeneity of accelerations among different walls at the same level were observed. There were homogeneities of time to peak acceleration during early systole in both longitudinal and latitudinal directions on left ventricular walls. In 82.29% of all segments, the onset of contraction acceleration during early systole could not be identified. Further research with larger populations is needed to clarify the role of myocardial acceleration in the assessment of the site of initial electrical stimulation and the sequence of ventricular depolarization.