Prognostic value of cardiac metaiodobenzylguanidine imaging and QRS duration in implantable cardioverter defibrillator patients with and without heart failure

Background: Cardiac metaiodobenzylguanidine (MIBG) imaging provides prognostic information in patients with heart failure (HF). Recent studies showed that the highest rate of ventricular tachyarrhythmias (VTs) is seen in HF patients with an intermediate decrease in MIBG uptake, rather than in those with the lowest values. However, prolonged QRS duration (QRSd) has been shown to be associated with VTs in HF patients. This study assessed the prognostic value of the combination of an intermediate decrease in MIBG uptake and prolonged QRSd for predicting VTs in patients with implantable cardioverter defibrillators (ICDs) in relation to the presence of heart failure (HF).

Methods and results: A total of 196 outpatients with ICDs (age: 64 ± 14 years, male: 81%, left ventricular ejection fraction [LVEF]: 49% ± 16%) were prospectively enrolled; 135 had HF (NYHA class: 2.0 ± 0.6). At entry, cardiac MIBG imaging was performed, and QRSd was measured on standard 12‑lead electrocardiography. An intermediate decrease in the heart-to-mediastinum ratio on the delayed planar image (ID-H/M) was defined as 1.40-1.89. During the 3.3 ± 2.2-year follow-up, 59 patients had appropriate ICD discharges (ATx) for VTs. On multivariate Cox analysis, ID-H/M and prolonged QRSd (≥147 ms) were significantly and independently associated with ATx. In both patients with and without HF, ATx were significantly more frequent in patients with ID-H/M and/or prolonged QRSd than in those with neither (with HF: 40% vs. 14%, p = 0.020; without HF: 43% vs. 10%, p = 0.0028).

Conclusions: The combination of ID-H/M and prolonged QRSd provided more prognostic information for predicting VTs in ICD patients, with and without HF.