الفهرس 
Pathophysiology and clinical presentation.Only 14 pages are availabe for public view
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Abstract
Hypertrophic cardiomyopathy (HCM) is the commonest inherited cardiovascular disease, presenting in about 1/500 adults in the general population.
Dynamic LVOT obstruction is induced by thickening of the interventricular septum and systolic anterior motion (SAM) of the mitral valve. Several invasive therapeutic modalities have been developed to diminish outflow tract obstruction by reduction of the interventricular septum width.
Septal myectomy is established as the most effective and proven approach for reversing the consequences of heart failure by providing amelioration of obstruction (and relief of mitral regurgitation) at rest, with restoration of functional capacity and acceptable quality of life at any age, exceeding that achievable with long-term administration of cardioactive drugs.
In our study we aim to know LV mechanics before surgical myectomy and the effect of myectomy on these mechanics.
Our study included Fifteen patients with hypertrophic obstructive cardiomyopathy refractory to medical treatment referred to surgical myectomy according to the recommendation of AHA.
Surgical Myectomy was successfully done for all fifteen patients. It was carried out at (Eight cases at Magdy Yacoub Cardiology Center, Two cases at Cardiology academy Ain Shams university, one case at National heart institute and Four cases at private hospitals.
All patients were subjected to the following Echo parameters before and within six monthes after myectomy, LAD, LAV, LAVI, LVEDD, LVESD, FS, EF, LVM, LVMI, LVOT PG, E vel, A vel, E/A, E/e´,LV circumferential strain, LV longitudinal strain, Basal rotation, apical rotation, LV twist and LV synchronization using TTP parameters.
In the present study, significant decrease in left atrial dimension (LAD) (46.53± 9.23 mm) before myectomy compared with (37.60 ± 4.54mm) after surgical myectomy (P value ˂ 0.0001), also significant decrease left atrial volume (LAV) (69.47 ±11.39 ml) compared with (48.83 ± 6.21 ml) after myectomy (P value ˂ 0.0001), and subsequent significant decrease in left atrial volume index (LAV Index) (37.8 ± 5.61 ) before mectomy, and (26.38 ± 3.37) after myectomy (P value ˂ 0.0001).
Also there were significant increase in left ventricular systolic dimensions (LVSD) (21.80 ± 4.0 mm) before and (26.53 ± 3.16mm) after surgical myectomy (P value ˂ 0.0001), with non significant increase in left ventricular diastolic dimensions (LVDD) (40.67 ± 6.1mm before and 43.06 ± 6.77mm after surgical myectomy) (P value 0.114).
We saw significant decrease in Fractional shortening (FS%) (47.93 ± 9.16 pre and 36.80 ± 3.62 post operative, with P value ˂0.0001) and ejection fraction (EF%) (74.27 ± 8.83 pre and 66.80 ± 3.70 post operative with P value 0.010). There were also significant decrease in E/E´ ratio after surgical myectomy (15.23 ± 2.39 before and 9.18 ± 1.42 after surgical myectomy with P value ˂0.0001).
In our study there were significant decrease in Circumferential strain (CS) after surgical myectomy (-28.47± 3.35 before and -18.26 ± 2.86 after with P value ˂0.0001). In current study there were significant Decrease in LV Twist after surgical myectomy (16.52 ± 2.25 before and 14.02 ± 2.27 after myectomy with P value ˂0.0001).
Apart from the basal septum of the LV that shows significant decrease in its €sys % after myectomy, the global LV Longitudinal strain shows non significant changes after myectomy.
Also there were non significant changes in global LV TTP after surgical myectomy.
from the above results; patients with HOCM, surgical myectomy improves symptoms, relieves LVOT obstruction, and decreases left atrial volume index. Myocardial mechanics showed opposing changes in myectomy and nonmyectomy longitudinal strain, resulting in no change in its average and reductions of circumferential strain and rotation dynamics.
Also although both groups of patients develop hypertrophy and compensatory myocardial mechanics in response to LV pressure overload, relief of LVOT obstruction does not reverse the additional structural abnormalities in patients with HCM. Disease extent and the presence of diastolic dysfunction seem to be related to partial symptomatic response to myectomy.