Efficacy of amiodarone treatment on cardiac symptom, function, and sympathetic nerve activity in patients with dilated cardiomyopathy: comparison with beta-blocker therapy.
BACKGROUND
Amiodarone, which is an antiarrhythmic drug used to treat life-threatening arrhythmias, is effective in patients with chronic heart failure. However, its effectiveness compared with beta-blockers has not yet been reported.


RESULTS
In 30 patients (mean age, 57 +/- 13 years) with dilated cardiomyopathy, we compared 15 patients receiving amiodarone (group A) with 15 patients receiving metoprolol (group B). Before and after 1 year of treatment, cardiac iodine 123 metaiodobenzylguanidine uptake was assessed from the total defect score, heart-to-mediastinum activity ratio based on delayed images, and washout rate. New York Heart Association class and echocardiographic left ventricular ejection fraction were also assessed. In both groups the total defect score decreased (from 25 +/- 11 to 16 +/- 10 in group A, P <.01; from 26 +/- 10 to 18 +/- 11 in group B, P <.01), the heart-to-mediastinum activity ratio increased (from 1.63 +/- 0.16 to 1.81 +/- 0.29 in group A, P <.01; from 1.63 +/- 0.21 to 1.85 +/- 0.3 in group B, P <.01), and the washout rate decreased (from 51% +/- 12% to 38% +/- 14% in group A, P <.01; from 48% +/- 11% to 37% +/- 8% in group B, P <.01). Left ventricular ejection fraction increased (from 30% +/- 9% to 42% +/- 11% in group A, P <.01; from 26% +/- 7% to 46% +/- 16% in group B, P <.01) and New York Heart Association functional class improved (from 3.1 +/- 0.5 to 1.8 +/- 0.7 in group A, P <.01; from 2.9 +/- 0.5 to 1.7 +/- 0.6 in group B, P <.01).


CONCLUSIONS
Amiodarone treatment can improve cardiac symptom, function, and sympathetic nerve activity, as evaluated by I-123 metaiodobenzylguanidine imaging in patients with dilated cardiomyopathy, which improves to a similar extent with beta-blocker treatment.
Toyama
Takuji
T
Guma Prefectural Cardiovascular Center, Maebashi, Japan. toyama.t@cvc.pref.gunma.jp
Hoshizaki
Hiroshi
H
Seki
Ryotaro
R
Isobe
Naoki
N
Adachi
Hitoshi
H
Naito
Shigeto
S
Oshima
Shigeru
S
Taniguchi
Koichi
K
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000638:Amiodarone / Q000627:therapeutic use*; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D002311:Cardiomyopathy, Dilated / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008790:Metoprolol / Q000627:therapeutic use*; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D020127:Recovery of Function; D013564:Sympathetic Nervous System / Q000000981:diagnostic imaging / Q000187:drug effects; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000209:etiology
D000319:Adrenergic beta-Antagonists; D000889:Anti-Arrhythmia Agents; D019275:Radiopharmaceuticals; D008790:Metoprolol; D000638:Amiodarone