Chapter 44: Transesophageal Cardiac Pacing

INTRODUCTION

Cardiac pacing is an essential skill for Emergency Physicians and can be accomplished through a variety of techniques. Transesophageal cardiac pacing is a time-proven and potentially lifesaving procedure. The esophagus has long been considered a noninvasive and useful window to the heart.

The ability to capture and record an electrocardiogram (ECG) transesophageally was first demonstrated by Max Cremer in 1906.¹ This was based on the close anatomic proximity of the cardiac atria to the esophagus. The proximity allows an electrical impulse in the esophagus to be transmitted to the left atrium. Electrode technology and pacing mechanisms have advanced. The ability to identify, stabilize, and terminate atrial dysrhythmias through this minimally invasive procedure persists.² Transesophageal pacing is well-tolerated by patients and effective for temporarily treating patients with atrial rhythm disturbances. This technique provides an additional tool for Emergency Physicians.

ANATOMY AND PATHOPHYSIOLOGY

The heart is the only muscle that produces its own electrical impulse. The electrical impulse originates from the sinoatrial node of the right atrium and is conducted through the heart’s intrinsic electrical conducting system to the atria and ventricles to produce coordinated and sequential mechanical contractions (Figure 39-2).³ The rate of impulse generation is governed by the sympathetic and parasympathetic nervous systems. The conversion of an electrical impulse to a mechanical action is a delicate balance between chemical signaling, electrolyte shifts, an intact cardiac conducting system, and healthy myocardial tissue. Abnormalities in conduction and resultant arrhythmias may be related to abnormalities in any of these factors. Aberrant conduction system development, impaired myocardium due to decreased blood supply, or impaired myocardium due to infarct often underlies arrhythmias.

The heart is in the anterior thoracic cavity. It is surrounded by the sternum and chest wall anteriorly, the lungs laterally, and in proximity to the esophagus posteriorly. The left atrium is typically the closest point of contact to the esophagus (Figure 44-1).⁴ Cadaveric models and imaging analysis show an atrioesophageal distance of typically less than 1 cm, and often only a few millimeters.⁵ This is impacted by individual variability and disease states that may alter cardiac muscle size.

INDICATIONS

Transesophageal cardiac pacing can be a simple and easily initiated procedure. Weigh its use against clinical circumstances. Transesophageal atrial pacing is most frequently used for management of symptomatic bradycardia, termination of atrial fibrillation, and termination of supraventricular tachycardia.^1,6-11 Sinus node dysfunction or delays in electrical impulse conduction may manifest as bradycardia. End-organ hypoperfusion can occur with decreased cardiac output and result in a variety of symptoms (e.g., altered mental status or fatigue). Use transesophageal pacing to temporarily restore a heart rate that ...