Marie Moonen

Prognostic Effect of Long-Axis Left Ventricular Dysfunction and B-Type Natriuretic Peptide Levels in Asymptomatic Aortic Stenosis

In aortic stenosis (AS), the increased afterload results in progressive structural and functional changes that precede the development of symptoms. We hypothesized that the detection of abnormalities in left ventricular long-axis function could identify patients with asymptomatic AS at increased risk of events. We prospectively examined the outcome of 126 patients with asymptomatic AS who underwent a comprehensive echocardiographic examination, including tissue Doppler imaging. B-type natriuretic peptide (BNP) was measured in all patients. During a median follow-up period of 20.3 + or - 17.8 months, 6 patients died, 8 developed symptoms but did not undergo surgery, and 48 underwent aortic valve replacement. On multivariate Cox regression analysis, the parameters associated with the predefined outcome were gender (p = 0.048), left atrial area index (p = 0.011), systolic annular velocity (p = 0.016), E/Ea ratio (p = 0.024), late diastolic annular velocity (p = 0.023), and BNP (p = 0.012). Using receiver operating characteristics curve analysis, a left atrial area index of > or = 12.4 cm(2)/m(2), systolic annular velocity of < or = 4.5 cm/s, E/Ea ratio >13.8, late diastolic annular velocity of < or = 9 cm/s, and BNP of > or = 61 pg/ml were identified as the best cutoff values to predict events. In conclusion, in asymptomatic AS, tissue Doppler imaging and BNP measurements provide prognostic information beyond that from clinical and conventional echocardiographic parameters.

The Value of 2D Strain Imaging during Stress Testing

Stress echocardiography is increasingly used but its major limitation is the subjective interpretation of wall motion changes requiring experience. Speckle tracking enables simultaneous evaluation of radial, longitudinal, and circumferential myocardial deformation. Recently, two‐dimensional (2D) strain has been found to be as reliable as sonomicrometry for the assessment of left ventricular (LV) regional function. In the presence of inducible ischemia, longitudinal and circumferential abnormalities preceed the decrease in radial deformation. Optimal cutoffs have been obtained from 2D strain rate (SR) at peak dobutamine stress to predict coronary artery disease. However, 2D strain rate does not yet provide incremental accuracy to visual interpretation by experts. Speckle tracking strain could be useful to better identify contractile reverse and biphasic response of viable myocardium but there are not yet clinical studies published in this setting. Preliminary results suggest that 2D strain obtained during exercise could be useful in asymptomatic patients with severe aortic stenosis or organic mitral regurgitation (MR). In conclusion, the reliability and clinical importance of 2D strain during stress will be specified by further investigations.

Impact of contractile reserve on acute response to cardiac resynchronization therapy

BackgroundCardiac resynchronization therapy (CRT) provides benefit for congestive heart failure, but still 30% of patients failed to respond to such therapy. This lack of response may be due to the presence of significant amount of scar or fibrotic tissue at myocardial level. This study sought to investigate the potential impact of myocardial contractile reserve as assessed during exercise echocardiography on acute response following CRT implantation.MethodsFifty-one consecutive patients with heart failure (LV ejection fraction 27% ± 5%, 67% ischemic cardiomyopathy) underwent exercise Doppler echocardiography before CRT implantation to assess global contractile reserve (improvement in LV ejection fraction) and local contractile reserve in the region of the LV pacing lead (assessed by radial strain using speckle tracking analysis). Responders were defined by an increase in stroke volume ≥ 15% after CRT.ResultsCompared with nonresponders, responders (25 patients) showed a greater exercise-induced increase in LV ejection fraction, a higher degree of mitral regurgitation and a significant extent of LV dyssynchrony. The presence of contractile reserve was directly related to the acute increase in stroke volume (r = 0.48, p < 0.001). Baseline myocardial deformation as well as contractile reserve in the LV pacing lead region was greater in responders during exercise than in nonresponders (p < 0.0001).ConclusionThe present study showed that response to CRT largely depends not only on the extent of LV dyssynchrony and the severity of mitral regurgitation but also on the presence of contractile reserve.

Comparison of contrast enhanced three dimensional echocardiography with MIBI gated SPECT for the evaluation of left ventricular function

BackgroundIn clinical practice and in clinical trials, echocardiography and scintigraphy are used the most for the evaluation of global left ejection fraction (LVEF) and left ventricular (LV) volumes. Actually, poor quality imaging and geometrical assumptions are the main limitations of LVEF measured by echocardiography. Contrast agents and 3D echocardiography are new methods that may alleviate these potential limitations.MethodsTherefore we sought to examine the accuracy of contrast 3D echocardiography for the evaluation of LV volumes and LVEF relative to MIBI gated SPECT as an independent reference. In 43 patients addressed for chest pain, contrast 3D echocardiography (RT3DE) and MIBI gated SPECT were prospectively performed on the same day. The accuracy and the variability of LV volumes and LVEF measurements were evaluated.ResultsDue to good endocardial delineation, LV volumes and LVEF measurements by contrast RT3DE were feasible in 99% of the patients. The mean LV end-diastolic volume (LVEDV) of the group by scintigraphy was 143 ± 65 mL and was underestimated by triplane contrast RT3DE (128 ± 60 mL; p < 0.001) and less by full-volume contrast RT3DE (132 ± 62 mL; p < 0.001). Limits of agreement with scintigraphy were similar for triplane andfull-volume, modalities with the best results for full-volume. Results were similar for calculation of LV end-systolic volume (LVESV). The mean LVEF was 44 ± 16% with scintigraphy and was not significantly different with both triplane contrast RT3DE (45 ± 15%) and full-volume contrast RT3DE (45 ± 15%). There was an excellent correlation between two different observers for LVEDV, LVESV and LVEF measurements and inter observer agreement was also good for both contrast RT3DE techniques.ConclusionContrast RT3DE allows an accurate assessment of LVEF compared to the LVEF measured by SPECT, and shows low variability between observers. Although RT3DE triplane provides accurate evaluation of left ventricular function, RT3DE full-volume is superior to triplane modality in patients with suspected coronary artery disease.

Afterload mismatch revealed by an exercise biphasic response in aortic stenosis

A 71-year-old man with asymptomatic severe aortic stenosis was referred to our stress echocardiography laboratory for risk stratification. He had no coronary risk factors but led a sedentary life. A symptom-limited bicycle exercise was performed in the supine position. The patient reached the target heart rate (128beats/min) and developed moderate dyspnoea at a workload of 100W. The systolic blood pressure initially increased from 130 to 150 mmHg whereas no further changes occurred at a higher exercise level. Baseline transthoracic echocardiography (rest) confirmed the presence of severe valvular aortic stenosis, with an aortic valve area of 0.78 cm 2 (outflow tract time velocity integral 20cm) and a mean transaortic pressure gradient of 40 mmHg. At low-level exercise, the increase in longitudinal long-axis function (peak negative strain rate obtained off-line by tissue Doppler reconstruction at the level of the septal and lateral walls) (Fig. Top panel) was accompanied by a significant rise in transaortic pressure gradients (Fig. Bottom panel). The calculated aortic valve area was 0.71 cm 2 (outflow tract time velocity integral 19 cm) indicating absence of valve compliance. At peak exercise, the transaortic pressure gradient decreased as a result of a significant impairment of left ventricular function (decrease in peak negative strain rate). The aortic valve area remained fairly unchanged (0.69 cm 2 ) whereas the left ventricular outflow tract time velocity integral decreased (15 cm), indicating reduced flow across the aortic valve. No inducible ischaemia was observed during test and no concomitant coronary artery stenosis was found at angiography.

Dynamic left ventricular dyssynchrony: a potential cause of no contractile reserve in patients with low-gradient aortic stenosis

Dobutamine stress echocardiography (DSE) has the potential to stratify patients with low-gradient aortic stenosis (AS) but little is known about ventricular dyssynchrony associated with AS. We report the case of a patient who presented AS associated with left ventricular (LV) dyssynchrony. A DSE was performed, which showed no contractile reserve but an increase in LV dyssynchrony. In this patient, the reduced aortic valve area was probably because of the association of inadequate forward stroke volume due to ischaemic cardiomyopathy and fixed severe AS. The cause of LV dysfunction may include a certain degree of intrinsic myocardial dysfunction due to ischaemic cardiomyopathy and afterload mismatch associated with dynamic LV dyssynchrony, which could be a determinant of forward stroke volume response.

An alien in the heart: giant infective endocarditis

A 78-year-old woman was referred to our depart-ment because of acute confusion and somnolence.Her usual medication was corticosteroid injectiononce a month for hip arthrosis. The clinical exami-nation showed an obese patient. Blood pressure was90/60∞∞mmHg and heart rate 160∞∞bpm. On admission,the patient had fever (38.6°C) and meningism, but nofocal neurologic deficits were found. Heart and lungauscultation was normal. Because of progressive res-piratory insufficiency, the patient was mechanicallyventilated. Blood analysis showed an inflammatorysyndrome and mild renal failure. The cerebral CTshowed no focal lesions. An antibiotic regimen withampicilline and geomycine was started on the basisof suspected bacterial meningitides on lumbar punc-ture. A transthoracic echocardiography revealed endo-carditis with a giant vegetation on the posterior mitralvalve leaflet (P2) and a severe valvular regurgitation(figure 1: A, B, C). Transoesophageal echocardio-graphy confirmed the diagnosis and did not showperivalvular extension (figure 1D). Methicillin-sensi-tive

Intérêt d’un nomogramme fondé sur le poids et géré par l’infirmière pour adapter la posologie de l’héparine non fractionnée

Resume Objectifs. – Etudier l’efficacite d’un nomogramme de posologie d’heparine non fractionnee intraveineuse fonde sur le poids et applique par l’infirmiere (HBPI) sans formation particuliere. Type d’etude. – Etude comparative prospective avant/apres intervention. Patients et methodes. – Dans une unite de soins intensifs medicaux, 19xa0patients recevant de l’heparine non fractionnee intraveineuse sur prescription medicale (HPM) uniquement ont ete compares a 19xa0patients soumis au schema HBPI (bolus intraveineux de 80xa0U kg–1, suivi d’une perfusion continue de 18xa0U kg–1 h–1 adapte ulterieurement en suivant le nomogramme selon le TCA). Resultats. – La posologie du bolus et de la perfusion continue initiale etait significativement plus elevee dans le groupe HBPI que dans le groupe HPM. Le temps necessaire a atteindre un TCA therapeutique d’au moins 60xa0s etait de 6xa0h (1–76xa0h) dans le groupe HPM et de 4xa0h (3–32xa0h) dans le groupe HBPI. Le TCA cible (60–85xa0s) etait atteint apres 13,5xa0h (1–76xa0h) et 9,5xa0h (3–32) respectivement. Bien que la reduction du delai soit en faveur du groupe HBPI, la difference n’atteignait pas la signification statistique. La proportion de TCA cible par rapport au nombre total de TCA par patient etait significativement plus elevee dans le groupe HBPI (41 [0–87] vs 31xa0% [0–54]). Le suivi des TCA et les modifications de posologie ont ete mieux appliques dans le groupe HBPI. Conclusions. – Le schema HBPI est facilement applicable sans formation particuliere. HBPI est associe a une anticoagulation plus stricte, bien que sa superiorite soit moins importante qu’attendu.