EFFICACY OF PERCUTANEOUS STELLATE GANGLION BLOCK ACCORDING TO VENTRICULAR ARRHYTHMIA CYCLE: A SUB–ANALYSIS OF THE STAR STUDY

Abstract Introduction The percutaneous stellate ganglion block (PSGB) is an effective treatment for electrical storm. The STAR study (184 PSGBs performed on 131 patients in 19 Italian centers) demonstrated a significant reduction in delivered electrical therapy (ATP/shock) in patients with electrical storm comparing both the 12 hours before and after PSGB, and 1 hour before and after PSGB. The current aim is to assess whether the efficacy of PSGB is influenced by the arrhythmias’ cycle length prior to the procedure. Methods This is a sub–analysis of the STAR study. We divided PSGBs into two groups according to the cycle length of the arrhythmia preceding PSGB: the fastVT–VF group included PSGBs performed following a ventricular tachycardia (VT) with a cycle <400 msec or a ventricular fibrillation (VF), whereas the slowVT group included PSGBs performed following a VT with a cycle ≥400 msec. Results The cycle length of the arrhythmia was available for 170 PSGBs. The fastVT–VF group included 127 PSGBs, performed on males in 83% of cases, with a mean age of 65±12 years, ejection fraction (EF) of 28±13% and ischaemic aetiology in 64%, while the slowVT group included 45 PSGBs, performed on males in 84% of cases, with a mean age of 68±13 years, EF of 24±11% and ischaemic aetiology in 60%. Comparing the number of electrical therapies delivered between the hour after and before PSGB in the two groups separately there was a significant reduction for both fastVT–VF group (Hodges–Lehmann median difference –3.5 [95%CI –4 to –2.5], p<0.001) and slowVT group (Hodges–Lehmann median difference –0.5 [95%CI –2 to 0], p=0.03). Comparing the difference in electrical therapies delivered in the first hour after PSGB compared to the previous hour between the two groups, a significantly greater reduction was observed for fastVT–VF group than for slowVT group (–2 [IQR –6 to 0] vs 0 [IQR –2 to 0], p<0.001). Considering the whole population, having a fast VT–VF was significantly associated with a reduction in therapies delivered in the hour following PSGB both at univariable analysis (OR 3.5, 95%CI 1.7–7, p<0.001) and after correction for the number of therapies delivered in the hour before (OR 2.5, 95%CI 1.1–5.6, p=0.03). Conclusions PSGB is an effective procedure to reduce the number of electrical therapies delivered in patients with both fast and slow ventricular arrhythmias, but the extent of benefit seems greater in those with fast ventricular arrhythmias or ventricular fibrillation.