Left stellate ganglion block impairs left ventricular function.

Abstract

Stellate ganglion block (SGB) is an established procedure for the diagnosis and treatment of chronic pain. SGB results in an acute sympathetic denervation of a part of the left ventricular (LV) wall innervated by the blocked ganglion, which may impair regional contractility. The resulting imbalance of myocardial contractility in different LV regions may affect LV function adversely by increasing LV asynchrony. Seven anesthetized open chest dogs were instrumented for measurement of aortic and LV pressure (tip manometers), cardiac output (CO, thermodilution), and regional LV wall thickness (WT, sonomicrometry) in the anteroapical (predominantly innervated by the right stellate ganglion) and posterobasal wall (left stellate ganglion). The contractility of both regions was assessed using the relationship between preload recruitable stroke work and end-diastolic WT relationship (MW). The timing of regional myocardial wall motion was evaluated by means of the phase of the first harmonic of the Fourier transform of the WT signals, LV asynchrony by the phase difference (PD) between both regions, and LV diastolic function by the time constant of isovolumic relaxation (tau). Measurements were performed before and after left SGB (LSGB). Mean arterial pressure was 105 +/- 25 (mean +/- SD) before and 97 +/- 10 mm Hg after LSGB (not significant). CO remained unchanged (3.09 +/- 1.03 vs 2.93 +/- 1.07 L/min). LSGB significantly reduced contractility in the posterobasal myocardium (MW -162 +/- 26 vs -80 +/- 7 mm Hg; P < 0.01), accompanied by a delay of regional wall motion within the cardiac cycle (phase 202 +/- 18 vs 223 +/- 17 degrees; P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)