Efeitos da ventriculectomia parcial nas propriedades mecânicas, forma e geometria do ventrículo esquerdo em portadores de cardiomiopatia dilatada / Effects of Partial Ventriculectomy on Left Ventricular Mechanical Properties, Shape and Geometry in Patients with Dilated Cardiomyopathy

ABSTRACT

PURPOSE: To investigate the short-term effects of the partial ventriculectomy (resection of lateral wall associated to mitral annuloplasty) on cardiac mechanics, contractility, shape and geometry of the left ventricle (LV). METHODS: Eleven male patients with severe congestive heart failure due to dilated cardiomyopathy were studied. The mean age was 51 +/- 7 years and the functional class was III (five patients) or IV (six patients) before the surgery. Patients were evaluated before and at 17 +/- 4 days after the surgery by simultaneous LV pressure and echocardiographic data. End-diastolic pressure (EDP-mmHg), wall stress (EDS-g/cm2) and diameter (EDD-cm); endsystolic wall stress (ESS) and diameter (ESD), fractional shortening (FS-) and maximal elastance (Emax-mmHg/ cm/s); the diastolic slope of the pressure-diameter (Kp-mmHg/cm) and stress-strain (Km-g/cm2) loops; shape (L/ EDD, adimensional, where L is the LV long axis) and geometry (Th/EDD, adimensional, where TH is the LV diastolic thickness) were obtained. RESULTS: 1) The ressected muscle fragments (diamond shape) were 10.8 +/- 1.3 cm in length and 5 +/- 0.6 cm in width; 2) all patients were discharged from hospital (15-29 days) in class I (eight cases), II (two), and III (one); 3) it was observed a decrease in EDP (24.3 +/- 7.7 x 17.5 +/- 3.2, p = 0.016); in EDD (8.0 +/- 0.7 x 7.2 +/- 0.8, p = 0.002); in EDS (57.9 +/- 26.8 x 37.4 +/- 19.2, p = 0.005); in ESS (199 +/- 46.9 x 102.8 +/- 33.1, p = 0.004); in ESD (7.1 +/- 0.7 x 5.7 +/- 0.8, p < 0.001); in Kp (22.3 +/- 15.9 x 11.5 +/- 6.9, p = 0.014); and in K(m) (467.4 +/- 212 x 214.6 +/- 87.4, p = 0.01); and, 4) it was noted an increase in FS (11.5 +/- 1.8 x 19.8 +/- 3.9, p < 0.001); in Emax (13.8 +/- 2.2 x 18.6 +/- 3.2, p < 0.001); and in L/EDD (1.32 +/- 0.1 x 1.47 +/- 0.13, p < 0.007) and Th/Dd (0.11 +/- 0.04 x 0.17 +/- 0.08, p < 0.038). CONCLUSION: The partial ventriculectomy showed multiple significant beneficial effects in these dilated myopathic hearts.