Doppler tissue imaging: regional myocardial function in hypertrophic cardiomyopathy and in athlete's heart

Right Heart Function in Systemic Lupus Erythematosus: Insights from Myocardial Doppler Tissue Imaging

The purpose of this study was to use Doppler tissue imaging to evaluate heart function and to investigate the correlation between Doppler imaging and pulmonary artery systolic pressure (PASP) and right ventricular (RV) ejection fraction (EF) in patients with systemic lupus erythematosus (SLE). Standard echocardiography and 2-dimensional and color Doppler imaging were used to assess cardiac function in patients given the diagnosis of SLE (n = 40) and healthy control subjects (n = 45). Half of the patients with SLE also presented with pulmonary hypertension (PH). Significant differences in PASP and RV EF (RVEF) were found between the control and SLE groups. The peak systolic velocity of tricuspid annulus was significantly lower in patients with SLE than in the control group. The calculated myocardial performance index of the RV, septum, and left ventricular lateral wall were significantly higher in patients with SLE than in the control group. Bivariate correlation analysis revealed a significant correlation among PASP, RVEF, and systolic tricuspid annular velocity. There was a significant correlation between each of these 3 parameters and the 6-minute walk distance in patients with SLE. Patients with SLE and PH had a significantly shorter 6-minute walk distance than patients with SLE without PH. Furthermore, in patients with SLE and PH, RVEF and systolic tricuspid annular velocity were lower than in the control subjects and patients with SLE without PH. Patients with SLE and PH had a longer isovolumic relaxation time and a higher myocardial performance index of RV than those without PH. Finally, by simple linear regression analysis, we found a significant positive relation between RVEF and systolic tricuspid annular velocity, but a negative relationship between PASP and systolic tricuspid annular velocity. These findings demonstrate that in patients with SLE, systolic tricuspid annular velocity determined by echocardiography and Doppler imaging can be used to assess RV function and PASP. Furthermore, systolic tricuspid annular velocity reflects exercise tolerance in patients with SLE and the length of the isovolumic relaxation time represents the progression of PH.

The athleteʼs heart and hypertrophic cardiomyopathy: two conditions which may be misdiagnosed and coexistent. Which parameters should be analysed to distinguish one disease from the other?

According to the statements from the International Cardiological Committees on Eligibility for Sports, athletes with a clinical diagnosis of hypertrophic cardiomyopathy (HCM) should be excluded from most competitive sports, with the possible exception of those of low intensity. Clinical distinctions between physiological athlete's heart and pathological conditions such as HCM have critical implications especially for trained athletes. Even if the standard two-dimensional echocardiography represents an irreplaceable method in the evaluation of cardiac adaptations to physical exercise, the data currently available suggest the usefulness of Doppler myocardial imaging (DMI) in the assessment of the myocardial systolic and diastolic function of the athlete's heart. On this ground, the combined use of standard two-dimensional echocardiography and DMI may be taken into account for a valid, non-invasive and easily repeatable evaluation of both physiological and pathological ventricular hypertrophy, and in selecting a subgroup of HCM patients at higher risk of cardiac events. In particular, DMI analysis in the trained individual has demonstrated an interesting opportunity for: (1) the differential diagnosis from pathological left ventricular hypertrophy due to HCM; (2) the prediction of cardiac performance during physical effort; (3) the evaluation of bi-ventricular interaction; (4) the analysis of myocardial adaptations to various training protocols; and (5) the early identification of specific genotypes associated with cardiomyopathies.

Usefulness of a New Proposed Tissue Doppler Imaging Global Function Index in Hypertrophic Cardiomyopathy

BACKGROUND

A global function index (GFI) derived from tissue Doppler imaging (TDI) has been proposed to improve the diagnosis of hypertrophic cardiomyopathy (HCM). We aimed to evaluate the usefulness of this index in a large selected HCM population.

METHODS

GFI =[E/Ea]/Sa, was calculated at mitral annulus lateral and septal borders in 164 HCM patients and in 40 healthy volunteers. Group comparisons and correlations between GFI and other variables were performed.

RESULTS

Of the 164 patients, 69 (42%) had a peak gradient >30 mmHg in the left ventricle outflow tract (LVOT). GFI (lateral or septal) was not normally distributed. There were differences among controls, obstructive HCM, and nonobstructive HCM (P < 0.0001), but significant overlap of GFI values were observed between groups. GFI was correlated to septal thickness (r = 0.44; P < 0.0001), left atrial diameter (r = 0.52; P < 0.0001), and LVOT gradient (r = 0.58; P < 0.0001).

CONCLUSION

In a selected HCM population, GFI was limited by its asymmetrical distribution and significant overlap of values between groups. Further studies are necessary to verify the reliability of GFI in the clinical practice and its position among other tissue Doppler indices.

Impaired coronary circulation in patients with apical hypertrophic cardiomyopathy: noninvasive analysis by transthoracic Doppler echocardiography

OBJECTIVES

We designed this study to examine the characteristics of coronary circulation in patients with apical hypertrophic cardiomyopathy (ApHCM) using noninvasive transthoracic Doppler echocardiography (TTDE).

BACKGROUND

Recent advances in TTDE have allowed noninvasive assessment of coronary circulation by the measurement of coronary flow velocity (CFV) patterns and coronary flow velocity reserve (CFVR). However, there have been no previous studies evaluating coronary circulation in ApHCM.

METHODS

We analyzed CFV and CFVR in the left anterior descending coronary artery (LAD), and apical wall thickness in the left ventricle, in 10 ApHCM subjects and 10 control subjects. Mean diastolic velocity (MDV) and time from the beginning of diastole to peak velocity (TPV), and CFVR, defined as a ratio of drug-induced hyperemic to basal MDV, were measured.

RESULTS

At baseline, MDV was higher, and TPV was longer, in ApHCM subjects than in control subjects (29 +/- 5.7 versus 19 +/- 6.5 cm/sec; p < 0.01 and 5.2 +/- 1.0 versus 3.5 +/- 0.6 msec; p < 0.005, respectively). CFVR in ApHCM subjects was significantly lower than in control subjects (1.9 +/- 0.4 versus 3.1 +/- 0.8; p < 0.005). CFVR and basal MDV in ApHCM subjects showed significant correlations with apical/posterior wall thickness ratio [CFVR; r =-0.84, p < 0.01 and MDV; r = 0.74, p < 0.05, respectively].

CONCLUSION

Noninvasive coronary flow assessment by TTDE revealed an impaired coronary circulation with reduced CFVR, high MDV at baseline and prolonged TPV. These results suggest that these characteristics of coronary circulation may provide an additional index for the assessment of ApHCM.

Isolated Type 2 Diabetes mellitus Causes Myocardial Dysfunction That Becomes Worse in the Presence of Cardiovascular Diseases: Results of the Myocardial Doppler in Diabetes (MYDID) Study 1

AIMS

Patients with type 2 diabetes mellitus (DM) often suffer disproportionately and have a worse outcome when burdened with cardiovascular complications compared with those without DM. A specific heart muscle disease reportedly caused by DM per se may explain this. We sought to investigate whether an echo Doppler diagnosis of such a myocardial disease is clinically relevant in DM with or without coexistent coronary artery disease (CAD) and/or hypertension (HTN).

SUBJECTS AND METHODS

Two hundred subjects (127 males, 73 females, 56 +/- 10 years) including controls (n = 23), patients with HTN (n = 20), CAD (n = 35), uncomplicated DM (n = 59), DM+HTN (n = 27), DM+CAD (n = 16) and DM+CAD+HTN (n = 20) underwent tissue Doppler-enhanced dobutamine stress echocardiography. Myocardial function was assessed by measuring left ventricular myocardial peak systolic velocity (PSV) and early diastolic velocity at rest and during peak stress, besides measurements of standard Doppler variables.

RESULTS

Average left ventricular PSV at rest was significantly lower in CAD (4.7 +/- 1.5) compared with controls (5.7 +/- 1.2) and in DM+CAD+HTN (4.6 +/- 1.4) compared with DM (5.6 +/- 1.3; all p < 0.05). During peak stress, lower PSV persisted in CAD (9.5 +/- 3.1) and DM+CAD+HTN (8.1 +/- 2.7), while appearing de novo in DM (11.3 +/- 2.6) and HTN (11.0 +/- 2.3) unlike in the controls (12.5 +/- 2.5; all p < 0.001). When pooled together, DM subjects with CAD and/or HTN or both had significantly lower PSV (9.1 +/- 2.7) than those without (10.0 +/- 2.8; p < 0.001). Early diastolic velocity response was equally lower in both groups compared with the controls.

CONCLUSION

The results suggest that dobutamine stress unmasks myocardial functional disturbances caused by uncomplicated DM. The discrete disturbances become quantitatively more pronounced in the presence of coexistent cardiovascular diseases.

Regional and Global Right Ventricular Function in Healthy Individuals Aged 20-90 Years: A Pulsed Doppler Tissue Imaging Study �Umeå General Population Heart Study

The aim of the present study was to describe regional and global right ventricular (RV) function in a wide age range of healthy subjects of both sexes. We studied 255 (125 females) healthy individuals randomly selected from the Umeå General Population Register, age 58 +/- 19 (range 22-89) years. RV function was studied using myocardial tissue Doppler imaging of the RV free wall. Isovolumic contraction (IVCv), systolic (Sv), early (Ev), and late (Av) diastolic velocities were measured. Furthermore, isovolumic periods and ejection time intervals were also measured. Conventional Doppler was used to study RV global filling properties. While systolic myocardial velocities were conserved over age, there was a decrease in myocardial E/A ratio with increasing age (r =-0.67, P < 0.001, for base) taken from the RV free wall. A similar age relation was found in RV global filling velocities with a reduced tricuspid E/A ratio (r =-0.57, P < 0.001). Furthermore, a significant correlation was found between global and regional E/A ratios at the basal (r = 0.58, P </= 0.001) and mid-segmental levels (r = 0.46, P </= 0.001). Systolic myocardial velocities behaved independent of age whereas regional as well as global E/A ratio were age-related. No relationship was found between regional isovolumic time intervals and age. Knowledge of these age-dependent relationships is fundamental when evaluating RV function in patients.

An overview of stress echocardiography in the study of patients with dilated or hypertrophic cardiomyopathy

Stress echocardiography is a useful noninvasive modality for measuring dynamic outflow gradient and contractility changes in patients with hypertrophic cardiomyopathy (HCM) or dilated cardiomyopathy (DCM). In patients with HCM, stress echocardiography may determine the degree of outflow tract obstruction at rest and with activity, can detect occult systolic dysfunction in symptomatic patients with a normal resting left ventricular ejection fraction, and can also be utilized to monitor the efficacy of treatment. In individuals suffering from DCM, stress echocardiography is an important aid in the evaluation of the etiology, diagnosis, and prognosis of the disease as well as the functional status of the patient during either exercise or simulated stress conditions. Dobutamine stress echocardiography, by providing a measurement of the myocardial reserve, is a useful tool to predict the systolic recovery and clinical outcome of patients with heart failure. The stress-induced change in the wall motion score index can also be used as an accurate alternative to predict the peak oxygen consumption rate and exercise capacity of the same patient population. Finally, stress echocardiography has also been used in the identification of the predilated phase of cardiomyopathy in individuals with high clinical suspicion of the disease.

Metallo-beta-lactamases: two binding sites for one catalytic metal ion?

During the past few years the results from molecular biological, biochemical, chemical, physical and theoretical approaches expanded the knowledge about metallo-beta-lactamases considerably. The main reason for the attracted interest is a persisting medical problem. Bacteria expressing metallo-beta-lactamases can be resistant to treatment with all the known beta-lactam antibiotics, and they are additionally invulnerable to combined treatment with inhibitors for the wider-spread serine-beta-lactamases. However, clinically useful inhibitors for metallo-beta-lactamases are not yet available. In spite of the rapidly expanding knowledge base a central question is still controversially discussed: is it the mononuclear, the binuclear or the metal-free state which might serve as the physiologically relevant target for inhibitor design? A summary of the present views of the roles and coordination geometries of metal ion(s) in metallo-beta-lactamases is combined with a discussion of the possibly variable metal ion content under physiological conditions.

Factors associated with mitral annular systolic and diastolic velocities in healthy adults

BACKGROUND

Measurements of systolic mitral annular velocity (S'), early diastolic mitral annular velocity (E'), and late diastolic mitral annular velocity (A') are used to assess left ventricular (LV) function.

OBJECTIVE

We sought to investigate the relationship between septal and lateral annular velocities and determine whether these velocities are related to body size (including body mass index [BMI]), heart rate (HR), blood pressure, or LV mass.

METHODS

A total of 60 healthy participants who were normotensive, between age 20 and 52 years, underwent standard echocardiography and measurement of septal and lateral S', E', and A'.

RESULTS

The lateral velocity exceeded the septal velocity for S', E', and A'. There was only weak to moderate correlation between the velocities at the two sites (r = 0.43-0.60). Septal S' was positively correlated with height and HR, and lateral S' was correlated with HR. Septal E' was negatively correlated with age, BMI, LV mass, and diastolic blood pressure, but lateral E' was only negatively correlated with age and BMI. Septal A' was positively correlated with age, HR, and BMI, whereas lateral A' was only positively associated with age.

CONCLUSIONS

S', E', and A' are not only of different magnitudes at the septal and lateral sites, but are not closely correlated. There are relationships between annular velocities and body size, HR, blood pressure, and LV mass that differ between the septal and lateral annulus, providing a possible explanation for the lack of close correlation in these velocities and suggesting that these variables may need to be considered when interpreting annular velocities.

Tissue Doppler imaging in Fabry disease

PURPOSE OF REVIEW

The development of effective enzyme replacement/enhancement therapy makes of clinical relevance considering Fabry disease in the differential diagnosis of patients with hypertrophic cardiomyopathy. In particular the opportunity to significantly modify the clinical progression of the disease has reinforced the need for early diagnosis of Fabry cardiomyopathy.

RECENT FINDINGS

The study with tissue Doppler of Fabry patients with endomyocardial biopsy-proven cardiac involvement showed a reduction of both diastolic and systolic myocardial velocities recorded at septal and lateral corners of mitral annulus. Tissue Doppler abnormalities were present not only in patients with left ventricular hypertrophy but also in younger patients with normal cardiac wall thickness and represent the first sign of myocardial damage. Furthermore tissue Doppler studies have been shown useful in detecting cardiac involvement in female carriers with no systemic manifestations of Fabry disease. In patients already submitted to enzyme-replacement therapy tissue Doppler and strain rate imaging represent useful noninvasive tools in assessing treatment efficacy.

SUMMARY

Tissue Doppler imaging can provide early detection of cardiac involvement in Fabry disease and represents the most accurate and sensitive noninvasive tool for the diagnosis of myocardial dysfunction and for the assessment of cardiac improvement during enzyme replacement therapy. The detection of tissue Doppler abnormalities in female carriers may represent a hint for an invasive assessment of cardiac involvement.

Tissue Doppler imaging for the evaluation of patients with hypertrophic cardiomyopathy

PURPOSE OF REVIEW

To discuss the role of tissue Doppler imaging for assessing regional myocardial function in patients with proven or suspected hypertrophic cardiomyopathy and review its application in clinical practice for diagnosis, estimation of filling pressures, and monitoring of treatment.

RECENT FINDINGS

Patients with hypertrophic cardiomyopathy have very abnormal systolic and diastolic myocardial function, even if global systolic function of the left ventricle appears normal. Regional function is most abnormal in walls that are markedly hypertrophied, but it is also abnormal in segments that are not affected by hypertrophy, and it is depressed in patients who have a mutation for hypertrophic cardiomyopathy but have not yet developed clear phenotypic changes. Genetic diagnosis remains difficult especially in sporadic cases, due to the very large number of mutations that have been identified; the hypertrophy may represent a nonspecific compensatory response to any mutation that impairs myofibrillar function. Subclinical changes especially affect long-axis ventricular function, and tissue Doppler imaging is the most sensitive test to identify reduced velocities of long-axis shortening and early diastolic lengthening of the left ventricle, prolonged contraction and relaxation times, and reduced strain in affected segments, both in patients with hypertrophy and in asymptomatic subjects with mutations. It can also discriminate well between hypertrophic cardiomyopathy and athlete's heart, and can be used with standard echocardiographic measurements to estimate left ventricular filling pressure or to monitor treatment.

SUMMARY

Tissue Doppler imaging can now be usefully incorporated into the routine echocardiographic study of patients with proven or suspected hypertrophic cardiomyopathy.

Application of tissue Doppler imaging in cardiology

Tissue Doppler imaging (TDI) is a new echocardiographic technique employing the Doppler principle to measure the velocity of myocardial segments and other cardiac structures. It is well suited for the measurement of long-axis ventricular function. Impairment of longitudinal myocardial fiber motion is a sensitive marker of early myocardial dysfunction and ischaemia, and TDI might therefore become an important tool in routine echocardiography. The technique allows truly quantitative measurement of regional myocardial function both at rest and during stress echocardiography. TDI has great potential in the diagnosis of diastolic left ventricular dysfunction, overcoming the load-dependence of conventional Doppler techniques. Right ventricular function, intracardiac and pulmonary artery pressures, transplant rejection and intraventricular dyssynchrony can also be assessed. This article reviews the current and evolving applications of TDI in cardiology.