What is the best therapy for symptomatic third-degree heart block?

In the case of symptomatic third-degree heart block, the most effective treatment is the use of a transcutaneous pacemaker. Third-degree heart block, also known as complete heart block, occurs when there is a complete dissociation between the atrial and ventricular activity, leading to significant bradycardia and potentially severe hemodynamic instability. This condition can present with symptoms such as dizziness, fatigue, and syncope due to inadequate cardiac output.

A transcutaneous pacemaker provides external pacing to stimulate the heart and restore an adequate heart rate and rhythm, thus alleviating symptoms and improving hemodynamics. It serves as a temporary measure until a more permanent solution, such as a surgical insertion of a permanent pacemaker, can be arranged. This is particularly important in acute settings where immediate intervention is needed to stabilize the patient.

In contrast, other options like lidocaine, atropine, and oxygen do not address the underlying issue of electrical conduction failure in third-degree heart block effectively. Lidocaine is primarily used for ventricular arrhythmias, while atropine may be useful in some bradycardic patients but is generally ineffective in complete heart block due to its mechanism of action. Oxygen, while essential for overall patient support, does not resolve the arrhythmia itself