Which therapy is best for symptomatic 3rd degree heart block?

In cases of symptomatic third-degree heart block, a transcutaneous pacer is the most effective and immediate therapy. This condition, characterized by a complete dissociation between atrial and ventricular activity, often leads to significant bradycardia and decreased cardiac output, manifesting as symptoms like syncope, dizziness, or even heart failure.

The transcutaneous pacer provides an external source of electrical stimulation to maintain an adequate heart rate temporarily. This method is particularly useful in acute settings, where immediate stabilization of the patient is critical. It is a non-invasive way to alleviate symptoms until permanent pacing can be initiated or the underlying cause is addressed.

Other options, like atropine, may not be effective in advanced high-degree heart blocks like third-degree block, particularly because there might not be adequate response from the AV node which atropine typically targets. Lidocaine is primarily used for managing ventricular arrhythmias and does not address the conduction issues associated with heart block. Oxygen, while beneficial for overall oxygenation, does nothing to correct the electrical conduction problem that defines third-degree block.

Thus, the transcutaneous pacer stands out as the best immediate therapy for symptomatic third-degree heart block, providing the necessary support to restore a safer heart rhythm and improve patient comfort and cardiovascular