Study objectives: Cardiac sympathetic nerve dysfunction is related to poor clinical outcome in patients with several different heart diseases. However, it is not clear whether cardiac sympathetic nerve activity is useful for predicting the onset of congestive heart failure (CHF) in patients with hypertrophic cardiomyopathy (HCM). The aim of this study was to examine the prognostic value of performing 123I-labeled metaiodobenzylguanidine (MIBG) scintigraphy in patients with HCM in comparison with other conventional prognostic variables.
Methods:123I-labeled MIBG images were obtained from 84 HCM patients without prior CHF. After measurement of cardiac function, the patients were followed up for 9 to 86 months in our hospital.
Results: According to the cutoff values for the heart/mediastinum ratio (H/M) on delayed images of control subjects (ie, mean − 1 and 2 SDs), the patients were subdivided into the following three groups: group A (H/M, > 2.11; 34 patients); group B (H/M, < 1.86 to ≤ 2.11; 30 patients); and group C (H/M, ≤ 1.86; 20 patients). The prevalence of CHF was 0% in group A, 3.3% in group B, and 55.0% in group C. Kaplan-Meier analysis showed a significant difference in the prevalence of CHF among the three groups. Multivariate analysis using the Wald χ2 test revealed that the delayed H/M was the most powerful predictor of CHF among the variables.
Conclusion: Cardiac sympathetic nerve activity is useful for predicting the onset of CHF in patients with HCM.