Effects of long-term treatment with carvedilol on myocardial blood flow in idiopathic dilated cardiomyopathy.
OBJECTIVE
To assess whether chronic treatment with carvedilol can increase myocardial blood flow (MBF) and MBF reserve in idiopathic dilated cardiomyopathy (IDC).


METHODS
In a double-blind, placebo-controlled trial, 16 consecutive patients with IDC were randomised to treatment with either carvedilol up to 25 mg twice a day (n = 8, 7 men, mean (SD) age 60 (9) years, mean (SD) left ventricular ejection fraction (LVEF) 30% (5%)), or placebo (n = 8, 6 men, mean (SD) age 62 (9) years, mean (SD) LVEF 28% (6%), NS vs carvedilol group). Before and 6 months after treatment, regional MBF was measured at rest and after intravenous injection of dipyridamole (Dip; 0.56 mg/kg in 4 min) by positron emission tomography and using (13)N-ammonia as a flow tracer. Exercise capacity was assessed as the time duration in a maximal bicycle exercise stress test.


RESULTS
Carvedilol induced a significant decrease in heart rate at rest and during maximal exercise, and an increase in exercise capacity. Absolute MBF values did not significantly change after carvedilol or placebo treatment, either at rest or during Dip injection, although Dip-MBF tended to improve after treatment. Coronary flow reserve significantly increased following carvedilol treatment (from 1.67 (0.63) to 2.58 (1.04), p<0.001), whereas it remained unchanged following the placebo treatment (from 1.80 (0.84) to 1.77 (0.60), NS). Stress-induced regional perfusion defects decreased after carvedilol treatment (from 38% to 15%).


CONCLUSIONS
Long-term treatment with carvedilol can significantly increase coronary flow reserve and reduce the occurrence of stress-induced perfusion defects, suggesting a favourable effect of the drug on coronary microvascular function in patients with IDC.
Neglia
Danilo
D
CNR Institute of Clinical Physiology, Pisa, Italy. dneglia@ifc.cnr.it
De Maria
Renata
R
Masi
Stefano
S
Gallopin
Michela
M
Pisani
Patrizia
P
Pardini
Silvia
S
Gavazzi
Antonello
A
L'abbate
Antonio
A
Parodi
Oberdan
O
D002227:Carbazoles / Q000627:therapeutic use*; D002311:Cardiomyopathy, Dilated / Q000188:drug therapy* / Q000503:physiopathology; D000077261:Carvedilol; D003326:Coronary Circulation / Q000187:drug effects*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011412:Propanolamines / Q000627:therapeutic use*; D014665:Vasodilator Agents / Q000627:therapeutic use*; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology
D002227:Carbazoles; D011412:Propanolamines; D014665:Vasodilator Agents; D000077261:Carvedilol