Reflections of inflections in hypertrophic cardiomyopathy.
The shape of Doppler velocity tracings in obstructive hypertrophic cardiomyopathy offers insights into its pathophysiology. Inflection points are the points on a curve where its shape changes from concave to convex, or vice versa. These dynamic systolic abnormalities are caused: 1) by the amplifying nature of the obstruction; and 2) by the adverse effect of the sudden imposition of afterload in midsystole. The midsystolic drop in left ventricular ejection velocities and the premature termination of longitudinal shortening are compelling evidence of the deleterious mechanical effect of obstruction on the ventricle. This dynamic systolic dysfunction, demonstrated on the Doppler curves, may contribute to heart failure symptoms and adverse outcome. In outflow obstruction, these abnormalities normalize after abolition of gradient. Therefore, their detection in an individual patient confirms obstruction as a therapeutic target.
Sherrid
Mark V
MV
Echocardiography Laboratory and Hypertrophic Cardiomyopathy Program, Division of Cardiology, St. Luke's-Roosevelt Hospital Center, Columbia University, College of Physicians and Surgeons, New York, New York 10019, USA. msherrid@chpnet.org
Wever-Pinzon
Omar
O
Shah
Ajay
A
Chaudhry
Farooq A
FA
D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003971:Diastole; D004452:Echocardiography; D018618:Echocardiography, Doppler, Color; D006333:Heart Failure; D006801:Humans; D013318:Stroke Volume; D013599:Systole; D016277:Ventricular Function, Left; D014694:Ventricular Outflow Obstruction / Q000000981:diagnostic imaging* / Q000209:etiology / Q000503:physiopathology