Electrical storm: Role of stellate ganglion blockade and anesthetic implications of left cardiac sympathetic denervation
A 52-year-old male, weighing 55 kg, received stents in left anterior descending artery (LAD) and first diagonal artery and a permanent pacemaker (VDD) following anteroseptal myocardial infarction (MI) with complete heart block 2 years ago. Postoperative course was complicated with recurrent ventricular tachycardia (VT) and syncopal attacks requiring hospitalization and DC cardioversion on four occasions. The pacemaker was found to be properly functioning during this period. He was readmitted 5 days ago for electrophysiological studies and radiofrequency ablation for VT. Cardiology evaluation revealed pulse rate of 70/min and systemic blood pressure (BP) of 100/70 mmHg. Findings on transthoracic echocardiography were a dilated left ventricle with a very low ejection fraction (20%), akinesia of LAD territory and grade-1 mitral regurgitation. Preoperative medication consisted of oral amiodarone 300 mg and sustained release metoprolol 50 mg once and twice a day respectively. During electrophysiological studies, VT could be easily induced, and the VT circuits were mapped and ablated at the anterobasal left ventricle. After an arrhythmia-free interval of 24 hours, he started having repeat episodes of monomorphic VT, degenerating into polymorphic VT and VF, requiring frequent cardioversions [].\nHypokalemia, hypomagnesemia and hypothyroidism were excluded as triggering factors for arrhythmias on laboratory investigations. Severe hypotension and episodes of transient loss of consciousness warranted ventilatory therapy and inotropic support with epinephrine 0.1 mcg/kg/min. The trachea was intubated after administration of 200 mcg of fentanyl, 3 mg midazolam, 30 mg propofol and muscle relaxation with vecuronium 10 mg. Sedation was maintained using infusions of midazolam 1 mg/hour and fentanyl 60 mcg/hour. As the VT was resistant to treatment with magnesium, amiodarone and lidocaine LSGB was performed under ultrasound guidance using a 7.5 MHz probe (Site-Rite ultrasound system, Bard Access, Inc., USA). A 23-G 4-cm long needle was advanced through the prevertebral fascia till its tip was placed in the longus colli muscle. Injection of 6-ml 0.25% Bupivacaine solution resulted in bulging of the longus colli compartment and caudad and cephalad spread, which was verified on ultrasound. Warming of left upper limb and left Horner's syndrome confirmed the success of LSGB. Patient remaining arrhythmia-free for 2 hours immediately after the blockade and incidents of VT were dramatically reduced subsequently for 12 hours.\nConsidering the benefits of LSGB toward pacifying the ES, we decided to perform LCSD under general anaesthesia via supraclavicular surgical approach. Placing high thoracic epidural catheter and video-assisted thoracoscopy (VAT)-guided ablation of left upper thoracic sympathetic ganglia were other options, which, however, were considered inappropriate given the unstable hemodynamic condition of patient and deranged left ventricular function. Upon arrival in the operation suite, his heart rate and systemic blood pressure were 78 bpm and 90/68 mmHg, respectively. External defibrillator paddles were placed around chest. Monitoring essentially consisted of electrocardiogram (leads II and V5) and invasive arterial blood pressure. Since the endotracheal tube was in situ, anaesthesia was deepened with bolus administration of fentanyl 200 mcg, midazolam 2 mg, propofol 25 mg and vecuronium 6 mg and maintained with sevoflurane adjusting concentration to maintain BIS between 50 and 60. Cervicothoracic sympathectomy was performed through neck excising left stellate ganglion and second thoracic ganglion with sympathetic chain. No further deterioration occurred in the intraoperative period and the patient was transferred back to the ICU for elective ventilation. The VT load significantly abated in the immediate postoperative period. Trachea was extubated 8 hours after surgery and inotropic support was tapered off over next 24 hours. He was discharged in a hemodynamically stable condition and remained symptom-free without any incident of VT for past 8 months.