Cardiac iodine-123 metaiodobenzylguanidine imaging predicts sudden cardiac death independently of left ventricular ejection fraction in patients with chronic heart failure and left ventricular systolic dysfunction: results from a comparative study with signal-averaged electrocardiogram, heart rate variability, and QT dispersion.
OBJECTIVE
We prospectively compared the predictive value of cardiac iodine-123 metaiodobenzylguanidine (MIBG) imaging for sudden cardiac death (SCD) with that of the signal-averaged electrocardiogram (SAECG), heart rate variability (HRV), and QT dispersion in patients with chronic heart failure (CHF).


BACKGROUND
Cardiac MIBG imaging predicts prognosis of CHF patients. However, the long-term predictive value of MIBG imaging for SCD in this population remains to be elucidated.


METHODS
At entry, cardiac MIBG imaging, SAECG, 24-h Holter monitoring, and standard 12-lead electrocardiography (ECG) were performed in 106 consecutive stable CHF outpatients with a radionuclide left ventricular ejection fraction (LVEF) <40%. The cardiac MIBG washout rate (WR) was obtained from MIBG imaging. Furthermore, the time and frequency domain HRV parameters were calculated from 24-h Holter recordings, and QT dispersion was measured from the 12-lead ECG.


RESULTS
During a follow-up period of 65 +/- 31 months, 18 of 106 patients died suddenly. A multivariate Cox analysis revealed that WR and LVEF were significantly and independently associated with SCD, whereas the SAECG, HRV parameters, or QT dispersion were not. Patients with an abnormal WR (>27%) had a significantly higher risk of SCD (adjusted hazard ratio: 4.79, 95% confidence interval: 1.55 to 14.76). Even when confined to the patients with LVEF >35%, SCD was significantly more frequently observed in the patients with than without an abnormal WR (p = 0.02).


CONCLUSIONS
Cardiac MIBG WR, but not SAECG, HRV, or QT dispersion, is a powerful predictor of SCD in patients with mild-to-moderate CHF, independently of LVEF.
Tamaki
Shunsuke
S
Division of Cardiology, Osaka General Medical Center, Osaka, Japan. tamaki-shunsuke@mwc.biglobe.ne.jp
Yamada
Takahisa
T
Okuyama
Yuji
Y
Morita
Takashi
T
Sanada
Shoji
S
Tsukamoto
Yasumasa
Y
Masuda
Masaharu
M
Okuda
Keiji
K
Iwasaki
Yusuke
Y
Yasui
Taku
T
Hori
Masatsugu
M
Fukunami
Masatake
M
D019797:3-Iodobenzylguanidine; D000368:Aged; D002908:Chronic Disease; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D015716:Electrocardiography, Ambulatory; D005260:Female; D054143:Heart Failure, Systolic / Q000000981:diagnostic imaging*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012720:Severity of Illness Index; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine