Matteo Pisani

Role of regional mechanical dyssynchrony as a determinant of functional mitral regurgitation in patients with left ventricular systolic dysfunction

Objective: To assess regional mechanical dyssynchrony as a determinant of the degree of functional mitral regurgitation (FMR). Setting: Tertiary cardiology clinic. Patients: 74 consecutive patients with left ventricular (LV) dysfunction (ejection fraction < 40%, mean 32.2 (SD 7.3)%) were evaluated. Methods: Effective regurgitant orifice (ERO) area, indices of mitral deformation (systolic valvular tenting, mitral annular contraction) and of global LV function and remodelling (ejection fraction, end systolic volume, sphericity index) and local remodelling (papillary-fibrosa distance, regional wall motion score index), and tissue Doppler-derived dyssynchrony index (DI) (regional DI, defined as the standard deviation of time to peak myocardial systolic contraction of eight LV segments supporting the papillary muscles attachment) were measured. Results: All the assessed variables correlated significantly with ERO. By multivariate analysis, systolic valvular tenting was the strongest independent predictor of ERO (R2  =  0.77, p  =  0.0001), with a minor influence of papillary-fibrosa distance (R2  =  0.77, p  =  0.01) and regional DI (R2  =  0.77, p  =  0.03). Local LV remodelling (regional wall motion score index: R2  =  0.58, p  =  0.001; papillary-fibrosa distance: R2  =  0.58, p  =  0.002) and global remodelling indices (sphericity index: R2  =  0.58, p  =  0.003) were the main determinants of systolic valvular tenting, whereas regional DI did not enter into the model. Regional DI was an independent predictor of ERO (R2  =  0.56, p  =  0.005) in patients with non-ischaemic LV dysfunction but not in patients with ischaemic LV dysfunction when these groups were analysed separately. Conclusions: The degree of FMR is associated mainly with mitral deformation indices. The regional dyssynchrony also has an independent association with ERO but with a minor influence; however, it is not a determinant of FMR in patients with ischaemic LV dysfunction.

Stress echocardiography in heart failure

Echocardiography has the ability to noninvasively explore hemodynamic variables during pharmacologic or exercise stress test in patients with heart failure. In this review, we detail some important potential applications of stress echocardiography in patients with heart failure. In patients with coronary artery disease and chronic LV dysfunction, dobutamine stress echocardiography is able to distinguish between viable and fibrotic tissue to make adequate clinical decisions. Exercise testing, in combination with echocardiographic monitoring, is a method of obtaining accurate information in the assessment of functional capacity and prognosis. Functional mitral regurgitation is a common finding in patients with dilated and ischaemic cardiomyopathy and stress echocardiography in the form of exercise or pharmacologic protocols can be useful to evaluate the behaviour of mitral regurgitation. It is clinical useful to search the presence of contractile reserve in non ischemic dilated cardiomyopathy such as to screen or monitor the presence of latent myocardial dysfunction in patients who had exposure to cardiotoxic agents. Moreover, in patients with suspected diastolic heart failure and normal systolic function, exercise echocardiography could be able to demonstrate the existence of such dysfunction and determine that it is sufficient to limit exercise tolerance. Finally, in the aortic stenosis dobutamine echocardiography can distinguish severe from non-severe stenosis in patients with low transvalvular gradients and depressed left ventricular function.

629 Validation of real-time 3D echocardiography study protocol in identification of anatomic mitral regurgitant defect in patients with prolapse or flail

Background: In patients with mitral regurgitation (MR), valve repair is a major incentive to early surgery and is decided on the basis of the mechanisms and anatomic mitral lesions. These lesions can be easily studied with transesophageal echocardiography (TEE). A study protocol of real-time 3D echocardiography (RT3D) for the identifications of the valve defect is not well validated. Objectives: This study was performed to validate a protocol of RT3D for assessment mitral valve for identification of anatomic valve defect due to prolapse or flail using TEE as gold standard. Methods: One hundred and nineteen consecutive patients with moderate to severe MR (mean age 64±3.4) were studied with RT3D and TEE to identify the valve defects causing MR and the results were evaluated in blind manner. RT3D study protocol was performed as follows: data were acquired in a zoom mode and in a full-volume mode from apical window. Then, using 3D Qlab software (version 2.0, Philips), a volume rendered en-face view of the mitral valve from the left atrium was reconstructed and guided by this view, a series of longitudinal cutplanes were reconstructed to visualise A1P1, A2-P2 and A3-P3. Segmental analysis of the valve was evaluated according to American Society of Echocardiography guidelines. Results: Among 119 patients, 66 had prolapse or flail by TEE. The accuracy of RT3D for prolapse lesion was 97% (p=0.0001), with a sensitivity and specificity of 95% and 96% , whereas for flail lesion the accuracy was 95% (p=0.0001) with a sensitivity and specificity of 91% and 97%. The diagnostic accuracy for the individual scallops is reported in Table 1. Conclusions: RT3D protocol using rendered en-face view and a series of longitudinal cutplanes is highly accurate in the identification of anatomic valve defect and its location, particularly showing high specificity values.