Cardiac sympathetic activity in patients suffering from heart failure with improved ejection fraction

The characteristics of cardiac sympathetic nerve activity among patients suffering from heart failure (HF) with improved ejection fraction (EF) (HFimpEF) remain unclear.

Patients admitted for HF with an EF ≤ 40% who underwent echocardiography and ¹²³I-metaiodobenzylguanidine scintigraphy before and 6 months after discharge were followed for 5.2 (2.8-6.1) years. At 6 months, patients with an EF ≤ 40% were classified into the HF with reduced EF (HFrEF) group. Meanwhile, patients with an EF of >40% were classified under the HFimpEF group.

Among the 188 patients analyzed, 78 (41.5%) and 110 (58.5%) were categorized into the HFimpEF and HFrEF groups, respectively. The HFimpEF group had a better heart-to-mediastinal (H/M) ratio at baseline than did the HFrEF group (1.76 [1.59-1.85] vs 1.64 [1.48-1.81], respectively; P = .011). The predictive factors of HFimpEF included ischemic heart disease (odds ratio [OR]: .45, 95% confidence interval [CI]: .21-.94, P = .034), H/M ratio (OR: 1.02, 95% CI: 1.00-1.04, P = .032), and EF (OR: 1.14, 95% CI: 1.08-1.21, P < .001).

The HFimpEF group had a higher H/M ratio than did the HFrEF group, suggesting lower cardiac sympathetic hyperactivity. The H/M ratio was identified as an independent predictor of HFimpEF.