MCQ: Irregular Heart Beat

Clinical Scenario:

A 12-year-old boy is referred to the pediatric cardiology clinic after an irregular heartbeat is noted during a school health examination. He is otherwise asymptomatic and has no history of syncope, chest pain or exercise intolerance. His physical examination is normal.

A 24-hour Holter monitor shows frequent premature ventricular complexes (PVCs), accounting for 18% of all ventricular beats. The PVCs have a single morphology and disappear during exercise. Echocardiography shows a structurally normal heart with normal left ventricular systolic function.

What is the most appropriate management?

A. Reassurance and follow-up
B. Start amiodarone
C. Start propranolol
D. Electrophysiological study
E. Implantable cardioverter-defibrillator

Correct answer Explanation:

Correct answer: A. Reassurance and follow-up

Explanation

In children with a structurally normal heart, isolated monomorphic PVCs are usually benign, particularly when they suppress with exercise and the child has no concerning symptoms.

However, this child has a relatively high PVC burden (18%). Frequent PVCs warrant assessment for ventricular function and periodic follow-up because a high PVC burden can occasionally be associated with PVC-induced cardiomyopathy.

The important reassuring features are:

  • Single (monomorphic) PVC morphology
  • No syncope or other concerning symptoms
  • Structurally normal heart
  • Normal ventricular systolic function
  • PVCs suppress with exercise

Therefore, immediate antiarrhythmic treatment or invasive electrophysiological intervention is not routinely indicated. Management is generally observation with periodic clinical assessment, ECG/Holter monitoring and echocardiographic evaluation of ventricular function.

When would PVCs be more concerning?

PVCs deserve greater attention when they are:

  • Polymorphic
  • Increasing with exercise
  • Associated with syncope or exertional symptoms
  • Occurring in couplets or runs of nonsustained ventricular tachycardia
  • Associated with structural heart disease or ventricular dysfunction
  • Associated with a concerning family history of sudden cardiac death

Exam pearl:

In an asymptomatic child with a structurally normal heart, monomorphic PVCs that suppress with exercise are generally benign, but frequent PVCs require follow-up for possible ventricular dysfunction.

Reference

Crosson JE, et al. PACES/HRS expert consensus statement on the evaluation and management of ventricular arrhythmias in the pediatric population. Heart Rhythm.

American Heart Association/American College of Cardiology. Pediatric ventricular arrhythmia guidance and contemporary pediatric electrophysiology literature.

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