Coronary vasodilator reserve is impaired in patients with hypertrophic cardiomyopathy and left ventricular dysfunction.
BACKGROUND
We tested the hypothesis that a reduced delivery of blood to the myocardium is involved in the development of systolic dysfunction of patients with hypertrophic cardiomyopathy (HCM).


RESULTS
Eighty-four patients with HCM (62 men, age 43 +/- 12 years) were studied. Left ventricular dimensions and function (fractional shortening) were evaluated by 2-dimensional echocardiography. Myocardial blood flow (MBF) was measured by N13 -ammonia or O15 -water and positron emission tomography at baseline and after dipyridamole; coronary vasodilator reserve (CVR) was calculated as dipyridamole/baseline MBF. Patients with HCM in advanced New York Heart Association (NYHA) classes had lower dipyridamole MBF (NYHA class I = 1.57 +/- 0.64 vs class II = 1.52 +/- 0.58 vs class III = 0.96 +/- 0.32 mL/min per gram; analysis of variance, P <.05) and CVR (NYHA class I = 1.93 +/- 0.64 vs class II = 1.69 +/- 0.54 vs class III = 1.40 +/- 0.43; analysis of variance, P <.05). A positive linear correlation between fractional shortening and dipyridamole MBF was demonstrated (R = 0.23, P <.05), and patients with abnormal fractional shortening had lower dipyridamole MBF (1.07 +/- 0.43 vs 1.58 +/- 0.62 mL/min per gram, P <.01).


CONCLUSIONS
Systolic dysfunction in HCM may be caused by a more severe alteration of the coronary vasodilator capacity.
Lorenzoni
R
R
MRC Clinical Sciences Centre and Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
Gistri
R
R
Cecchi
F
F
Olivotto
I
I
Chiriatti
G
G
Elliott
P
P
McKenna
W J
WJ
Camici
P G
PG
D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D014055:Tomography, Emission-Computed; D014463:Ultrasonography; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*