Treating cardiac dysrhythmias by targeting the neck: Off target or on the right track?

Abstract

The history of cardiology provides many examples of attempts to target cardiovascular pathophysiology by modulating the autonomic nervous system (ANS). The most widely used form of nonspecific and global autonomic modulation is beta-receptor blockade. Beta-blockers are proven to improve outcomes in patients with heart failure and myocardial infarction 1,2 and prevent ventricular arrhythmias and sudden cardiac death. 3 However, beta-blockade is not perfect. It often is ineffective for the prevention of ventricular arrhythmias. Moreover, on occasion, excessive or nonspecific sympathetic blockade may not be helpful. 4,5 In theory, targeted modulation of the ANS has the potential to restore autonomic balance in organs affected by autonomic dysfunction. Autonomic modulation has several potential and beneficial mechanisms, including sympathetic and parasympathetic effects via either the efferent and/or afferent limbs of each system. Examples of targeted autonomic modulation therapies for cardiovascular disorders include: (1) thoracolumbar sympathectomy and renal denervation for the treatment of hypertension 6 ; (2) baroreceptor stimulation for the management of heart failure and hypertension 7 ; (3) vagus nerve stimulation for the treatment of heart failure 8 ; and (4) carotid body modulation for the treatment of heart failure and hypertension. 9,10 Despite promising phase II studies for each of the aforementioned interventions, there are no conclusive phase III data to support their clinical use.In the last several years the field of neuromodulation has increasingly focused on cardiac autonomics as a potential therapeutic target in the treatment of heart rhythm disorders. For example, in the case of atrial fibrillation, several approaches to modulate the ANS directly 11,12 or indirectly via sensory input from the periphery 13,14 are in continued development. Ventricular arrhythmia is one of the last (but not new) frontiers for neuromodulation. Ventricular arrhythmias are complex electrical phenomenon that can occur in patients with or without structural heart disease. Electrical storm (≥3 episodes of ventricular tachycardia or fibrillation in 24 hours) represents a particularly complicated and life-threatening emergency. Electrical storm is more common than often appreciated, as recently shown in a meta-analysis of 5,600 patients with implanted cardiac defibrillators, where 15% experienced electrical storm during 30-month followup. 15 Not surprisingly, electrical storm is more common in secondary prevention patients and its occurrence is associated with a threefold increased risk of mortality. 15,16 However, it is also notable that electrical storm carries a 2.5-fold higher risk of death compared with isolated VT/VF episodes. This suggests that electrical storm is not just the frequent occurrence of ventricular arrhythmias in a 24-hour window but is an indicator of severe cardiac dysfunction and global autonomic imbalance. Early therapeutic intervention is the key to successful management of electrical storm, given th...

Percutaneous stellate ganglion block as an adjunctive therapy in the treatment of incessant ventricular tachycardia

“…Furthermore, implementation of SGB into the arsenal of antiarrhythmic treatment methods seems to be reasonable. However, its use is limited by the lack of randomised studies or multicentre registries [13]. Moreover, there is no established technique of SGB.…”

“…Usually left SGB is preferred, although some papers report on bilateral or right-sided SGB. Since there is an asymmetry in the innervation of the heart, that means the left and right sympathetic nerves affect different areas of the heart and impose different functional effect as well, the optimal side of SGB may depend on underlying disease, type of arrhythmia and its origin [11,13]. In the presented cases both left-and right-sided SGBs were effective, but the beneficial effect of right-sided SGB lasted for less time, although this may have been an accidental finding.…”