Cardiac I123-MIBG Correlates Better than Ejection Fraction with Symptoms Severity in Systolic Heart Failure

Background

The association of autonomic activation, left ventricular ejection fraction (LVEF)and heart failure functional class is poorly understood.

Objective

Our aim was to correlate symptom severity with cardiac sympathetic activity,through iodine-123-metaiodobenzylguanidine (¹²³I-MIBG) scintigraphy andwith LVEF in systolic heart failure (HF) patients without previous beta-blockertreatment.

Methods

Thirty-one patients with systolic HF, class I to IV of the New York HeartAssociation (NYHA), without previous beta-blocker treatment, were enrolled andsubmitted to ¹²³I-MIBG scintigraphy and to radionuclideventriculography for LVEF determination. The early and delayed heart/mediastinum(H/M) ratio and the washout rate (WR) were performed.

Results

According with symptom severity, patients were divided into group A, 13 patientsin NYHA class I/II, and group B, 18 patients in NYHA class III/IV. Compared withgroup B patients, group A had a significantly higher LVEF (25% ± 12% in group Bvs. 32% ± 7% in group A, p = 0.04). Group B early and delayed H/M ratios werelower than group A ratios (early H/M 1.49 ± 0.15 vs. 1.64 ± 0.14, p = 0.02;delayed H/M 1.39 ± 0.13 vs. 1.58 ± 0.16, p = 0.001, respectively). WR wassignificantly higher in group B (36% ± 17% vs. 30% ± 12%, p= 0.04). The variablethat showed the best correlation with NYHA class was the delayed H/M ratio (r=-0.585; p=0.001), adjusted for age and sex.

Conclusion

This study showed that cardiac ¹²³I-MIBG correlates better thanejection fraction with symptom severity in systolic heart failure patients withoutprevious beta-blocker treatment.