During inhalation induction with halothane, a child's rhythm changes to multifocal ventricular ectopy. The most likely explanation is:

During inhalation induction with halothane, a child's rhythm changes to multifocal ventricular ectopy. The most likely explanation is:

• A. Undiagnosed viral myocarditis
• B. Hypoxia
• C. Halothane irritability
• D. Pheochromocytoma

Answer: (C)

The key idea is that halothane can make the heart more sensitive to circulating catecholamines, leading to arrhythmias during induction. Halothane irritability means it lowers the threshold for ventricular ectopic activity when endogenous adrenaline/noradrenaline surges during the stress of induction. This can produce multifocal ventricular ectopy in a child. Other scenarios are less likely in this context: viral myocarditis would not be specifically triggered by halothane induction, hypoxia would typically present with changes linked to oxygenation issues rather than a distinctive multifocal ectopy pattern, and pheochromocytoma is rare in children and would present with broad signs not clearly tied to halothane exposure.

The key idea is that halothane can make the heart more sensitive to circulating catecholamines, leading to arrhythmias during induction. Halothane irritability means it lowers the threshold for ventricular ectopic activity when endogenous adrenaline/noradrenaline surges during the stress of induction. This can produce multifocal ventricular ectopy in a child.

Other scenarios are less likely in this context: viral myocarditis would not be specifically triggered by halothane induction, hypoxia would typically present with changes linked to oxygenation issues rather than a distinctive multifocal ectopy pattern, and pheochromocytoma is rare in children and would present with broad signs not clearly tied to halothane exposure.