A house officer terminates supraventricular tachycardia in a 7-month-old infant with a single intravenous bolus of verapamil. The most serious immediate complication to anticipate in this age group is:

• A Transient hypertension with bradycardia
• B Profound hypotension with cardiac arrest ✓
• C Immediate conversion to ventricular fibrillation via pre-excitation
• D Hyperkalemia causing peaked T waves

Explanation

Intravenous verapamil is contraindicated in infants under 1 year of age because immature calcium-channel physiology and reduced myocardial reserve make them prone to severe hypotension, bradycardia, and cardiac arrest after the bolus. Adenosine is the preferred terminating agent at any pediatric age. Option C describes a theoretical risk in pre-excited arrhythmias with verapamil, but the dominant examination-tested hazard in infancy is cardiovascular collapse.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.