Behavior of both epicardial and intramural coronary artery flow velocities in various models of myocardial hypertrophy: role for left ventricular outflow tract obstruction.
BACKGROUND
The assessment of coronary flow velocity is becoming crucial in the diagnosis and management of several cardiac dysfunctions and conventional Doppler echocardiography is currently the technique most widely used for detecting their abnormalities noninvasively.


METHODS
We sought to evaluate the differences in coronary flow velocity using conventional transthoracic Doppler echocardiography, measuring both the left anterior descending and such intramural (IM) coronary arteries' flow, among the following 4 categories of patients with myocardial hypertrophy: group A, obstructive hypertrophic cardiomyopathy (n = 12); group B, nonobstructive hypertrophic cardiomyopathy (n = 10); group C, left ventricular hypertrophy (LVH) due to hypertension (n = 10); and group D, LVH due to aortic valve stenosis (n = 10).


RESULTS
No significant difference between the 4 groups was found with respect to the left anterior descending velocity. Diastolic peak (P < .01) and mean (P < .05) velocities in the IM arterioles were significantly higher in patients from groups A and D than in groups B and C. At multivariate analysis, both dynamic (group A) and fixed (group D) systolic peak gradients, measured by continuous wave Doppler sampling through the left ventricular (LV) outflow tract or the aortic valve, respectively, were found to be major determinants of the IM diastolic velocity, independently on the LV mass. About 75% of patients with obstructive hypertrophic cardiomyopathy showed IM peak and mean velocity >100 cm/s and >70 cm/s, respectively (P = .005).


CONCLUSIONS
These findings likely suggest [corrected] a role for the LV systolic obstruction within the intricate adaptive mechanisms of coronary blood flow to LVH.
Clinical and Experimental Department of Medicine and Pharmacology, Cardiology and Cardiac Rehabilitative Unit, University Hospital of Messina, Messina, Italy. cesaredegregorio1@virgilio.it
Cesare
C
de Gregorio
Antonio
A
Micari
Patrizia
P
Grimaldi
Thanjavur
T
Bragadeesh
Francesco
F
Arrigo
Sebastiano
S
Coglitore
D000368:Aged; D001783:Blood Flow Velocity; D006332:Cardiomegaly / Q000503:physiopathology*; D002312:Cardiomyopathy, Hypertrophic / Q000503:physiopathology*; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010496:Pericardium; D014694:Ventricular Outflow Obstruction / Q000503:physiopathology*