Utilidade de Ecocardiografia da Sobrecarga Farmacológica com Dobutamina nas Cardiomiopatias Dilatadas não Isquémicas

INTRODUCTION: Low-dose dobutamine stress echocardiography is a common and useful technique to assess myocardial viability in patients with ischemic cardiomyopathy. OBJECTIVE: To evaluate the use of low-dose dobutamine stress echocardiography in determining the functional status of patients with idiopathic dilated cardiomyopathy (IDCM). METHODS: Prospective study of 28 patients with IDCM by transthoracic echocardiography (2D), low-dose dobutamine stress echocardiography, cardiopulmonary exercise testing (CPET) and measurement of pro-BNP. RESULTS: The mean age of the population was 50.3 +/- 11.5 years, 9 female and 19 male. Mean ejection fraction was 32.1 +/- 9.8%. All were in sinus rhythm. The following parameters were analyzed in 2D echocardiography and after dobutamine: dimensions of left atrium (LA) and of left ventricle in diastole and systole, shortening fraction (%), left ventricular end-diastolic (EDV) and end-systolic volumes (ESV), ejection fraction (EF), and mitral inflow (E, A, E/A ratio and deceleration time). In CPET, we considered the following parameters: peak VO2 and % maximal peak VO2 attained. We compared echo results with CPET. There was a correlation between age and peak VO2 (r = -0.38 with p = 0.049). In 2D echo, there was a correlation between baseline EF and LA dimensions and peak VO2 (r = 0.45 / p = 0.004 and r = -0.49 / p = 0.014, respectively). After dobutamine echo, there was a correlation between some echo parameters and peak VO2: EF - r = 0.59 / p = 0.001, LA dimensions - r = 0.56 / p = 0.007, and ESV - r = -0.45 / p = 0.026. Percentage maximal peak VO2 attained correlated with LA dimensions measured in 2D echo and after dobutamine (r = -0.398 / p = 0.036 and r = -0.674 / p = 0.02 respectively) and EF after dobutamine (r = -0.389 / p = 0.04). The value of pro-BNP correlated with LA dimensions and baseline EF (r = 0.44 / p = 0.02 and r = -0.57 / p = 0.002, respectively), and the correlation was maintained after inotropic stimulation with dobutamine (r = 0.57 / p = 0.001 and r = -0.55 / p = 0.0039). CONCLUSION: Low-dose dobutamine stress echocardiography showed stronger correlations with cardiopulmonary exercise testing than the parameters evaluated by conventional echocardiography and could be used to determine the functional status of patients with dilated cardiomyopathy; patients with greater ejection fraction after inotropic stimulation had better cardiopulmonary tests.

Importância Prognóstica do Doppler Tecidular nos Doentes com Miocardiopatia Dilatada

Previous studies have shown that a ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus (E/E') of > 15, obtained by tissue Doppler imaging (TDI), correlates with left ventricular filling pressure. OBJECTIVE: The aim of our study was to assess whether E/E' provides prognostic information in patients with dilated cardiomyopathy. METHODS: We studied 33 patients with dilated cardiomyopathy and mean ejection fraction of 31%. All the patients underwent routine two-dimensional and Doppler echocardiographic examination and TDI to determine early peak velocity of the mitral annulus. Pro-B-type natriuretic peptide (pro-BNP) and peak oxygen consumption (VO2max) were also measured. Patients were divided into two groups according to the value of E/E': Group I (n = 15 patients) with E/E' > or = 15 and Group II (n = 18 patients) with E/E' < 15. Patients were followed for 12+/-4 months; new hospital admission due to heart failure, heart transplantation and death were considered as cardiac events. RESULTS: There were significant differences between the two groups in conventional two-dimensional echocardiographic measurements (dimensions and ejection fraction) and Doppler parameters (mitral inflow). With regard to mitral annular velocities obtained by TDI at two different points (septum and lateral wall), the E', A' and S' velocities differed significantly between the two groups, with lower velocities in Group I. Systolic velocity measured in the lateral portion of the mitral annulus showed the most significant difference: Group I - 4.46 cm/sec versus Group II - 7.19 cm/sec, p < 0.00001. Pro-BNP was 5622 pg/ml in Group I, and 1254 pg/ml in Group II, p = 0.004. VO2 max was significantly different between the two groups: Group I - 17.6 ml/kg/min versus Group II - 22.8 ml/kg/min, p = 0.004. During follow-up, events were more common in Group I, with 9 patients (60%) having events, while in Group II, the event rate was 11.1% (2 patients), p = 0.004. CONCLUSION: The ratio of early transmitral flow velocity to early diastolic velocity of the mitral annulus is a powerful predictor of clinical outcome. Lower velocities of mitral annulus on TDI are expected in patients with E/E' > or = 15. Systolic velocities of under 5 cm/sec measured in the lateral portion of the mitral annulus appeared to be strongly related to prognosis.

Mitral Valve Myxomas: an Unusual Entity

Primary tumours of the heart are uncommon entities, cardiac myxomas being the most frequent. However, mitral valve myxomas are exceptionally rare. In the last 12 years, there have been 25 myxomas diagnosed at our institution, with only two of them originating from the mitral valve. Both patients were female, the first, 25, and the second, 72 years old. The younger patient was very symptomatic with a large mass, 4 cm long, which involved both leaflets causing significant obstruction to the left ventricular inflow. The second one had a smaller mass located at the atrial side of the posterior leaflet that only produced some flow divergence. Neither of them had constitutional nor embolic symptoms. Both patients were submitted to emergent surgical resection that in the first case involved the mitral valve and replacement with mechanical prosthesis. The macroscopic appearance of these tumours suggested a malignant aetiology which may represent somewhat different features of the myxomas when originating from the cardiac valves. Both patients are well reflecting the good prognosis of this illness after resection, although the younger patient was re-operated because of prosthetic valve obstruction and suspicion of recurrence that was not confirmed. Because of the illustrative images and different presentations, we found it interesting to report and discuss them together.