Aims

Impaired myocardial sympathetic innervation assessed by ¹²³Iodine-Metaiodobenzylguanidine (¹²³I-MIBG) scintigraphy is associated with cardiac events. Since regional disparities of structural abnormalities are common in inherited arrhythmia syndromes (iAS), a chamber-specific innervation assessment of the right (RV) and left ventricle (LV) could provide important insights for a patient-individual therapy. Aim of this study was to evaluate chamber-specific patterns of autonomic innervation by Single-photon emission computed tomography/computed tomography (SPECT/CT) in patients with iAS with respect to clinical outcome regarding cardiac events.

Methods and results

We assessed ventricular sympathetic innervation (LV, RV and planar heart/mediastinum-ratios, and washout-rates) by ¹²³I-MIBG-SPECT/CT in 48 patients (arrhythmogenic right ventricular cardiomyopathy [ARVC], n = 26; laminopathy, n = 8; idiopathic ventricular fibrillation [iVF], n = 14) in relation to a composite clinical endpoint (ventricular arrhythmia; cardiac death; cardiac hospitalization). RV tracer uptake was lower in patients with ARVC than in laminopathy and iVF patients (1.7 ± 0.4 vs. 2.1 ± 0.7 and 2.1 ± 0.5, respectively). Over a median follow-up of 2.2 years, the combined endpoint was met in 18 patients (n = 12 ventricular tachyarrhythmias, n = 5 hospitalizations, n = 1 death). LV, but not RV H/M ratio was associated with the combined endpoint (hazard-ratio 2.82 [1.30–6.10], p < 0.01). After adjustment for LV and RV function, LV H/M-ratio still remained a significant predictor for cardiac events (hazard-ratio 2.79 [1.06–7.35], p = 0.04).

Conclusion

We demonstrated that chamber-specific ¹²³MIBG-SPECT/CT imaging is feasible and that reduced LV sympathetic innervation was associated with worse outcome in iAS. These findings provide novel insights into the potential role of regional autonomic nervous system heterogeneity for the evolution of life-threatening cardiac events in iAS.

中文翻译：

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123I-SPECT / CT评估的左室神经支配与遗传性心律不齐综合征中的心脏事件有关。

目的

¹²³ Iodine-Metaiodo苄基胍（¹²³ I-MIBG）闪烁显像评估的心肌交感神经受损与心脏事件有关。由于遗传异常性心律失常综合征（iAS）中常见结构异常的区域差异，因此对右（RV）和左心室（LV）进行腔室特定的神经支配评估可以为患者个体化治疗提供重要的见识。这项研究的目的是评估关于iAS患者心脏事件的临床结局，通过单光子发射计算机断层扫描/计算机断层扫描（SPECT / CT）来评估自主神经支配的特定腔室模式。

方法与结果

我们以¹²³评估了室性交感神经（LV，RV和平面心脏/纵隔-比率和冲刷率）与综合临床终点（室性心律失常）相关的48例患者（I-MIBG-SPECT / CT）（心律失常性右室心肌病[ARVC]，n = 26；椎板病，n = 8；特发性室颤[iVF]，n = 14） ；心脏死亡；心脏住院）。ARVC患者的RV示踪剂摄取低于椎板病和iVF患者（分别为1.7±0.4和2.1±0.7和2.1±0.5）。在2.2年的中位随访中，有18位患者达到了合并终点（n = 12室速性心律失常，n = 5住院，n = 1死亡）。左室容积率与左室容积率无关，但与合并终点相关（危险比2.82 [1.30–6.10]，p <0.01）。调整LV和RV功能后，LV H / M比率仍是心脏事件的重要预测指标（危险比2.79 [1.06-7.35]，p = 0.04）。

结论

我们证明了特定于室的¹²³ MIBG-SPECT / CT成像是可行的，并且LV交感神经支配的减少与iAS的预后差有关。这些发现提供了关于区域自主神经系统异质性对iAS中威胁生命的心脏事件发展的潜在作用的新颖见解。