A 21-year-old college student is seen in the emergency room for lightheadedness and palpitations. He has no prior medical history and takes no medications or illicit drugs. He has noted several episodes of palpitations over the past several months, usually lasting 20 minutes and terminating when he bears down. Today’s episode did not break with bearing down. He is still aware of a fast heart rate, but feels it is a bit slower and irregular in nature.

His physical examination is normal, with an irregular pulse of 122 bpm and blood pressure of 100/72 mm Hg. His ECG is shown (Figure 1). He is treated with direct-current (DC) cardioversion after an anesthesiologist sedated him.

Figure 1


Which of the following would most likely decrease his risk of recurrent symptoms?

  1. Pulmonary vein isolation.
  2. Catheter ablation of the accessory pathway. 
  3. Modification of the AV node.
  4. Oral digoxin.
  5. Insertion of an implantable cardioverter-defibrillator (ICD).

Correct answer: B.


This is AF with intermittent pre-excitation. Acute treatment with intravenous (IV) procainamide, ibutilide, or DC cardioversion should be performed (Table 1). Catheter ablation of the accessory pathway will usually significantly decrease the risk of recurrent AF, especially in a young man without prior heart disease. It will also treat his likely AV reciprocating tachycardia responsible for his palpitations that feel regular in quality. Pulmonary vein isolation is a treatment for AF, usually not related to having an accessory pathway.

Modification of the AV node is a term used to describe both a treatment for AV nodal reentrant tachycardia, eliminating or modifying the conductive properties of one of the pathways, such that the tachycardia can no longer occur. Modification of the AV node was also a procedure that was used as an attempt to slow the ventricular response to AF. The procedure resulted in a high chance of complete heart block requiring permanent pacing, and thus, is now very rarely performed. Since this patient’s elevated heart rate is mainly due to conduction over an accessory pathway, modifying the AV node would have very little effect on the heart rate, and would not eliminate AF.

Oral digoxin is contraindicated in patients with a manifest accessory pathway, as it may enhance conduction down the accessory pathway and cause faster heart rates, occasionally leading to hemodynamic collapse. Insertion of an ICD is a treatment for ventricular tachyarrhythmias, not a treatment for pre-excited AF.

Table 1



Register today for Cardiovascular Conference at Snowmass and you will receive the most pioneering innovations and therapies in cardiovascular medicine for immediate use in your practice.

This course spans the full spectrum of cardiovascular disease from a variety of perspectives.

This course has it all — an MOC session, the most up-to-date science and education in cardiology, networking opportunities and fantastic skiing in a gorgeous location. Snowmass has already received a significant amount of snow!

Take advantage of the lowest rates and register now!