Author: Sana Ullah, MB ChB, FRCA - Children’s Medical Center, Dallas
A 14-year-old boy with a history of Wolff-Parkinson-White (WPW) Syndrome is admitted to the hospital with acute appendicitis. He is brought to the operating room for an appendectomy and 30 seconds after intubation he develops atrial fibrillation. The blood pressure and heart rate are stable. Which of the following interventions is the MOST APPROPRIATE to treat the arrhythmia?
Correct!
Wrong!
Question of the Week 323
Wolff-Parkinson-White (WPW) syndrome is a form of pre-excitation with characteristic abnormalities on the ECG and an increased predisposition to tachyarrhythmias involving an accessory pathway. It results from the presence of one or more accessory pathways (AP) of conduction between the atria and the ventricles. The AP conducts electrical impulses faster resulting in a shorter PR interval in the surface ECG and has a shorter refractory period than the atrioventricular node (AVN). The typical findings of AP function in sinus rhythm are preexcitation, in which depolarization of the ventricles occurs in part or fully through the accessory pathway that is separate from the AVN and earlier than expected after atrial depolarization. This results in shortening of the PR interval and a delta wave followed by a prolonged or widened QRS complex. The short refractory period leads to more rapid transmission of atrial impulses, which can result in supraventricular tachycardia. The typical supraventricular tachycardia associated with WPW syndrome is atrioventricular reentrant or reciprocating tachycardia (AVRT). AVRT is further classified into orthodromic AVRT and antidromic AVRT. Pre-excited atrial fibrillation or atrial flutter with rapid ventricular response may also occur.
The perioperative period is a particularly high-risk time period in which arrhythmias are more likely to occur due to an imbalance in parasympathetic and sympathetic tone. For example, the administration of neostigmine which causes slowing of the heart rate due to decreased atrioventricular nodal conduction can divert conduction to the accessory pathway. Similarly, sympathetic stimulation due to pain, laryngoscopy or emergence from anesthesia can cause tachycardia with a resultant increased number of impulses being transmitted via the AP.
Acute treatment of arrhythmias in the setting of WPW can be challenging. Patients are typically treated for symptomatic arrhythmias or if certain high-risk features are present in asymptomatic patients. Hemodynamically significant arrhythmias require immediate direct current (DC) cardioversion. Catheter ablation is almost always preferred for long-term prevention of recurrent arrhythmias involving an accessory pathway. In situations of stable hemodynamics and acute onset, pharmacological treatment is usually effective. If time allows or if there is any doubt about the diagnosis, expert cardiology consultation is warranted. The presence of an accessory pathway influences the choice of correct pharmacologic treatment.
A stable narrow complex tachycardia typically results from orthodromic AVRT with antegrade conduction via the AVN followed by retrograde conduction along the AP. Orthodromic AVRT occurs in 90 to 95 percent of reentrant tachycardias linked with WPW syndrome. AV nodal blocking drugs are the first-line therapy. Adenosine is usually effective. Verapamil is also effective, but caution is advised in the setting of hypotension or diminished ventricular function. A short-acting beta-blocker such as esmolol is another option.
A stable wide-complex tachycardia results from antidromic AVRT with antegrade conduction over the accessory pathway and onto the ventricles followed by retrograde conduction back to the atria via the AVN. Wide complex tachycardia may also result from orthodromic AVRT with aberrant QRS conduction resulting in a wide QRS complex. Stable wide complex tachycardia may also be ventricular tachycardia. In the case of antidromic AVRT, the best option is procainamide, which is classified as a sodium-channel blocker that slows conduction in both the AVN and the AP. If the exact mechanism of wide complex is not certain, the presumptive diagnosis should be ventricular tachycardia and treated accordingly.
Atrial fibrillation (AF) can be very dangerous in the setting of WPW, as conduction of atrial impulses at rates of up to 500 beats per minute can result in ventricular tachycardia or ventricular fibrillation. In this setting, AV nodal blocking drugs such as adenosine, verapamil, digoxin and esmolol are contraindicated as their use will divert atrial impulses to the AP. The recommended first-line treatment is procainamide to restore sinus rhythm. For young children, the dose recommended is 10-15 milligrams per kilogram over 15 to 30 minutes followed by an infusion of 20 to 80 micrograms per kg per minute. If ineffective, an intravenous loading dose of amiodarone followed by an infusion can be attempted. However, amiodarone use should be carried out with caution as its av-nodal blocking properties may increase conduction via an accessory pathway. Practitioners should be prepared to treat degradation of atrial fibrillation to ventricular fibrillation with immediate defibrillation. Pharmacologic cardioversion of atrial fibrillation may be slow. While under anesthesia, DC cardioversion is still an appropriate option for treatment, even in the setting of a stable rhythm if resolution with pharmacologic agents does not occur within a short period of time.
References
(1) Di Biase, L, Walsh EP. Treatment of symptomatic arrhythmias associated with Wolff-Parkinson-White Syndrome. In UpToDate, Levy S, Knight BP (Eds), UpToDate, Waltham, MA. (Accessed on June 17, 2021.)
(2) Di Biase, L, Walsh EP. Wolff-Parkinson syndrome: Anatomy, epidemiology, clinical manifestations, and diagnosis. In UpToDate, Levy S, Knight BP (Eds), UpToDate, Waltham, MA. (Accessed on June 17, 2021.)
(3) Di Biase, L, Walsh EP.Wolff-Parkinson syndrome: Atrioventricular reentrant tachycardia (AVRT) associated with an accessory pathway. In UpToDate, Levy S, Knight BP (Eds), UpToDate, Waltham, MA. (Accessed on June 17, 2021.)
(4) January CT, Wann LS, Alpert JS et al. ACC/AHA Task Force Members. 2014 AHA/ACC/HRS Guideline for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society. Circulation. 2014; 130(23): 2071-2104.
(5) Bengali R, Wellens HJJ, Jiang Y. Perioperative Management of the Wolff-Parkinson-White Syndrome. J Cardiothorac Vasc Anesth. 2014; 28(5): 1375-1386. doi: 10.1053/j.jvca.2014.02.003. Epub 2014 Jul 11.
The perioperative period is a particularly high-risk time period in which arrhythmias are more likely to occur due to an imbalance in parasympathetic and sympathetic tone. For example, the administration of neostigmine which causes slowing of the heart rate due to decreased atrioventricular nodal conduction can divert conduction to the accessory pathway. Similarly, sympathetic stimulation due to pain, laryngoscopy or emergence from anesthesia can cause tachycardia with a resultant increased number of impulses being transmitted via the AP.
Acute treatment of arrhythmias in the setting of WPW can be challenging. Patients are typically treated for symptomatic arrhythmias or if certain high-risk features are present in asymptomatic patients. Hemodynamically significant arrhythmias require immediate direct current (DC) cardioversion. Catheter ablation is almost always preferred for long-term prevention of recurrent arrhythmias involving an accessory pathway. In situations of stable hemodynamics and acute onset, pharmacological treatment is usually effective. If time allows or if there is any doubt about the diagnosis, expert cardiology consultation is warranted. The presence of an accessory pathway influences the choice of correct pharmacologic treatment.
A stable narrow complex tachycardia typically results from orthodromic AVRT with antegrade conduction via the AVN followed by retrograde conduction along the AP. Orthodromic AVRT occurs in 90 to 95 percent of reentrant tachycardias linked with WPW syndrome. AV nodal blocking drugs are the first-line therapy. Adenosine is usually effective. Verapamil is also effective, but caution is advised in the setting of hypotension or diminished ventricular function. A short-acting beta-blocker such as esmolol is another option.
A stable wide-complex tachycardia results from antidromic AVRT with antegrade conduction over the accessory pathway and onto the ventricles followed by retrograde conduction back to the atria via the AVN. Wide complex tachycardia may also result from orthodromic AVRT with aberrant QRS conduction resulting in a wide QRS complex. Stable wide complex tachycardia may also be ventricular tachycardia. In the case of antidromic AVRT, the best option is procainamide, which is classified as a sodium-channel blocker that slows conduction in both the AVN and the AP. If the exact mechanism of wide complex is not certain, the presumptive diagnosis should be ventricular tachycardia and treated accordingly.
Atrial fibrillation (AF) can be very dangerous in the setting of WPW, as conduction of atrial impulses at rates of up to 500 beats per minute can result in ventricular tachycardia or ventricular fibrillation. In this setting, AV nodal blocking drugs such as adenosine, verapamil, digoxin and esmolol are contraindicated as their use will divert atrial impulses to the AP. The recommended first-line treatment is procainamide to restore sinus rhythm. For young children, the dose recommended is 10-15 milligrams per kilogram over 15 to 30 minutes followed by an infusion of 20 to 80 micrograms per kg per minute. If ineffective, an intravenous loading dose of amiodarone followed by an infusion can be attempted. However, amiodarone use should be carried out with caution as its av-nodal blocking properties may increase conduction via an accessory pathway. Practitioners should be prepared to treat degradation of atrial fibrillation to ventricular fibrillation with immediate defibrillation. Pharmacologic cardioversion of atrial fibrillation may be slow. While under anesthesia, DC cardioversion is still an appropriate option for treatment, even in the setting of a stable rhythm if resolution with pharmacologic agents does not occur within a short period of time.
References
(1) Di Biase, L, Walsh EP. Treatment of symptomatic arrhythmias associated with Wolff-Parkinson-White Syndrome. In UpToDate, Levy S, Knight BP (Eds), UpToDate, Waltham, MA. (Accessed on June 17, 2021.)
(2) Di Biase, L, Walsh EP. Wolff-Parkinson syndrome: Anatomy, epidemiology, clinical manifestations, and diagnosis. In UpToDate, Levy S, Knight BP (Eds), UpToDate, Waltham, MA. (Accessed on June 17, 2021.)
(3) Di Biase, L, Walsh EP.Wolff-Parkinson syndrome: Atrioventricular reentrant tachycardia (AVRT) associated with an accessory pathway. In UpToDate, Levy S, Knight BP (Eds), UpToDate, Waltham, MA. (Accessed on June 17, 2021.)
(4) January CT, Wann LS, Alpert JS et al. ACC/AHA Task Force Members. 2014 AHA/ACC/HRS Guideline for the management of patients with atrial fibrillation: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on practice guidelines and the Heart Rhythm Society. Circulation. 2014; 130(23): 2071-2104.
(5) Bengali R, Wellens HJJ, Jiang Y. Perioperative Management of the Wolff-Parkinson-White Syndrome. J Cardiothorac Vasc Anesth. 2014; 28(5): 1375-1386. doi: 10.1053/j.jvca.2014.02.003. Epub 2014 Jul 11.
