Lieven Herbots

Cardiac resynchronization therapy can reverse abnormal myocardial strain distribution in patients with heart failure and left bundle branch block.

OBJECTIVES We studied the effects of cardiac resynchronization therapy (CRT) on regional myocardial strain distribution, as determined by echocardiographic strain rate (SR) imaging. BACKGROUND Dilated hearts with left bundle branch block (LBBB) have an abnormal redistribution of myocardial fiber strain. The effects of CRT on such abnormal strain patterns are unknown. METHODS We studied 18 patients (12 males and 6 females; mean age 65 +/- 11 years [range 33 to 76 years]) with symptomatic systolic heart failure and LBBB. Doppler myocardial imaging studies were performed to acquire regional longitudinal systolic velocity (cm/s), systolic SR (s(-1)), and systolic strain (%) data from the basal and mid-segments of the septum and lateral wall before and after CRT. By convention, negative SR and strain values indicate longitudinal shortening. RESULTS Before CRT, mid-septal peak SR and peak strain were lower than in the mid-lateral wall (peak SR: -0.79 +/- 0.5 [septum] vs. -1.35 +/- 0.8 [lateral wall], p < 0.05; peak strain: -7 +/- 5 [septum] vs. -11 +/- 5 [lateral wall], p < 0.05). This relationship was reversed during CRT (peak SR: -1.35 +/- 0.8 [septum] vs. -0.93 +/- 0.6 [lateral wall], p < 0.05; peak strain: -11 +/- 6 [septum] vs. -7 +/- 6 [lateral wall], p < 0.05). Cardiac resynchronization therapy reversed the septal-lateral difference in mid-segmental peak strain from -46 +/- 94 ms (LBBB) to 17 +/- 92 ms (CRT; p < 0.05). CONCLUSIONS Left bundle branch block can lead to a significant redistribution of abnormal myocardial fiber strains. These abnormal changes in the extent and timing of septal-lateral strain relationships can be reversed by CRT. The noninvasive identification of specific abnormal but reversible strain patterns should help to improve patient selection for CRT.

Prevalence of Left Ventricular Diastolic Dysfunction in a General Population

Background—Because the process of myocardial remodelling starts before the onset of symptoms, recent heart failure (HF) guidelines place special emphasis on the detection of subclinical left ventricular (LV) systolic and diastolic dysfunction and the timely identification of risk factors for HF. Our goal was to describe the prevalence and determinants (risk factors) of LV diastolic dysfunction in a general population and to compare the amino terminal probrain natriuretic peptide level across groups with and without diastolic dysfunction. Methods and Results—In a randomly recruited population sample (n=539; 50.5% women; mean age, 52.5 years), we measured early and late diastolic peak velocities of mitral inflow (E and A), pulmonary vein flow by pulsed-wave Doppler, and the mitral annular velocities (Ea and Aa) at 4 sites by tissue Doppler imaging. A healthy subsample of 239 subjects (mean age, 43.7 years) provided age-specific cutoff limits for normal E/A and E/Ea ratios and the differences in duration between the mitral A and the reverse pulmonary vein flows during atrial systole (&Dgr;Ad−ARd). The number of subjects in diastolic dysfunction groups 1 (impaired relaxation), 2 (elevated LV end-diastolic filling pressure), and 3 (elevated E/Ea and abnormally low E/A) were 53 (9.8%), 76 (14.1%), and 18 (3.4%), respectively. We used &Dgr;(Ad<ARd+10) to confirm possible elevation of LV filling pressures in group 2. Compared with subjects with normal diastolic function (n=392, 72.7%), group 1 (209 versus 251 pmol/L; P=0.015) and group 2 (209 versus 275 pmol/L; P=0.0003) but not group 3 (209 versus 224 pmol/L; P=0.65) had a significantly higher adjusted NT-probrain natriuretic peptide. Higher age, body mass index, heart rate, systolic blood pressure, serum insulin, and creatinine were significantly associated with a higher risk of LV diastolic dysfunction. Conclusions—The overall prevalence of LV diastolic dysfunction in a random sample of a general population, as estimated from echocardiographic measurements, was as high as 27.3%.

Left ventricular strain and strain rate in a general population

AIMS Strain and strain rate (SR) are measures of deformation that reflect left ventricular (LV) function. To our knowledge, no previous study described these indexes in a general population. We therefore described peak-systolic strain and SR of the LV in the general population and derived diagnostic thresholds for these measurements in a healthy subgroup. METHODS AND RESULTS In 480 subjects enrolled in a family-based population study (50.5% women; mean age, 50.5 years; 37.2% hypertensive), we measured: (i) end-systolic longitudinal strain and peak-systolic SR from the basal portion of the LV inferior and inferolateral free walls; (ii) radial deformation of the LV inferolateral wall. Longitudinal (mean, 22.9%) and radial (59.2%) strain and longitudinal (1.31 s(-1)) and radial (3.40 s(-1)) SR decreased with age (P </= 0.007). Longitudinal and radial strain independently decreased (P </= 0.006) with relative wall thickness (RWT), longitudinal strain with the waist-to-hip ratio, and radial strain with body weight. In contrast, LV ejection fraction increased (P </= 0.0001) with age and RWT. Longitudinal and radial stain rate increased with heart rate (P </= 0.05). In healthy subgroup (n = 236), the fifth percentiles were 18.4 and 44.3%, and 0.99 and 2.43 s(-1), for longitudinal and radial strain and SR, respectively. CONCLUSION We explored the early signs of LV systolic dysfunction in a general population, using tissue Doppler imaging technique. LV strain and SR decrease with age, body weight, central obesity, and RWT. Our current study resulted in the proposal for diagnostic thresholds for strain and SR, based on a healthy subgroup recruited via random sampling of the population.

One-dimensional ultrasonic strain and strain rate imaging: a new approach to the quantitation of regional myocardial function in patients with aortic stenosis

Abnormalities in regional left ventricular (LV) function in aortic stenosis (AS) have yet to be appropriately characterized. One-dimensional strain (epsilon) and strain rate imaging (SRI), new ultrasound (US) indices for quantifying regional wall deformation, might allow this. The aims of this study were 1. to define regional radial and longitudinal epsilon /SR in AS; 2. to establish if they are related to the severity of the disease; and 3. to determine if regional deformation is further altered by coexistent coronary artery disease (CAD). A total of 40 patients were studied: Group I with isolated AS (10 women, 10 men; mean age 66 years) and group II with AS and concomitant CAD (CAD/AS) (13 women, 7 men, mean age 68 years). Data were compared to 20 age-matched healthy people (N). Regional systolic maximal velocity/SR and end-systolic and maximal epsilon were measured. The maximal systolic velocity/SR in AS and CAD/AS patients were significantly reduced compared to N. The two patient groups could be further differentiated by end-systolic and maximal epsilon, which demonstrated a further reduction in both epsilon indices in CAD/AS (i.e., maximal radial epsilon 29.3%, AS; 23.7%, CAD/AS; 40.4%, N; AS and CAD/AS vs. N, AS vs. CAD/AS, p < 0.05). Indices of radial and longitudinal deformation correlated both with aortic valve area (AVA) and stroke volume (SV) (i.e., radial maximal epsilon and AVA, r = 0.77, p < 0.05). A significant correlation was also found between epsilon indices and the severity of left anterior descending (LAD) or circumflex artery (CX) coronary artery. Regional myocardial deformation in AS is abnormal. In the absence of CAD, the degree of abnormality correlates with aortic valve area (AVA). The severity of the disease was best expressed by changes in regional epsilon. In CAD/AS patients, there was a significant further reduction in end-systolic and maximal epsilon. These changes correlated with the severity of coronary narrowing in the subtending vessel.

New aspects of the ventricular septum and its function: an echocardiographic study

Objectives: To examine whether the line dividing the septum into two layers is found consistently by conventional echocardiography and to evaluate functional differences in the right and left side of the septum in terms of wall thickening, strain rate, and strain imaging. Design: In a systematic study in 30 normal subjects, M mode and Doppler myocardial imaging data from the interventricular septum (IVS) were recorded. Velocity curves, regional strain rate, and strain profiles were obtained. Systolic deformation (wall thickening, radial and longitudinal strain rate, and strain) of both sides were assessed. Furthermore, three patients with one sided abnormalities were studied. Results: A bright echo consistently segmented the IVS into a left and right part. In this normal population radial deformation was different for the left and right side of the septum (mean (SD) wall thickening on the left, 49 (46)%, and on the right, 17 (38)%; strain rate on the left, 3.8 (0.6) 1/s, and on the right, 2.1 (1.9) 1/s; strain on the left, 41 (17)%, and on the right, 22 (14)%), whereas longitudinal deformation was found to be similar (strain rate on the left, −2.2 (0.7) 1/s, and on the right, −2.0 (0.6) 1/s; strain on the left, −28 (12)%, and on the right, −25 (12)%). The presented clinical examples show that abnormalities can be strictly limited to one layer. Conclusions: Differential radial deformation and knowledge of fibre architecture showing an abrupt change in the middle of the septum, together with the clinical cases, suggest the septum to be a morphologically and functionally bilayered structure potentially supplied by different coronary arteries.

Quantitative dobutamine stress echocardiography for the early detection of cardiac allograft vasculopathy in heart transplant recipients

Background: A non-invasive method to detect the presence of cardiac allograft vasculopathy (CAV) remains an important goal in clinical cardiology. Objective: To assess the value of quantitative dobutamine stress echocardiography (DSE) for the early detection of CAV. Methods: 42 heart transplant recipients underwent DSE with acquisition of both conventional two-dimensional and colour tissue Doppler data. All studies were analysed conventionally and quantitatively using regional deformation parameters—that is, peak systolic longitudinal strain (∊peak sys), strain rate (SRpeak sys) and post-systolic strain index. Myocardial segments were classified as normal, mildly abnormal or severely abnormal based on correlative angiographic findings. Results: At baseline, ∊peak sys was significantly lower in severely abnormal segments than in normal ones. However, at peak stress, ∊peak sys was able to separate three groups of segments. Receiver operating characteristic analysis showed an SRpeak sys response of <0.5/s to identify patients with CAV with a sensitivity of 88%, specificity of 85% and a negative predictive value of 92%. Conclusion: Regional myocardial function is impaired in heart transplant recipients with CAV even when the disease is considered to be non-significant on conventional angiography. Systolic deformation parameters tended to detect the existence of CAV more accurately than conventional visual DSE assessment. Strain rate imaging during stress can therefore safely be used as a non-invasive screening test for detecting CAV in heart transplant recipients.

Differential changes in regional right ventricular function before and after a bilateral lung transplantation: an ultrasonic strain and strain rate study

The evaluation of regional right ventricular function by ultrasound remains a challenge. This case report demonstrates the potential value of the new cardiac deformation indices, strain and strain rate imaging, in determining the differing regional abnormalities in longitudinal right ventricular function before and after bilateral lung transplantation. These indices were measured in a patient with severe right ventricular dysfunction as a result of primary pulmonary hypertension.

Characterizing abnormal regional longitudinal function in arrhythmogenic right ventricular dysplasia. The potential clinical role of ultrasonic myocardial deformation imaging.

Arrhythmogenic right ventricular dysplasia or cardiomyopathy is a familial disorder characterized pathologically by the progressive replacement of right ventricular myocardium by fibrous and fatty tissue and clinically by malignant arrhythmias. The clinical course is highly variable. The diagnosis remains a challenge, especially in the early stages when patients are frequently asymptomatic. The identification of typical fatty infiltration of the right ventricular free wall by magnetic resonance imaging (MRI) is currently the most frequently used imaging approach to establishing the diagnosis. However, the identification of abnormal deformation properties in the right ventricular free wall using the new ultrasound modalities, regional strain rate and strain ( ) imaging, could offer a new non-invasive approach to characterizing the pathophysiologic changes induced by the replacement of myocardium by fibro-fatty tissue. In this report we present a case of severe arrhythmogenic right ventricular dysplasia in which the findings of ultrasonic strain rate and strain imaging were correlated both with MRI findings and excised heart pathology in a patient with end-stage heart failure who underwent cardiac transplantation. Case Report

Systolic and diastolic left ventricular dysfunction: from risk factors to overt heart failure

Because life expectancy and the prevalence of risk factors such as hypertension, obesity and diabetes are rising globally, heart failure (HF) is growing into a major health problem. Impairment of left ventricular (LV) diastolic function as well as systolic function appear very early in the course of heart disease. Recent HF guidelines, therefore, place special emphasis on the detection of subclinical LV dysfunction and the timely identification of risk factors for HF. Conventional echocardiography combined with new imaging techniques such as tissue Doppler and tissue tracking are sensitive tools to detect early subclinical deterioration of LV function. Community-based studies revealed a higher prevalence of LV systolic and diastolic dysfunction using the new echocardiographic imaging techniques. Future prospective studies will clarify the hitherto unknown prognosis associated with early symptom-free LV dysfunction.

Determining optimal noninvasive parameters for the prediction of left ventricular remodeling in chronic ischemic patients.

Abstract Objectives. DOPPLER-CIP aims to determine the optimal noninvasive parameters (myocardial function, perfusion, ventricular blood flow, cell integrity) and methodology (ergometry, echocardiography, scintigraphy, MRI) in a given ischemic substrate that best predicts the impact of an intervention (or the lack thereof) on adverse morphological ventricular remodeling and functional recovery. Moreover, the relative predictive value of each of these parameters, in respect to the cost of extracting this information in order to enable optimization of cost-effectiveness for improved health care, will be determined by this project. Design. DOPPLER-CIP is a multi-center registry study. All patients with ischemic heart disease included in this study undergo at least two noninvasive stress imaging examinations at baseline. The presence/or absence of left ventricular (LV) remodeling will be assessed after a follow-up of 2 years, during which all cardiac events will be registered. Results. 676 patients were included. Currently, baseline data analysis is almost finished and the follow-up is ongoing. Conclusions. After completion, DOPPLER-CIP will provide evidence-based guidelines toward the most effective use of cardiac imaging in the chronically ischemic heart disease patient. The study will generate information, knowledge, and insight into the new imaging methodologies and into the pathophysiology of chronic ischemic heart disease.