Myocardial adrenergic innervation in patients, with neurocardiogenic syncope measured with 123I-MIBG uptake

Aim: To study the global and regional adrenerg myocardial innervation in patients with vasovagal syncope which was demonstrated by head up tilt table testing. Patients and methods: 14 adult patients (age: 42+/-11 ys (17-68), F/M 8/6) with vasovagal syncope were studied. To investigate cardiac sympathetic innervation 250-370 MBq I-123-MIBG was used. 15 minutes after the intravenous administration of I-123-MIBG early, and 2-3 hours later delayed planar myocardial and tomographic (SPECT) scintigraphies were performed. The heart-to-mediastinum count ratio (H/M) was calculated for both early and delayed images, together with the wash out rate (WR). Results: In 11 from among 14 patients the late H/M ratio was below the normal range. All patients had regional (12)3I-MIBG uptake deficit in different regions: 5 in the inferior, infero-septal, and 9 in the anteriolateral area. The mean WR was 17+/-27%. Conclusion: In our patients with vasovagal syncope global I-123-MIBG deficit was present frequently, and all patients had regional adrenerg nerve function deficit