Usefulness of meta-[123I]iodobenzylguanidine myocardial scintigraphy for predicting cardiac events in patients with dilated cardiomyopathy who receive long-term beta blocker treatment.
OBJECTIVE
Large-scale clinical trials have demonstrated that beta blocker therapy improves the prognosis of dilated cardiomyopathy (DCM), but cardiac events sometimes occur even in patients showing favourable response to the therapy. In this study, the usefulness of meta-iodobenzyguanidine (MIBG) in predicting cardiac events was investigated in DCM patients successfully receiving long-term treatment with beta blockers.


METHODS
The subjects were 53 patients with DCM (including 10 women; mean age, 56.5+/-10.9 years) who could continue beta blocker therapy for more than 6 months. MIBG was performed within 1 year of commencing the therapy. The extent score, severity score and washout rate were obtained from single photon emission computed tomography images. At the same time, left ventricular ejection fraction (LVEF) and left ventricular end diastolic diameters were measured by echocardiography. The endpoints were cardiac events (cardiac death and admission to hospital due to heart failure or arrhythmia), and patients were observed for an average of 1314+/-986 days (150-4100 days).


RESULTS
Cardiac events occurred in nine patients during the observation period. The multivariate statistical analysis demonstrated that the delayed extent score was the strongest significant predictive factor, (hazard ratio 1.036, P<0.01). while LVEF was not a predictive factor. Both the improvement of LVEF and MIBG were significant predictive factors. The improvement of washout rate was the strongest.


CONCLUSIONS
Parameters of MIBG but not of LVEF were useful in predicting cardiac events in DCM patients whose condition had been successfully stabilized by the introduction of beta blockers.
Fujimoto
Shinichiro
S
Division of Cardiovascular Medicine, Ohmori Hospital, Toho University School of Medicine, Tokyo, Japan. s-fujimo@tj8.so-net.ne.jp
Inoue
Aritomo
A
Hisatake
Shinji
S
Yamashina
Shohei
S
Yamashina
Hisayo
H
Nakano
Hajime
H
Yamazaki
Junichi
J
D019797:3-Iodobenzylguanidine; D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage*; D001145:Arrhythmias, Cardiac / Q000000981:diagnostic imaging* / Q000401:mortality; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000401:mortality; D018572:Disease-Free Survival; D005260:Female; D006333:Heart Failure / Q000000981:diagnostic imaging* / Q000401:mortality; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012720:Severity of Illness Index; D016019:Survival Analysis
D000319:Adrenergic beta-Antagonists; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine