Which inhalational agent is MOST likely to produce a decrease in systemic blood pressure by causing a junctional rhythm?

Which inhalational agent is MOST likely to produce a decrease in systemic blood pressure by causing a junctional rhythm?

• A. Desflurane
• B. Halothane
• C. Isoflurane
• D. Sevoflurane

Answer: (B)

Inhaled anesthetics can lower blood pressure by two main routes: direct myocardial depression and vasodilation. The question asks which agent is most likely to drop systemic blood pressure by causing a junctional rhythm, a bradyarrhythmia where the AV node becomes the pacemaker after the SA node slows or fails. Halothane stands out because it has a strong depressant effect on the myocardium and a notable tendency to slow AV nodal conduction. This can shift the heart’s rhythm to a junctional rhythm, characterized by a slower rate that reduces cardiac output and, in turn, lowers blood pressure. Other volatile agents mainly reduce BP through vasodilation and less frequently induce significant conduction disturbances like junctional rhythm. Desflurane, isoflurane, and sevoflurane can cause hypotension due to decreased systemic vascular resistance, but they are less likely to produce a junctional rhythm compared with halothane.

Inhaled anesthetics can lower blood pressure by two main routes: direct myocardial depression and vasodilation. The question asks which agent is most likely to drop systemic blood pressure by causing a junctional rhythm, a bradyarrhythmia where the AV node becomes the pacemaker after the SA node slows or fails. Halothane stands out because it has a strong depressant effect on the myocardium and a notable tendency to slow AV nodal conduction. This can shift the heart’s rhythm to a junctional rhythm, characterized by a slower rate that reduces cardiac output and, in turn, lowers blood pressure.

Other volatile agents mainly reduce BP through vasodilation and less frequently induce significant conduction disturbances like junctional rhythm. Desflurane, isoflurane, and sevoflurane can cause hypotension due to decreased systemic vascular resistance, but they are less likely to produce a junctional rhythm compared with halothane.