الفهرس 
Chapter ( 1 ) Hypertrophic cardiomyopathyOnly 14 pages are availabe for public view
 |  | from | 110 |  |  |
| | | from | 110 | | |
Abstract
Left ventricular outflow tract obstruction is an independent predictor of adverse outcome in hypertrophic cardiomyopathy (HCM). Provocative test may be required for risk stratification. It is of major importance that the provocation modalities used are validated against each other and correlated with the mechanical behavior of the hypertrophied myocardium Aim-: To define the magnitude of LVOT gradients at rest and during both isosorbide dinitrate (ISDN) inhalation and treadmill exercise in non obstructive HCM and analyze the correlation to the mechanical deformation using speckle tracking. Methods-: We studied 39 HCM pts (64% males, mean age 38±13 years) regional LV longitudinal strain and electromechanical delay (TTP) was analyzed at rest using speckle tracking. LVOT gradient was measured at rest and after ISDN then patients underwent a treadmill exercise echocardiography (EE) and LVOT gradient was measured at peak exercise. Results-: the maximum effect of ISDN on LVOT gradient was obtained at 5 minute, it increased to significant level in 12(31%), and in 14(36%) patients using EE, with 85.6% sensitivity and the 100% specificity. Patients with latent obstruction had larger left atrial volume and lower E/A ratio compared to the non-obstructive group (P<0.01). While LVOTG using ISDN was significantly correlated with that using EE (P<.0001), resting LVOTG (P<0.0001), SAM (P<0.0001), EF% (P<0.02) and regional electromechanical delay it was not related to global LV longitudinal strain. Using multivariate regression, resting LVOTG (P=0.006) & TTP mid septum (P=0.01) were found to be independent predictors of latent LVOT obstruction using ISDN. Conclusion-: The present study demonstrates a comparable diagnostic value of nitrate inhalation to exercise testing in provocation of LVOT obstruction in HCM. Latent obstruction in LVOT is predominantly dependent on regional electromechanical delay.