Introduction
Ventricular tachycardia storm or Electrical Storm is defined as m ore than 2 episodes of sustained VT or ventricular fibrillation (VF) within the last 24-h or the occurrence of incessant VT for at least 12-h.1,2,3 V entricular tachycardias present with multiple episodes of ventricular arrythmias in a short duration, affecting the cardiac function and leading unresponsive hypotension. Hemodynamic instability if not corrected promptly may result in cardiogenic shock and multiple organ failure. Most of the cases are unresponsive to standard medical therapy and shock. Stellate Ganglion block for such ventricular storm is now a well-recognized option.4 We report 2 cases of ventricular tachycardia storm refractory to medical management who were successfully treated with ultrasound guided Left stellate Ganglion Block.
Case Reports
Case I
A 56-year-old male hypertensive, diabetic patient admitted with a history of loose motions, vomiting and giddiness. Investigations revealed severe coronary artery disease with acute coronary syndrome. He underwent coronary angiography and coronary stent to left circumflex artery. After stentinghe developed ventricular arrythmias that were unresponsive to medical treatment with Amiodarone, Xylocard. He received multiple shocks of 150 joules which temporarily terminated the ventricular tachycardia. Echocardiogram revealed an ejection fraction of 35%. Due to unstable condition and persistent hypotension he was put on mechanical ventilation support, Dobutamine, Dopamine, Noradrenaline, Amiodarone and Xylocard infusions. Biochemical parameters showed low Magnesium levels and accordingly magnesium correction was given. Patient was receiving Dytor, Ecosprin, Clopitab and Ivabrad. A left sided Stellate Ganglion block was administered under ultrasonography guidance with 12 ml of 0.25% bupivacaine in aliquots. The arrythmias reverted back within one hour after the block was given. There were no new episodes of arrythmias. Patient’s hemodynamics started improving and he was weaned off from the ventilator, inotropes and antiarrythmics in next 48 hours. Patient made an uneventful recovery.
Case II
A 27 year old male presented with breathlessness, palpitations and giddiness. On evaluation was diagnosed as Acute anterior wall Myocardial infarction with severe LVdysfunction (EF-34%). Coronary angiography revealed single vessel disease which was recannulated. Patient then developed refractory ventricular tachycardia and was unresponsive to amiodarone, DC shocks. In view of unstable hemodynamics patient was intubated, put on mechanical ventilator support and inotropes- Noradrenaline, Dobutamine. A stellate ganglion block was administered under USG guidance with 10cc 0.25% Bupi vacaine. The tachycardia was reverted after an hour. Patient was weaned off from the ventilator and inotropes over next 24 hrs. Patient had an episode of ventricular tachycardia which was treated with medication. Patient made an uneventful recovery.
Discussion
The sympathetic innervation to the heart is derived from the left and right stellate ganglia via post-ganglionic fibers with left stellate ganglion predominant at the ventricular level. Myocardial ischemia, decompensated heart failure, electrolyte imbalance, ICD recipients, Scar-mediated reentrant phenomenon due to a previous MI are contributing factors for triggering ventricular tachycardia.5 Partial denervation of sympathetic fibers at the level of the myocardium in MI induces a hypersensitivity to catecholamines, making heart more vulnerable to electrical storm. Both of our patients had acute MI with low ejection fraction and had undergone recannulation of the stenosed coronaries. The treatment options for sustained ventricular arrythmias include correction of the causative factors, beta blockers, Amiodarone, class I antiarrythmic agents, epidural anaesthesia, stellate ganglion block. Non pharmacologic options include intra-aortic balloon pump (IABP), left ventricular assist device (LVAD), implantable cardioverter-defibrillator (ICD), and cardiac sympathetic denervation with radiofrequency ablation.6 Pateints require an intensive care unit admission, inotropes, correction of metabolic abnormalities if any, supportive care and mechanical ventilation in critical cases. Pateints with persistent hypotension requiring incremental doses of vasopressors, severe LV dysfunction, major comorbidities like chronic kidney disease and severe pulmonary disease fall in high risk groups. Intra-aortic balloon pump (IABP), left ventricular assist device (LVAD), or extracorporeal membrane oxygenation (ECMO) is reserved for patients with circulatory collapse.7 Attempts should be made to suppress ventricular arrythmias and preventing further deterioration in cardiac function. By blocking the stellate ganglion, the amount of sympathetic outflow to the heart is decreased, which may in turn decrease the sensitivity of the myocardium to arrhythmias. Stellate ganglion block can be performed under Fluoroscopy, CT, MRI, or Ultrasound imaging. Lingjin Meng et al in a systemic review from previously published data analysed the efficacy of SGB. They observed that stellate ganglion block is effective in reducing the episodes and therapies for ventricular arrythmias irrespective of the type of arrythmias, presence of structural abnormality or degree of left ventricular dysfunction.8 Vaseghi M et al in a retrospective study observed the beneficial effects of both bilateral and left SGB with freedom from ICD shocks beyond the postsymathetectomy period.9 Amarjeet Kumar et al, Rajesh MC et al, Hayase J et al have reported the benefits of Ultrasound-guided stellate ganglion blockade in ventricular storm.10,11,12 The stellate ganglion is formed by the lower cervical and first thoracic ganglia is located at the level of C7, below the subclavian artery. Ideally the needle should be placed anterolateral to the longus colli muscle, deep to the prevertebral fascia and superficial to the fascia investing the longus colli muscle. The subfascial plane facilitates the caudal spread of the injectate to reach the stellate ganglion at C7-T1 level, even if the needle is placed at C6 level.13 Hoarseness of voice (recurrent laryngeal nerve), Horner’s syndrome, phrenic nerve invo lvement are known side effects. Complications such as accidental intravascular, epidural or intrathecal injection, brachial plexus and recurrent laryngeal nerve palsy, injury to trachea, esophagus, pneumothorax can occur but are rare. Left SGB can also result in an imbalance in myocardial contractility and asynchrony of the left ventricle. An ultrasound guided block is technically easy, confers better anatomical delineation, facilitates correct needle placement and avoids injury to surrounding structures. The ability to revert ventricular arrythmias and duration of remission is independent of the choice of local anaesthetic used.8 An ultrasound guided left Stellate Ganglion Block may prove to be highly beneficial, bedside treatment option for refractory ventricular tachyarrythmias with complete or significant periods of remission.
Conclusion
Ultrasound guided left stellate ganglion block provides a safe alternative to treat ventricular arrythmias in hemodynamically unstable patients that are refractory to other treatment modalities. It’s usefulness as a first line of management in ventricular tachycardia storm needs to be evaluation.